SDR Radio Blog

SDR Television v1.1.7

Sat, 24 Oct 2026 05:26:08 GMT

SDR Television v1.1.7

October 26th, 2026, Important bug fix and enhanced user interface. I've been using ChatGPT to help with both DSP and user interface design. Here we see the result of interface design.

Receiver

Finally found the cause of a bad memory leak. Every time

User Interface

Added an Octave Spectrum display, this is selected on the Receive and Transmit displays from the main dropdown, sub-menu "Audio Display..." as shown below.
Added a new Style, SDR Television - Modern. Select the style from the Style dropdown in the top right-hand corner of the main display.

Downloads are at the bottom of this page.

SDR Television v1.1.6

September 14th, 2026. To avoid confusion with the test versions of 1.1.5, this kit is now 1.1.6.

Receiver

Improved Gardner timing recovery.
Improved Sum-product decoding.
Redesigned soft decoder.
Redesigned RRC matched filter.

Note: this kit should be able to gain a dB or so sensitivity when detecting the frame header. v1.1.6 will have even better frame detection, hence better weak signal decoding.

LDPS Settings, important!

Open this page, select Defaults . There is no need to adjust the Sum-product optons, these options are only for development and may be hidden in future kits.

Transmit

Provider changed from SDR Television to SDR TV, some receivers only display a maximum of 18 characters in the provider field.

Downloads are at the bottom of this page.

SDR Television v1.1.4

User Interface

Rearranged ribbon bar, added Forward Error Correction (FEC) to the Home panel.

Receiver

Currently trying to improve LDPC decoding for low SNR. Part of this work involves reducing CPU load in the LDPC decoder. Planning to add advanced decoding in v1.1.5.

Changed the list of FEC / LDPC algorithms, removing min-sum and min-sum correction.
Optimised offset min-sum algorithm to reduce CPU load.
Optimised Bose-Chaudhuri-Hocquenghem (BCH) processing.
Added sum-product.
Corrected LLR soft scaling for QPSK.
Changed default RRC filter length to 12 symbols, previous value of 30 was too long.
Updated Feed-Forward AGC with a design from CoPilot.
Optimised Gardner TED RRC filter length, now 25 taps.
Increased the receive RRC filter rolloff factor by 25% to capture more energy with weak signals.
Reset LDPC after 1 second of inactivity.

FEC - LDPC

There are now two LDPC algorithms,

Offset min-sum, and
Sum-product.

Sum-product is more sensitive than offset min-sum but currently doesn't work at all for FEC rates lower than 1/2 (1/4, 1/3 and 2/5). When sum-product is selected and the rate is lower than 1/2 then offset min-sum is used. The default damping settings for sum-product are shown below.

The aim is to work on sum-product with the help of ChatGPT in 2027 to get the maximum possible sensitivity.

Downloads are at the bottom of this page.

SDR Television v1.1.3

User Interface

Fixed erroneous cursor flicker in Settings help text and Receive, Transmit panes.
Fixed error in the spectrum squelch logic.
Minor fix/improvement in QPSK LUT lookup for low values.

Receiver

Use highest possible quality decimation for symbol rates of 333ksps and lower.
Added optional Doppler correction for LEO/MEO satellites such as MARMOTsat (July 2026). This will most probably be tweaked when the DVB-S2 transmissions started.

Downloads are at the bottom of this page.

SDR Television v1.1.2

June 12th, 2026: Add option to disable audio, thus making more bits available for video, this is for use in DATV contests.

Note: 66 ksps sample rate is still experimental, will be improved.

Downloads are at the bottom of this page.

SDR Television v1.1.1

June 9th, 2026: Fixes a fatal bug in the Settings, Camera page.

SDR Television v1.1

May 18th, 2026: This is the official v1.1 release , code exactly the same as 1.0.16 which has survived testing for a few weeks. Lots of improvements since the last official kit. As with any software project, there's always room for improvements and new features, but for now here's a stable solution which works well with the QO-100 satellite.

Many thanks to Sigi and the DATV test team.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

The Decoding Overlay now shows Tracking instead of Offset . The first value is the offset applied to the IQ data from the SDR, the second the current offset from the first value. The first value is updated when the second value is greater than 1/10,000 of the symbol rate.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

A FIR filter at the end of the IQ generation processing was too narrow and too sharp, must have been degrading reception of signals created with previous kits. This filter is now wider and uses fewer taps.

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

From the AD9363 product sheet: "The AD9363 transmitters use a direct conversion architecture that achieves high modulation accuracy with ultralow noise. This transmitter design produces a best-in-class Tx EVM of −34 dB, allowing significant system margin for the external power amplifier (PA) selection."

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1.7

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television v1.1.7, 64-bit, 2026-10-24_0530.exe
Dropbox: SDR Television v1.1.7, 64-bit, 2026-10-24_0530.exe

SDR Radio

Requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

New Noise Blanker

Fri, 09 Oct 2026 05:36:36 GMT

Introduction

During September and October 2026 new noise blankers have been implemented to improve what was a weak part of the SDR Console signal processing chain. Using the knowledge of ChatGPT, this exercise took only five days and the result is shown below. These noise blankers will be available sometime in October 2026.

Impulse Noise

A noise blanker should remove Impulsive interference such as electrical switching noise, electric-fence pulses, ignition interference and short static crashes

The screenshot below shows the new wideband noise blanker in action.

The top half of the main waterfall shows the noise created by an electric fence,
The bottom half shows the noise removed by the new wideband noise blanker.

Listen to a recording made using AM on 1,287kHz, a signal is present . In the recording the wideband noise blanker is engaged after 10 seconds then disengaged after 20 seconds. The result is good!

Listen to a recording made using AM on 709kHz, there is no signal present, just noise . In the recording the wideband noise blanker is engaged after 15 seconds.

Receiver Noise Blanker

Predictive Impulse Repair

Predictive Impulse Repair (PIR) is a new noise-blanking technique designed to remove short-duration impulsive interference such as electrical switching noise, electric-fence pulses, ignition interference and static crashes. Unlike a conventional noise blanker, PIR does not simply mute or zero the samples affected by an impulse. Instead, it identifies the damaged region and attempts to reconstruct the original complex IQ waveform using the undamaged signal immediately before and after the disturbance.

Impulse detection is performed in the complex IQ domain by looking for sudden changes that are inconsistent with the recent behaviour of the received signal. Adaptive background measurements allow the detector to distinguish normal signal variations from genuinely impulsive events over a wide range of signal levels. Additional amplitude-envelope analysis helps identify disturbances that might otherwise be difficult to detect, while rejecting normal modulation as far as possible.

Once an impulse has been identified, PIR determines the extent of the damaged region and replaces it using information from the surrounding clean IQ samples. Very short disturbances can be repaired by interpolation, while longer events use bidirectional predictive reconstruction. Predictions are made from both sides of the damaged region and smoothly combined, preserving both amplitude and phase continuity through the repair.

This is fundamentally different from traditional noise blanking. A conventional blanker deliberately creates a gap in the received waveform; PIR instead tries to repair the gap. This is particularly effective with SSB reception, where abrupt blanking can itself produce audible clicks and distortion. The result is that strong impulsive interference can often be removed with remarkably little indication that an impulse was ever present.

Predictive Impulse Repair operates on the complex IQ signal before demodulation, so the repair is performed while both amplitude and phase information are still available. It is modulation-independent and can therefore be used ahead of SSB, AM, SAM and other demodulators. In testing with SSB signals affected by severe repetitive impulse interference, the reconstructed audio can remain continuous even where conventional blanking would produce clearly audible artifacts.

Wideband Noise Blanker

The Wideband Noise Blanker in SDR Console is designed to suppress short-duration impulsive interference before it reaches individual receivers or the spectrum display.

Typical sources of impulsive interference include electric fences, ignition systems, switching equipment, electrical machinery, thermostats, power-line faults and atmospheric static. These disturbances can produce very short but extremely powerful bursts of RF energy which may cover a large part, or even all, of the received spectrum.

Unlike a conventional noise blanker which simply removes or zeros samples, the SDR Console Wideband Noise Blanker detects the damaged section of the received IQ data and attempts to replace it with a reconstructed signal.

This technique is referred to as Predictive Impulse Repair (PIR) .

Why Wideband?

The important difference between this noise blanker and a conventional receiver noise blanker is where the processing takes place .

The Wideband Noise Blanker operates directly on the incoming wideband complex IQ data, before the data is sent to the spectrum display and before individual receivers are extracted from the wideband data.

The processing chain is approximately:

SDR wideband IQ

|

v

Wideband Noise Blanker

|

+--------> Spectrum / Waterfall

|

+--------> Receiver 1

|

+--------> Receiver 2

|

+--------> Receiver 3

|

+--------> ...

This has an important advantage. An electrical impulse is normally broadband. If several receivers are operating within the same SDR bandwidth, the same impulse may be heard simultaneously in every receiver and may also appear as a vertical line on the waterfall. By detecting and repairing the impulse in the original wideband IQ stream, the interference is removed before the individual receivers see it .

One operation can therefore improve all receivers using that IQ stream as well as reducing impulsive interference visible on the spectrum and waterfall displays.

Processing

Impulsive Interference

An impulse can be extremely short in time while containing energy across a very wide range of frequencies. On a waterfall display this often appears as a vertical line because a single disturbance affects many frequencies simultaneously.

An electric fence is a good example. The fence produces a powerful electrical discharge at regular intervals. Although the disturbance may last only a fraction of a millisecond, its amplitude can be much greater than the wanted signals.

A traditional noise blanker attempts to detect this event and suppress it. The difficulty is deciding exactly which samples have been damaged. Remove too few samples and part of the impulse remains. Remove too many and useful received signal is unnecessarily destroyed.

The Wideband Noise Blanker therefore uses an adaptive detector which continuously examines both the received signal power and how well each new complex IQ sample agrees with the recent signal behaviour.

Adaptive Impulse Detection

The detector does not simply look for samples exceeding a fixed amplitude. A fixed threshold performs poorly with SDR signals because the received signal level and spectral occupancy can vary considerably. Instead, the Wideband Noise Blanker continuously estimates the normal background behaviour of the wideband IQ stream.

For each incoming complex sample it examines the difference between the actual sample and the value expected from immediately preceding samples. This difference is called the prediction residual .

During normal reception the residual follows the statistical behaviour of the received wideband signal.

When a sudden electrical impulse occurs, the received IQ can change far more rapidly than would normally be expected. The prediction residual can then increase dramatically.

The detector combines this residual measurement with signal-power information. This helps distinguish genuine impulsive interference from ordinary changes in the received signal.

The background estimates continuously adapt, so the detector automatically follows changes in normal received signal conditions.

Finding the Damaged Region

Detecting the peak of an impulse is only part of the problem. The samples immediately before and after the strongest part of the impulse may also have been corrupted. SDR Console therefore identifies a strongly detected core of the impulse and then examines a limited region around it to estimate where the damaged waveform actually begins and ends. This prevents a short impulse from being incorrectly expanded into a much longer event while still allowing the lower-energy edges of the disturbance to be included in the repair.

This distinction proved particularly important with real wideband recordings. The strongest portion of an electrical impulse may be very short, while the complete disturbed region can extend for considerably longer.

Predictive Impulse Repair

Once the damaged region has been identified, simply setting those IQ samples to zero is not ideal. A sudden transition from the received signal to zero, followed by another sudden transition back to the received signal, is itself a discontinuity. In the frequency domain this discontinuity can create additional broadband energy. Instead, the Wideband Noise Blanker uses the undamaged complex IQ surrounding the impulse to construct replacement samples.

SDR Console calls this technique Predictive Impulse Repair .

Clean IQ samples immediately before and after the damaged region are examined. The behaviour of the complex signal on both sides is used to predict into the missing region. A prediction is made forward in time from the clean signal preceding the impulse and backwards in time from the clean signal following the impulse. The two predictions are then smoothly combined across the damaged interval.

Conceptually:

Clean IQ Damaged IQ Clean IQ

--------- | X X X X X X X X | ------------

\ /

Forward Backward

prediction prediction

\ /

Reconstructed IQ

The objective is not to claim that the original RF waveform can always be recovered perfectly. Once interference has completely overwhelmed the receiver, the original information in those samples may no longer exist.

Instead, the objective is to replace a very large impulsive disturbance with a waveform which is consistent with the clean signal surrounding it and which does not itself introduce another sharp discontinuity. For impulsive interference this can be remarkably effective.

Look-Ahead Processing

Predictive repair requires samples from both sides of an impulse.

This means the Wideband Noise Blanker must wait briefly for clean samples following the disturbance before it can reconstruct the damaged region. SDR Console therefore uses a small amount of look-ahead buffering.

The additional latency is approximately 0.3 milliseconds , which is insignificant for normal receiver operation but gives the repair algorithm access to clean IQ following the impulse.

The processing is fully streaming. The number of samples entering and leaving the noise blanker remains the same; the output is simply delayed slightly to provide the required look-ahead.

Maximum Impulse Duration

There is an important limitation to any impulse-repair algorithm. If interference destroys a sufficiently long section of the received signal, there is no mathematical method which can recreate arbitrary missing wideband RF information perfectly. For this reason SDR Console deliberately limits the duration of an event which will be automatically reconstructed.

The current Wideband Noise Blanker is designed to repair impulses up to approximately 200 microseconds . This is long enough to handle many severe electrical impulses while avoiding increasingly speculative reconstruction of much longer disturbances. Events exceeding the permitted duration are left unchanged. This is particularly relevant to atmospheric noise.

A lightning discharge can produce anything from a relatively short impulse to a much longer static crash. The short impulsive components may respond well to Wideband Noise Blanking, but a long crash may contain hundreds of microseconds or several milliseconds of corrupted data.

There is simply not enough information available to reconstruct such a long section of arbitrary wideband RF accurately. The Wideband Noise Blanker is therefore intended primarily for impulsive interference , not continuous noise or long-duration interference.

Electric Fence Interference

Electric-fence interference has been particularly useful during development because it provides strong, repeatable real-world impulses. Testing was performed using recorded wideband IQ containing a powerful electric-fence pulse approximately once per second. The detector identifies the short electrical disturbances automatically. Some of the strongest events occupy considerably more than 100 microseconds of IQ data.

With Predictive Impulse Repair enabled, these pulses can be reconstructed at the wideband IQ level before the data reaches the receivers. The result is especially useful because the interference does not have to be independently detected by every active receiver. It is repaired once at the source.

Spectrum and Waterfall

Because processing occurs before spectrum generation, the Wideband Noise Blanker can also reduce the characteristic vertical streaks produced by broadband electrical impulses on the waterfall. This is an important difference from an audio noise blanker.

An audio noise blanker may make a particular receiver more pleasant to listen to, but the original impulse is still present in the SDR's wideband IQ and therefore remains visible on the spectrum and waterfall.

Wideband processing attacks the interference earlier in the signal chain.

Independent of Demodulation Mode

The Wideband Noise Blanker operates on complex IQ before demodulation, so it does not need to know whether a receiver is subsequently using:

SSB
CW
AM
Synchronous AM
FM
Digital modes

The impulse detection and repair take place before these modulation-specific operations. This makes Wideband Noise Blanking particularly useful when several receivers using different modes are active simultaneously.

Threshold

The Threshold control determines how sensitive the detector is to impulsive events.

A lower threshold makes the detector more sensitive and therefore more likely to classify unusual signal transitions as interference.
A higher threshold makes detection more conservative.

The default setting has been selected to provide good detection of strong electrical impulses without unnecessarily modifying normal wideband IQ.

As with any noise blanker, the optimum setting can depend on the type of interference and the signals being received.

Increasing sensitivity too far can cause legitimate signal transitions to be mistaken for interference, so the lowest possible threshold is not necessarily the best setting.

Maximum Width

The Maximum Width setting determines the longest detected event which the Wideband Noise Blanker is permitted to reconstruct.

Short impulses are ideal candidates for repair because clean IQ exists very close to both sides of the damaged region.

As the duration increases, predicting the missing wideband waveform becomes progressively less certain.

The maximum width therefore provides an important safeguard: events longer than the selected duration are detected but are not reconstructed.

A value around 200 microseconds accommodates the strong electrical impulses encountered during development while remaining conservative about much longer disturbances.

What the Wideband Noise Blanker Cannot Do

The Wideband Noise Blanker should not be confused with general-purpose noise reduction. It cannot remove ordinary receiver noise, atmospheric background noise, adjacent-channel interference or continuous electrical interference.

It also cannot recover information which has been completely destroyed by a long-duration disturbance.

Its purpose is much more specific: detect short, abnormal, broadband impulsive disturbances and replace the damaged IQ with a smoother estimate derived from the surrounding clean signal.

When the interference matches this description, processing the original wideband IQ has a major advantage over trying to remove the resulting clicks independently from every receiver.

Wideband and Receiver Noise Blanking

Wideband and receiver-level noise reduction solve related but different problems.

A receiver-level blanker operates after the SDR has selected and filtered a particular receiver bandwidth. It has much less bandwidth to analyse and may therefore be able to make use of characteristics specific to that receiver.

The Wideband Noise Blanker sees the complete SDR bandwidth instead. Its task is more difficult because the wideband IQ may contain many signals simultaneously, but successful repair benefits everything downstream.

The two approaches are therefore complementary rather than mutually exclusive.

Summary

The SDR Console Wideband Noise Blanker uses Predictive Impulse Repair to suppress short broadband electrical disturbances directly in the incoming complex IQ stream.

Rather than simply blanking samples, it:

Continuously learns the normal wideband signal behaviour.
Detects abnormal impulsive changes using signal power and prediction residuals.
Determines the approximate beginning and end of the damaged region.
Buffers a very small amount of future IQ.
Uses clean IQ before and after the impulse to predict replacement samples.
Smoothly combines forward and backward predictions.
Passes the repaired wideband IQ to the spectrum display and all receivers.

Processing the interference at this point in the SDR signal chain means that a single repair can benefit the waterfall and every receiver using the same wideband data.

It is particularly effective against short, powerful electrical impulses such as those produced by electric fences and similar sources.

There are unavoidable limits: a sufficiently long disturbance destroys information which cannot genuinely be recreated. For this reason the algorithm deliberately restricts repair to relatively short events rather than attempting increasingly uncertain reconstruction of long static crashes.

The aim is not to manufacture information which no longer exists.

The aim is to identify a short section of IQ which has been overwhelmed by an impulse and replace that destructive transient with a well-behaved estimate based on the undamaged signal immediately surrounding it.

For suitable impulsive interference, this can make the disturbance effectively disappear before it reaches the receiver.

New Noise Reduction

Fri, 09 Oct 2026 05:36:33 GMT

RadioClear AI – A New Approach to Speech Noise Reduction

Improving Weak Signal Reception

One of the biggest challenges when listening to weak radio signals is separating speech from background noise. As signals become weaker, the noise can overwhelm the speech, making conversations difficult or sometimes impossible to understand.

Conventional noise reduction has been available in software-defined radios for many years. Most systems analyse the received audio, estimate which frequencies contain noise, and reduce their amplitude. This can work very well, but there is always a compromise. Too little suppression leaves distracting background noise, while too much can make speech sound metallic, watery or unnatural. Important speech information may disappear along with the noise.

For some time, I have wanted to develop a better approach for SDR Console, particularly for weak SSB reception. The objective was not simply to produce quieter audio, but to improve intelligibility while preserving the natural characteristics of the speaker's voice.

The result is RadioClear AI , a new noise-reduction system combining adaptive digital signal processing with a recurrent neural network and complex temporal filtering.

Comparison With RNNoise

RadioClear AI and RNNoise both use neural networks to improve speech intelligibility by reducing unwanted background noise, but they employ different approaches.

RNNoise is a well-established, computationally efficient solution that combines traditional signal processing with recurrent neural networks to estimate frequency-dependent suppression gains. It performs well across a variety of speech applications and has the advantage of being lightweight and widely tested.
RadioClear AI has been developed specifically with radio communications in mind, particularly weak SSB signals affected by receiver noise. It combines adaptive noise estimation and speech-aware spectral processing with a recurrent neural network that generates complex temporal filter coefficients. Unlike conventional gain-based suppression, this approach uses information from consecutive audio frames to adjust both the amplitude and phase of the enhanced signal.

Both approaches have strengths, and their relative performance depends on the type of interference, signal conditions and training material. RNNoise benefits from its maturity, efficiency and general-purpose design, while RadioClear offers a more specialised processing architecture tailored to weak radio reception.

In initial listening tests, RadioClear AI has produced encouraging results, with cleaner background noise and natural-sounding speech compared with RNNoise on the signals tested. However, these observations are subjective, and controlled comparisons across a wider range of recordings would be needed to establish a consistent performance advantage. Further improvements to RadioClear's training data are planned, particularly using cleaner speech recordings and a greater variety of speakers and receiver noise conditions.

Combining Traditional DSP with Artificial Intelligence

Rather than relying entirely on artificial intelligence, RadioClear AI uses two complementary processing stages.

The first stage is based on conventional digital signal processing. It continuously estimates the background noise and analyses the incoming audio to identify frequencies likely to contain speech. It also examines harmonic relationships, which are particularly important for voiced speech.
This information is used by an adaptive spectral suppressor to reduce background noise while protecting important speech components.

The result is an initial noise-reduced signal that provides a stable foundation for the neural network. This arrangement has an important advantage. The neural network does not need to learn everything about noise estimation and suppression from scratch. Instead, it receives a partially cleaned signal together with detailed information about the speech and noise characteristics. The neural network can then concentrate on improving the result.

Looking Beyond Individual Audio Frames

One of the limitations of conventional spectral noise reduction is that it generally operates by adjusting the amplitude of individual frequency components. However, speech is not a collection of unrelated frequencies. It is a continuously evolving signal with strong relationships between consecutive moments in time. RadioClear AI takes advantage of this.

The incoming audio is divided into overlapping frames, and each frame is converted into a frequency-domain representation using a Fast Fourier Transform (FFT).

The neural network receives 400 features describing the signal across 40 frequency bands. These include information about signal power, estimated noise, signal-to-noise ratio, speech probability, harmonic content and the relationships between consecutive complex spectra.

At the heart of the system are two Gated Recurrent Unit (GRU) layers. Unlike a simple feed-forward neural network, a GRU maintains information about previous frames, allowing the system to recognise how speech changes over time.

This temporal information is particularly valuable when the speech is partially obscured by noise.

Complex Temporal Filtering

The most significant difference between RadioClear AI and a conventional neural noise reducer is the way the network processes the audio. Many neural noise-reduction systems generate a set of gains that are applied to individual frequency bins. Although effective, this approach primarily controls amplitude.

RadioClear AI goes further by generating complex-valued filter coefficients . For each frequency bin, the system combines information from the current audio frame and the previous two frames. The neural network determines how these spectra should be combined to produce the enhanced signal.

Because the coefficients are complex, the system can modify both amplitude and phase. It can also exploit the relationships between consecutive frames rather than treating each frame independently. This gives the network considerably more flexibility than a conventional spectral gain mask.

The neural network produces coefficients for 40 frequency bands, which are interpolated across the 257 FFT frequency bins. A three-tap complex temporal filter then generates the enhanced spectrum, which is converted back into audio.

The complete process operates continuously in real time.

Training the Neural Network

The neural network is trained offline using examples of speech mixed with receiver noise. During training, the system is provided with both the noisy signal and the corresponding clean speech. It learns to generate complex filter coefficients that make the processed spectrum resemble the clean reference as closely as possible.

An important development decision was to train the network against the actual reconstructed complex spectrum , rather than simply asking it to reproduce a set of ideal filter coefficients. This means the training process directly rewards improvements in the enhanced signal.

