Hi Scott
We in turn owe much credit to the GNU Radio developers, and a host of others including
the osmosdr team.
There is an app osmocom_fft -- see
http://sdr.osmocom.org/trac/wiki/GrOsmoSDR .
That app should already be installed and all set to run since gr-osmosdr is installed by
pybombs as a prereq for op25.
It has GUI controls for setting the variable RF gain(s). You should see a separate
slider for each programmable gain that the RTL stick supports (assuming it has this at all
I suppose). I don't have an RTL USB stick - still waiting for my order to be
delivered. Would be interested to hear what happens in osmocom_fft - are you able to see
any of the LSM CC's using that? There are a few other things to try also using
osmocom_fft - first instead of tuning to the exact frequency of the signal, tune (say) 50
KHz offset from the frequency - so if the station you want is at 157.125 try tuning
157.175 - then look for your desired signal 50 KHz leftward from center. Reason for this
is to try to avoid the dreaded "DC offset" problem. Another thing to do is add
an FM trap (if needed). Anyway, both of the above tuning issues are taken care of with
extra parameters to scope.py. But first it's necessary to confirm your RTL can see
the signal at all, so it would be good to give osmocom_fft a spin. Also please paste the
command line you're using when running scope.py
Max