Updates to a Month of RTL-SDR by Keenerd

Back in August of this year RTL-SDR code contributer Keenerd aka Kyle Keen ran an Indiegogo campaign to raise funds to pay for him to work on upgrading RTL-SDR related code for one month. As Kyle only counts the days he manages to put a good effort in towards the upgrades, the coding is still ongoing. He recently put out an update which we quote below.

Programming Report – Week 3

Hey all, sorry about dropping off the radar there.  There were several large unexpected events in recent months, but nothing bad.  I’ve still been hacking on the project.  An anonymous donor gave me a Lyons DSP textbook, which I’ve been working through for more solid foundations.  But studying doesn’t generate any new code for you to play with, so hasn’t been counted towards the project.

I’ve also been working on a very ambitious ADS-B related side project.  It is something no one has ever done before with the RTL-SDR, but mathematically it is feasible and progress is steady.  Not anywhere near for a release (and might yet be impossible in practice), and thus also hasn’t been counted towards the project.

So what has been completed since the last report?

* Automatic audio gain.  Crucial for AM/SSB listening.

* Audio padding (constant rate audio).  If you are streaming rtl_fm, this will prevent stutters when the tuner is busy hopping.

* Heatmap fixes.  The font is downloaded automatically and image slicing is completed.  Run rtl_power 24×7 but render a heatmap of only the last hour, for example.

* Rtl_power fixes.  Including one tricky corner case that caused crashes.

Also a big thank you to Kacper Michajłow who fixed and fleshed out a couple of Windows issues that were giving me trouble.

25 days remain.  As always, if you have comments or suggestions you can reach me by email or in ##rtlsdr.

The latest feature requests and links to the GitHub repositories and Windows builds can be found at http://igg.kmkeen.com/.


Notify of

Inline Feedbacks
View all comments
Steve Spain

I’m delighted to see the work on the rtl_fm zero padding as it’s been driving me nuts on windows. I’m still trying to get it set up so it scans, pads and outputs a constant stream of audio to ezstream, but as yet either the audio stream drops out or ezstream crashes completely. Does anyone have any light to shed on this? I hate having to run it on windows but it’s my only 24/7 machine and I need the dreaded M$ for another bit of software.


+1 for multiple demodulators.


I’m really hoping for: DCS and CTCSS squelch and multiple demodulators. I think those really are the two most requested features.