The current network contains approximately 568,000 parameters and was trained using speech mixed with real receiver noise at signal-to-noise ratios ranging from +15 dB to −10 dB.

The training and evaluation process showed substantial reductions in complex spectral error compared with the initial deterministic noise-reduction stage. The improvements were particularly encouraging at the lowest signal-to-noise ratios, where additional noise reduction is most valuable.

Of course, mathematical measurements are only part of the story. A lower spectral error does not automatically guarantee better-sounding speech, so listening tests remain essential.

Real-Time Processing and Listening Results

The neural network was originally developed and trained using Python and PyTorch. The complete inference engine was then implemented in C++ for integration into SDR Console. To ensure that the C++ implementation behaved correctly, its results were compared directly with the Python reference. This included the recurrent network, complex coefficient generation, frequency interpolation and final spectral filtering. The results agreed to floating-point precision, giving confidence that the real-time implementation reproduces the trained model accurately.

Initial listening tests have been very encouraging.

On weak SSB signals, RadioClear AI produces natural-sounding speech with substantial background-noise reduction. In my own listening comparisons, the results have been noticeably better than RNNoise, particularly in preserving speech quality while reducing unwanted noise.

An additional aggressiveness control has also proved useful, allowing stronger suppression of residual noise where desired.

As always, the best setting depends on the received signal. Maximum noise reduction is not necessarily the same as maximum intelligibility, so the listener retains control over the amount of processing applied.

What Comes Next?

Although the current results are very promising, development is far from finished.

One area where I expect further improvements is the training material. The first model was trained using a relatively small amount of speech, and the supposedly clean reference recording contained a little background noise.

This is not ideal. If noise is present in the clean training reference, the network can learn to preserve some of that noise because it is treated as part of the wanted signal.

The next step will therefore be to create a much better training dataset using genuinely clean speech recordings, ideally from several different speakers, together with a wider variety of real receiver noise.

I intend to retain the existing neural architecture initially so that improvements from better training data can be evaluated independently.

There is also potential to extend the system to other receiving modes, including AM and music, while retaining the existing 8 kHz neural processing engine.

Final Thoughts

RadioClear AI represents a significant step forward in my work on speech noise reduction for SDR Console. The most interesting aspect is not simply that it uses artificial intelligence, but how conventional DSP, recurrent neural processing and complex temporal filtering work together .

By combining an adaptive noise estimator, speech-aware spectral processing and a neural network capable of exploiting relationships between consecutive audio frames, the system can perform noise reduction that would be difficult to achieve using conventional spectral attenuation alone.

The aim has always been straightforward: make weak radio signals easier and more pleasant to listen to, without destroying the speech we are trying to recover.

The initial results suggest that this approach has considerable potential, and I look forward to seeing how much further it can be improved with better training recordings.

RadioClear AI is still evolving, but it is already producing some of the best weak-signal speech noise reduction I have achieved in SDR Console.

Better SSB Demodulation

Fri, 09 Oct 2026 05:36:28 GMT

Can We Build a Better SSB Demodulator?

Improving weak-signal SSB reception

Over the years, SDR Console has benefited from improvements in digital signal processing, noise reduction, filtering, and interference suppression. Recent work on wideband noise blanking has demonstrated that there are still opportunities to improve established SDR techniques.

Soon I'll start another interesting project: investigating whether we can develop a better SSB demodulator. The objective is simple: can I make weak SSB signals easier to understand, particularly when they are close to the noise floor?

This is an experimental project. There are no guarantees of improvement, but several techniques are worth investigating.

How SSB Demodulation Works Today

Most software-defined radio receivers use a relatively straightforward approach to SSB demodulation.

Once the incoming signal has been filtered and shifted to the correct frequency, the receiver extracts the real component of the complex IQ samples.

In simplified C++:

float audio = IQ.real();

That's essentially it!

Of course, a complete receiver includes frequency conversion, filtering, AGC, and other processing, but the actual coherent SSB demodulation is remarkably simple. Importantly, this method is mathematically correct. Under ideal conditions, there is no alternative demodulation formula that will magically recover additional information.

However, real-world signals are rarely ideal. They suffer from noise, fading, frequency errors, interference, and propagation-related distortion. The question is whether more sophisticated processing of the complex IQ signal, before converting it to audio, can improve the recovered speech.

1. Automatic Frequency Correction

One possibility is to improve the accuracy of SSB tuning. Unlike AM or FM, suppressed-carrier SSB has no continuously transmitted carrier that the receiver can simply lock onto. Even a small frequency error changes the pitch of the recovered speech.

For example, a station may be tuned 20 or 30 Hz away from its ideal frequency. The resulting audio is perfectly intelligible, but it is not quite correct. We could investigate an adaptive frequency estimator that analyses the received signal and automatically corrects small tuning errors.

The challenge is distinguishing genuine frequency errors from natural variations in human speech.

Potential benefit: More accurate tuning and improved speech reproduction without manual adjustment.

2. Adaptive Phase Correction

Another interesting area is phase distortion. Radio signals can experience phase changes due to propagation, fading, and receiver imperfections. A conventional SSB demodulator simply takes the real component of the received complex signal.

But what if we could identify and compensate for unwanted phase variations before demodulation?

A simplified mathematical representation is:

z(t)=s(t)e^{j\phi(t)}+n(t)

Here, the received signal consists of the wanted SSB signal, phase variations, and noise. If we can reliably estimate the unwanted phase variations, we may be able to compensate for them before producing audio.

There is an important complication: SSB does not normally provide an absolute carrier-phase reference, and a constant phase rotation is not necessarily a distortion.

Any correction algorithm must therefore avoid introducing errors of its own.

Potential benefit: Better audio under certain fading and phase-distortion conditions.

3. Complex-Domain Weak-Signal Processing

This is perhaps the most interesting part of the project. An SDR receiver processes complex IQ samples, containing both in-phase (I) and quadrature (Q) components. In a conventional SSB demodulator, the final audio is obtained from the real component. However, before this conversion, the complex signal contains relationships that may be useful for estimating the wanted transmission.

Could we exploit those relationships to distinguish weak speech from noise and interference?

Possible techniques include:

Complex-domain spectral estimation.
Adaptive interference suppression.
Statistical signal estimation.
Time-frequency analysis.
Processing that exploits the mathematical structure of SSB signals.

There is an important distinction here. The I and Q components are not two independent copies of the speech. In an ideal SSB signal, they are mathematically related through the Hilbert transform. We cannot simply combine them to obtain a free improvement in signal-to-noise ratio. Nevertheless, more sophisticated processing may exploit information about the signal, interference, or propagation channel that conventional demodulation does not explicitly use.

Potential benefit: Improved recovery of weak SSB signals, especially in difficult interference or fading conditions.

4. Speech-Aware Processing

Human speech has a great deal of structure. Voiced speech contains harmonics, while the resonances of the vocal tract produce formants that change relatively smoothly over time. These characteristics provide opportunities for distinguishing speech from noise.

I have already investigated speech-processing techniques in SDR Console, and one lesson is particularly important: aggressive processing can easily damage the wanted audio. Different speakers have different voices, pitches, and spectral characteristics. An algorithm that works well with one voice may distort another.

For this project, I would prefer to concentrate initially on recovering the actual received signal rather than generating speech that an algorithm predicts should be present. Speech-aware processing may become useful later, but it should not be the starting point.

5. Carrier Estimation and Tracking

Another possibility is to estimate the missing SSB carrier frequency from the received speech. Because the carrier is suppressed, this is not straightforward. However, the statistical properties of speech may provide clues that help determine the correct tuning frequency.

I could also investigate tracking certain propagation-related phase variations. The challenge is obtaining a reliable estimate without confusing normal speech characteristics with carrier or channel errors.

This is another area worth investigating experimentally.

Proposed Signal Processing Architecture

The experimental demodulator would operate directly on the complex IQ samples, before conversion to real audio.

The proposed processing chain is:

Not every stage will necessarily prove useful. Some may provide little improvement, while others may introduce unacceptable distortion.

The purpose of the project is to find out through controlled experiments.

Development Plan

I'll develop the new demodulator in C++17 and integrate it experimentally into SDR Console.

The initial development stages will be:

V1 Conventional coherent SSB demodulator for reference

V2 Adaptive residual frequency correction

V3 Adaptive phase and channel correction

V4 Complex-domain weak-signal estimation

V5 Combined adaptive demodulator

Each version will be compared against the conventional SSB demodulator using the same recorded IQ signals.

This is important. Any claimed improvement must be repeatable and not simply the result of different signal levels, filtering, or subjective listening conditions.

Where suitable reference recordings are available, I can also make objective measurements.

What Am I Trying to Improve?

There are two main objectives.

1. Better speech quality

Improve the audio from signals that are already reasonably strong but suffer from fading, frequency errors, or distortion.

2. Better weak-signal sensitivity

Recover more intelligible speech from extremely weak signals, particularly those close to the noise floor. The second objective is the one I find most interesting. If a signal is already strong and intelligible, improvements in audio quality are welcome, but they are not necessarily revolutionary.

The real challenge is improving the intelligibility of signals that are currently difficult to copy. For example, could a new algorithm make a weak station easier to understand without the unnatural artefacts sometimes introduced by aggressive noise reduction?

That would be a worthwhile achievement.

A Realistic Assessment

There are fundamental mathematical limits to what can be recovered from a noisy signal. A conventional coherent SSB demodulator is already an excellent starting point, and under ideal assumptions it is optimal for recovering the transmitted waveform. I should not expect an enormous improvement simply by replacing the familiar IQ.real() operation with something more complicated.

Any genuine improvement will need to come from better estimation of the received signal, correction of impairments, exploitation of additional information, or carefully designed processing that improves intelligibility. It is entirely possible that some experiments will produce no measurable improvement. That's part of research.

The important thing is to test each idea carefully and retain only those techniques that provide a genuine benefit.

Starting Soon

Soon I'll begin work on the first experimental SSB demodulator. I'll establish a reference implementation and then investigate the most promising signal-processing techniques, concentrating particularly on weak-signal reception.

As with recent noise-blanker development, I'll use actual SDR recordings, compare the results, and refine the algorithms based on what I hear and measure.

The ultimate objective is not simply to create a more complicated demodulator. It's to find out whether we can hear and understand weak SSB signals that are currently difficult to receive.

Whether we achieve a small improvement, a significant improvement, or discover that conventional SSB demodulation is already close to the practical limit, the results should be interesting.

I'll report our progress as the project develops.

Using ChatGPT

Fri, 09 Oct 2026 05:35:33 GMT

The Future of SDR Software

Working with ChatGPT is like having a very experienced and importantly professional software engineer in the team. I'm currently paying £20 a month to have a team member who would cost at least £15,000 a month to employ.

So far I've worked on:

Weak signal detection in SDR Television,
Decoding using the layered Sum-Product algorithm,
A new noise blanker, and
A new noise reduction solution.

Coming soon:

Better SSB demodulation,
User interface design.

Possibly, Maybe:

Digital Mode companion for SDR Console supporting modes such as:
FT-2/4/8
JT65, Q65
MSK144

Professional Engineering

A good software engineer always:

Documents code.
Includes a reference to algorithms used in the code.
For each stage of the development adds unit tests which must be run before moving to the next stage.

Benefits of ChatGPT

A thorough understanding of digital signal processing (DSP),
Performance - what would take a week for a human may only take a few seconds for ChatGPT,
Coding style,
Ability to analyse the many research papers, summarise and extract pertinent design in short time,
A total understanding of SDR Console. Ask a question about something and immediately know whether it's relevant to my software.

Mistakes

Yes, ChatGPT makes mistakes but corrects them with my feedback.

PlutoSky R2

Mon, 14 Sep 2026 11:48:30 GMT

History

As radio amateurs, we’ve witnessed the evolution of Software Defined Radios (SDRs) like the Pluto SDR, a game-changer in both amateur and professional radio realms.

Launched by Analog Devices, the Pluto SDR brought an affordable yet powerful platform for experimentation and innovation. Its variants, including the LibreSDR, have expanded upon this foundation, offering improved features and flexibility for diverse applications.

These SDRs allow enthusiasts and professionals alike to push the boundaries of radio communications, turning complex signal processing into an accessible hobby. Whether you're tuning in to distant signals or developing cutting-edge applications, the Pluto and its variants open up a world of possibilities.

OpenSourceSDRLab New Version PlutoSky R2

Looking for a compatible SDR with can easily be locked to a 10MHz reference, I came across the OpenSourceSDRLab New Version PlutoSky R2 . From the images on the website it looks well-built and has the option of a built-in pre-amp.

Quoting from the web site:

PlutoSky R2 is an upgraded high-performance software-defined radio (SDR) development platform launched by OpenSourceSDR Lab, based on the classic ADALM-Pluto architecture.
It adopts hardware main chip upgrade, abundant peripheral resources expansion, onboard hardware phase-locked loop and PL-side Ethernet optimization.
It supports 70MHz-6GHz frequency range by firmware hack, 200K~20MHz bandwidth and full-duplex transceiver.
The core hardware adopts Xilinx Zynq XC7Z020-2CLG484I SoC, integrating dual-core ARM Cortex-A9 Processor System (PS) and FPGA Programmable Logic (PL). The RF front-end is equipped with AD9363BBCZ RFIC, which can be hacked to achieve full-band performance equivalent to AD9361.

Options

There are various options, I bought the 9361 with PA as I don't need the extra bandwidth offered by the 9363.

It should arrive this week, I'll report back when I get it working.

SDR Television v1.1.6

Mon, 14 Sep 2026 11:19:09 GMT

SDR Television v1.1.6

September 14th, 2026. To avoid confusion with the test versions of 1.1.5, this kit is now 1.1.6.

Receiver

Improved Gardner timing recovery.
Improved Sum-product decoding.
Redesigned soft decoder.
Redesigned RRC matched filter.

Note: this kit should be able to gain a dB or so sensitivity when detecting the frame header. v1.1.6 will have even better frame detection, hence better weak signal decoding.

LDPS Settings, important!

Open this page, select Defaults . There is no need to adjust the Sum-product optons, these options are only for development and may be hidden in future kits.

Transmit

Provider changed from SDR Television to SDR TV, some receivers only display a maximum of 18 characters in the provider field.

Downloads are at the bottom of this page.

SDR Television v1.1.4

User Interface

Rearranged ribbon bar, added Forward Error Correction (FEC) to the Home panel.

Receiver

Currently trying to improve LDPC decoding for low SNR. Part of this work involves reducing CPU load in the LDPC decoder. Planning to add advanced decoding in v1.1.5.

Changed the list of FEC / LDPC algorithms, removing min-sum and min-sum correction.
Optimised offset min-sum algorithm to reduce CPU load.
Optimised Bose-Chaudhuri-Hocquenghem (BCH) processing.
Added sum-product.
Corrected LLR soft scaling for QPSK.
Changed default RRC filter length to 12 symbols, previous value of 30 was too long.
Updated Feed-Forward AGC with a design from CoPilot.
Optimised Gardner TED RRC filter length, now 25 taps.
Increased the receive RRC filter rolloff factor by 25% to capture more energy with weak signals.
Reset LDPC after 1 second of inactivity.

FEC - LDPC

There are now two LDPC algorithms,

Offset min-sum, and
Sum-product.

The aim is to work on sum-product with the help of ChatGPT in 2027 to get the maximum possible sensitivity.

Downloads are at the bottom of this page.

SDR Television v1.1.3

User Interface

Fixed erroneous cursor flicker in Settings help text and Receive, Transmit panes.
Fixed error in the spectrum squelch logic.
Minor fix/improvement in QPSK LUT lookup for low values.

Receiver

Use highest possible quality decimation for symbol rates of 333ksps and lower.
Added optional Doppler correction for LEO/MEO satellites such as MARMOTsat (July 2026). This will most probably be tweaked when the DVB-S2 transmissions started.

Downloads are at the bottom of this page.

SDR Television v1.1.2

June 12th, 2026: Add option to disable audio, thus making more bits available for video, this is for use in DATV contests.

Note: 66 ksps sample rate is still experimental, will be improved.

Downloads are at the bottom of this page.

SDR Television v1.1.1

June 9th, 2026: Fixes a fatal bug in the Settings, Camera page.

SDR Television v1.1

Many thanks to Sigi and the DATV test team.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1.6

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television v1.1.6, 64-bit, 2026-09-14_1025.exe
Dropbox: SDR Television v1.1.6, 64-bit, 2026-09-14_1025.exe

SDR Radio

Requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

Improving DVB-S2 PLHEADER Detection at Low SNR

Mon, 14 Sep 2026 05:18:13 GMT

Improving DVB-S2 PLHEADER Detection at Low SNR

Reliable detection of the DVB-S2 Physical Layer Header (PLHEADER) is one of the first challenges faced by a DVB-S2 receiver. Before the receiver can decode the payload, it must determine where a physical-layer frame begins, establish carrier phase and frequency sufficiently accurately, and decode the signalling contained in the PLS code.

This becomes particularly interesting at very low SNR.

I have been comparing two approaches:

A traditional differential SOF/PLS detector.
A new coherent, maximum-likelihood-oriented PLHEADER detector designed to exploit substantially more of the information contained in the DVB-S2 header.

Both methods are trying to answer essentially the same question:

At what symbol does the DVB-S2 PLHEADER begin, and what carrier frequency and phase best explain the received 90-symbol header?

The difference is how much of the available information they use to answer that question.

The full PDF is here .

FT-8 Project?

Sun, 13 Sep 2026 11:37:01 GMT

Project for 2027?

Love it or hate it, FT-8 is here to stay. I use WSJT-X to monitor 2m and sometimes 70cms. As a software developer, it's always rewarding to use one's own software. So I just asked ChatGPT whether it (he, she, they) even knew about FT-8. The response was amazing.

So, this could be the start of a project which is also used for EME and meteor scatter modes. Read on dear reader, read on.

Question (Me)

I've been working with ChatGPT to optimise the digital signal processing (DSP) in my SDR Television software, so ChatGPT and myself have history, ChatGPT knows me well.

I asked ChatGPT "Do you know what FT-8 is? Do you think we could write a better decoder?". That's all I asked.

Reply (ChatGPT)

ChatGPT immediately replied!

Yes — very familiar with FT8, and yes, I think we could build a substantially better decoder , particularly if we approach it as a DSP/SDR problem rather than simply reimplementing WSJT-X.

FT8 is actually a very interesting fit for the sort of work we've been doing with your DVB-S2 decoder.

The current FT8 waveform is:

15-second receive/transmit period
79 symbols
8-FSK
6.25 baud
6.25 Hz tone spacing
50 Hz occupied bandwidth
three 7×7 Costas sync blocks
174 transmitted coded bits
77-bit payload + 14-bit CRC
LDPC(174,91)
Gray-coded 3-bit symbols

The really interesting part is that the LDPC decoder isn't necessarily where the biggest gains are . The front end and candidate generation are extremely important.

I'd build it as a multi-stage decoder, something along these lines:

And then we could add the really powerful stuff:

1. Much better signal detection

Rather than simply looking for obvious FT8 traces in an FFT, I'd exploit the known Costas structure .

The three Costas blocks are known completely, so we effectively have a matched-filter/reference-correlation problem.

That lets us search for:

frequency,
fractional symbol timing,
frequency drift,
signal amplitude,
phase,
possibly time offset

simultaneously.

This is very similar philosophically to what we've been doing with your DVB-S2 SOF/PLHEADER detector.

2. Proper soft 8-FSK metrics

This is where I think we could make a significant improvement.

For every data symbol I'd calculate something like:

E0 E1 E2 E3 E4 E5 E6 E7

and convert those eight tone energies into soft bit LLRs .

Because each tone represents three Gray-coded bits, we can calculate the exact bit likelihood:

LLR(bit0)
LLR(bit1)
LLR(bit2)

rather than making a hard decision on the strongest tone. That gives the LDPC decoder substantially better information.

This is analogous to the lesson we found with your DVB-S2 QPSK decoder: the quality and scaling of the soft information going into LDPC can matter enormously.

3. Better LDPC decoding

FT8's code is LDPC(174,91), with the 91 bits consisting of the 77-bit message plus the CRC.

I'd initially implement:

normalized/offset min-sum,
sum-product,
layered scheduling if applicable,
adaptive damping,
early termination,
CRC-assisted termination.

But I'd also investigate OSD / ordered-statistics decoding as a second-stage decoder . That's particularly interesting for FT8 because the block is tiny. Some modern implementations already experiment with BP, OSD and a-priori-assisted decoding.

4. A-priori decoding

This is probably one of the biggest opportunities.

Suppose we know:

CQ G4ABC IO91

or we're in the middle of a QSO and already know one callsign. We don't have to treat all 77 payload bits as completely unknown. We can inject known information into the LDPC decoder. WSJT-X already uses several AP decoding strategies, including known callsigns and known message structures. But we could make this considerably more systematic.

For example:

5. Multi-signal decoding

This is where I'd really like to push it.

Imagine:

We decode A.

Once A is known, we know exactly what waveform A should have produced .

So:

That can potentially expose signals that were completely buried underneath stronger FT8 transmissions. The original WSJT-X development notes explicitly contemplated signal subt raction and two-pass decoding.

I'd go further and make it iterative:

6. Frequency drift estimation

For HF FT8, a signal isn't necessarily sitting at one perfectly constant frequency.

We could estimate:

f(t) = f0 + f1*t + f2*t²

using the three Costas sequences. Then compensate the entire signal before extracting the data. That should help considerably with marginal signals and drifting oscillators.

And there's a particularly interesting experiment I'd like to do. Rather than immediately trying to beat WSJT-X, I'd build a reference-quality C++17 decoder and compare it against WSJT-X under controlled conditions.

For example:

Generate thousands of known FT8 messages at each SNR, with controlled:

frequency offset
timing offset
frequency drift
AWGN
fading
adjacent signals
overlapping signals

and measure actual decode probability.

That would let us identify where the extra dB are coming from , rather than just saying "it decodes better".

FT8 is already capable of roughly −20 dB-class decoding under suitable conditions, with AP decoding providing additional sensitivity. And I think your existing DSP experience would transfer extremely well.

In particular, the things we've learned with your DVB-S2 work:

soft metrics → synchronization → noise estimation → LLR scaling → iterative decoding

are almost exactly the areas I'd concentrate on here.

I would not start by copying the WSJT-X decoder line-for-line.

I'd start with a clean C++17 implementation:

Ft8Decoder,
Ft8Synchronizer,
Ft8Detector,
Ft8SoftDemodulator,
Ft8Ldpc,
Ft8Message

with AVX2 where it actually helps.

Then we can benchmark each stage independently.

If you're interested, I think the first thing to build should be the FT8 soft demodulator + Costas synchronizer , because that will tell us whether there are meaningful gains available before we spend time on the LDPC side.

SDR Console, Beta August 27th 2026

Thu, 27 Aug 2026 09:54:22 GMT

August 27th, 2026

Default Audio Device

When changing the default audio device selection in Windows, SDR Console was following the change but not reapplying the latest volume change. Example: I start playback, adjust the volume, then after a while enable my Bluetooth speaker an go outside. When the speaker is enabled SDR Console switches but didn't apply the change in volume.

RDS processing

AGC replaced with normalisation,
Hilbert filter redesigned.

Shouldn't make much difference.

MIDI Startup

I believe I have found the cause of the slow start of SDR Console. As part of the SDR Console startup I always call midiInGetNumDevs() to get the number of attached MIDI devices, even if the user hasn't enabled MIDI. At some stage in 2026 Microsoft introduced a bug where the first call to midiInGetNumDevs() after starting the computer results in blocking all asynchronous activity if there are no MIDI devices connected. If there are MIDI devices connected then it returns after ~100ms.

