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Assorted ramblings from the developer


DRM in 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:

  1. Patent / royalty issues with the audio codec, and
  2. The Dream project works well.

Brendan Wahl, WA7HL, co-Moderator, of the DRM North America Newsgroup explained the lagal minefiled 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.
 

 


Spectrum Markers

Now that I'm spending more time on 2m (144.5 MHz) I decided to add spectrum markers as it makes beacon identiciation easier.

Here's a 2m screenshot taken today, as you can see there's not a lot happening.

A simple window for adding definitions:

And another for the appearance:

When time permits I'll add support for adding data from a CSV file.


WiNRADiO Sigma (G65DDC)

Nils Schiffhauer dk8ok has helped me a lot in the past, so when he asked me to support the WiNRADiO Sigma aka G65DDC how could I refuse?

This is a beast of a radio, I've not encountered anything like it before. There's one problem - I don't have one, so testing could have been a nightmare. However, the API is very clear and well documented. After just two days exchanging code with Nils he has now reported that the Sigma is working, and working well with the features in SDR Console that he needs.

This is the first time I've added support without ever seeing the hardware, so kudos to the team at WiNRADiO. The SDK's API is here: https://www.winradio.com/home/g65ddc_sdk.htm .

I'm so impressed, I may add support for more WiNRADiO radios if there's demand.

Here's an example of the Sigma running with a 33.3MHz sample rate and we see the whole of HF!

Support will be in version 3.0.11 of SDR Console which at the time of writing has not been released.


Release: 3.0.10

Download here [Link].

What's new / changed in 3.0.10:

General

  • Audio device dropdown now shows a check mark next to the current device and L/R channel selection.
  • SDRplay radios – sanity check that the default frequency is valid – must be in the range 10 kHz to 2 GHz. previously a user started with the default frequency of 10Ghz which is not supported by the SDRplay library.
  • FM Stereo RDS logging was not working properly with multiple active receivers.
  • Fixed a long-standing bug in the tuning bar at the bottom of the main waterfall; this was an error which existed since the code was originally written over four years ago. A determined fool-hardy user could expose the problem and crash the program.
  • Scrolling at 8.333 kHz with rapid middle wheel spinning works properly.
  • Identity title now optionally shown in the program title bar.

DSP

  • More taps available for filters.
  • Corrected DSB filter editor.
  • Narrow FM de-emphasis redesigned to avoid audio pumping.
  • NR3 reworked. Threshold changed to Level, working much better.
  • Filters:
    • Changed appearance of the Filter design window.
    • Added more windowing options.
    • (I may add Remez design methodology later.)

Favourites

  • Sorting favourites by frequency is now reliable.

Installation

  • Slight change to installer appearance, kit now has updated images.
  • In previous kits an extra folder SDR-Radio.com was being created in the user folders, this extra folder was not used.

Memory

  • Applying a memory now restores the original center frequency and bandwidth if the memory frequency would not otherwise be visible.

Pluto

  • Pluto visible gain range changed to -60dB to 30dB.
  • Digital filter opened up to 0.95 and the offset tuning range increased to +/- 200kHz.

    Looking at the code I was enabling the Transmit Digital Filter with a normalised bandwidth of 0.2, so at 550kHz that’s 110kHz and with 128 taps not very sharp. This is why we were seeing lower outputs with greater offsets because offset tuning means just that – tuning at an offset from the center frequency.

    SoTo test, I set the digital filter to 0.95 of normalised bandwidth and this did not change the signal(s) seen on the remote receiver (Airspy HF+ Discovery). I was testing on 144.300 and the Discovery was picking up signals 60dB above the noise.

Recordings

  • Fixed a problem with audio recording of Broadcast FM when in mono, previousy a new file was created every time the mode switched between mono and stereo.
  • When the playback of a file starts the display bandwidth is set to the bandwidth of the recording. A more intelligent algorithm will be developed in 3.0.11.
  • ELAD files which are not valid WAV format are supported.
  • IQ recording now has a Range option, specify the center frequency and the bandwidth.

