Has always done a terrible job of selling itself. A $25 dtv receiver and a chickenwire antenna parabola and code your own satellite TV decoder, learn what radar guns emit, emulate a modem... maybe even shift to IR and do TV controls.. it's, latent in this stuff.

But the frontpage doesn't take you there.

What are some good resources to start playing with SD add an amateur?

https://pysdr.org/ is a good introduction to DSP/SDR using Python.

Previous discussion on HN: https://news.ycombinator.com/item?id=24750588.

Ham Radio Workbench podcast on GNU Radio: https://www.hamradioworkbench.com/podcast/GNU-Radio.

In terms of hardware, there is a large spectrum, from inexpensive RTL-SDR (receive only, ~$25), PlutoSDR (transmit and receive, $229, which PySDR covers) all the way to $x000+ for USRP etc.

https://osmocom.org/projects/osmo-fl2k/wiki (repurposing a USB-VGA dongle as analog source)

https://github.com/F5OEO/rpitx (repurposing bitbang/PWM GPIO; we had weird problems with data corruption when we were trying to use it as a radio modem, but maybe you will have more luck)

https://bellard.org/dvbt/ (repurposing standard VGA card, but it's probably not worth it since fl2k is way better)

(beware that low quality of the transmitter usually means it will cause interference with other stuff. However, all of these have such a low power that if you will not use an amplifier, it will be OK, the interference will be probably undetectable outside of the room where the transmitter is)