For complete information on this project, see the APRS page.
While experimenting with the Raspberry Pi 3B+ APRS receiver, the Pi is temporarily running Gqrx SDR software with an AFSK1200 decoder.
How does the RPi 3B+ handle the demand of processing with the SDR? The CPU is averaging a pretty busy 55% load. The Argon programmable fan is doing a good job keeping everything cool as it cycles on at 42C with 10% fan speed, and off at 38C. The fan cycle time is about 1:3 minutes on/off in a 69F degree environment.
In comparison, monitoring the CPU load on the K9KMS MMDVM repeater while it's in use (not idle), I found it to be less than a 2% load. This MMDVM repeater runs on a Raspberry Pi 4B, so it's not exactly an apples-to-apples comparison, but running the Gqrx software to get the APRS data is obviously much more demanding. This will likely result in a shorter life expectancy for the RPi using this approach, so scratch Gqrx off the list and find something to process data, not radio frequency.
On Sep 21, 2020 at 17:39 UTC, the decoder ran until 00:30 (6+ hours) and logged 1,029 hits, an average of 171.5 hits per hour. Not too bad considering the surrounding forest and lowland lakefront area.
Read about this project's exciting continuation on the APRS page!
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