Ribbon Bar

  • Memory editor now supports 11 digits – frequencies up to 99.9GHz.
  • Adding a dropdown entry to the Quick Access Toolbar (QAT) now does not inhibit correct initialisation of the original dropdown. The dropdown in the QAT does not work though, this is being investigated. An example of a dropdown is Ribbon Bar, Home Bandwidth.
  • Entries added to the ribbon bar’s QAT (Quick Access Toolbar) are removed when starting if they contain dropdown entries. This is related to random crashes in the console.

RX

  • When a new receiver is added the default frequency is no longer the center of the display, rather an unused frequency in the visible display.
  • Adding a new receiver now clones the currently active receiver. It was working this way when 3.0 was released but was broken in a previous minor update.

Satellites

Spectrum

  • Implemented the One Euro Filter as default in the Spectrum Smoothing. This is much better than the other options, it preserves the peaks while reducing noise.
  • Fixed a slightly obscure bug only seen while scrolling the receiver frequency.

Transmit

  • Added Serial Port PTT.

  •  

E's To Morocco

A very nice opening this morning to Morocco on Band II Stereo (88 - 108MHz).


Simon's World Map 1.0.8

 

Download here [link].

 

I wrote this program because I wanted to see:

  • Current Time (local, GMT)

  • Sunrise / Sunset

  • Greyline map

  • DX stations

There are commercial geo clock solutions such as the excellent Geochron, but as a programmer with spare HD monitors and computers I decided to write my own, that way I have exactly what I want.

Anyway, this weekend I finally found time to update Simon's World Map to version 1.0.8. Here's what is new:

  • Installs a 64-bit executable on 64-bit Windows, previously the 32-bit executable was used on 64-bit Windows.

  • Text colour in Clock, Sunrise / Sunset etc. is user-selectable.

  • Sunrise / sunset shown for entries in the station list.

  • Timezone markers updated

It doesn't need much CPU at all- anything running Windows 7 or higher is fine.


Airspy HF+ Discovery

Listening to France Musique, a station whose output is sorely missed in the UK.

Using the latest little stunner from Airspy.


Release: 3.0.9

Download here [Link].

Note: The main reason for this release is the fixes to transmit with the Pluto SDR.

What's new / changed in 3.0.9:

General

  • The 8.333 kHz tuning rate wasn’t working properly as it’s really 8.333 recurring.
  • The Analyser now correctly processes the Invert Spectrum option (swap IQ from the recording file).
  • The Ribbon Bar, Home. Radio, Bandwidth dropdown now shows the currently selected bandwidth when using radios where the actual bandwidth may differ slightly from the displayed bandwidth (Perseus at 95, 96 and 192kHz).
  • The bit smoothing option in RDS processing was not being set correctly.
  • USB Relay option now also part of the general Program Options.
  • Broadcast FM audio recordings now always created in stereo (two channel) mode – previously the recording was restarted every time the audio switched between mono and stereo.
  • RDS logfile now has a delay option in the Database selection pane, this is designed to be used in situations where there is considerable latency, for example when using a remote server.

Pluto

  • Transmit data is now controlled by a high-resolution timer with an accuracy < 1 millisecond.
  • Flow control has been added to compensate for the difference between the Pluto clock and the input device (microphone, VAC, …).
  • Added offset tuning, this ensures that the spur at the transmit LO is offset from the actual transmit frequency.

Airspy HF+ Discovery
Airspy HF+ Discovery

Screenshots taken with a prototype Airspy HF+ Discovery. This beauty is half the size of the Airpsy HF+ and it's as good if not better. Proper comparison data later.

If you suffer from strong signals then Discovery will not let you down.


Release: 3.0.8

Download here [Link].

What's new / changed in 3.0.8:

Broadcast FM

New features and changes for 88 - 108MHz FM broadcast reception and the RDS decoder.

RDS decoding has been improved by making PI code detection mor sensitive.

US Callsign logic now uses data from NRSC for callsign and location.

Spectrum window now a docking pane. Display the spectrum window by selecting Ribbon Bar, Receive, Broadcast FM. 

Logging of station from the RDS decoding has been added, this is the RDS Logfile option. To display the logfile click the Log button in the BFM Spectrum.