I now only call midiInGetNumDevs() on startup if there are user definitions.
Some programs are experiencing even worse behaviour.
There should be a Windows update soon with a fix, but for now the kit below should resolve this problem in 99% of cases.

Downloads

Download beta kits here .

July 26th, 2026

Reuter RSR200B

Added initial support.

Fobos

Finalised support for Fobos SDR, only the Agile firmware is supported. Some early Fobos SDR units had HF2 and HF1 swapped on the case printing.

FFT

When using NVIDIA CUDA for the FFT the returned buffers now use memory from the heap rather than pinned memory (*).
Reduced the CPU load in the FFT Helper DLL. The data from the FFT (CUDA, IPP, OpenCL) is processed to match the display DIPs. When running Broadcast-FM with x4 resolution there were 550 FFT bins per display pixel (DIP). These 550 bins were averaged which takes quite some processing, especially when running a matrix display with many receivers enabled. I now down-sample the bins to a maximum of (about) 32 which doesn't affect the display or any DSP but does reduce the CPU.

Frequency Database

Loading of the frequency database into memory-mapped backing now much faster.

Pluto

TX Doppler support for Pluto / LibreSDR. Have tested this by adding debug info, seems OK �� .

RDS

Added variable font size in the RDS editor window.
Forced uppercase of PS text in the RDS Editor removed.
Change to RDS Logfile updates while the editor is open & visible. Updates are now allowed, previously not so.

Recordings

Fixed font size error in the playback, navigation window (was incorrect logic).
When starting the video recorder a sanity check makes sure the selected folder exists and is accessible.

Satellite

Satellite definition file format has changed, no need to update your settings but support for the new OMM (.xml) format is included.
I'm hosting satellite data on my (new) Akamai server, these is currently a cache of the Celestrak data. I'll add a web page soon which explains what's been happening.

Transmit

Audio mute is now a per-profile setting.

Other

Fixed an error opening the matrix display while the SDR was already started.
Crash when selecting "Configure" from the Select Radio window fixed.
Does not create an error when the graphics driver restarts.

February 10th, 2026

Pluto

Correct the FIR filter definitions, this has improved reception.

November 1st, 2025

Analyser

Analyser tag window change, as suggested by Jim.
Analyser tags now saved and restored correctly.
Analyser font size now supports small, medium and large.
Analyser loads saved projects faster.
Saving project now much faster and uses less memory.
More display lines available if you have enough RAM:
Less than 16GB then 50,000 lines.
16GB to 32GB then 100,000 lines.
32GB or more then 250,000 lines.
Fixed minor font issue with definition window.
Fixed issue scrolling when more than 32768 lines in display.

Data File Playback

Selecting a playback folder now creates the list of files much faster.

Emulation

Added a diagnostic check for the use of emulators. This code only works on W10 and above, so I dynamically load IsWow64Process2 from kernel32 which avoids issues on older versions of Windows.

In the logfile you see something like this:

05:23:48.185: Vendor ....: GenuineIntel

05:23:48.185: Brand .....: Intel(R) Core(TM) Ultra 7 265K

05:23:48.185: -

05:23:48.185: x86 Emulation:

05:23:48.185: Process .......: 0x0000, "Not emulated"

05:23:48.185: Architecture ..: 0x8664, "AMD64"

05:23:48.185: -

Favourites

Updated the default 60m bandwidth.
Changed Broadcast :: VHF CCIR title to Band II.
Groups now have user-selectable files.
Default definitions renames to main.
Changed the ribbon bar, Selection entry to Options (see image below). The dropdown options have been replaced with a single window, allowing more room for text.

Locked Receivers

If the program is stopped or a favourite created when a receiver is locked, this caused problems with the receiver being locked but no indication. With this kit receiver lock state is not applied in a favourite definition.

Logfile

Automatically save the logfile when closing, really added so I can check program responding correctly to Shutdown and Restart.
Old logfiles are purged after the program has been running for one minute.

Logging

Added logbook FA option as below, FA is the command to read/write RX1.

Narrow FM

Added 150Hz CTCSS squelch tone.
De-emphasis is now optional, selected from: Ribbon bar, Receive, Mode..., Narrow FM.

Persistent Display

Got a crash inside the persistent display logic, my sanity checks weren't good enough so have improved this.

Remote Server

After connecting to a remote server, the input fields can now be edited to change connection parameters.

Ribbon Bar

View panel tidied up.

Signal Meter (SMeter)

Added more presets for the Signal meter, Ribbon bar, View, Spectrum, Signal Meter.

Spectran ECO

Changed SPECTRAN path order to pick up DLLs from the SDK folder rather than the main folder.

Status Bar

GPU, Audio entries on status bar now optional, selected from Program Options, Performance, CPU Memory.

System Shutdown / Restart

If SDR Console is running when the system shuts down or restarts then SDR Console closes gracefully. What happens - five seconds after SDR Console receives the SHUTDOWN message a timer calls the OnClose() processing, so you have five seconds to about the shutdown / restart.

Previous Kits...

I'm now back to 90% SDR Console support, so here's the first beta for at least eight months. Scroll to the bottom for a link to the beta kit.

The source is fully archived, so crash dumps can be analysed.

September 4th, 2025

Ad ded Simple-Radio-Control-Protocol (SR CP) as per JB's Dx Info and tested only with StationList. SRCP specifies a method to control a radio and get its status back to StationList (or a similiar application). To avoid any headache on user and software writer a very simple method was chosen. Communication is done by sending UDP string messages.
If there are other logging programs which support SRCP please let me know.
I have not added support for RDS, only frequency changes.
After the first message is sent from StationList the protocol is activated.
This should be documented somewhere in the Settings somewhere, but where?
What's missing?

August 30th, 2025

If the RDS Database c annot be opened / created an error is now displayed.
RDS Logfile window now shows Entry when displaying all fields, see image below.
RDS Logfile window now supports data sorting by clicking on the column headers.

R adio Data System (RDS) is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts. RDS standardizes several types of information transmitted, including time, station identification and program information.

August 28th, 2025

SSB / AM squelch was missing the start and cutting off too soon. Also, the Raised cosine rise/fall was missing. Now, the SSB/AM squelch is more pleasant to listen to. Note : SSB / AM squelch uses voice activity detection, it is not rf-based.
RDS Logfile display no longer auto-updates if any of:
Edit window is visible,
Mouse has been active in the previous five seconds,
First entry is not visible.

August 23rd, 2025

Su pports Winradio IQ files > 4 GB . These files, like ELAD's do not honour the WAV format correctly, but hey-ho.
When searching for Airspy HF+ / Discovery / ... SDRs the firmware is now shown in the Options field in the list of SDRs. Also shown in the logfile when connecting to the Airspy.
Option added to suppo rt logging programs when using a transmit up/ down converter definition, as we do with the Pluto on QO-100, see image below.
Previously FA, FB, ... returned the receive frequency (10 GHz) but on QO-100 we're actually transmitting at 2.4 GHz on the up-link.
When enabled, the actual transmit frequency (2.4 GHz) is returned.

Mode Mapping page is now Frequency, Mode.

June 28th, 2 025

Scheduled recordings now have an option to shut down the computer when the recording is finished.
Streaming now compresses th e data when the bandwidth is 5MHz or greater.

June 26 th, 2025

Preset recording definitions now include the action to take when the recording finishes, see image below.
The Stop button in Ribb on bar, Home, Radio now stops the recording playback.

June 25th, 2025

Left and Right channels in Broadcast-FM swapped over, was reported that they were previously wrong. Please check!

June 22nd, 2025

Custom layouts now restore the collapsed / expanded state of the Receive and Transmit panes.

June 20th, 2025

When the Microphone dropdown is opened in the Transmit panel the list of capture devices is re-enumerated and updated, so anything you plug in / out is reflected in the dropdown list without having to restart. Unplugging the microphone you are using is not supported, but you don't do that, right?
The TX relay can now be connected after starting, it will be opened when the next transmission is made.

June 19th, 2025

Reworked some MIDI support to reduce / eliminate crashes.

June 18th, 2025

Pluto updated for wideband transmit - SDR Television
Fixed SPECTRAN V6 support
NR3 (rrnoise) updated to version 0.2 Release RNNoise 0.2 · xiph/rnnoise .

Kits

The beta kits are here: https://www.sdr-radio.com/download#Beta

AI Assistance - QO-100

Wed, 26 Aug 2026 06:15:43 GMT

QO-100 Footprints

In my map software I've wanted to correctly display a set of footprints for the QO-100 / Es' Hail 2 satellite but could not find the algorithm anywhere, especially one which corrects for atmospheric refraction which is the reason why conact can be made when the satellite is just below the horizon. Microsoft's CoPilot took ~30 seconds to show me the algorithm and then deliver a nice C++ class!

Below is the code - very readable and fully commented. The only change I made is to play 1440 points (360 * 4).

#pragma once

#include <cmath>

#include <vector>

// Lat/Lon pair (in radians)

struct LatLon {

double lat; // latitude (radians)

double lon; // longitude (radians)

};

// Compute satellite footprint polygon with atmospheric refraction correction.

// This uses the standard radio‑propagation "k‑factor" model:

// R_eff = k * R_E

// where k ≈ 4/3 for normal atmospheric conditions.

// IMPORTANT:

// - R_eff is used ONLY inside the geometry to compute the central angle ψ.

// - The final footprint is still drawn on the REAL Earth (R_E).

class RefractedSatelliteFootprintPolygon

{

public:

// Physical Earth radius (mean WGS‑84)

static constexpr double EarthRadius = 6371008.8;

// Compute effective Earth radius for refraction.

// k_factor = 1.0 → no refraction

// k_factor = 4/3 → standard radio horizon model

static double EffectiveEarthRadius(double k_factor)

{

return k_factor * EarthRadius;

}

// Compute central angle ψ (radians) from satellite to footprint boundary.

// This is the key geometry:

// ψ = acos( (R_eff / (R_eff + h)) * cos(e) ) - e

// where:

// R_eff = effective Earth radius (refraction corrected)

// h = satellite altitude above surface (meters)

// e = minimum elevation angle (radians)

// ψ is the angular distance from the sub‑satellite point to the footprint edge.

static double CentralAngle(double altitude_m,

double elevation_deg,

double k_factor = 4.0 / 3.0)

{

// Convert elevation angle from degrees → radians

const double e = elevation_deg * M_PI / 180.0;

// Effective Earth radius (refraction corrected)

const double Re = EffectiveEarthRadius(k_factor);

// Satellite distance from Earth's center

const double r = Re + altitude_m;

// Compute geometric term inside acos()

const double term = (Re / r) * std::cos(e);

// Clamp to [-1, 1] to avoid numerical domain errors in acos()

const double x = std::max(-1.0, std::min(1.0, term));

// Full central angle formula

return std::acos(x) - e;

}

// Compute the full 360‑point footprint polygon.

// For each bearing θ = 0…359 degrees:

// - Move ψ radians away from the sub‑satellite point

// - Along bearing θ

// - Using great‑circle forward‑geodesic equations

// Output lat/lon are in radians.

static std::vector<LatLon> ComputePolygon(double satLat_deg,

double satLon_deg,

double altitude_m,

double elevation_deg,

double k_factor = 4.0 / 3.0)

{

// Convert satellite sub‑point to radians

const double lat0 = satLat_deg * M_PI / 180.0;

const double lon0 = satLon_deg * M_PI / 180.0;

// Compute refraction‑corrected central angle ψ

const double psi = CentralAngle(altitude_m, elevation_deg, k_factor);

// Precompute trig values for speed

const double sin_lat0 = std::sin(lat0);

const double cos_lat0 = std::cos(lat0);

const double sin_psi = std::sin(psi);

const double cos_psi = std::cos(psi);

std::vector<LatLon> poly;

poly.reserve(360);

// Loop over bearings 0° → 359°

for (int bearing_deg = 0; bearing_deg < 360; ++bearing_deg)

{

// Bearing θ in radians

const double theta = bearing_deg * M_PI / 180.0;

// Great‑circle forward‑geodesic:

// lat = asin( sin(lat0)*cos(ψ) + cos(lat0)*sin(ψ)*cos(θ) )

const double sin_lat =

sin_lat0 * cos_psi +

cos_lat0 * sin_psi * std::cos(theta);

const double lat = std::asin(sin_lat);

// lon = lon0 + atan2( sin(θ)*sin(ψ)*cos(lat0),

// cos(ψ) - sin(lat0)*sin(lat) )

const double y = std::sin(theta) * sin_psi * cos_lat0;

const double x = cos_psi - sin_lat0 * sin_lat;

const double lon = lon0 + std::atan2(y, x);

poly.push_back({ lat, lon });

}

return poly;

}

};

SDR Television v1.1.4

Wed, 26 Aug 2026 05:41:32 GMT

SDR Television v1.1.4

User Interface

Rearranged ribbon bar, added Forward Error Correction (FEC) to the Home panel.

Receiver

Currently trying to improve LDPC decoding for low SNR. Part of this work involves reducing CPU load in the LDPC decoder. Planning to add advanced decoding in v1.1.5.

Changed the list of FEC / LDPC algorithms, removing min-sum and min-sum correction.
Optimised offset min-sum algorithm to reduce CPU load.
Optimised Bose-Chaudhuri-Hocquenghem (BCH) processing.
Added sum-product.
Corrected LLR soft scaling for QPSK.
Changed default RRC filter length to 12 symbols, previous value of 30 was too long.
Updated Feed-Forward AGC with a design from CoPilot.
Optimised Gardner TED RRC filter length, now 25 taps.
Increased the receive RRC filter rolloff factor by 25% to capture more energy with weak signals.
Reset LDPC after 1 second of inactivity.

FEC - LDPC

There are now two LDPC algorithms,

Offset min-sum, and
Sum-product.

The aim is to work on sum-product with the help of ChatGPT in 2027 to get the maximum possible sensitivity.

Downloads are at the bottom of this page.

SDR Television v1.1.3

User Interface

Fixed erroneous cursor flicker in Settings help text and Receive, Transmit panes.
Fixed error in the spectrum squelch logic.
Minor fix/improvement in QPSK LUT lookup for low values.

Receiver

Use highest possible quality decimation for symbol rates of 333ksps and lower.
Added optional Doppler correction for LEO/MEO satellites such as MARMOTsat (July 2026). This will most probably be tweaked when the DVB-S2 transmissions started.

Downloads are at the bottom of this page.

SDR Television v1.1.2

June 12th, 2026: Add option to disable audio, thus making more bits available for video, this is for use in DATV contests.

Note: 66 ksps sample rate is still experimental, will be improved.

Downloads are at the bottom of this page.

SDR Television v1.1.1

June 9th, 2026: Fixes a fatal bug in the Settings, Camera page.

SDR Television v1.1

Many thanks to Sigi and the DATV test team.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1.4

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television v1.1.4, 64-bit, 2026-08-26_0559.exe
Dropbox: SDR Television v1.1.4, 64-bit, 2026-08-26_0559.exe

SDR Radio

Requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

SDR Console, Beta July 26th 2026

Mon, 27 Jul 2026 17:38:20 GMT

July 26th, 2026

Reuter RSR200B

Added initial support.

Fobos

Finalised support for Fobos SDR, only the Agile firmware is supported. Some early Fobos SDR units had HF2 and HF1 swapped on the case printing.

FFT

When using NVIDIA CUDA for the FFT the returned buffers now use memory from the heap rather than pinned memory (*).
Reduced the CPU load in the FFT Helper DLL. The data from the FFT (CUDA, IPP, OpenCL) is processed to match the display DIPs. When running Broadcast-FM with x4 resolution there were 550 FFT bins per display pixel (DIP). These 550 bins were averaged which takes quite some processing, especially when running a matrix display with many receivers enabled. I now down-sample the bins to a maximum of (about) 32 which doesn't affect the display or any DSP but does reduce the CPU.

Frequency Database

Loading of the frequency database into memory-mapped backing now much faster.

Pluto

TX Doppler support for Pluto / LibreSDR. Have tested this by adding debug info, seems OK �� .

RDS

Added variable font size in the RDS editor window.
Forced uppercase of PS text in the RDS Editor removed.
Change to RDS Logfile updates while the editor is open & visible. Updates are now allowed, previously not so.

Recordings

Fixed font size error in the playback, navigation window (was incorrect logic).
When starting the video recorder a sanity check makes sure the selected folder exists and is accessible.

Satellite

Satellite definition file format has changed, no need to update your settings but support for the new OMM (.xml) format is included.
I'm hosting satellite data on my (new) Akamai server, these is currently a cache of the Celestrak data. I'll add a web page soon which explains what's been happening.

Transmit

Audio mute is now a per-profile setting.

Other

Fixed an error opening the matrix display while the SDR was already started.
Crash when selecting "Configure" from the Select Radio window fixed.
Does not create an error when the graphics driver restarts.

February 10th, 2026

Pluto

Correct the FIR filter definitions, this has improved reception.

November 1st, 2025

Analyser

Analyser tag window change, as suggested by Jim.
Analyser tags now saved and restored correctly.
Analyser font size now supports small, medium and large.
Analyser loads saved projects faster.
Saving project now much faster and uses less memory.
More display lines available if you have enough RAM:
Less than 16GB then 50,000 lines.
16GB to 32GB then 100,000 lines.
32GB or more then 250,000 lines.
Fixed minor font issue with definition window.
Fixed issue scrolling when more than 32768 lines in display.

Data File Playback

Selecting a playback folder now creates the list of files much faster.

Emulation

Added a diagnostic check for the use of emulators. This code only works on W10 and above, so I dynamically load IsWow64Process2 from kernel32 which avoids issues on older versions of Windows.

In the logfile you see something like this:

05:23:48.185: Vendor ....: GenuineIntel

05:23:48.185: Brand .....: Intel(R) Core(TM) Ultra 7 265K

05:23:48.185: -

05:23:48.185: x86 Emulation:

05:23:48.185: Process .......: 0x0000, "Not emulated"

05:23:48.185: Architecture ..: 0x8664, "AMD64"

05:23:48.185: -

Favourites

Updated the default 60m bandwidth.
Changed Broadcast :: VHF CCIR title to Band II.
Groups now have user-selectable files.
Default definitions renames to main.
Changed the ribbon bar, Selection entry to Options (see image below). The dropdown options have been replaced with a single window, allowing more room for text.

Locked Receivers

If the program is stopped or a favourite created when a receiver is locked, this caused problems with the receiver being locked but no indication. With this kit receiver lock state is not applied in a favourite definition.

Logfile

Automatically save the logfile when closing, really added so I can check program responding correctly to Shutdown and Restart.
Old logfiles are purged after the program has been running for one minute.

Logging

Added logbook FA option as below, FA is the command to read/write RX1.

Narrow FM

Added 150Hz CTCSS squelch tone.
De-emphasis is now optional, selected from: Ribbon bar, Receive, Mode..., Narrow FM.

Persistent Display

Got a crash inside the persistent display logic, my sanity checks weren't good enough so have improved this.

Remote Server

After connecting to a remote server, the input fields can now be edited to change connection parameters.

Ribbon Bar

View panel tidied up.

Signal Meter (SMeter)

Added more presets for the Signal meter, Ribbon bar, View, Spectrum, Signal Meter.

Spectran ECO

Changed SPECTRAN path order to pick up DLLs from the SDK folder rather than the main folder.

Status Bar

GPU, Audio entries on status bar now optional, selected from Program Options, Performance, CPU Memory.

System Shutdown / Restart

If SDR Console is running when the system shuts down or restarts then SDR Console closes gracefully. What happens - five seconds after SDR Console receives the SHUTDOWN message a timer calls the OnClose() processing, so you have five seconds to about the shutdown / restart.

Previous Kits...

I'm now back to 90% SDR Console support, so here's the first beta for at least eight months. Scroll to the bottom for a link to the beta kit.

The source is fully archived, so crash dumps can be analysed.

September 4th, 2025

Ad ded Simple-Radio-Control-Protocol (SR CP) as per JB's Dx Info and tested only with StationList. SRCP specifies a method to control a radio and get its status back to StationList (or a similiar application). To avoid any headache on user and software writer a very simple method was chosen. Communication is done by sending UDP string messages.
If there are other logging programs which support SRCP please let me know.
I have not added support for RDS, only frequency changes.
After the first message is sent from StationList the protocol is activated.
This should be documented somewhere in the Settings somewhere, but where?
What's missing?

August 30th, 2025

If the RDS Database c annot be opened / created an error is now displayed.
RDS Logfile window now shows Entry when displaying all fields, see image below.
RDS Logfile window now supports data sorting by clicking on the column headers.

August 28th, 2025

SSB / AM squelch was missing the start and cutting off too soon. Also, the Raised cosine rise/fall was missing. Now, the SSB/AM squelch is more pleasant to listen to. Note : SSB / AM squelch uses voice activity detection, it is not rf-based.
RDS Logfile display no longer auto-updates if any of:
Edit window is visible,
Mouse has been active in the previous five seconds,
First entry is not visible.

August 23rd, 2025

Su pports Winradio IQ files > 4 GB . These files, like ELAD's do not honour the WAV format correctly, but hey-ho.
When searching for Airspy HF+ / Discovery / ... SDRs the firmware is now shown in the Options field in the list of SDRs. Also shown in the logfile when connecting to the Airspy.
Option added to suppo rt logging programs when using a transmit up/ down converter definition, as we do with the Pluto on QO-100, see image below.
Previously FA, FB, ... returned the receive frequency (10 GHz) but on QO-100 we're actually transmitting at 2.4 GHz on the up-link.
When enabled, the actual transmit frequency (2.4 GHz) is returned.

Mode Mapping page is now Frequency, Mode.

June 28th, 2 025

Scheduled recordings now have an option to shut down the computer when the recording is finished.
Streaming now compresses th e data when the bandwidth is 5MHz or greater.

June 26 th, 2025

Preset recording definitions now include the action to take when the recording finishes, see image below.
The Stop button in Ribb on bar, Home, Radio now stops the recording playback.

June 25th, 2025

Left and Right channels in Broadcast-FM swapped over, was reported that they were previously wrong. Please check!

June 22nd, 2025

Custom layouts now restore the collapsed / expanded state of the Receive and Transmit panes.

June 20th, 2025

When the Microphone dropdown is opened in the Transmit panel the list of capture devices is re-enumerated and updated, so anything you plug in / out is reflected in the dropdown list without having to restart. Unplugging the microphone you are using is not supported, but you don't do that, right?
The TX relay can now be connected after starting, it will be opened when the next transmission is made.

June 19th, 2025

Reworked some MIDI support to reduce / eliminate crashes.

June 18th, 2025

Pluto updated for wideband transmit - SDR Television
Fixed SPECTRAN V6 support
NR3 (rrnoise) updated to version 0.2 Release RNNoise 0.2 · xiph/rnnoise .

Kits

The beta kits are here: https://www.sdr-radio.com/download#Beta

SDR Television v1.1.3

Fri, 10 Jul 2026 04:37:08 GMT

SDR Television v1.1.3

User Interface

Fixed erroneous cursor flicker in Settings help text and Receive, Transmit panes.
Fixed error in the spectrum squelch logic.
Minor fix/improvement in QPSK LUT lookup for low values.

Receiver

Use highest possible quality decimation for symbol rates of 333ksps and lower.
Added optional Doppler correction for LEO/MEO satellites such as MARMOTsat (July 2026). This will most probably be tweaked when the DVB-S2 transmissions started.

Downloads are at the bottom of this page.

SDR Television v1.1.2

June 12th, 2026: Add option to disable audio, thus making more bits available for video, this is for use in DATV contests.

Note: 66 ksps sample rate is still experimental, will be improved.

Downloads are at the bottom of this page.

SDR Television v1.1.1

June 9th, 2026: Fixes a fatal bug in the Settings, Camera page.

