Persistence Spectrum

Simon Brown • December 22, 2023

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.

SDR Television v1 (Release)

By Simon Brown • September 13, 2025
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.

SDR Console, Beta Sept. 9th 2025

By Simon Brown • September 9, 2025
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.

SDR Television Beta #6

By Simon Brown • August 28, 2025
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.

SDR Television Beta #5

By Simon Brown • July 18, 2025
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.

SDR Television Beta #4

By Simon Brown • June 30, 2025
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 Beta #3

By Simon Brown • June 18, 2025
Major Change Scroll down to the SDR Radio information. The bandwidths available for SDR Television when using a Pluto / LibreSDR have changed.

Simon (G4ELI) Live!

By Simon Brown • May 25, 2025
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

By Simon Brown • May 25, 2025
UI Refresh And More...

No More Wireless

By Simon Brown • May 13, 2025
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.