Lots is possible using the RTL dongles, here’s a few images of what can be done:
1. Messaging, APRS at 144.8 MHz (or 145.8 MHz for the ISS)
The images show Tx’ing via Android Phone, Rx’ing at home – getting to France, or the data packets from the International Space Station (ISS):
Tools used: gqrx > sox > direwolf (or just gqrx using the built in AFSK1200 decoder)
2. Aircraft Tracking using ADS-B at 1090 MHz
Tools used: dump1090
3. Downloading NOAA Images at 137.X MHz
Here, you see the regular image, multispectral image and thermal image. When you receive them, it looks like this:
Try from the ISS amateur radio transmitter, you may catch some astronaut postcards:
Tools used: gpredict, gqrx > sox > .wav, then wxtoImg.
4. Receiving Pagers at 153.3 MHz
Tools used: gqrx > sox > multimon (for the POCSAG decoders)
Notes it is illegal to act on these messages and have personal information on there too.