SDR Television v1.1

Many thanks to Sigi and the DATV test team.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1.3

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television v1.1.3, 64-bit, 2026-07-10_0502.exe
Dropbox: SDR Television v1.1.3, 64-bit, 2026-07-10_0502.exe

SDR Radio

Requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

SDR Television v1.1.2

Fri, 12 Jun 2026 05:14:14 GMT

SDR Television v1.1.2

June 12th, 2026: Add option to disable audio, thus making more bits available for video, this is for use in DATV contests.

Note: 66 ksps sample rate is still experimental, will be improved.

Downloads are at the bottom of this page.

SDR Television v1.1.1

June 9th, 2026: Fixes a fatal bug in the Settings, Camera page.

SDR Television v1.1

Many thanks to Sigi and the DATV test team.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1.2

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television v1.1.2, 64-bit, 2026-06-12_0549.exe
Dropbox: SDR Television v1.1.2, 64-bit, 2026-06-12_0549.exe

SDR Radio

Requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

SDR Television v1.1.1

Tue, 09 Jun 2026 17:11:36 GMT

SDR Television v1.1.1

June 9th, 2026: Fixes a fatal bug in the Settings, Camera page.

Downloads are at the bottom of this page.

SDR Television v1.1

Many thanks to Sigi and the DATV test team.

Downloads are at the bottom of this page.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download v1.1 from either:

OneDrive: SDR Television v1.1.1, 64-bit, 2026-06-09_1406.exe
Dropbox: SDR Television v1.1.1, 64-bit, 2026-06-09_1406.exe

SDR Radio

V1.1 requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

Simon's World Map 1.6.2

Sat, 23 May 2026 05:00:53 GMT

Version 1.6.2

This release fixes two bugs in the new DX Spot feature.

The spot age logic incorrectly affected spot display.
When the map was zoomed, station markers off the map would be displayed at the top left (0, 0).

Downloads are on the World Map page .

Version 1.6.1

This release fixes two fatal bugs in the new DX Spot feature.

When the graphics engine is restarted, resources are correctly released.
Fixed a resource leak when processing the MoseMove logic.

Downloads are on the World Map page .

Version 1.6

This release adds the display of DX Spots. Display spots are submitted to PSK Reporter which in turn are relayed by a MQTT Broker running on a high performance Akamia node.

Spot Format

Each spot consists of these fields:

Sequence
Frequency
Band
Mode
Signal level
Time stamp
Sending station call, square, country
Receiving station call, square, country

Note: The country is the ADIF country.

Spots are displayed as they arrive, currently no on-demand database.

Bandwidth

To reduce bandwidth from the broker, filtering is required for 80m up to and including 15m. Filtering requires at least one field below to be set in a definition:

Receiver callsign, square or country.
Sender callsign, square or country.

Without filtering the bandwith from the broker could be excessive. For LF and VHF+ no filtering is required due to the lower number of spots sent on these bands. In a later version the bandwidth restriction may be reduced.

Download

Downloads are on the World Map page .

Previous: Version 1.5.4

This release fixes a bug, improves the user interface. Download link is at the bottom of this page.

Aurora

Previously the JSON parser would close the program by raising an exception when the downloaded data was invalid. This behaviour was not intentional, as of this kit the program is not closed, instead an entry is added to the logfile explaining the problem.

Corrected Clock Display

The clock display now correctly supports fonts with non-standard text metrics such as Georgia. These fonts are, of course perfectly legal, it was an oversight in this program which prevented their correct display.

To select a system font use the ribbon bar entry: Clock, Font, System Fonts. The image below shows Georgia.

Previous: Version 1.5.2

This release fixes a bug, improves the user interface and adds a new calendar. Download link is at the bottom of this page.

Sleep

After resuming from computer sleep, the program would often lock up. This has been fixed (graphics restarted).

Country Prefixes

The database shipped with this kit is the very latest available from Log4OM , update timestamp is 2025-08-05 09:52:27z.

Updating the database has been simplified: from the ribbon bar select Prefixes, Database.

Select Open to display the latest available database in your default XML browser, usually Microsoft Edge or Google Chrome.
Select Save as default to overwrite the current database with the latest available database. Sanity checks are applied, the display refreshed.

Sunrise Calendar

This is a simple way to generate a sunrise, sunset calendar for your home location.

From the ribbon bar, select Sunrise, Calendar, Show.
As you change the selected month, the calendar is updated, it's that simple!
Select Text Viewer to open the list of times in your default text editor.

Previous: Version 1.5.1

This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.

Appearance

The Appearance window has been refreshed, simplified. The defaults have been changed to have a dark background and a light text. A HLS (Hues, Lightness, Saturation) colour editor has been added, selected from the colour-wheel button to the right to the main colour-selection options.

The Space weather and Sunrise windows now have a border, drawn with the text colour.

Aurora

The aurora legend has been increased in size to make it easier to read.

Clock

The clock now has its own colour setting (see Appearance above).

Grid Squares

Added a Help button to the grid squares panel in the ribbon bar.

Layouts

The layouts (Ribbon bar, View, Layout) have been updated to fix a few minor bugs, also a Reset button has been added.

Maps

A new map, purchased from Vecteezy for 'Detailed Physical Green' by Sam Kal.

Stations

When changing definitions and layout options the map is dynamically updated.
When displayed on the side of the map, the station windows are now centred vertically.
The station layout window also supports the new HLS colour editor.

Previous: Version 1.5

May 25th, 2025: After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

If you use the geostationary Es'hail 2 (a.k.a. Qatar-OSCAR 100 or QO-100) satellite then the LNB skew is important (the correct term is Polarisation Tilt). Although websites exist which show the skew for a given location, I wanted to know how to calculate this myself. So, many thanks to Mike G0MJW who showed me the formula. As a result the tilt is now shown as part of the satellite data. below you see a tilt value of -23.2 degrees, to compensation the LNB is rotated anticlockwise.

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

The data is extracted from geonames, a very exhaustive list of worldwide toponyms. This datapackage only lists cities above 15,000 inhabitants. Each city is associated with its country and subcountry to reduce the number of ambiguities. Subcountry can be the name of a state (eg in United Kingdom or the United States of America) or the major administrative section (eg ''region'' in France''). See admin1 field on geonames website for further info about subcountry.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

When you select an entry, an attempt is made to select the corresponding timezone. There's no guarantee that this is correct, the selection must be verified. A timezone is required if the time is to be shown.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are on the World Map page .

Simon's World Map 1.6.1

Thu, 21 May 2026 05:11:37 GMT

Version 1.6.1

This release fixes two fatal bugs in the new DX Spot feature.

When the graphics engine is restarted, resources are correctly released.
Fixed a resource leak when processing the MoseMove logic.

Downloads are on the World Map page .

Version 1.6

This release adds the display of DX Spots. Display spots are submitted to PSK Reporter which in turn are relayed by a MQTT Broker running on a high performance Akamia node.

Spot Format

Each spot consists of these fields:

Sequence
Frequency
Band
Mode
Signal level
Time stamp
Sending station call, square, country
Receiving station call, square, country

Note: The country is the ADIF country.

Spots are displayed as they arrive, currently no on-demand database.

Bandwidth

To reduce bandwidth from the broker, filtering is required for 80m up to and including 15m. Filtering requires at least one field below to be set in a definition:

Receiver callsign, square or country.
Sender callsign, square or country.

Download

Downloads are on the World Map page .

Previous: Version 1.5.4

This release fixes a bug, improves the user interface. Download link is at the bottom of this page.

Aurora

Corrected Clock Display

To select a system font use the ribbon bar entry: Clock, Font, System Fonts. The image below shows Georgia.

Previous: Version 1.5.2

This release fixes a bug, improves the user interface and adds a new calendar. Download link is at the bottom of this page.

Sleep

After resuming from computer sleep, the program would often lock up. This has been fixed (graphics restarted).

Country Prefixes

The database shipped with this kit is the very latest available from Log4OM , update timestamp is 2025-08-05 09:52:27z.

Updating the database has been simplified: from the ribbon bar select Prefixes, Database.

Select Open to display the latest available database in your default XML browser, usually Microsoft Edge or Google Chrome.
Select Save as default to overwrite the current database with the latest available database. Sanity checks are applied, the display refreshed.

Sunrise Calendar

This is a simple way to generate a sunrise, sunset calendar for your home location.

From the ribbon bar, select Sunrise, Calendar, Show.
As you change the selected month, the calendar is updated, it's that simple!
Select Text Viewer to open the list of times in your default text editor.

Previous: Version 1.5.1

This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.

Appearance

The Space weather and Sunrise windows now have a border, drawn with the text colour.

Aurora

The aurora legend has been increased in size to make it easier to read.

Clock

The clock now has its own colour setting (see Appearance above).

Grid Squares

Added a Help button to the grid squares panel in the ribbon bar.

Layouts

The layouts (Ribbon bar, View, Layout) have been updated to fix a few minor bugs, also a Reset button has been added.

Maps

A new map, purchased from Vecteezy for 'Detailed Physical Green' by Sam Kal.

Stations

When changing definitions and layout options the map is dynamically updated.
When displayed on the side of the map, the station windows are now centred vertically.
The station layout window also supports the new HLS colour editor.

Previous: Version 1.5

May 25th, 2025: After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are on the World Map page .

Simon's World Map 1.6

Wed, 20 May 2026 05:16:56 GMT

Version 1.6

This release adds the display of DX Spots. Display spots are submitted to PSK Reporter which in turn are relayed by a MQTT Broker running on a high performance Akamia node.

Spot Format

Each spot consists of these fields:

Sequence
Frequency
Band
Mode
Signal level
Time stamp
Sending station call, square, country
Receiving station call, square, country

Note: The country is the ADIF country.

Spots are displayed as they arrive, currently no on-demand database.

Bandwidth

To reduce bandwidth from the broker, filtering is required for 80m up to and including 15m. Filtering requires at least one field below to be set in a definition:

Receiver callsign, square or country.
Sender callsign, square or country.

Download

Downloads are on the World Map page .

Previous: Version 1.5.4

This release fixes a bug, improves the user interface. Download link is at the bottom of this page.

Aurora

Corrected Clock Display

To select a system font use the ribbon bar entry: Clock, Font, System Fonts. The image below shows Georgia.

Previous: Version 1.5.2

This release fixes a bug, improves the user interface and adds a new calendar. Download link is at the bottom of this page.

Sleep

After resuming from computer sleep, the program would often lock up. This has been fixed (graphics restarted).

Country Prefixes

The database shipped with this kit is the very latest available from Log4OM , update timestamp is 2025-08-05 09:52:27z.

Updating the database has been simplified: from the ribbon bar select Prefixes, Database.

Select Open to display the latest available database in your default XML browser, usually Microsoft Edge or Google Chrome.
Select Save as default to overwrite the current database with the latest available database. Sanity checks are applied, the display refreshed.

Sunrise Calendar

This is a simple way to generate a sunrise, sunset calendar for your home location.

From the ribbon bar, select Sunrise, Calendar, Show.
As you change the selected month, the calendar is updated, it's that simple!
Select Text Viewer to open the list of times in your default text editor.

Previous: Version 1.5.1

This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.

Appearance

The Space weather and Sunrise windows now have a border, drawn with the text colour.

Aurora

The aurora legend has been increased in size to make it easier to read.

Clock

The clock now has its own colour setting (see Appearance above).

Grid Squares

Added a Help button to the grid squares panel in the ribbon bar.

Layouts

The layouts (Ribbon bar, View, Layout) have been updated to fix a few minor bugs, also a Reset button has been added.

Maps

A new map, purchased from Vecteezy for 'Detailed Physical Green' by Sam Kal.

Stations

When changing definitions and layout options the map is dynamically updated.
When displayed on the side of the map, the station windows are now centred vertically.
The station layout window also supports the new HLS colour editor.

Previous: Version 1.5

May 25th, 2025: After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are on the World Map page .

SDR Television v1.1

Tue, 19 May 2026 05:01:31 GMT

SDR Television v1.1

Many thanks to Sigi and the DATV test team.

Downloads are at the bottom of this page.

To Do

The items below may be completed for a future release.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.016 (same as v1.1)

Transmitter

Better detection of OBS Studio running state; started or not started.
The selecting a video source the list is reloaded as the state of a source may have changed and become available.
Using Microsoft Video Resizer DSP (CLSID_CResizerDMO).
Optional: Extra resolutions added when using OBS-Camera (OBS Studio) and/or other video sources.
Tested 360 x 180 using 125 ksps, support for 66 ksps will be added in a future release.
Resolutions and frame rates are now sorted high to low in the Transmit, Video selection window.

v1.0.15

Receiver

Switching channels is now faster if the background threads have data to process.

Transmitter

Worked around a problem with the OBS VirtualCamera plugin which offers 'bogus' FPS values. The resolution and frame rate set in OBS Studio is the first value returned when enumerating OBS-Camera, all other values are now ignored.
Video input throttling is now disabled in callbacks to the Encoding window - this was an early attempt to limit video data rates.

User Interface

Added Always On Top button to Ribbon Bar, Home, Layout. When selected, SDR Television stays on top of other programs.

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.1

The minimum version of SDR Radio is shown below. You must download it if SDR Television displays an error message when starting.

SDR Television

Download v1.1 from either:

OneDrive: SDR Television v1.1, 64-bit, 2026-05-18_1743.exe
Dropbox: SDR Television v1.1, 64-bit, 2026-05-18_1743.exe

SDR Radio

V1.1 requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

SDR Television v1.0.14

Sun, 12 Apr 2026 06:17:01 GMT

SDR Television v1.0.14

April 12th, 2026: A new kit, lots of improvements since the last official kit. As with any software project, there's always room for improvements and new features, but for now here's a stable solution which works well with the QO-100 satellite.

Many thanks to Sigi and the DATV test team.

Downloads are at the bottom of this page.

To Do

The items below may be completed for the release of v1.1, target date is April/May 2026.

Correct a possible logic error when a change of PCR is received; audio and video frames in the presentation queue are unnecessarily discarded.
Add 8PSK.
Performance improvements (reduced CPU): Feed forward AGC and BCH.
Update the manual, add a Quick Start chapter.
For noisy decoding, consider:
Applying adaptive algorithms to estimate and correct I-Q mismatch in real-time.
Techniques like blind source separation (BSS) or least mean square (LMS) filters can effectively compensate for mismatches.
https://rahsoft.com/2025/01/31/i-q-mismatch-in-communication-systems/

Release Notes

v1.0.14

User Interface

FFT Resolution added to Settings: Spectrum: Display, FFT
Matched filter roll-off and length moved from Receive: Configuration to Settings: Receive: Frame Search.
Gardner timing recovery using better dot product code.

v1.0.13

Receiver

Gardner timing recovery and IQ imbalance are now always enabled.
Gardner timing recovery filters now use fewer taps as the symbol rate increases.
Updated frequency tracking by adding a rotator (NCO) after the SDR data decimation (NCO, Downconverter). This help with signal locking and possibly decoding of weak signals.

User Interface

Updated the ribbon bar.
Spectrum FFT resolution reduced from 100% to 25% as there's no need for a super-sharp display.

v1.0.13

Receiver

Frequency Tracking: Fixed error in the receiver matched filter; in the Dot Product processing the filter coefficients were not conjugated, so the frequency offset was roughly doubled instead of being corrected!

The dot product of two complex vectors is defined as the sum of the products of the corresponding entries of the two sequences of numbers. For complex vectors, the dot product is calculated using the complex conjugate of the second operand. This is important because the dot product is a bilinear form, which means it is symmetric and positive definite.

Use Interface

Start Stream cannot be deselected while sending.
In the Receiver panel, Bit Rates all meta data packets (PAT, SDT etc.) are shown as Other.

v1.0.11

Receiver

Dish Alignment features:
Optionally speak the MER value using Microsoft's text-to-speech.
Display either the average MER or (new) peak MER, peak being better for alignment.

v1.0.10

Receiver

SDR-Radio kits dated March 18th (build 4008) or later now have the Pluto/LibreSDR previous filtering logic restored:
Up to and including 2MHz bandwidth use a standard bandpass design with Blackman windowing. There is neither decimation nor interpolation in the Pluto.
There is more gain but the filtering quality is reduced.
Recommended: 2.5MHz and above use pre-defined generic filters from the Analog Devices AD9361 library libad9361-iio. These are the cleanest filters, however the output signal is ~1dB lower than firmware-based solutions from Evariste Courjaud, F5EOE.

User Interface

The current QO-100 channel selection is highlighted.
Added 175% and 200% to the Decoding Overlay, Font Sizes. Useful when using a laptop for dish adjustment, larger text size makes reading MER easier.

SDR Television v1.0.9

March 13th, 2026: A new kit, lots of receive improvements since the last official kit. As with any software project, there's always room for improvements and new features, but for now here's a stable solution which works well with the QO-100 satellite.

Many thanks to the DATV test team.

Downloads are at the bottom of this page.

To Do

The items below will be completed for the release of v1.1, target date is April/May 2026.

Redesign IQ from timing error detector to the S2 frame processing. This will save considerable CPU resources when searching for a signal.
Change frequency tracking to add a NCO (rotator) after the decimation (NCO, Downconverter). This will help with signal locking and possible decoding of weak signals.

Release Notes

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

SDR Television v1.0.6

February 13th, 2026: A new kit, lots of receive improvements since the last official kit. As with any software project, there's always room for improvements and new features, but for now here's a stable solution which works well with the QO-100 satellite.

Downloads are at the bottom of this page.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download v1.0.14

This minimum version of SDR Radio is shown below. You must download if SDR Television displays an error message when starting.

SDR Television

Download v1.0.14 from either:

OneDrive: SDR Television v1.0.14, 64-bit, 2026-04-12_0603.exe
Dropbox: SDR Television v1.0.14, 64-bit, 2026-04-12_0603.exe

SDR Radio

V1.0.14 requires a SDR Radio 64-bit kit build 4008 March 18th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-03-18_1731.exe

SDR Television v1.0.9

Fri, 13 Mar 2026 05:53:13 GMT

SDR Television v1.0.9

Many thanks to the DATV test team.

Downloads are at the bottom of this page.

To Do

The items below will be completed for the release of v1.1, target date is April/May 2026.

Redesign IQ from timing error detector to the S2 frame processing. This will save considerable CPU resources when searching for a signal.
Change frequency tracking to add a NCO (rotator) after the decimation (NCO, Downconverter). This will help with signal locking and possible decoding of weak signals.

Release Notes

v1.0.9

Receive

Replaced Gardner timing error detection (TED) with a corrected design based on the book "Digital Communications: A Discrete-Time Approach" by Michael Rice. This uses a second-order continuous-time phase locked loop (figure C.2.2). This implementation is designed to be robust when unexpected IQ samples are processed.
AGC Target default set to 1.
Changed IQ Imbalance design, now using code from Airspy (Youssef Touil, Leif Asbrink).
Removed 'None' from the list of bandpass filter options as it is superfluous.

General

Fixed startup error "Encountered an improper argument" when no microphones are available.

User Interface

When transmitting, the resolution and frame rate are shown in the transmit timer. If either value is greater than the recommended default, a warning symbol is added.

v1.0.8

Receive

Fixed a bug with RMS calculation in IQ Imbalance.
Tuned IQ Imbalance for weak signals.

v1.0.7

User Interface

The audio and video windows now resize the selection dropdown to the width of the main windows.

Receive

Improved carrier tracking, used when there are no pilots. This benefits weak signals with low FEC values, for example FEC (LDPC) 1/4.

SDR Television v1.0.6

Downloads are at the bottom of this page.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download

This minimum version of SDR Radio is shown below. Only download if SDR Television displays an error message when starting. SDR Radio has not changed since v1.0.6 was released.

SDR Television

Download v1.0.9 from either:

OneDrive: SDR Television V1.0.9, 64-bit, 2026-03-08_1857.exe
Dropbox: SDR Television V1.0.9, 64-bit, 2026-03-08_1857.exe

SDR Television

Previous version. Download v1.0.6 from either:

OneDrive: SDR Television V1.0.6, 64-bit, 2026-02-13_0531.exe
Dropbox: SDR Television V1.0.6, 64-bit, 2026-02-13_0531.exe

SDR Radio

V1.0.9 and V1.0.6 require a SDR Radio 64-bit kit build 3972 February 10th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-02-11_1214.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-02-11_1214.exe

Reuter RSR200B

Wed, 11 Mar 2026 19:59:31 GMT

First Impressions

The RSR200 is a high performance black box receiver (“SDR”) for direct digitization of RF signals up to above 250 MHz and feeding SDR programs on PCs with data rates up to 90 MS/s (16 bit I/Q, lower rates with 24 bit resolution). Source https://www.reuter-elektronik.com/html/rsr200.html .

Above is an image of SDR Console using a RSR200B at 15 MHz bandwidth, antenna is an 8 element Yagi from Innov Antennas . I have started with the USB interface in single channel mode. The API is well documented, it took less than three days to get this SDR integrated into SDR Console.

Using 16-bit ADCs instead of tuner chips is an advantage - apart from antenna selection, the only adjustment you may use is the gain control which ranges from -28dB to +7dB.

P rice: € 1,090.00 see Technical Documentation .

When TCP and dual channel mode is supported I'll update this post, in the meantime here's a test report from Fenu-Radio .

SDR Television v1.0.6

Fri, 13 Feb 2026 10:45:46 GMT

SDR Television v1.0.6

Downloads are at the bottom of this page.

Release Notes

v1.0.6

Transmit

Pluto Support

(This is part of SDR Console.) The FIR filter support for the Pluto has been corrected:

Images reduced if not completely removed.
Transmit now works reliably when the Pluto bandwidth is greater than 2 MHz.
The digital filter uses a FIR design from Analog Devices, taken from the file ad9361_baseband_auto_rate.c in the libad9361-iio library.
The analog filter is unchanged. It will appear wider than expected to allow for roll-off.

With QO-100 and other DVB-S2 operation there really is little if any need for any filtering.

v1.0.5

Receive

Added optional inversion of the incoming signal inversion (swap I and Q).

Transmit

Now setting the Quantization Parameter (QP) to the default value of 26. I had come across this before but never really understood what it does. I was just querying the value, not trying to set it.

https://www.oupree.com/knowledge/Whats-Quantization-Parameter-QP-in-Video-Encoder.html

v1.0.4

Receive

Improved initial frequency detection when searching for a signal.
Optional advanced signal detection options.
Found and fixed a bug causing a lockup when a 188 byte packet checksum failed.

v1.0.3

Testing

Added optional Gaussian noise when in loopback mode, this is for development use only.

User Interface

Added display of elapsed time to the Receive Audio window. Gaps in reception of up to 10 seconds are allowed. Later use of AI may support a 'speech quality' metric, determined from quality and technical content.
Added tuning bars in the spectrum, these show the frequency and symbol rate for the current mouse position.
Added extra categories in the Log window, now Main, Radio, Transmit, Debug.
Audio and video windows optionally hide controls when the cursor leaves the corresponding window.

Receiver

Added initial Gardner timing error detection (TED).
Changed AGC algorithm, target output now ~0.7 using 32-bit IEEE floats.
Redesign #1 of the IQ to Transport Stream (TS) processing, still plenty of refactoring to do.
Changed default LDPC algorithm.
Fixed BCH implementation which was not correcting any bits, also not detecting errors.
Changed default matched filter (RRC) defaults.
Added Quadrature Imbalance correction.
Interpolation filter roll-off dynamically updated with the value in the base-band header byte MATYPE-1. This value is also shown in the Decoding overlay and Decode Status window.
Refined the list of receive filter bandwidths.