The logfile has all the options you need:

  • Enable / Disaply updates
  • The number of recent entries displayed
  • Detail level (brief, full)
  • Font size for ageing eyes
  • Delete entries
  • Edit an entry
  • Export as text
  • Options

Click ••• to display the options.

Airspy Options

The Airspy options have moved from the ribbon bar to the Receive DSP panel.

USB Relay

The USB relay terminology has been changed to avoid confusion.

  • ON = Turn ON a relay channel (Activate).
  • OFF = Turn OFF a relay channel (Deactivate).

Data (IQ) Recording

Playback now correctly detects ELAD recerdings and displays the format as ELAD. later the contents of the elad chunk in the WAV file will be supported.

Scheduled Recordings

  • Now can select single file in the definition, this uses WAV RF64.
  • Fixed display issues.
  • Tidied up the code.

Geostationary Beacon

  • Increased bandwidth for LNBs with very serious drift!
  • Fixed crash when bandwidth changed past the minimum / maximum supported.

Frequency Database

AOKI URL updated and new format supported.

Font size selection for ageing eyes.

Defauly field order changed, will be user-configurable in a future release.

Perseus

The sample rates 192kHz, 96kHz and 95khz are now calibrated.

Satellites

Tidying up and extending the Select Satellite option. Instead of just selecting a satellite, pressing Select in the Satellite ribbon bar now display the Select Satellite window which provides an overview of the entries in the Satellite List as well as selection of new satellites.

Footprint configuration is now consolidated into a property page.

Narrow FM

Uses the original version 3 de-emphasis and has better peak volume control.

Pluto

Problems with the transmit signal bursting reduced by redesigned inefficient code, see Pluto support page for more information.



Recent Posts

  • DRM in SDR Console Posted 3 days ago
    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 lagal minefiled 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 ...
  • Spectrum Markers Posted last week
    Now that I'm spending more time on 2m (144.5 MHz) I decided to add spectrum markers as it makes beacon identiciation easier. Here's a 2m screenshot taken today, as you can see there's not a lot happening. A simple window for adding definitions: And another for the appearance: When time permits I'll add support for adding data from a CSV file.
  • WiNRADiO Sigma (G65DDC) Posted last week
    Nils Schiffhauer dk8ok has helped me a lot in the past, so when he asked me to support the WiNRADiO Sigma aka G65DDC how could I refuse? This is a beast of a radio, I've not encountered anything like it before. There's one problem - I don't have one, so testing could have been a nightmare. However, the API is very clear and well documented. After just two days exchanging code with Nils he has now reported that the Sigma is working, and working well with the features in SDR Console that he needs. This is the first time I've added support without ever seeing the hardware, so kudos to the team at WiNRADiO. The SDK's API is here: https://www.winradio.com/home/g65ddc_sdk.htm . I'm so impressed, I may add support for more WiNRADiO radios if there's demand. Here's an example of the Sigma running with a 33.3MHz sample rate and we see the whole of HF! Support will be in version 3.0.11 of SDR Console which at the time of writing has not been released.
  • Release: 3.0.10 Posted last month
    Download here [Link]. What's new / changed in 3.0.10: General Audio device dropdown now shows a check mark next to the current device and L/R channel selection. SDRplay radios – sanity check that the default frequency is valid – must be in the range 10 kHz to 2 GHz. previously a user started with the default frequency of 10Ghz which is not supported by the SDRplay library. FM Stereo RDS logging was not working properly with multiple active receivers. Fixed a long-standing bug in the tuning bar at the bottom of the main waterfall; this was an error which existed since the code was originally written over four years ago. A determined fool-hardy user could expose the problem and crash the program. Scrolling at 8.333 kHz with rapid middle wheel spinning works properly. Identity title now optionally shown in the program title bar. DSP More taps available for filters. Corrected DSB filter editor. Narrow FM de-emphasis redesigned to avoid audio pumping. NR3 reworked. Threshold changed to Level, working much better. Filters: Changed appearance of the Filter design window. ...
  • E's To Morocco Posted last month
    A very nice opening this morning to Morocco on Band II Stereo (88 - 108MHz).
Read More »