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

op25 at zellners.com op25 at zellners.com
Fri Sep 4 18:06:27 UTC 2020


Quoting Graham Norbury <gnorbury at bondcar.com>:

> Airspy @ 15,15,15
>
>
> RTL @ 47
>

I'll have to rerun the test to see.. I don't think real numbers were  
put in as I was expecting to get an option for "MASTER"

I've since disabled that in the other software to use CORRECTLY as the  
device provides gain versus some pseudo control which I don't know  
what its doing..

I didn't get any movement at all in the signal on any of those gain  
settings, but I also don't think I limited to 1-15 either..

I will retry since I've play'd with the other software to see what  
settings seem to give the best SNR...


> Of course, in the real world you'd tune the gain(s) to find the best
> SNR, which is typically the point just before the noise floor starts
> rising appreciably. 

Thats what is done, on the production unit. I admit to upping it a  
little for rain fade, stray pine needles etc. for some fade margin.  
Which does resolve those... I also use dedicated and professional LMR  
antenna and cables, ie:LMR400, yagi at site etc.. I try to make up  
with things at the antenna not at the other end.

I also use the constellation to get a good pattern and go from there.  
With a good pattern there 99% of the time the rest will take of  
itself. Mostly.

Now that I know the other is creating a fake setup, and what really  
should be done I can test again.

Thanks.



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