AGC

Added selectable reference level.
Added alternative algorithm, Feed forward (the default algorithm is Feedback). Feed forward is experimental.
Searching for a signal in the noise uses considerable CPU, especially at higher symbol rates. The spectrum data is now used to detect the possible presence of a signal, thus saving CPU while a signal is not present. When a signal is believed to be present:
The arrows at the top, bottom of the bandwidth display are filled in,
The receiver is enabled.

Transmit

The transmitted BB Header roll-off value in byte MATYPE-1 now matches the roll-off value used in the filter, rather than preset to 0.35.
Removed 12-bit camera formats, problem discovered using a new DELL laptop.
Added optional transmit signal inversion (swap I and Q).

Pluto

Pluto RX FIR Filter gain set to 6, example: "RX 3 GAIN 6 DEC 1 TX 3 GAIN 0 INT 1 ..."
Removed Pluto/Libre bandwidths below 1.5 MHz.
Changed filter taps for bandwidths above 2MHz, was 64 now 128. Signal is now cleaner, ~40dBm SNR.

v1.0.2

Improved receiver sensitivity, still not as good as it can be.

v1.0.1

Fixed fatal bug in receive audio AGC when the output device sample rate was 192kHz.

Download

This minimum version of SDR Radio is shown below. Only download if SDR Television displays an error message when starting.

SDR Television

Download v1.0.6 from either:

OneDrive: SDR Television V1.0.6, 64-bit, 2026-02-13_0531.exe
Dropbox: SDR Television V1.0.6, 64-bit, 2026-02-13_0531.exe

SDR Radio

V1.0.6 requires a SDR Radio 64-bit kit build 3972 February 10th, 2026 or any newer kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2026-02-11_1214.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2026-02-11_1214.exe

SDR Console, Beta Feb 10th 2026

Fri, 13 Feb 2026 10:45:11 GMT

February 10th, 2026

Pluto

Correct the FIR filter definitions, this has improved reception.

November 1st, 2025

Analyser

Analyser tag window change, as suggested by Jim.
Analyser tags now saved and restored correctly.
Analyser font size now supports small, medium and large.
Analyser loads saved projects faster.
Saving project now much faster and uses less memory.
More display lines available if you have enough RAM:
Less than 16GB then 50,000 lines.
16GB to 32GB then 100,000 lines.
32GB or more then 250,000 lines.
Fixed minor font issue with definition window.
Fixed issue scrolling when more than 32768 lines in display.

Data File Playback

Selecting a playback folder now creates the list of files much faster.

Emulation

Added a diagnostic check for the use of emulators. This code only works on W10 and above, so I dynamically load IsWow64Process2 from kernel32 which avoids issues on older versions of Windows.

In the logfile you see something like this:

05:23:48.185: Vendor ....: GenuineIntel

05:23:48.185: Brand .....: Intel(R) Core(TM) Ultra 7 265K

05:23:48.185: -

05:23:48.185: x86 Emulation:

05:23:48.185: Process .......: 0x0000, "Not emulated"

05:23:48.185: Architecture ..: 0x8664, "AMD64"

05:23:48.185: -

Favourites

Updated the default 60m bandwidth.
Changed Broadcast :: VHF CCIR title to Band II.
Groups now have user-selectable files.
Default definitions renames to main.
Changed the ribbon bar, Selection entry to Options (see image below). The dropdown options have been replaced with a single window, allowing more room for text.

Locked Receivers

If the program is stopped or a favourite created when a receiver is locked, this caused problems with the receiver being locked but no indication. With this kit receiver lock state is not applied in a favourite definition.

Logfile

Automatically save the logfile when closing, really added so I can check program responding correctly to Shutdown and Restart.
Old logfiles are purged after the program has been running for one minute.

Logging

Added logbook FA option as below, FA is the command to read/write RX1.

Narrow FM

Added 150Hz CTCSS squelch tone.
De-emphasis is now optional, selected from: Ribbon bar, Receive, Mode..., Narrow FM.

Persistent Display

Got a crash inside the persistent display logic, my sanity checks weren't good enough so have improved this.

Remote Server

After connecting to a remote server, the input fields can now be edited to change connection parameters.

Ribbon Bar

View panel tidied up.

Signal Meter (SMeter)

Added more presets for the Signal meter, Ribbon bar, View, Spectrum, Signal Meter.

Spectran ECO

Changed SPECTRAN path order to pick up DLLs from the SDK folder rather than the main folder.

Status Bar

GPU, Audio entries on status bar now optional, selected from Program Options, Performance, CPU Memory.

System Shutdown / Restart

If SDR Console is running when the system shuts down or restarts then SDR Console closes gracefully. What happens - five seconds after SDR Console receives the SHUTDOWN message a timer calls the OnClose() processing, so you have five seconds to about the shutdown / restart.

Previous Kits...

I'm now back to 90% SDR Console support, so here's the first beta for at least eight months. Scroll to the bottom for a link to the beta kit.

The source is fully archived, so crash dumps can be analysed.

September 4th, 2025

Ad ded Simple-Radio-Control-Protocol (SR CP) as per JB's Dx Info and tested only with StationList. SRCP specifies a method to control a radio and get its status back to StationList (or a similiar application). To avoid any headache on user and software writer a very simple method was chosen. Communication is done by sending UDP string messages.
If there are other logging programs which support SRCP please let me know.
I have not added support for RDS, only frequency changes.
After the first message is sent from StationList the protocol is activated.
This should be documented somewhere in the Settings somewhere, but where?
What's missing?

August 30th, 2025

If the RDS Database c annot be opened / created an error is now displayed.
RDS Logfile window now shows Entry when displaying all fields, see image below.
RDS Logfile window now supports data sorting by clicking on the column headers.

August 28th, 2025

SSB / AM squelch was missing the start and cutting off too soon. Also, the Raised cosine rise/fall was missing. Now, the SSB/AM squelch is more pleasant to listen to. Note : SSB / AM squelch uses voice activity detection, it is not rf-based.
RDS Logfile display no longer auto-updates if any of:
Edit window is visible,
Mouse has been active in the previous five seconds,
First entry is not visible.

August 23rd, 2025

Su pports Winradio IQ files > 4 GB . These files, like ELAD's do not honour the WAV format correctly, but hey-ho.
When searching for Airspy HF+ / Discovery / ... SDRs the firmware is now shown in the Options field in the list of SDRs. Also shown in the logfile when connecting to the Airspy.
Option added to suppo rt logging programs when using a transmit up/ down converter definition, as we do with the Pluto on QO-100, see image below.
Previously FA, FB, ... returned the receive frequency (10 GHz) but on QO-100 we're actually transmitting at 2.4 GHz on the up-link.
When enabled, the actual transmit frequency (2.4 GHz) is returned.

Mode Mapping page is now Frequency, Mode.

June 28th, 2 025

Scheduled recordings now have an option to shut down the computer when the recording is finished.
Streaming now compresses th e data when the bandwidth is 5MHz or greater.

June 26 th, 2025

Preset recording definitions now include the action to take when the recording finishes, see image below.
The Stop button in Ribb on bar, Home, Radio now stops the recording playback.

June 25th, 2025

Left and Right channels in Broadcast-FM swapped over, was reported that they were previously wrong. Please check!

June 22nd, 2025

Custom layouts now restore the collapsed / expanded state of the Receive and Transmit panes.

June 20th, 2025

When the Microphone dropdown is opened in the Transmit panel the list of capture devices is re-enumerated and updated, so anything you plug in / out is reflected in the dropdown list without having to restart. Unplugging the microphone you are using is not supported, but you don't do that, right?
The TX relay can now be connected after starting, it will be opened when the next transmission is made.

June 19th, 2025

Reworked some MIDI support to reduce / eliminate crashes.

June 18th, 2025

Pluto updated for wideband transmit - SDR Television
Fixed SPECTRAN V6 support
NR3 (rrnoise) updated to version 0.2 Release RNNoise 0.2 · xiph/rnnoise .

Kits

The beta kits are here: https://www.sdr-radio.com/download#Beta

Adding A Radio Definition

Sat, 27 Dec 2025 20:01:57 GMT

Follow These Steps

If you're unsure how you add a radio definition to SDR Console, here are the steps you must follow.

Start SDR Console (quite obvious really).
From the Home tab on the ribbon bar, in the Radio panel click Select Radio , the Select Radio window is displayed.
At the bottom right of the Select Radio window, click Definitions... , the Radio Definitions window is displayed.
At the top left of the Radio Definitions window click Search , a list of all supported radios is displayed.
Select the radio you want to add, for example Airspy, SDRplay. In this example the RX-888 will be added.
When you select an option from the list in step 4, either a radio is found or not.
If the radio is found, a window is displayed with the option of adding the new definition.
If the radio is not found, an error window is displayed. If this is a radio connected by USB, make sure the USB port can supply enough power.
After adding the definition, click Save in the Radio Definitions window.
You can now select your radio in the Select Radio window.

That's all folks!

SDRplay

If you are using a SDRplay you select SDRplay > V3 in step 5 above. Make sure you have also installed either SDRconnect , SDRuno or the latest API (currently 3.15 at the time of writing).

Gallery

Simon's World Map 1.5.4

Fri, 19 Dec 2025 05:34:03 GMT

Version 1.5.4

This release fixes a bug, improves the user interface. Download link is at the bottom of this page.

Aurora

Corrected Clock Display

To select a system font use the ribbon bar entry: Clock, Font, System Fonts. The image below shows Georgia.

Previous: Version 1.5.2

This release fixes a bug, improves the user interface and adds a new calendar. Download link is at the bottom of this page.

Sleep

After resuming from computer sleep, the program would often lock up. This has been fixed (graphics restarted).

Country Prefixes

The database shipped with this kit is the very latest available from Log4OM , update timestamp is 2025-08-05 09:52:27z.

Updating the database has been simplified: from the ribbon bar select Prefixes, Database.

Select Open to display the latest available database in your default XML browser, usually Microsoft Edge or Google Chrome.
Select Save as default to overwrite the current database with the latest available database. Sanity checks are applied, the display refreshed.

Sunrise Calendar

This is a simple way to generate a sunrise, sunset calendar for your home location.

From the ribbon bar, select Sunrise, Calendar, Show.
As you change the selected month, the calendar is updated, it's that simple!
Select Text Viewer to open the list of times in your default text editor.

Previous: Version 1.5.1

This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.

Appearance

The Space weather and Sunrise windows now have a border, drawn with the text colour.

Aurora

The aurora legend has been increased in size to make it easier to read.

Clock

The clock now has its own colour setting (see Appearance above).

Grid Squares

Added a Help button to the grid squares panel in the ribbon bar.

Layouts

The layouts (Ribbon bar, View, Layout) have been updated to fix a few minor bugs, also a Reset button has been added.

Maps

A new map, purchased from Vecteezy for 'Detailed Physical Green' by Sam Kal.

Stations

When changing definitions and layout options the map is dynamically updated.
When displayed on the side of the map, the station windows are now centred vertically.
The station layout window also supports the new HLS colour editor.

Previous: Version 1.5

May 25th, 2025: After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are on the World Map page .

SDR Console, Beta Nov 1st 2025

Sat, 01 Nov 2025 06:37:04 GMT

November 1st, 2025

Analyser

Analyser tag window change, as suggested by Jim.
Analyser tags now saved and restored correctly.
Analyser font size now supports small, medium and large.
Analyser loads saved projects faster.
Saving project now much faster and uses less memory.
More display lines available if you have enough RAM:
Less than 16GB then 50,000 lines.
16GB to 32GB then 100,000 lines.
32GB or more then 250,000 lines.
Fixed minor font issue with definition window.
Fixed issue scrolling when more than 32768 lines in display.

Data File Playback

Selecting a playback folder now creates the list of files much faster.

Emulation

Added a diagnostic check for the use of emulators. This code only works on W10 and above, so I dynamically load IsWow64Process2 from kernel32 which avoids issues on older versions of Windows.

In the logfile you see something like this:

05:23:48.185: Vendor ....: GenuineIntel

05:23:48.185: Brand .....: Intel(R) Core(TM) Ultra 7 265K

05:23:48.185: -

05:23:48.185: x86 Emulation:

05:23:48.185: Process .......: 0x0000, "Not emulated"

05:23:48.185: Architecture ..: 0x8664, "AMD64"

05:23:48.185: -

Favourites

Updated the default 60m bandwidth.
Changed Broadcast :: VHF CCIR title to Band II.
Groups now have user-selectable files.
Default definitions renames to main.
Changed the ribbon bar, Selection entry to Options (see image below). The dropdown options have been replaced with a single window, allowing more room for text.

Locked Receivers

If the program is stopped or a favourite created when a receiver is locked, this caused problems with the receiver being locked but no indication. With this kit receiver lock state is not applied in a favourite definition.

Logfile

Automatically save the logfile when closing, really added so I can check program responding correctly to Shutdown and Restart.
Old logfiles are purged after the program has been running for one minute.

Logging

Added logbook FA option as below, FA is the command to read/write RX1.

Narrow FM

Added 150Hz CTCSS squelch tone.
De-emphasis is now optional, selected from: Ribbon bar, Receive, Mode..., Narrow FM.

Persistent Display

Got a crash inside the persistent display logic, my sanity checks weren't good enough so have improved this.

Remote Server

After connecting to a remote server, the input fields can now be edited to change connection parameters.

Ribbon Bar

View panel tidied up.

Signal Meter (SMeter)

Added more presets for the Signal meter, Ribbon bar, View, Spectrum, Signal Meter.

Spectran ECO

Changed SPECTRAN path order to pick up DLLs from the SDK folder rather than the main folder.

Status Bar

GPU, Audio entries on status bar now optional, selected from Program Options, Performance, CPU Memory.

System Shutdown / Restart

If SDR Console is running when the system shuts down or restarts then SDR Console closes gracefully. What happens - five seconds after SDR Console receives the SHUTDOWN message a timer calls the OnClose() processing, so you have five seconds to about the shutdown / restart.

Previous Kits...

I'm now back to 90% SDR Console support, so here's the first beta for at least eight months. Scroll to the bottom for a link to the beta kit.

The source is fully archived, so crash dumps can be analysed.

September 4th, 2025

Ad ded Simple-Radio-Control-Protocol (SR CP) as per JB's Dx Info and tested only with StationList. SRCP specifies a method to control a radio and get its status back to StationList (or a similiar application). To avoid any headache on user and software writer a very simple method was chosen. Communication is done by sending UDP string messages.
If there are other logging programs which support SRCP please let me know.
I have not added support for RDS, only frequency changes.
After the first message is sent from StationList the protocol is activated.
This should be documented somewhere in the Settings somewhere, but where?
What's missing?

August 30th, 2025

If the RDS Database c annot be opened / created an error is now displayed.
RDS Logfile window now shows Entry when displaying all fields, see image below.
RDS Logfile window now supports data sorting by clicking on the column headers.

August 28th, 2025

SSB / AM squelch was missing the start and cutting off too soon. Also, the Raised cosine rise/fall was missing. Now, the SSB/AM squelch is more pleasant to listen to. Note : SSB / AM squelch uses voice activity detection, it is not rf-based.
RDS Logfile display no longer auto-updates if any of:
Edit window is visible,
Mouse has been active in the previous five seconds,
First entry is not visible.

August 23rd, 2025

Su pports Winradio IQ files > 4 GB . These files, like ELAD's do not honour the WAV format correctly, but hey-ho.
When searching for Airspy HF+ / Discovery / ... SDRs the firmware is now shown in the Options field in the list of SDRs. Also shown in the logfile when connecting to the Airspy.
Option added to suppo rt logging programs when using a transmit up/ down converter definition, as we do with the Pluto on QO-100, see image below.
Previously FA, FB, ... returned the receive frequency (10 GHz) but on QO-100 we're actually transmitting at 2.4 GHz on the up-link.
When enabled, the actual transmit frequency (2.4 GHz) is returned.

Mode Mapping page is now Frequency, Mode.

June 28th, 2 025

Scheduled recordings now have an option to shut down the computer when the recording is finished.
Streaming now compresses th e data when the bandwidth is 5MHz or greater.

June 26 th, 2025

Preset recording definitions now include the action to take when the recording finishes, see image below.
The Stop button in Ribb on bar, Home, Radio now stops the recording playback.

June 25th, 2025

Left and Right channels in Broadcast-FM swapped over, was reported that they were previously wrong. Please check!

June 22nd, 2025

Custom layouts now restore the collapsed / expanded state of the Receive and Transmit panes.

June 20th, 2025

When the Microphone dropdown is opened in the Transmit panel the list of capture devices is re-enumerated and updated, so anything you plug in / out is reflected in the dropdown list without having to restart. Unplugging the microphone you are using is not supported, but you don't do that, right?
The TX relay can now be connected after starting, it will be opened when the next transmission is made.

June 19th, 2025

Reworked some MIDI support to reduce / eliminate crashes.

June 18th, 2025

Pluto updated for wideband transmit - SDR Television
Fixed SPECTRAN V6 support
NR3 (rrnoise) updated to version 0.2 Release RNNoise 0.2 · xiph/rnnoise .

Kits

The beta kits are here: https://www.sdr-radio.com/download#Beta

SDR Television v1.0.1 (Bugfix)

Wed, 29 Oct 2025 05:52:02 GMT

SDR Television v1.0.1

October 29th, 2025: Fixed a fatal bug in the receive AGC if the output soundcard sample rate is 96kHz or 192kHz.

Downloads are at the bottom of this page.

SDR Television v1

September 10th, 2025: This release is actually beta 6 with a few small updates, so I've left the beta 6 text here. I hope to start working on this in November 2025, adding the Gardner timing error detection which should improve the decoding with low SNR.

Downloads are at the bottom of this page.

About Gardner timing error detection

Gardner timing error detection is a widely used technique in digital communications for estimating and correcting timing errors in the received signal. It is commonly employed in symbol timing recovery circuits, particularly because of its effectiveness even when the carrier phase is unknown or rotating—making it carrier phase independent.

How Gardner Timing Error Detector Works

Gardner's method operates by sampling the received signal at twice the symbol rate (two samples per symbol).
The timing error is calculated by comparing the signal sample at the midpoint of the symbol (between two symbol peaks) to the samples at the symbol boundaries.

Zero-Crossing Principle

Gardner's TED is based on a zero-crossing concept—detecting timing errors by observing differences across symbol transitions, not requiring knowledge of the transmitted data. This is known as a non-data-aided approach. If data symbols are known, this becomes a data-aided/decision-directed form called Zero Crossing Timing Error Detector.

Applications and Advantages

Carrier Phase Independence : It is robust even with phase offsets or frequency drifts, which is essential when the carrier recovery is not perfect.
Historical Relevance : Gardner timing error detection was notably used in Mariner Mars 1969 missions for symbol synchronization in telemetry receivers.
Multi-level Modulations : While originally used for QPSK (quadrature phase shift keying), the principle extends to other digital modulation schemes, though modifications may be needed for Nyquist pulses with low roll-off.

Summary of Use

Gardner TED is popular for timing synchronization in digital receivers, such as those used in wireless communications, SDRs, QAM, and OFDM systems.
It helps align sampling instants to symbol boundaries for accurate symbol detection, crucial for bit error rate performance.

In conclusion, Gardner timing error detection is a foundational algorithm ensuring precise symbol timing in modern communication systems, prized for its carrier independence and non-data-aided operation.

Download

This minimum version of SDR Radio is shown below. Only download if SDR Television displays an error message when starting.

SDR Television

Current : V1.0.1 Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-10-28_1852.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-10-28_1852.exe

Old: V1 Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-09-10_1341.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-09-10_1341.exe

SDR Radio

The latest SDR Radio 64-bit kit is Build 3818, September 9th, 2025. This has been released as an official beta. Use the kit below or any newer SDR Radio kit .

OneDrive: SDR-Radio V3.4, 64-bit, 2025-09-09_0631.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2025-09-09_0631.exe

Simon's World Map 1.5.2

Sat, 25 Oct 2025 05:49:30 GMT

Previous: Version 1.5.2

This release fixes a bug, improves the user interface and adds a new calendar. Download link is at the bottom of this page.

Sleep

After resuming from computer sleep, the program would often lock up. This has been fixed (graphics restarted).

Country Prefixes

The database shipped with this kit is the very latest available from Log4OM , update timestamp is 2025-08-05 09:52:27z.

Updating the database has been simplified: from the ribbon bar select Prefixes, Database.

Select Open to display the latest available database in your default XML browser, usually Microsoft Edge or Google Chrome.
Select Save as default to overwrite the current database with the latest available database. Sanity checks are applied, the display refreshed.

Sunrise Calendar

This is a simple way to generate a sunrise, sunset calendar for your home location.

From the ribbon bar, select Sunrise, Calendar, Show.
As you change the selected month, the calendar is updated, it's that simple!
Select Text Viewer to open the list of times in your default text editor.

Previous: Version 1.5.1

This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.

Appearance

The Space weather and Sunrise windows now have a border, drawn with the text colour.

Aurora

The aurora legend has been increased in size to make it easier to read.

Clock

The clock now has its own colour setting (see Appearance above).

Grid Squares

Added a Help button to the grid squares panel in the ribbon bar.

Layouts

The layouts (Ribbon bar, View, Layout) have been updated to fix a few minor bugs, also a Reset button has been added.

Maps

A new map, purchased from Vecteezy for 'Detailed Physical Green' by Sam Kal.

Stations

When changing definitions and layout options the map is dynamically updated.
When displayed on the side of the map, the station windows are now centred vertically.
The station layout window also supports the new HLS colour editor.

Previous: Version 1.5

May 25th, 2025: After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are here .

AMSAT UK 2025 Award

Sun, 12 Oct 2025 12:46:58 GMT

And the award goes to...

Me! For SDR Console's contribution to QO-100 and the new SDR Television software. Sadly I couldn't attend, so Mike G0MJW accepted on my behalf.

I would like to thank all members of the AMSAT UK Academy, especially ...

Simon's World Map 1.5.1

Thu, 09 Oct 2025 13:13:53 GMT

Version 1.5.1

This is a mainly cosmetic update to version 1.5, nevertheless well worth installing.

Appearance

The Space weather and Sunrise windows now have a border, drawn with the text colour.

Aurora

The aurora legend has been increased in size to make it easier to read.

Clock

The clock now has its own colour setting (see Appearance above).

Grid Squares

Added a Help button to the grid squares panel in the ribbon bar.

Layouts

The layouts (Ribbon bar, View, Layout) have been updated to fix a few minor bugs, also a Reset button has been added.

Maps

A new map, purchased from Vecteezy for 'Detailed Physical Green' by Sam Kal.

Stations

When changing definitions and layout options the map is dynamically updated.
When displayed on the side of the map, the station windows are now centred vertically.
The station layout window also supports the new HLS colour editor.

Previous: Version 1.5

May 25th, 2025: After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are here .

SDR Television v1 (Release)

Sat, 13 Sep 2025 05:59:18 GMT

SDR Television

This release is actually beta 6 with a few small updates, so I've left the beta 6 text here. I hope to start working on this in November 2025, adding the Gardner timing error detection which should improve the decoding with low SNR.

Downloads are at the bottom of this page.

About Gardner timing error detection

How Gardner Timing Error Detector Works

Gardner's method operates by sampling the received signal at twice the symbol rate (two samples per symbol).
The timing error is calculated by comparing the signal sample at the midpoint of the symbol (between two symbol peaks) to the samples at the symbol boundaries.

Zero-Crossing Principle

Applications and Advantages

Carrier Phase Independence : It is robust even with phase offsets or frequency drifts, which is essential when the carrier recovery is not perfect.
Historical Relevance : Gardner timing error detection was notably used in Mariner Mars 1969 missions for symbol synchronization in telemetry receivers.
Multi-level Modulations : While originally used for QPSK (quadrature phase shift keying), the principle extends to other digital modulation schemes, though modifications may be needed for Nyquist pulses with low roll-off.

