I finally got OP25 installed on my RPi, but am having some issues.
Here's the trunking info for my county:
https://www.radioreference.com/apps/db/?sid=8201852.9375 seems to be the currently active control channel.
I use this command to run OP25:
./rx.py --args 'rtl' -N 'LNA:47' -S 2400000 -f 852.9375 e6 -o 25000 -q -2
It runs. but nothing happens. So I hit 1 to bring up the spectrum display with gnuplot. I can see the signals, although they seem to be offset, by the 25 khz offset in the cmd line arguments.
Question: should I offset the control frequency by this amount? Or is the spectrum display offset a bug?
I then get the 6 or so zeros displayed, which I interpret as I have the wrong ppm value (-q -2). I have played around with the ppm setting, but it never seems to help.
I understand I can get a constellation plot with 2, which shows up, but how to interpret it, to know when I am correctly tuned?
Any other pages I can check out for details on using OP25 on a RPi?