I have a couple of NESDR Smart dongles from NooElec [1], that have worked very well for me. I run them on a Raspberry Pi 3 and pipe audio output to my desktop or laptop with PulseAudio.

Aside from SDR# on Windows and gqrx on Linux, there's also GNU Radio [2] and a variety of lightweight applications that can run on, let's say, a Raspberry Pi Zero [3]. Oona Räisänen has a fascinating blog that touches on digital signal processing as well, applicable to SDRs as well.

Me? No ham license, but that may come someday.

[1] https://www.nooelec.com/store/

[2] https://www.gnuradio.org/

[3] https://osmocom.org/projects/rtl-sdr/wiki/Rtl-sdr

[4] https://www.windytan.com/

You can even get started without buying anything, there's an SDR website where you can experiment with a remote SDR. It's in the Netherlands.

Just browse to here: http://websdr.ewi.utwente.nl:8901/

The sub $30 RTL-SDR and SDR# software, is more or less the defacto standard starting point.

“RTL-SDR” is amazing!

“RTL” is from a particular chipset that has great support for hackability.”

There a few different apps that can decode signals from it.

I even got a USB-OTG (“on-the-go”) adapter and used my RTL dongle with an app on an Android phone. And that was 5ish years ago.

See this post I wrote in an earlier thread:

https://news.ycombinator.com/item?id=23468796

Get this one: https://www.amazon.com/dp/B009U7WZCA/ref=cm_sw_r_cp_apa_i_jl...

Or this nicer one: https://www.amazon.com/dp/B011HVUEME/ref=cm_sw_r_cp_apa_i_Zl...

Sdr# for Windows. GQRX for the others. For a blog with help and project ideas check out http://www.rtlsdr.com/