Summary of Use

Gardner TED is popular for timing synchronization in digital receivers, such as those used in wireless communications, SDRs, QAM, and OFDM systems.
It helps align sampling instants to symbol boundaries for accurate symbol detection, crucial for bit error rate performance.

Download

This minimum version of SDR Radio is shown below. Only download if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-09-10_1341.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-09-10_1341.exe

SDR Radio

The latest SDR Radio 64-bit kit is Build 3818, September 9th, 2025. This has been released as an official beta. Use the kit below of any newer SDR Radio kit.

OneDrive: SDR-Radio V3.4, 64-bit, 2025-09-09_0631.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2025-09-09_0631.exe

SDR Console, Beta Sept. 9th 2025

Tue, 09 Sep 2025 16:35:14 GMT

Hello Again

I'm now back to 90% SDR Console support, so here's the first beta for at least eight months. Scroll to the bottom for a link to the beta kit.

The source is fully archived, so crash dumps can be analysed.

September 4th, 2025

Ad ded Simple-Radio-Control-Protocol (SR CP) as per JB's Dx Info and tested only with StationList. SRCP specifies a method to control a radio and get its status back to StationList (or a similiar application). To avoid any headache on user and software writer a very simple method was chosen. Communication is done by sending UDP string messages.
If there are other logging programs which support SRCP please let me know.
I have not added support for RDS, only frequency changes.
After the first message is sent from StationList the protocol is activated.
This should be documented somewhere in the Settings somewhere, but where?
What's missing?

August 30th, 2025

If the RDS Database c annot be opened / created an error is now displayed.
RDS Logfile window now shows Entry when displaying all fields, see image below.
RDS Logfile window now supports data sorting by clicking on the column headers.

August 28th, 2025

SSB / AM squelch was missing the start and cutting off too soon. Also, the Raised cosine rise/fall was missing. Now, the SSB/AM squelch is more pleasant to listen to. Note : SSB / AM squelch uses voice activity detection, it is not rf-based.
RDS Logfile display no longer auto-updates if any of:
Edit window is visible,
Mouse has been active in the previous five seconds,
First entry is not visible.

August 23rd, 2025

Su pports Winradio IQ files > 4 GB . These files, like ELAD's do not honour the WAV format correctly, but hey-ho.
When searching for Airspy HF+ / Discovery / ... SDRs the firmware is now shown in the Options field in the list of SDRs. Also shown in the logfile when connecting to the Airspy.
Option added to suppo rt logging programs when using a transmit up/ down converter definition, as we do with the Pluto on QO-100, see image below.
Previously FA, FB, ... returned the receive frequency (10 GHz) but on QO-100 we're actually transmitting at 2.4 GHz on the up-link.
When enabled, the actual transmit frequency (2.4 GHz) is returned.

Mode Mapping page is now Frequency, Mode.

June 28th, 2 025

Scheduled recordings now have an option to shut down the computer when the recording is finished.
Streaming now compresses th e data when the bandwidth is 5MHz or greater.

June 26 th, 2025

Preset recording definitions now include the action to take when the recording finishes, see image below.
The Stop button in Ribb on bar, Home, Radio now stops the recording playback.

June 25th, 2025

Left and Right channels in Broadcast-FM swapped over, was reported that they were previously wrong. Please check!

June 22nd, 2025

Custom layouts now restore the collapsed / expanded state of the Receive and Transmit panes.

June 20th, 2025

When the Microphone dropdown is opened in the Transmit panel the list of capture devices is re-enumerated and updated, so anything you plug in / out is reflected in the dropdown list without having to restart. Unplugging the microphone you are using is not supported, but you don't do that, right?
The TX relay can now be connected after starting, it will be opened when the next transmission is made.

June 19th, 2025

Reworked some MIDI support to reduce / eliminate crashes.

June 18th, 2025

Pluto updated for wideband transmit - SDR Television
Fixed SPECTRAN V6 support
NR3 (rrnoise) updated to version 0.2 Release RNNoise 0.2 · xiph/rnnoise .

Kits

The beta kits are here: https://www.sdr-radio.com/download#Beta

SDR Television Beta #6

Thu, 28 Aug 2025 05:43:57 GMT

SDR Television

Improved phase detection at the start of each frame (SOF, PLS) which in turn improves sensitivity.
Added 2,000 ksps receive, confirmed as working with GB3NQ.
Sensitivity still not as good as a Serit 4334 NIM as used in the MiniTioune receiver, what's missing is synchronisation timing, I will be using Gardner timing error detection (TED). This will be added in Q1, 2026 when this project is extended for terrestrial use.

Downloads are at the bottom of this page.

About Gardner timing error detection

How Gardner Timing Error Detector Works

Gardner's method operates by sampling the received signal at twice the symbol rate (two samples per symbol).
The timing error is calculated by comparing the signal sample at the midpoint of the symbol (between two symbol peaks) to the samples at the symbol boundaries.

Zero-Crossing Principle

Applications and Advantages

Carrier Phase Independence : It is robust even with phase offsets or frequency drifts, which is essential when the carrier recovery is not perfect.
Historical Relevance : Gardner timing error detection was notably used in Mariner Mars 1969 missions for symbol synchronization in telemetry receivers.
Multi-level Modulations : While originally used for QPSK (quadrature phase shift keying), the principle extends to other digital modulation schemes, though modifications may be needed for Nyquist pulses with low roll-off.

Summary of Use

Gardner TED is popular for timing synchronization in digital receivers, such as those used in wireless communications, SDRs, QAM, and OFDM systems.
It helps align sampling instants to symbol boundaries for accurate symbol detection, crucial for bit error rate performance.

Download

This minimum version of SDR Radio is shown below. Only download if SDR Television displays an error message when starting.

SDR Television

Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-08-28_0613.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-08-28_0613.exe

SDR Radio

Download from either:

OneDrive: SDR-Radio V3.4, 64-bit, 2025-07-16_1114.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2025-07-16_1114.exe

SDR Television Beta #5

simon@sdr-radio.com (Simon Brown) — Fri, 18 Jul 2025 12:41:39 GMT

SDR Television

Found and fixed an unused massive memory allocation (up to 10GB), may have caused systems to freeze.
Fixed fatal bug in matched filter array allocation.
Changed the default transmit bandpass shaping filter roll-off to 0.20 in transmit and receive. Please look at the images below and apply the change.

SDR Pluto

Now show the AGC gain and RSSI.
Added Default link to select the recommended gain - Fast Attack, 0dB visual.

Known Problems

Add support for tracking transmissions with (?) non-standard PCR data, example is G8GKQ.
Using Pluto & variants, sensitivity is not as good as a NIM (hardware tuner). Will compare with SPECTRAN ECO in a week or so.

Download

This kit requires a new version of SDR Radio, below.

SDR Television

Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-07-18_0642.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-07-18_0642.exe

SDR Radio

Download from either:

OneDrive: SDR-Radio V3.4, 64-bit, 2025-07-16_1114.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2025-07-16_1114.exe

SDR Television Beta #4

simon@sdr-radio.com (Simon Brown) — Mon, 30 Jun 2025 13:16:31 GMT

Unexpected Beta #4

I wasn't planning to release another beta, but there was an error with a download link in the Blog post for Beta #3, also a few worthwhile improvements have been made, so here I go.

SDR Television

Improved matched filter (root-raised cosine).
Changed LDPC algorithm to use the Offset-Min-Sum (self-corrected) layered schedule', constant factor = 2 .
Fine tuned the receiver constellation.
Changed the default transmit bandpass shaping filter roll-off to 0.25. Please look at the image below and apply the change.

Known Problems

Switching from a transmission using short frames to another transmission using normal frames and a lower sample rate may cause the program to abruptly exit. The good news - I have a data recording I can replay to reproduce this.

SDR Radio

No changes.

Download

This new kit does not require a new version of SDR Radio, the links below are for the kit released with beta #3 on June 16th, 2025.

SDR Television

Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-06-30_1338.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-06-30_1338.exe

SDR Radio

Download from either:

OneDrive: SDR-Radio V3.4, 64-bit, 2025-06-16_0559.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2025-06-16_0559.exe

New Paragraph

SDR Television Beta #3

simon@sdr-radio.com (Simon Brown) — Wed, 18 Jun 2025 18:23:47 GMT

Major Change

Scroll down to the SDR Radio information. The bandwidths available for SDR Television when using a Pluto / LibreSDR have changed.

SDR Television

Now supporting vMix, this was a bug in the DirectShow camera support.
Diagnostics overlay now shows Symbol rate instead of Omega.
Fixed a (stupid) bug when a LNB offset was enabled.
Detects the version of SDR Console, install will fail if the required version is not installed.
Added Preset frequencies.
Added (actually restored) the Decode panel to the ribbon bar, you can now restart the audio & video decoders should they freeze.
Added a data recorder. This saves the data (IQ) from your SDR as a .WAV file in a folder you select on this page. Recordings help to diagnose decoding issues; transmissions can be replayed through SDR Console and streamed to SDR Television. The file format is:
16-bit (unsigned short) complex (IQ) samples.
RF64 format (unrestricted file size) https://en.wikipedia.org/wiki/RF64 .
Fixed problem when received AAC switches between mono and stereo.
Improved matched filter (root-raised cosine).
Added Centre Receiver button to the ribbon bar. This centres the current signal in the receiver passband.
Enabling high-quality fractional resampling when decimating IQ data from the SDR.
Changed LDPC algorithm to use the Min Sum self-corrected algorithm, constant factor = 2.

Known Problems

Switching from a transmission using short frames to another transmission using normal frames and a lower sample rate may cause the program to abruptly exit. The good news - I have a data recording I can replay to reproduce this,

Preset Frequencies

Although this program is designed for use on the QO-100 satellite, it can also be used for terrestrial communication. This is where Preset Frequency definitions are used.

Frequency List

First create a list of frequencies you will use for receive and/or transmit. Select the list editor from: Ribbon Bar, Home, QO-100, Presets, Edit List.

Selecting

When you select a Preset from the ribbon bar, QO-100 panel the frequency is applied to both receive and transmit.

Receive

To select for receive only, go to the Configuration window in the Receive panel. The spectrum will be updated if a radio is started.

Transmit

To select for transmit only, go to the Configuration window in the Transmit panel.

SDR Radio

You will now see a different set of bandwidths when connecting to Pluto / LibreSDR: 1.5, 2 and 2.5 MHz. These have been carefully chosen to ensure the upsampling from the selected Sample Rate to the Transmit Bandwidth works as required. At a later date the upsampling logic will be extended, but for now this should fix an issue with incorrect sample rate selection.

For Pluto/LibreSDR the t ransmit filter width is now fixed at 100% and cannot be adjusted.

Download

This new kit requires a new version of SDR Radio.

SDR Radio

Download from either:

OneDrive: SDR-Radio V3.4, 64-bit, 2025-06-16_0559.exe
Dropbox: SDR-Radio V3.4, 64-bit, 2025-06-16_0559.exe

SDR Television

Download from either:

OneDrive: SDR Television V1.0, 64-bit, 2025-06-16_0549.exe
Dropbox: SDR Television V1.0, 64-bit, 2025-06-16_0549.exe

Simon (G4ELI) Live!

simon@sdr-radio.com (Simon Brown) — Sun, 25 May 2025 17:28:54 GMT

BATC Net, May 22nd 2025

Here's a snippet from the British Amateur Television Club net on QO-100. I hope it doesn't scare you.

Simon's World Map 1.5

simon@sdr-radio.com (Simon Brown) — Sun, 25 May 2025 17:23:43 GMT

UI Refresh And More...

After spending almost 18 months on the SDR Television project, Simon's World map has been given some attention.

User Interface

I find user interfaces (UI) difficult, I've never been much good at them. Here's what's changed:

Ribbon Bar, Home panel:
Now starts with the Home location configuration, this was previous found mixed up with the Centre buttons.
Some centre icons updated.
Most importantly, the Maps selection has its own panel!
New Maps panel, this makes map selection far easier.

Satellites

The formula in C++:

double dStationLatitude = 50.10496000; // In degrees, North

double dStationLongitude = -5.12795000; // In degrees, West

double dLongitudeDifference = dStationLongitude - dSatelliteLongitude; // In degrees

double dRadian = RADIANS_TO_DEGREES;

double dTan = tan(dStationLatitude/dRadian);

double dSin = sin(dLongitudeDifference/dRadian);

double dSkew = dRadian * atan(dSin/dTan);

Now have the skew in degrees.

Stations

This has annoyed me for quite some time. Using feedback from users, the display can be configured as below. There are major changes:

Stations can be shown to the left and right of the map.
A database has been incorporated from Github which contains 7,322 major cities including country, region, latitude and longitude.
A new default list can be selected.

Definitions

From the ribbon bar, select Stations, Show, Definitions; the approach should be intuitive. When you create or modify a definition a new option is available: World Cities.

Notice that :

some cities like Vatican city or Singapore are a whole state so they don't belong to any subcountry. Therefore subcountry is N/A.
There is no guaranty that a city has a unique name in a country and subcountry (At the time of writing, there are about 60 ambiguities). But for each city, the source data primary key geonameid is provided.

Configuration

From the ribbon bar select Stations, Show, Layout. This window is divided into two parts:

Overlay on map - select the information to display.
Show on the left-hand side (LHS) and, if more room is needed the right-hand side (RHS). Also select the colours and width of the station display.

Download

Downloads are here .

No More Wireless

simon@sdr-radio.com (Simon Brown) — Tue, 13 May 2025 10:24:28 GMT

After too much grief, I've decided to stop using Wi-Fi to connect the small NUC systems in the computer room to my network:

DX Cluster (Ubuntu)
SDR Server (Windows)
User Forums (Windows)

These servers are in constant use, causing the wireless transmitter on my TP-Link AX50 to fail. By switching over to a wired network there's less demand on the wireless transmitter and the whole network has become far more reliable.

In future I will only use Wi-fi when there's no alternative. I'm keeping a spare router ready just in case the AX50 fails.

SDR Television - My Station

Tue, 06 May 2025 04:54:05 GMT

Inside

All this equipment is installed in my computer room, next to the office.

Some people mount on metal, I prefer wood, much easier! So, what do we see here?

Early ADALM Pluto version A/B modified by Matthias, DD1US to support a 40MHz reference.
Analog Devices CN0417 RF amplifier , powered by micro-USB, optimized to operate on 2400 MHz with 18dBm maximum output, gain of 20-21dB, an integrated bandpass filter 2400 to 2500Mhz. Powered by 5V directly via a micro-USB jack. RF input and output connector in SMA.
Leo Bodnar GPS reference.
USB relay board which switches the power amplifier.

Also you see two USB hubs, one supplying power only, the other connected to the computer. To keep everything cool a nice USB fan which runs at its lowest setting. The RSHTECH USB hub will soon be replaced, I've had two PSUs die, one generated massive HF interference which was only recently found.

Now the power amplifier. This is a PowerBlast™ 300 , a compact, highly efficient, solid state power

amplifier that delivers over 250 watts of RF power over the 100MHz BW of ISM 2.45GHz

frequency band.

The amplifier accepts a nominal 22 dBm (160 mW) RF input and provides 33 dB of gain from

2400 MHz to 2500 MHz for continuous wave (CW) and constant envelope input signals. Based

on the latest and more mature LDMOS technology, this high power amplifier achieves drain

efficiency of 60% (final stage) and more than 57% in module level at rated power.

I haven't finished the screening, so it's held in place by two rolls of solder! Cooling comes from a pair of 80mm USB variable speed fans. Temperature does not exceed 35°C.

The power supply is a RUZIZAO 30V 20A Bench Power Supply which runs at 28V. I like this device as it also shows the wattage.

Outside

Here you see:

1.4 prime focus dish with ~300kg of ballast.
POTY feed.
Bullseye LNB.
LDF4-50 1/2″ Andrew HELIAX Coaxial Cable, length 10m.
A plastic plant pot which keeps the rain off (last image only).

I've had problems with the Bullseye LNBs. They are very good with low phase noise, but the two I own have lost their calibration so a G4EML Bullseye Tuner is used to recalibrate. Many thanks to Mike, G0MJW for building this.

Future

In a month or three I'll be using a LibreSDR. Also, I'm hoping to find a Raven 2.4m dish someday, this would give a gain of approximately 3 (4.77 dB) over the 1.4m dish (compare the surface areas).

Summary

So, that's it. The amplifier puts out far more power than I actually need on DATV - typically running 40w output with plenty in reserve, so I have enough for a good 1,000 ksps transmission.

I'm occasionally on the BATC and WW nets, you have been warned!

SDR Television - Australia

simon@sdr-radio.com (Simon Brown) — Thu, 01 May 2025 05:03:19 GMT

SDR Television video from Australia

This is the VK3RTV net from Tuesday 29th April 2025, an in-depth look at SDR Television by Joe VK3TET. It's always interesting to see what others think of my efforts, even when just a first beta release.

Out friends 'down under' don't have access to QO-100, the next release of SDR Television will have a better UI for terrestrial use.

Found It!

simon@sdr-radio.com (Simon Brown) — Wed, 30 Apr 2025 19:25:36 GMT

Sounds Like...

And before I start, may I apologise for the delay in finding the cause of the noise.

A month or two ago my public SDR servers were hit with some nasty noise. At first I thought it was builders next door who always leave tools plugged in. Then the complaints started...

Yesterday (April 29th, 2025), with the help of Tim M0AFJ I located the source of the noise, it was coming from somewhere in my SDR server setup.

Today I found the cause. The power supply for a USB hub had gone 'wonky', generating lots of noise which was radiated by the devices attached to the hub, such as 2 x Airspy Discovery, Perseus, ELAD S1 and S2, NetSDR.

This is not the first time I've had a PSU on these hubs go bad, so I replaced the hub with a good semi-commercial Exsys hub which was sitting in the cupboard, and now the problem is solved.

Sadly the PSU on my NetSDR stopped working, later tomorrow a new PSU will arrive from Amazon, so that will be back on the server.

SDR Television - The Movie

simon@sdr-radio.com (Simon Brown) — Fri, 25 Apr 2025 20:09:41 GMT

YouTube

Many thanks to Tech Minds, aka Matt M0DQW for this very complimentary YouTube video. I hope you enjoy it as much as I did.

SDR Television Beta #2

simon@sdr-radio.com (Simon Brown) — Thu, 24 Apr 2025 18:20:18 GMT

The first Major Update

First of all, a big thank-you to everyone who has been trying the software, for the feedback and the help finding a very stupid bug which caused the "Encountered an improper argument" error.

Don't worry - if you use QO-100 then I'll be watching you!

At the bottom of this blog entry are new kits for both SDR Radio and SDR Television, but first here's what's been happening.

SDR Radio

Attacked two problems,

Selecting Pluto/LibreSDR connected to the network,
Slow startup when selecting Pluto/LibreSDR connected via USB.

Network Connection

This was a bug I introduced when adding custom LibreSDR support. I do hope it's fixed, if you have a problem please show me the Address field in your Radio definitions.

Slow Startup

It's always good to revisit code with a fresh brain - sometimes design errors jump out and smack you between the eyes. When starting a USB device I was searching in all backends (network, usb, ...) for the device when I knew already that it was a USB device. Now I just look for the device I want to open in the USB devices, this has significantly reduced the startup!

TX Filter Width

Now disabled while transmitting.

TX Offset.

The default TX offset is ignored in wideband (DATV) mode, this was causing stations to be 25kHz off frequency.

Bad Waveform

I'll be working on a problem when running the Pluto/LibreSDR with a bandwidth < 1,000 kHz where the signal appears to have a small crown! Recommended bandwidth is 1,536 kHz or higher.

SDR Television

If you select Transmit > Send a check is made to ensure you have entered your Callsign and Name in the TX: Configuration panel in the program settings (see below). If you haven't then you are prompted to do so.

NVIDIA Broadcast App

I also stumbled across NVIDIA Broadcast App which "transforms any room into a home studio". To use this you'll need a modern RTX GPU from NVIDIA. More information on this page. It's worth trying, has some good audio features.

NVIDIA Broadcast App

NVIDIA Broadcast is a free application designed to enhance the quality of livestreams, video calls, and voice chats by using artificial intelligence (AI) to upgrade standard webcams and microphones into smart, premium devices. It leverages the dedicated Tensor Core AI processors found on NVIDIA GeForce RTX, TITAN RTX, or Quadro RTX GPUs to provide real-time AI-powered effects[1][2][5][8].

Key Features

Noise Removal: Removes unwanted background noise from your microphone feed, such as keyboard clicks, pets, or street noise. This feature can also clean up incoming audio from others[1][5][8].
Virtual Background: Allows you to remove or replace your webcam background with images, gameplay footage, or a blur effect, similar to a green screen, without needing special equipment[1][5][6][8].
Auto Frame: Uses AI to track your face and keep you centered in the camera frame, even as you move around[1][5][6][8].
Video Noise Removal: Reduces visual noise and graininess from your webcam feed, especially helpful in low-light conditions, making the video appear clearer and more professional[5][6].
Room Echo Removal: Filters out echo from your microphone, improving clarity during calls and recordings[6].
Virtual Key Light and Studio Voice (Beta): Additional features in development to further enhance video and audio quality[5].

Compatibility and Use Cases

Works with most popular livestreaming, video conferencing, and voice chat apps, including OBS, Discord, Zoom, and more[1][2][5].
Requires a compatible NVIDIA RTX GPU for full functionality, as the AI effects rely on Tensor Cores[1][5][8].
Can be used for game streaming, professional video calls, online teaching, content creation, or simply improving everyday communication quality[2][3][7].

How It Works

NVIDIA Broadcast processes your audio and video feeds in real-time, applying AI effects to clean up noise, improve image quality, and add professional touches—all without the need for expensive hardware or a dedicated studio setup[1][2][5][8].

In summary, NVIDIA Broadcast is a powerful, AI-driven tool that transforms any room into a home studio, making high-quality streaming and communication accessible to anyone with a compatible NVIDIA RTX GPU[2][5][8].

Citations:

[1] https://www.nvidia.com/en-gb/geforce/news/gfecnt/202009/nvidia-broadcast-app/

[2] https://www.nvidia.com/en-gb/geforce/broadcasting/broadcast-app/

[3] https://www.nvidia.com/en-gb/design-visualization/software/broadcast-app/

[4] https://www.youtube.com/watch?v=gTbb_giw4lc

[5] https://www.nvidia.com/en-gb/geforce/broadcasting/broadcast-app/faq/

[6] https://www.youtube.com/watch?v=_kHFTeL1RVU

[7] https://www.nvidia.com/en-gb/geforce/broadcasting/broadcast-sdk/resources/

[8] https://www.windowscentral.com/what-nvidia-broadcast

---

Description created (because I'm lazy today) by Perplexity: https://www.perplexity.ai/

The Kits

So, finally here are the kits:

SDR Radio:

SDR Television:

Any problems - just shout!

Let's Grok!

simon@sdr-radio.com (Simon Brown) — Wed, 23 Apr 2025 10:06:50 GMT

Great For Images

Use in SDR Software

I wanted a startup image to display in SDR Television. While sites such as Deviantart.com have many, many different images, I decided none we what I wanted. A recent posting on the BATC website used Grok for repeater images, until I saw this post I had never heard of Grok!

Here are the images I have created with Grok, the only limitation is my explaining to Grok what I want to see. I find Grok to be much better than ChatGPT but that's probably the user :) .

What's not to like? It's free. I'll definitely be using Grok in the future.

Background

Grok is a multimodal AI model developed by xAI, designed to handle both text and image generation tasks. The most recent version, Grok 3, is significantly more powerful than its predecessors, capable of understanding and generating high-quality, photorealistic images from text prompts. It can also perform basic image editing, such as adding objects or applying artistic effects, and it incorporates features like step-by-step reasoning and error detection to improve output quality[1][6][3].

