Last night I set up an Automatic Packet Reporting System (APRS) iGate to listen on 144.390 MHz for packets and report them to APRS Internet Service (APRS-IS). This is like a listening station that will improve my area APRS coverage.
The latest RTL-SDR v3 is a capable little Software Defined Radio (SDR) receiver that can even receive to HF frequencies. For much cheaper than a standalone HF receiver, you can get the kit that includes a whip dipole, extension SMA cables, and mounting hardware. I lengthened the whips to 2m resonance (~19 inches each side).
Using software in linux: rtl_fm and direwolf, one is able to listen for APRS traffic on 144.390 MHz, decode it, and with the Raspberry Pi connected to the Internet, can send what it hears to the main APRS servers for visibility on aprs.fi.
Now that this is up, I can monitor the firehose of digital packet information that is constantly on the frequency, and relay some close-by transmissions to the rest of the world.
Special thanks goes to my friend briandef (who is studying and may soon become a ham) for his insight and pre-struggle with SDR opensource software to help me debug out how to cleanly set up the RTL-SDR dongle.