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wllmbecks at gmail.com wllmbecks at gmail.comSetting the manual gain mode in op25 will take away AGC and more importantly will remove the false spike in the center of the spectrum. This is quite so that you can visualize the "Real" control channel from a figment of the Airspy's imagination. Note that a full reboot or removal and re-plugging of the SDR into the USB port will be required to clear the Airspy from previous linearity or sensitivity modes. Changing of the rx.py command line arguments and restarting rx.py will not clear the internal registers of the device, something that it took me a while to figure out. I would still recommend starting with (-q 0) while checking for the presence of TSBK's coming from the control channel, and/or verification of a legitimate p25 signal by observing the constellation or symbols plots. But I think you'll be ok in using FFT once you have the AGC gain modes disabled. Please let us know how you make out. Good luck! Bill -----Original Message----- From: op25-dev <op25-dev-bounces at lists.osmocom.org> On Behalf Of op25 at zellners.com Sent: Sunday, September 6, 2020 9:29 AM To: op25-dev at lists.osmocom.org Subject: Re: [op25-dev] rx.py Airspy MASTER GAIN Setting option????? Quoting wllmbecks at gmail.com: > The yellow highlighted text below in my rx.py command line is an > example of how my R2 device was set to manual gain mode whereby the > device responds to user specified LNA, MIX, > > and IF gain settings. > > > > ./rx.py --args "airspy=0,sensitivity=0,linearity=0,bias=0" -N > 'LNA:15,MIX:15,IF:10' -S 2500000 -T trunk.tsv ……… > Thanks... I think that may be the magic,airspy=0,sensitivity=0,linearity=0,bias=0, as those names are present in the other program, but hmm... I would expect since I nuked them in that program it would persist? I guess not.. I will try this during some tests today... have to work on a more mission critical option at first. Thanks....