Gain options

Like a fair number of forums in any topic/genre, there’s an eclectic mix of deeply experienced and frequent folks, then experienced but infrequent reader/posters, and then my class, new people.
So what. I’ve read a lot about gain, and have had several replies that were very helpful.
My final query before I go mashing on keys to edit PiAware-config is this. If I’m going to use adaptive gain, do I comment out or remove the rtl-sdr gain xx.x line. It would seem so to me, but then there’s always the design logic behind the dump1090-fa code (behind the curtain in Oz).
Thanks to a great community of enthusiasts!

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Leave it in, it sets the starting gain, and then adaptive gain adjusts it from there. You can leave it set to max if you want.

If you’re interested in seeing the adaptive gain in action, run the command below in the PiAware terminal window to follow the dump1090 log. You’ll see it starting at your rtlsdr-gain and adjusting every few moments. To quit use Ctrl-c.

journalctl -f -u dump1090-fa.service
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Welcome. There is a recent discussion line called “Improving signal noise” that has a lot of detailed discussion regarding “gain” as it relates to site performance and noise. Certainly helped me work through getting off the “AGC Max” gain setting and improving my site with a fixed gain config. Suggest you get yourself set up with the 1090-graphs software early on in this journey so you can see detailed performance and real-time change results as you fine tune your system.

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Thx for that info. I’m not connected to a terminal on that Pi, and am not sure I’d see that through ssh, but more great info from this great community.

Craig, thx for that. Tom put me onto the graphs in my Nooelec post. I have them. I read the Improve SNR post and found a gold mine before this last question. I’m going to go with adaptive gain and see where it takes me.

A tool for easily adjusting gain manually directly from Skyaware map:

https://github.com/abcd567a/set-gain/blob/master/README.md

 

set_gain_skyaware_map

 

The “Set-Gain” add-on does NOT determine or tell anything about which gain is the optimum.
It is simply a manual gain adjustment tool. You don’t need to ssh and in terminal open the file /etc/default/dump1090-fa to edit the gain manually. Just select the gain value from drop-down of the set-gain app embedded in Skyaware map, and click button “Set Gain”, and gain will reset to your chosen value, and dump1090-fa will restart with new value of gain in about 5 seconds.

Click on Screenshot to See Larger Size

 

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