Is Grok Good for Image Creation?

Strengths:

Grok 3 produces high-quality, photorealistic images that closely match user prompts, outperforming some competitors like ChatGPT in terms of realism and prompt accuracy[1][2][6].
It can render precise visual details, including real-world entities, text, logos, and realistic human portraits[3][8].
Grok is capable of some photo editing tasks, such as adding objects or applying stylistic effects, making it versatile for both image creation and basic editing[2][5].
The platform is accessible and fast, with a user-friendly interface available on X (formerly Twitter) and a dedicated website[6].

Limitations:

While Grok's image editing features are impressive for casual use, they are not yet a replacement for professional tools like Photoshop. The results can sometimes appear artificial or lack fine detail, especially in complex edits or artistic transformations[5].
Some users note that Grok's image quality, while strong, may not always reach the highest standards set by specialized tools like Midjourney for certain styles or complex compositions[7].
There are occasional anatomical inaccuracies and limitations in generating complex poses or highly detailed illustrations[7].

Conclusion

Grok is a robust and accessible AI tool for image creation, excelling at generating realistic, prompt-specific visuals and basic edits. While not yet a full substitute for professional editing software, it is highly effective for most casual and creative image generation needs, and it stands out for its speed, versatility, and relatively minimal content restrictions[1][2][5][6].

Citations:

[1] https://www.cyberlink.com/blog/photo-editing-tips/3514/grok3-image-generator

[2] https://www.reddit.com/r/ChatGPT/comments/1huf97b/how_and_why_grok_is_much_much_better_than_chatgpt/

[3] https://x.ai/news/grok-image-generation-release

[4] https://www.pocket-lint.com/x-grok-vs-dall-e-image-generator/

[5] https://www.techradar.com/computing/artificial-intelligence/i-tried-groks-new-ai-image-editing-features-theyre-fun-but-wont-replace-photoshop-any-time-soon

[6] https://generativeai.pub/grok-3-ai-image-generator-is-it-any-good-dedea0a7b04a

[7] https://www.youtube.com/watch?v=imIbb2CougY

[8] https://x.ai/blog/grok-image-generation-release

---

Text created by Perplexity: https://www.perplexity.ai/

SDR Television Beta #1

simon@sdr-radio.com (Simon Brown) — Mon, 21 Apr 2025 10:57:08 GMT

Post Date: April 21st, 2025

Updated: April 23rd, 2025 with new download links for SDR Television (scroll down)

Overview

This is the first publicly available kit for a project I've been working on for roughly 18 months. SDR Television is a DVB-S2 / AAC / H264 / H265 program for use on the QO-100 satellite. It uses many DLLs from SDR Console, mainly to control a Pluto / LibreSDR.

Why?

Why not? This is an area of software I had not previously encountered, so a huge learning curve, not only the programming but also building a DATV station for QO-100 (more about that later).

Proof of Concept

This first release, v1.0 is a proof of concept, showing that it's possible to develop a full-duplex DATV solution on a modern x86 computer. If there is enough interest, future kits will extend the features by adding H266 / AV1 / Opus and a better cross-band user interface. For now, the project is focused on QO-100.

Host Requirements

Windows 11 is recommended. Windows 10 is also supported.
64-bit architecture.
Ideally 8 cores or more but has been used at 333ksps with an i5-7200u.
AVX2 (so no Core2Duo support).
Use with emulators such as Prism and Parallels is initially disabled, possibly available later in 2025.

User Guide

If you just want to read the guide (PDF) then click here to download. Reading the user guide is highly recommended!

Support

For now, please use the SDR-Radio.com mailing list . This is a traditional mailing list.

Crash Dumps

If you experience a crash, please save the file and either

upload to the cloud - OneDrive, Dropbox etc., or
use WeTransfer.

Then send a link to mailto:simon@sdr-radio.com .

Pluto & LibreSDR

You must create new definitions as the previous are now not supported.

Kits

All code-signed, there's nothing to worry about.
You must install the SDR Radio kit as it now supports wideband mode which is required for Pluto. Even if you will not be using a Pluto (or similar) this kit must be installed.
After installing the SDR Radio kit, install the SDR Television kit in the same folder.

Downloads

These kits were created on April 21st, 2025. You must install both kits.

SDR Radio v3.4 build 3677 (April 21st, 2025)

SDR Television v1.0 build 727, (April 23rd, 2025)

LibreSDR Revisited

simon@sdr-radio.com (Simon Brown) — Sun, 23 Feb 2025 07:09:37 GMT

16 MHz Bandwidth!

Default Firmware

Here you see a screenshot from SDR Television (work in progress) running the LibreSDR at 16MHz bandwidth.

This is the standard firmware from Evariste, F5OEO who has done a great job.

Compare 16MHz with LibreSDR to 5MHz with the PlutoSDR, a big difference!

Many thanks to Mike, G0MJW for the screenshot.

Overclocking

Other firmware is available which overclocks the LibreSDR, but I've not looked at this. Here are the key points:

This is an unofficial port of PlutoSDR onto LibreSDR a.k.a. ZynqSDR. The repo is based on day0wl's repo with several enhancements:

Optimized linux kernel and buildroot to support higher practical sampling rates with libiio/PlutoSDR API (20 MSPS without overlock, compared to ~10 MSPS stock)
Xilinx Zynq SoC overclock support (27.5 MSPS achieved with overclock to 1100 MHz CPU + 750 MHz DDR)
Use LVDS mode for AD9361 to support max sampling rates in 2T2R mode
Based on PlutoSDR v0.38 firmware (Nov 17, 2023)
Prebuilt firmware with different overclocking options

Support

To support bandwidths higher than 6MHz a new release of SDR Console is required, so keep an eye out for announcements.

PC Audio - Microsoft Bug

simon@sdr-radio.com (Simon Brown) — Thu, 30 Jan 2025 13:44:09 GMT

Microsoft admits bug that kills PC’s audio

As reported on TechRadar , Microsoft has confirmed that Windows 11 has an audio bug (that we reported on yesterday), a glitch which can take out the PC’s sound completely, and it’s now clear that this affects multiple Windows versions.

It's hit my development system, audio now always plays on a monitor's speakers, not my nice Edifier speakers through my external Behringer DAC.

I would like to point out that it's not funny!

LibreSDR

simon@sdr-radio.com (Simon Brown) — Mon, 13 Jan 2025 06:28:44 GMT

On Order

After talking on QO-100 with Mike, G0MJW, I've ordered a LibreSDR from AliExpress where it's known as "SDR AD9363 AD9361 ZYNQ7020 ADI Pluto communication experiment platform". The device is available in the OpenSourceSDRLab Store .

Reasons for the order:

This device is becoming quite popular,
Is compatible with the ADALM Pluto from Analog Devices,
Has an ethernet port,
Offers more bandwidth than the ADALM Pluto, something I've been looking for.

When it arrives and I have it working I'll report back with another blog entry.

Specification

Using XC7Z020-2CLG400I chip 7z020-2I
The AD9363 chip is configured as the AD9361 chip, the frequency range is 70MHz~6GHz, and the maximum sampling rate is 61.44MHz. As a result, the laboratory test shows that it is significantly different from the AD9361
PS 1GB DDR3 32bit bit width, frequency 1066M
32MB QSPI Flash, support TF card
Onboard JTAG circuit and USB to serial port, one line for power supply and debugging
Support USB OTG, can be master or slave, all USB interfaces use TYPE-C interface, OTG mode is automatically recognized, and the USB port is turned on for power supply
Adopt VCXO, support PPS or 10MHz tame Gigabit Ethernet interfaces
Adopt 10-layer PCB wiring, impedance matching, signal integrity design
The product adopts CNC shell to strengthen heat dissipation and ensure strength;

Images Etc.

Images and text in this post from AliExpress . If the links change then just search for "Software defined radio SDR AD9363 AD9361 ZYNQ7020 ADI Pluto communication experiment platform".

All image copyright AliExpress and Open Source SDR Lab. They're not mine.

Happy New Year 2025

simon@sdr-radio.com (Simon Brown) — Wed, 01 Jan 2025 06:10:48 GMT

Sums Up My Life

This is an old meme, very old. Happy New Year everyone, I wonder what I'll be doing in 2025?

In September I'll have been licenced as G4ELI for 50 years.

Warm Paws for Coders

simon@sdr-radio.com (Simon Brown) — Sat, 28 Dec 2024 07:16:00 GMT

Heated Mouse Mat

If, like me you have cold hands then a heated mouse mat is essential. Before I bought this I had two options - either wear thin arthritis gloves or heat the room to a silly temperature.

Anyway, this popped up on Facebook with an Amazon link, so I bought one. This now makes coding even more of a pleasure as not only are my hands warm, the heat also rises onto my face and head so it's bye-bye cold.

It's not a substitute for a two week holiday in the Caribbean, but possibly the next best thing.

Here's a Amazon Link , if it fails, just search for Heated Mouse Mat .

Why didn't I think of this a few years ago?

Pluto Firmware v3.9

simon@sdr-radio.com (Simon Brown) — Thu, 26 Dec 2024 16:47:12 GMT

Big Improvement!

I recently upgraded the firmware on the Pluto I use for QO-100. Previously I was using v3.5, now v3.9 (the latest). An immediate improvement with DATV on the wideband transponder was seen - the MER (modulation error ratio) improved by up to 0.5 db due to better internal FIR filter design.

Although 0.5dB may not seem like much, with DVB-S2 it really is! Better MER results in fewer errors, so less FEC computation required. Forward error correction is the main consumer of CPU in this program.

There's not always an upside - there were issues starting the Pluto due to errno (a pre-processor macro used for error indication) not being set to 0.

New beta Kit

A new beta kit will be available before the end of December 2024.

RSGB - 50 Years Membership

simon@sdr-radio.com (Simon Brown) — Sun, 22 Dec 2024 14:02:42 GMT

50 Years A Member

It came as a surprise to receive the letter below confirming I've been a member for 50 years! Seems like only yesterday.

Membership of the RSGB is important - not only a great monthly magazine (Radcom) but also spectrum defence.

Here's to the next 50 years.

SignalSDR Pro Update #1

simon@sdr-radio.com (Simon Brown) — Thu, 19 Dec 2024 16:38:54 GMT

Sad news

Further to my previous post , this potentially excellent device can't be shipped to the UK, only Canada and the USA which is a tad odd as it's a Hong Kong project.

Price is $899. For purchasing, just go to this page on Crowd Supply .

Update December 20th 2024

From the developer: "Not my call. It's Crowd Supply cutting my CE. I am doing the CE. It will he a week".

Update December 21st 2024

xwings, Today at 00:42

SignalSDR Pro is now available for sale in the EU. !

SignalSDR Pro

simon@sdr-radio.com (Simon Brown) — Thu, 19 Dec 2024 12:52:33 GMT

An Up-Market Pluto?

This looks like it could be a decent solution for QO-100, offering more bandwidth than the standard ADALM-Pluto.

I think the maximum bandwidth quoted as being 85kHz is wrong, surely it'll be 85MHz?

Project home page is here .

Pluto Temperature, SDRConnect Files (Updated December 19th, 2024)

simon@sdr-radio.com (Simon Brown) — Thu, 19 Dec 2024 09:46:24 GMT

Pluto Temperatures

October 7th, 2024

Manfred (DC2MH) contacted me recently with a question about the Pluto FPGA temperature display.

Using scripts from Analog Devices the display is 20°C higher, so there's possibly an error in SDR Console. It only took a few minutes to find the problem - during early Pluto support I had added a fixed 20°C to reduce the displayed FPGA temperature to a value similar to the tuner.

Future kits will now show a correct value for the Pluto FPGA temperature as per the screenshot.

Update, October 14th 2024

Siegfried Jackstien ( DG9BFC ) reports that when starting Pluto the FPGA temperature is shown as 20°C higher than the tuner, even with a massive heatsink connected. This is obviously incorrect as on switch-on the temperature of both chips should be roughly room temperature.

As a result the fixed 20°C reduction has been restored.

Update, December 19th 2024

See this github post . "First of all the temperature readings are die temperatures. Even if you have a high thermal conductivity cooling solutions, the temperatures will never be the same."

So this explains the difference - the fact that these are die temperatures.

PDF with Github post .

SDRConnect IQ Files

October 7th, 2024: Currently adding support for the new SDRConnect IQ file format which is RF64 but implementing header fields and file chunks in a manner which is totally legal but confused SDR Connect.

The WAVE RF64 specification is here .

As an aside, an easy way to check that a WAV file is structurally correct is to simply display the properties as per the screenshot. If you see a value for both Length and Bit rate then it's OK.

Many thanks to Bjarne Mjelde in Arctic Norway for his help.

DATV Update

simon@sdr-radio.com (Simon Brown) — Tue, 17 Dec 2024 07:25:05 GMT

DATV Update, December 17th 2024

So, here's an update on my DATV project . This is a pure software solution for DATV (DVB-S2) which can be used with Pluto, Lime (later) and other SDRs. No extra hardware such as the BATC MiniTiouner is needed.

Summary

Good progress is being made:

CPU load is low, see Task Manager screenshot below, CPU is i5-13600F at only 2.7%. Low CPU is important for this type of application it shows good design and implementation
Can view QO-100 transmissions:
BATC Thursday evening net hosted by Martin, G4FKK
Sunday afternoon WWW net hosted by Gary ZS6YI
Transmit code is all in place, tested via a loopback option where the transmit IQ data is fed back into the receive chain.
Currently only Normal frames (64,800 bits) are supported. Short frames (16,200 bits) will be supported.
All FEC rates work, the BCH code is been highly optimised.

Next step is some live transmissions before the end of December 2024!

And here's a video!

NSA Using Github Code

simon@sdr-radio.com (Simon Brown) — Wed, 20 Nov 2024 16:39:53 GMT

Netflix Intelligence

If you watch the Netflix series Intelligence, Season 1 Episode 4 you see some code on the screen when there's 13 minutes and 24 seconds remaining of the episode.. Looks like the NSA have swiped this code from Bhavesh Jaswani who is from Udaipur, Rajasthan. Or maybe he hacked into the NSA and 'copied' the code? Anyway, it's not super-efficient.

The original code is below.

#include <iostream>

using namespace std;

typedef struct complex

{

float real;

float imag;

} complexNumber;

complexNumber addComplexNumbers(complex, complex);

int main()

{

complexNumber n1, n2, temporaryNumber;

char signOfImag;

cout << "For 1st complex number," << endl;

cout << "Enter real and imaginary parts respectively:" << endl;

cin >> n1.real >> n1.imag;

cout << endl << "For 2nd complex number," << endl;

cout << "Enter real and imaginary parts respectively:" << endl;

cin >> n2.real >> n2.imag;

signOfImag = (temporaryNumber.imag > 0) ? '+' : '-';

temporaryNumber.imag = (temporaryNumber.imag > 0) ? temporaryNumber.imag : -temporaryNumber.imag;

temporaryNumber = addComplexNumbers(n1, n2);

cout << "Sum = " << temporaryNumber.real << temporaryNumber.imag << "i";

return 0;

}

complexNumber addComplexNumbers(complex n1,complex n2)

{

complex temp;

temp.real = n1.real+n2.real;

temp.imag = n1.imag+n2.imag;

return(temp);

}

Wideband Auto-Mute

simon@sdr-radio.com (Simon Brown) — Sun, 13 Oct 2024 12:39:18 GMT

Using a local transmitter?

If you use a local transmitter which overloads your SDR then consider the Wideband Auto-Mute.

This mutes the SDR IQ input as soon as anpower threshold is exceeded, so there will not be unpleasant sounds from the speakers - or worse headphones!

From the Ribbon bar, Home, Wideband DSP select Auto-mute.

The Auto-Mute option mutes the audio and blanks the waterfall when a very strong signal is detected, usually a transmitter very close to the receiver. Auto-mute is a simple approach to handling strong signal overload situations.

Note: normally you use the External Radio support when transmitting with an external 'standard' transceiver (eg FTDX-5000) and receiving with a SDR receiver (eg NetSDR). This logic can be used in conjunction with the External Radio support as the software will usually not immediately detect when the external radio starts transmitting.

The Auto-Mute logic runs directly after data is read from the SDR receiver and before the waterfall (FFT) processing, so the data is still in the time domain (FFT processing converts to the frequency domain). The Current values will not correspond directly with the values in the waterfall.

Data buffer read from radio, usually in intervals of 5 milliseconds
Current peak and/or mean level for the buffer compared to the maximum possible level (usually use the mean level)
If the peak and/or mean exceeds the configurable threshold the mute / restore logic is applied
During the mute phase the radio data is set to zero, no audio is heard, the waterfall level is zero
During the restore phase the signal level restored to the normal level (similar to an AGC)

Suggested settings when using an external radio in VOX are:

Peak: disabled
Mean: enabled, -30dB to -50dB threshold
Mute: 100ms
Restore: 50ms

The Current values can be used as a guide, the value you select should be greater than the current when a strong signal is not present.

If using this option in conjunction with External Radio support, the mute and restore levels can be reduced, use trial-and-error.

SSL Security

simon@sdr-radio.com (Simon Brown) — Sun, 13 Oct 2024 09:27:35 GMT

Forums SSL Certificate

Let’s dive into the SSL certificate in a way that’s easy to understand.

An SSL certificate, which stands for Secure Sockets Layer , is essentially a digital padlock. It creates a secure connection between a web server and a browser, ensuring that any data exchanged between the two remains private and secure. For a website like SDR-Radio.com Ltd., where you aim to provide software for both professional and amateur radio enthusiasts, having an SSL certificate is super important.

When users visit your site, the SSL certificate helps ensure that their information—whether it’s a payment or personal details—is encrypted and safeguarded from prying eyes. You know that feeling of peace of mind when you see that little padlock icon in the browser? That’s thanks to the SSL certificate!

Moreover, search engines like Google tend to favor websites with SSL certificates, which can help improve your site’s visibility in search results. So not only does it build trust with your visitors, but it can also give your site a nice little SEO boost!

In short, an SSL certificate is all about creating a secure, trustworthy environment for your users, allowing them to engage with your software confidently. Think of it as an essential tool for protecting your community of radio enthusiasts!

This blog post is really for my own records, so here I go.

The forums (forum.sdr-radio.com) run under XAMPP which uses Apache. The forums has its own SSL certificate purchased from CheapSSLSecurity . This must be renewed every year before October 8th.

Login to https://cheapsslsecurity.com/ .
From the Dashboard select Orders, then Complete Orders.
Click under view.
Use saved key.
Follow instructions.
Update DNS CNAME & TXT records.

After a few hours an email is received from digicert.com with a download link to the new certificate. The files in this links are:

DigiCer tCA.crt
forum_sdr-radio_com.crt
Truste dRoot.crt

On the forums host (a small N95 NUC) edit C:\xampp\apache\conf\extra\httpd-ssl.conf with new certificates, then restart Apache.

Planetary A-Index 116

simon@sdr-radio.com (Simon Brown) — Sat, 12 Oct 2024 05:30:40 GMT

Never seen this!

There has been massive Aurora over the last few days, now the A index is 116. I've never experienced anything like this before, Northern Lights seen down in the Scilly Isles.

From services.swpc.noaa.gov/text/wwv.txt

:Product: Geophysical Alert Message wwv.txt

:Issued: 2024 Oct 12 0305 UTC

# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center

# Geophysical Alert Message

Solar-terrestrial indices for 11 October follow.

Solar flux 214 and estimated planetary A-index 116.

The estimated planetary K-index at 0300 UTC on 12 October was 3.67.

Space weather for the past 24 hours has been severe.

Geomagnetic storms reaching the G4 level occurred.

Solar radiation storms reaching the S1 level occurred.

Radio blackouts reaching the R1 level occurred.

Space weather for the next 24 hours is predicted to be minor.

Geomagnetic storms reaching the G1 level are likely.

Radio blackouts reaching the R1 level are likely.

As expected, no 80m DX today.

SDRPlay RSPdx-R2

simon@sdr-radio.com (Simon Brown) — Tue, 08 Oct 2024 05:44:03 GMT

Now Supported!

May 26th, 2024: The latest and greatest from SDRPlay is fully supported in SDR Console. Really didn't require much programming - just grab the latest API files, a few additions here and there and that was all.

For your further viewing, here are some seals from the Lizard Peninsular of Cornwall.

Data Recording

simon@sdr-radio.com (Simon Brown) — Mon, 07 Oct 2024 14:09:26 GMT

Close The Radio

August 8th, 2024: This is a simple update which releases the radio when the recording finishes.

After starting a recording, select Power, a new option Close the radio is shown.

This is most useful when using a radio on a remote server as it frees the radio for other users.

Scheduler Overload

simon@sdr-radio.com (Simon Brown) — Mon, 07 Oct 2024 13:53:21 GMT

Too Many Entries

July 15th, 2024: Recently I was looking at issues with very large Scheduled Recording databases (thousands of entries), as scheduled runs were being missed.

As part of this work, I reduced the amount of information written to the logfile, this could have been:

Clogging up the main thread processing, also increasing the memory footprint.
Delaying the start of a recording.

I'm glad to say this solved the problem.

SDR Television, Sept. 19th 2024

simon@sdr-radio.com (Simon Brown) — Thu, 19 Sep 2024 17:58:27 GMT

QO-100 Beacon

SDR Television is a pure software solution for DVB-S2 H.264 / H.265 / AAC digital television. No hardware such as the MiniTiouner is required, just a SDR such as Pluto or Lime if transmit support is required, otherwise even a RTL SDR suffices.

Here's a recording showing SDR Television playing content from the geostationary QO-100 beacon. This software is still being developed, tentative preview date before February 2025, official preview April 2025.

CPU load is low - typically 2% or less of an i5-13600F
MER is around 10 dB
Diagnostic display show key decoding status values

Much more to come over the next weeks and months including transmit support.

Persistence Spectrum

simon@sdr-radio.com (Simon Brown) — Fri, 22 Dec 2023 12:51:38 GMT

Finally - it's here!

Dec 22nd, 2023: For a long time I've wanted to add a Persistence Spectrum, now I've had the time to do this and see how it enhances SDR Console. This is a powerful tool that allows radio enthusiasts to fine-tune their reception and transmission. With the Persistence Spectrum, users can explore a wide range of frequencies and persistently pursue the perfect signal

So, what is a persistence spectrum? From mathworks.com: The persistence spectrum is a time-frequency view that shows the percentage of the time that a given frequency is present in a signal. The persistence spectrum is a histogram in power-frequency space. The longer a particular frequency persists in a signal as the signal evolves, the higher its time percentage and thus the brighter or "hotter" its color in the display. Use the persistence spectrum to identify signals hidden in other signals.

And there's more good news - the persistence spectrum does not consume significant resources.

For more information:

Mathworks.com a simple explanation of a persistence spectrum, how to generate.
Signalhound implementation is an industry-leading solution.
ROHDE & SCHWARZ FSVR real-time spectrum analyser
Description
Flyer

In Action

Below is a video with an Airspy R2 running on Band II (stereo FM). The video starts with persistence off, then persistence is enabled and you see the spectrum building up.

Resources & Performance

simon@sdr-radio.com (Simon Brown) — Tue, 09 Nov 2021 11:17:50 GMT

Resource Leaks

During the testing phase of version 3.1 two major resource leaks have been found and resolved. Resource leaks cause one or more of:

Steading increasing memory (Commit size),
User interface slowing, and
Program freezing.

XML

The XML library used was Microsoft's MSXML version 6.0. SDR Console was leaking memory and handles each time the library loaded or saved a definition. As XML is used a lot in SDR Console MSXML has been replaced with pugixml .

