[op25-dev] rx.py Airspy MASTER GAIN Setting option?????

Graham Norbury gnorbury at bondcar.com
Sat Sep 5 12:25:29 UTC 2020

This happens when the agc is turned on.  Bill Becks and I experimented with
it a while back and found a way to enable/disable, but at this moment I
don't recall the magic incantation.


On Sat, Sep 5, 2020, 7:23 AM <op25 at zellners.com> wrote:

> Quoting Graham Norbury <gnorbury at bondcar.com>:
> > I'm not aware of a master gain parameter.   LNA, MIX, IF are the three
> gain
> > controls.  All take value between 0-15.
> >
> >>
> >> ./rx.py --args 'airspy' -N 'IF:10,MIX:5,LNA:15' -S 2500000 -f
> >> 774.55625e6 -v 7 -T P25PC.tsv -q 2 -V -2  -U -x 2 2>> airspy.log
> I reran my tests on this again, using -N 'IF:,MIX:,LNA:' like above
> with 0-15 values.
> The spike for the CC, as a test, didn't budge at all, all 15, or
> anything in between, no changes.
> It is significantly lower to start -20 to -40db lower v. other
> programs and depending on antenna.
> Its almost like the gains are set to 0 or something and never
> change??? ? ? ? ?
> Even using a duck direct to the Airspy with another program results in
> much higher signals on its spectrum, and gains will adjust accordingly.
> Changes will occur in another program with adjustments to all 3
> (outside its faked single slider mode, using just the REAL GAINS),
> gains shows changes in the signals and noise floor.
> In op25, not a bit of change at all in any thing. noise or signal.
> Like these are not being sent? Or not taking affect?? ? ? 15 for all,
> combos of values, even things like 50 for all three, no changes.
> I am not sure what to even try at this point? Other than missing lib
> when it was compiled??? I didn't have the airspy then or airspy
> pacakges installed when compiled.. does that change anything??? It
> seems to work regardless of that, it tunes, it will trunk, voice etc.,
> just the gains don't seem to do a thing at all. IF there was something
> missing in this, I would expect it to fail to tune, audio etc..
> Ideas?????
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