RTL-SDR Retrogram: ASCII Art Spectrum Analyzer

Over on GitHub, Rakesh Peter (r4d10n) has uploaded a new terminal/ssh based console application called "retrogram~rtlsdr". This program uses an RTL-SDR and terminal window to display a spectrum analyzer drawn in ASCII art. Because it is terminal based, it is even possible to view the spectrum of a remote device over an SSH connection. The program is based on software designed for Ettus USRP SDRs, and has been adapted for RTL-SDR.

For other SDRs r4d10n has also worked on a "retrogram~soapysdr" version which should work with any SoapySDR compatible SDR, and "retrogram~plutosdr" for PlutoSDR SDRs.

Notify of

Inline Feedbacks
View all comments

Just found “by accident” you can launch GQRX then retrogram, and interact retrogram –> GQRX. However a little bit unstable. Not working with SDRangel.


i built the retrogram-soapysdr on Linux and it works great with SDRPlay, it would be awesome if more features were added like audio and demodulation mode for AM, FM wide and narrow, and SSB, maybe a notch filter too


nice!! 🙂 worked very easily on a RPi 3



Yeah, well, the computers that would’ve benefited from that (old portables/laptops with text-only LCDs) didn’t have USB, so this is fun, but pretty much useless 🙂


I think the fun factor may be higher than the necessity, but i like it


Using it over a remote connection (SSH) is useful even on a modern computer. For example, when you’re setting up some command-line application that is going to listen continuously to some signal, you might want to inspect certain frequency range visually to make sure than the signal is there.
Today a “remote computer” can be just a cheap router running OpenWRT


Tested retrogram-plutosdr, easy to compile. Nice piece of work, we can even change settings or walk into spectrum. Thanks @r4d10n !