SDR Dongle and APRS with GQRX on Kali

I just upgraded my pen test machine to Kali Linux (Ubuntu was getting heavy and slow). I discovered Kali has a great collection of SDR tools and, since I have both a receive-only SDR dongle AND a HackRF platform, I thought it would be interesting to see if I can receive and decode APRS packets. Today's experiment was using GQRX, which is a user-friendly UI-based SDR utility. Here's how I did it.

1. I may have installed GQRX from the Applications/System Tools/Add Remove Software utility. I can't remember; I added a ton of stuff.
2. Plugged in my SDR dongle with an antenna connected
3. Opened GQRX
4. Set the frequency to 144.390 (US frequency for APRS)
5. Opened the AFSK1200 decoder

And... nothing. I could hear the packets on my HT, I could see the transmission on GQRX's waterfall, but AFSK1200 Decoder wasn't receiving anything. I poked around for 20 min on the Internet. Then on a whim I switched the filter from "Normal" to "Wide" and voila! APRS packets are being decoded:

This is great, as I'm getting a "radio on a chip" in a day or two, to use with Arduino  for a rocketry/balloon telemetry package. Now I can test decoding my APRS packets.

Next up: using HackRF to decode - and then to encode - APRS packets.