GDI Objects

A coding error from the early days of SDR Console version 2 has been found and resolved. GDI Objects were being frequency created but never released.

Monitoring

Use the Task Manager to monitor process size, handles and GDI objects. To select the columns shown in the display just right-click on the title bar (Name, PID, Status...), then click on Select Columns .

As you interact with SDR Console the Handle and GDI object count will increase but should now stay within this range:

Handles - maximum of 2,000
GDI object - maximum of 2,000 (in practice closer to 1,200).

Multi-Band Display

simon@sdr-radio.com (Simon Brown) — Mon, 08 Nov 2021 17:00:49 GMT

In Action

The multi-band display has been a long time coming but now it's here. As you see from the video, you can tune in any band just as you would in the main window.

Selecting

To open select Multi-Band from the Ribbon Bar, Receive, View pane. The display opens with the default definition selected.

Definitions

To edit definitions click the Organiser button, this is the first button in the ribbon bar. Click Add to create a new definition or Edit to update an existing definition. The Bands Organiser is displayed.

Bands Organiser

Design the layout using the matrix. Add as many bands as you want, band frequency ranges can even overlap. The used space is scaled to the monitor, so unused rows at the top and bottom as well as rows on the left and right are ignored.

Band Selection

If you select a band from the ribbon bar's bands panel the band frequency range is transferred to the main display in SDR Console.

Contrast

Either use the same contrast setting in each band window as the main SDR Console display or compute an optimum contrast for each band widow. Make this selection with the options in the ribbon bar's Contrast panel.

Version 3.1 Betas

simon@sdr-radio.com (Simon Brown) — Sat, 21 Aug 2021 19:15:41 GMT

Starting today August 21st, 2021 Betas of version 3.1 are available for download.

Here's the link .

Simon's World Map v1.1

simon@sdr-radio.com (Simon Brown) — Thu, 29 Jul 2021 05:40:21 GMT

Introduction

I need a simple display which shows me at the very least:

Current Time
Sunrise / Sunset
Greyline map
DX stations

There are commercial geo clock solutions such as Geochron , but as a programmer with spare 4k monitors and computers I decided to write my own, that way I have exactly what I want.

Updates

Kit updated July 29th, 2021 to fix CPU usage problems.

What's New

A few days spent on this program in July 2021:

Added the Explorer map - thanks to Nasa,
Map can be dragged and zoomed with the mouse,
Reworked the ribbon bar.

So it's time to call it v1.1.

The downloads will be hosted from sdr-radio.com later this year, for now you download from the author's own website.

Download this program here .

3.1 Release

simon@sdr-radio.com (Simon Brown) — Mon, 26 Jul 2021 20:51:28 GMT

Release Date

Version 3.1 is the cumulation of 6 1/2 years of programming, SDR Console can now be considered a mature program. This kit will be released on August 2nd, 2021.

The main updates are much improved performance (reduced CPU and GPU load) and the addition of a voice keyer. For a full list of fixes and changes look at the release notes . Download this release here .

After the release some weeks will be spent updating the website.

Performance

As a result of a complaint that SDR Console was slowing down after many hours of use, I looked at the user interface (Direct2D) and noticed that every time a window (render target) is updated all the resources owned by the window are validated, even if it's not necessary.

As a result I've been working on reducing the number of Direct2D resources created in each window which has had a very big effect on CPU when refreshing / updating a window. This is very important in the Spectrum and Waterfall windows which are regularly refreshed.

As a result this kit runs very well on a 32-bit W7 laptop which uses a Core2DUO 2GHz T5870 CPU from 2008. In fact, it runs so well that I've completely removed the automatic low power settings, these are now an option in the Ribbon bar, Tools, Settings panel.

The screenshot below shows an Airspy HF+ running on an i5-7260U laptop (2 cores, 4 threads), CPU load is an amazing 0.6%.

Conclusion

If the program uses any fewer resources it'll start running backward (joke).

Voice Keyer

Finally added a voice keyer, located in the Transmit panel.

Click the ••• button to configure the voice keyer. The configuration options support recording, selection of recordings and other options.

Format

Recordings are saved as WAV files, the default format is 48kHz single channel (mono) 16-bit samples. These files can be edited with most popular audio editing software, just make sure the sample rate is 48kHz and the sample size 16 bits (signed short integers).

Record

Here you create a recording. The input is the current microphone selection in the transmit panel. Save the recording as a 48kHz, mono wave (WAV) file.

Select

Select the WAV file(s) assigned to the [1], [2], [3] buttons in the voice keyer window.

Options

A roger beep recording followed by a silence tail.

Dragonfly RX-666

simon@sdr-radio.com (Simon Brown) — Thu, 27 Aug 2020 13:40:35 GMT

Working in SDR Console

I've just got the RX-666 working in SDR Console. Still a lot to do though.

Here it's running with an amazing 32MHz bandwidth, when the video recorder is not started the CPU load on a i5-8600k is roughly 10% with the heavy FFT work performed on a NVIDIA (CUDA) GTX 1650 Super.

Gigabyte BRIX PC

simon@sdr-radio.com (Simon Brown) — Thu, 13 Aug 2020 21:15:01 GMT

Teeny-Tiny PC from Gigabyte

I received an offer from https://mini-itx.com , and as a developer can never have enough computers I bought this and added 8 GB RAM. I put Windows 10 professional on.

The Spec

Gigabyte Brix GB-BLCE-4000C fully assembled PC. The Gigabyte Brix GB-BLCE-4000C features a dual core Celeron CPU, ram up to 8GB Ram. It is a total fanless PC.

Base specification (this is configurable using options)

Intel Celeron N4000 2.6GHz
4GB Ram DDR4
500Gb Hard Disk
Gigabit lan (Realtek RTL8111HS)
Includes Wireless- Intel® Dual Band Wireless-AC 3168 & Bluetooth
Intel UHD Graphics 600 onboard, dual display capable with HDMI and VGA outputs.
Front 1 x Power Button, 1 x USB3.0, 1 x USB3.0 type-C
1 x Headphone Jack, 1 x Microphoce Jack
Rear 1 x HDMI(1.4b), 2 x USB 3.0, 1 x RJ45, 1 x VGA
Side 1 x Kensington lock slot
Dimension 56.22 mm x 103 mm x 116.52 mm (2.21″ x 4.06″ x 4.59″)
Vesa mountable bracket included Supports 75 x 75 and 100 x 100 mm
1 year parts and labour warranty

System:

Don't forget - this is a two core N4000 Celeron chip!

Verdict:

Hardware build quality is excellent.
Looks very good.
I received a 240 GB SSD instead of 120 GB as Gigabyte had run out of 120 GB!
Plenty of CPU power considering only two cores.
Runs a NetSDR at 1 MHz bandwidth acceptably, also fine at 2 MHz bandwidth.
Graphics on a HD monitor is usable but not fantastic.
Would struggle to run another resource-intensive program such as WSJT.
Would be fine as a server for one or two SDRs.

Future Use

This will be used for running the g4eli.sdr-radio.com DX Cluster sometime in 2020.

Hermes-Lite 2 Available

simon@sdr-radio.com (Simon Brown) — Wed, 06 May 2020 04:58:06 GMT

Good News!

I've just received an e-mail from Steve Haynal KF70:

Since you've expressed past interest, this e-mail is to let you know that you can now order an assembled Hermes-Lite 2.0, filter board and enclosure from Makerfabs . Please see this wiki page for details. Also, please see www.hermeslite.com for a full collection of HL2-related links.

Makerfabs

The Makerfabs links are:

If you want a great little transceiver with SDR Console support which costs less than $300 then you should seriously consider this offer!

SDR Console

The Hermes-Lite 2 support page is here .

What You Need

Steve kf7o added this information (May 8th 2020): I've received several inquiries about what exactly is need to finish or use the HL2 if purchased from Makerfabs. Here is a general reply: If you buy the HL2, N2ADR filter board, and enclosure form Makerfabs, you will need to provide the following:

Drill.
M3 nut and bolt.
Thermal grease, commonly used with computer CPU heatsinks.
File or thin metal ruler wrapped with sandpaper. This is to provide the PA heat dissipation as described here: https://github.com/softerhardware/Hermes-Lite2/wiki/Enclosure-and-PA-Heatsink#pa-thermal-dissipation .
Screwdriver. This is to attach the end plates. Depending on exactly what Makerfabs sends, you may need or choose to use slightly different M3 (I think) screws to affix the end plates.
3A 11-16V power supply with barrel power connector. See https://github.com/softerhardware/Hermes-Lite2/wiki/Power-Supply .
Computer capable of running SDR software. The HL2 is not a standalone radio. You need to be able to install and use SDR software as described at https://github.com/softerhardware/Hermes-Lite2/wiki/Software .
Tuned HF antenna system with SMA connector

RSGB Louis Varney Cup

Sat, 25 Apr 2020 11:38:07 GMT

And the winner is...

April 25th, 2020

The RSGB Board and Spectrum Forum have agreed that you (Simon, G4ELI) should receive the Louis Varney Cup. This award is made to recognise advances in Space Communication, for developing SDR console, enabling amateurs around the world to explore the possibilities offered by the QO-100 geostationary satellite in particular, and SDR in general.

Steve Thomas, M1ACB

RSGB General Manager

So a very big thank-you to everyone who has helped with SDR Console - bug reports, suggestions for improvement and of course just using this software.

Link to official announcement: https://rsgb.org/main/about-us/agm-2020/2019-trophies-and-awards/

Simon, G4ELI

88-109MHz Tropo - Video & Data

simon@sdr-radio.com (Simon Brown) — Wed, 25 Mar 2020 20:26:58 GMT

Great conditions, here's a video and the data

Here's a two minute video from the opening of March 25th, 2020. Recorded with an ELAD S3, 8 element Yagi.

And here's the IQ data which you can replay in SDR Console - approx. 12GB [ link ].

4 x Channel Isles in Stereo

Wed, 25 Mar 2020 20:07:44 GMT

Great conditions on FM stereo 88-108 MHz

Great tropo today March 25th, 2020. Picked up all four main stations on the Channel isles. Although not too far away from Mawnan Smith, these are lower power transmitters which were received in fully quieting glorious stereo.

Received with the ELAD S3, 8 element Yagi from Innov Antennas.

80m Splatter Contest

simon@sdr-radio.com (Simon Brown) — Wed, 18 Mar 2020 17:22:08 GMT

OT4A Unhappy with YL2GB

Listening to 80m DX this evening and I heard Theo OT4A get annoyed for YL2GB. Just watch the video.

Video created with SDR Console's internal video recorder.

March 2020 Status Update

simon@sdr-radio.com (Simon Brown) — Mon, 09 Mar 2020 17:40:29 GMT

What's happening

Version 3.0.22

I'm working on the LimeRFE support for version 3.022 which I hope to release by March 16th 2020.

Version 3.1 LTS

Version 3.1 with be LTS (long term support), I am targeting this for April 13th, 2020.

Remote Server Status - Fixed!

simon@sdr-radio.com (Simon Brown) — Sat, 07 Mar 2020 16:39:58 GMT

Old code, new bug

The code which manages the status of the V3 remote servers started to blow up - this was due to more servers becoming available which in turn exposed a bug which in turn exposed another which in turn caused misery for the poor programmer.

Anyway, the code is now running very stably on a small Intel i5-NUC. The status is here [ link ].

More information about remote servers here [ link ].

W7 - Satellite Tracking crash is Fixed

Sat, 07 Mar 2020 16:09:38 GMT

Good news if you're using Windows 7

Finally a long-standing bug with some Windows 7 systems has been fixed. The code would crash when loading a background image of the world, but not on all W7 systems.

A description of the problem and the solution is here [ link ] - breaking change a while ago from Microsoft.

Anyway, it's now time to rejoise if you were affected - your satellite tracking is fixed with version 3.0.22 which will be released 'soon'.

SDR Console - The Movie

Thu, 23 Jan 2020 07:43:59 GMT

Video Recorder added to 3.0.20

For a long time I wanted to add a built-in video recorder to SDR Console, finally it's happened.

H.264,
AAC and MP3 Audio,
Optionally record from your microphone if a SDR with transmit support is started.

With a single click in the ribbon bar you're creating a video in your Windows account's videos folder. It really is that simple.

Available in 3.0.20 for Windows 8 and higher.

The Video

In the ribbon bar the Video, Start button was pressed.
Recording status shown in the status bar.

Vertical Docking

simon@sdr-radio.com (Simon Brown) — Mon, 20 Jan 2020 18:55:09 GMT

Vertical Docking of RX Pane

Did you know that the receiver pane docks intelligently when the height is greater than width (i.e. docked vertically) as shown below. In this screenshot the Pluto SDR is being used with the QO-100 satellite.

To display the receiver pane:

Ribbon bar
Receive
View
Receiver Pane

Running on a nice 4k monitor.

Users Of SDR-Radio.com

simon@sdr-radio.com (Simon Brown) — Sun, 19 Jan 2020 07:54:07 GMT

General Share of Operating Systems

In the area of desktop and laptop computers, Microsoft Windows is generally above 70% in most markets and at 77% globally, Apple's macOS at around 13%, Google's ChromeOS at about 6% (in the US) and Linux at around 2%. All these figures vary somewhat in different markets, and depending on how they are gathered. From Wikipedia .

I personally dislike Apple and will never develop for macOS. Linux is OK but I’ve been there before and prefer Windows. As a developer on Windows the tools from Microsoft are superb,

Operating System use in Gaming

There’s a reason Windows / Xbox is dominant in gaming, just look at this chart: Share of Steam (gaming platform) users in October 2019, by operating system used .

DirectX is an amazing tour de force, something I want to master over the next three years.

Users by Browser and OS

This is a duda.co website running on Amazon Web Services (AWS). The site gathers visitor information, below is a breakdown by browser and operating system. Note: all website know the browser you use and your IP address.

Of interest is the ratio of Windows to Linux users, 16.75 : 1. Similarly the ratio of Windows to MacOS users is 13.5 : 1.

So there's absolutely no chance of a rewrite of this project for either Linux or or MacOS.

Sorry Folks...

80m Splatter

simon@sdr-radio.com (Simon Brown) — Sat, 18 Jan 2020 07:24:11 GMT

Rather noisy on 80m

Listening to the 80m SSB DX window - stations complaining about each other splattering.

At least there's the civilised world of CW.

New Features

simon@sdr-radio.com (Simon Brown) — Sat, 18 Jan 2020 07:04:55 GMT

Your change to request a feature

The clock is ticking! Once version 3.1 is released it'll be time to consider user requests.

The request list is here . To request a feature in a future version of this software you must post in the User Group :

Add the tag #Future in the subject
Add a brief description in the subject

Example:

Subject: #Future Add 3D waterfall

There's no guarantee that your requested feature will be added, but if it's on the list then at least it's being considered.

Pluto on QO-100

simon@sdr-radio.com (Simon Brown) — Fri, 17 Jan 2020 07:28:06 GMT

Works Well!

One of my Pluto units has been modified to use an external 40 MHz reference input, I use a unit from Leo Bodnar so it's nice and stable.

The pluto drives a CN 0417 pre-amplifier which in turn is driving a SG Labs 20W amplifier , output ~ 5W.

Website Complaints!

simon@sdr-radio.com (Simon Brown) — Sat, 11 Jan 2020 09:23:27 GMT

Font Size and Colour

So, the new website was launched two days ago and some viewers with ageing eyes complained about the text font - just not enough contrast. I find that I use the Chrome and Edge browsers with a default 125% zoom as I'm no spring chicken!

Also, I'm just a simple programmer with absolutely no graphic design skills at all but I do know how to use Google and found ux movement's website which has a very interesting article " Why You Should Never Use Pure Black for Text or Backgrounds ". This article covers:

Pure Black Text & Backgrounds
High Contrast for Accessibility
Balanced Contrast for Readability

It's well worth reading.

As a result the default font is now bigger and the colour darker.

New Website

simon@sdr-radio.com (Simon Brown) — Tue, 07 Jan 2020 17:55:26 GMT

Using duda.co

Two weeks ago I made the decision to leave the DotNetNuke (DNN) platform because:

It's open source which is a risk as any security flaws are open to nasty hackers,
It's not getting the 'love' it deserves,
During 2019 DNN Summit, CEO of DNN Software, Andy Tryba publicly admitted to using Squarespace over DNN for former's ease of use and overall user experience. So if the CEO of DNN doesn't use DNN then it's time to jump ship.

In a mailing list I saw glowing reports of duda.co from companies which had moved sites from DNN to duda so I started a duda trial and never looked back.

Fast, very fast.
Excellent support.
Runs on Amazon Web Services (AWS).
A company moving forward.

So here's the same content built with the duda.co website builder.

Airspy HF+ Discovery

simon@sdr-radio.com (Simon Brown) — Mon, 06 Jan 2020 14:14:58 GMT

WRTH Awards 2020 : Best Value SDR

"We assessed the Airspy HF+ in last years’ WRTH and were very impressed by it. The reason for a further review this year was occasioned by the introduction of the HF+ ‘Discovery’ which on paper represents a further advance on what was a very good low-cost-SDR."

Read the rest of this review here .

Bandplan Wallpaper

Sun, 05 Jan 2020 18:22:03 GMT

Excellent!

I came across great wallpaper from Mindaugas Macijauskas on Facebook, the link is here .

DRM in SDR Console

simon@sdr-radio.com (Simon Brown) — Sun, 05 Jan 2020 06:09:37 GMT

Why I haven't added DRM to SDR Console

I'm often asked to incorporate a Digital Radio Mondiale (DRM) receiver into SDR Console. The reasons why I haven't done this are:

Patent / royalty issues with the audio codec, and
The Dream project works well.

Brendan Wahl, WA7HL, co-Moderator, of the DRM North America Newsgroup explained the legal minefield recently. The text below is reproduced with his permission.

Hi all, got some background here for you. I've been following DRM since the beginning, and still admire it for its broadcast quality and capabilities.

The DRM system was originally written by the Frauenhofer Institute in Germany, with the first software for personal use requiring a license key that cost the individual listener somewhere around ~€49/$49. I've got one somewhere, but I haven't had to use it since the freeware "DReaM" came out. No key needed when using that software package, which is still available on Github IIRC. The original commercial software still works, but it's very simple and doesn't provide a lot of bells and whistles. I'm not sure it's available anymore.

What happened was that the AAC codec (and it's variants, esp. XE-AAC...) was developed some years after the receiving software was first published with older codecs already available freely. The Frauenhofer Institute in the meantime had sold its work and code already done on that codec to Dolby Inc., who didn't want to give anything away. Hobbyists went from being able to receive all codec forms of broadcast DRM with little to no cost, to technically having to remove the FAAD.DLL file and receiving nothing, period. Since all DRM broadcasters switched to the XE-AAC codec due to it's efficiencies, hobbyists got left out in the cold with that shift. That .DLL file has been known to circulate privately, since even Dolby admitted that trying to get people to delete a file that they already had was like screaming in the wind.

Currently, as I understand it and as Simon indicates, radio manufacturers and developers must pay a license fee upfront to use the now-Dolby owned codecs. The listeners no longer have to pay, but the commercial party 'pays' on their behalf. This would include Simon of course, since he is both a commercial and hobbyist software developer, working as one entity.

Simply put, DRM is a minefield for someone like Simon. It's not only a bit of a coding time-suck, the potential legal exposure is horrible. It is a big enough issue that most radio manufacturers are simply avoiding the whole issue by not making DRM capable receivers. A Chinese manufacturer, Gospell, and a couple of Indian companies have stuck their financial necks out for DRM, since it is being introduced in both countries, but actual production of quality consumer equipment has been difficult, to say the least.

I should note that SDRC works wonderfully with the DReaM software being fed via a virtual cable. Was listening to Radio New Zealand International just the other night while they were doing some DRM testing, had perfect reception using my HF+. Can't wait for my Discovery to get here!

I'll back Simon on his choice of not including DRM. I use SDRC more than any other radio software, and I appreciate all of his his hard, SOLO, work on it. No wonder he needs our beer money...and of course, the canine is always hungry. I know, I have one too.

73,

Brendan WA7HL

Co-Moderator, DRM North America Newsgroup

So there you have it. Thanks Brendan. If you want to listen to DRM use Dream and a virtual audio cable.

Windows Upgrade

simon@sdr-radio.com (Simon Brown) — Sun, 05 Jan 2020 06:05:55 GMT

Free upgrade from Windows 7 to Windows 10 is still available!

Yesterday I powered on a small ATOM 330 server which was last started five years ago. Well, up came Windows 7 Professional and of course the normal zillions of updates appeared. Anyway, I wondered whether the now officially expired free update from Windows 7 to Windows 10 was still available. Google brought me to this link on www.zdnet.com .

In https://www.zdnet.com/article/heres-how-you-can-still-get-a-free-windows-10-upgrade/ the suggestion is to go to the Download Windows 10 webpage which I did. then I clicked the Download too now button. Thereafter I just followed my nose and two hours later my little server was proudly running a licenced version of Windows 10.

So the free upgrade from Windows 7 to Windows 10 is till available!

Toodles

Pluto on Es'Hail 2

simon@sdr-radio.com (Simon Brown) — Sun, 05 Jan 2020 05:57:24 GMT

Shows suggested settings for Pluto

Here's a screenshot of my Pluto SDR on Es'Hail 2, this screenshot shows the suggested settings for Pluto (bottom left-hand side).

Note the RX Gain is set to Slow Attack (Manual value is ignored) and the Visual is set to -40dB.

Google Turbo

simon@sdr-radio.com (Simon Brown) — Sat, 04 Jan 2020 21:51:51 GMT

Turbo, An Improved Rainbow Colormap for Visualization

On Tuesday, August 20, 2019 Google posted an interesting colour scheme which they named 'Turbo'. Read more about this in the blog entry (link is above). Below is the colour map in action on the 25m shortwave broadcast band. As of 3.0.13 this is a standard colourmap[ in SDR Console.

Also of interest is the use of a SNR (Signam to Noise) S Meter option.

Transparent S Meter

simon@sdr-radio.com (Simon Brown) — Sat, 04 Jan 2020 21:38:05 GMT

Analog S meter transparency

Version 3.0.13 introduced analog S meters and resulted in requests for transparency. One of the big features of SDR Console is the use of Direct2D graphics which is a lot more complicated than the GDI/GDI+ used in many other ham radio programs such as Ham Radio Deluxe.

Working out transparency wasn't easy, finally a Microsoft example showed me how to do this. A day when you don't learn something is a day wasted.

Here's an example of transparency. This will be part of 3.0.14.

Hermes-Lite 2 (HL2)

simon@sdr-radio.com (Simon Brown) — Sat, 04 Jan 2020 21:34:35 GMT

HF transceiver based on a broadband modem chip

The Hermes-Lite is an outstanding low-cost direct down/up conversion software defined amateur radio HF transceiver based on a broadband modem chip and the Hermes SDR project. If you are looking for a small QRP transceiver with excellent performance for the price then consider HL2.

Below are images of the build 9 boards published on the Hermes Lite mailing list by Steve KF7O.

For more information visit the Hermes Lite page .

ELAD S3 - It's Here

simon@sdr-radio.com (Simon Brown) — Sat, 04 Jan 2020 20:08:11 GMT

A great new radio from ELAD

Yesterday I integrated SDR Console with a beta S3 receiver from ELAD. My first impression is that it's a terrific receiver and will be of great interest to SWPs, DX-ers and government organisations. I'll make some videos later. With the front end wide-open there's no overload at all, despite a few close medium wave transmitters.

E's To Morocco

Tue, 28 May 2019 05:14:39 GMT

Good opening

A very nice opening this morning to Morocco on Band II Stereo (88 - 108MHz).