But it’s not yet shown as “warning” in the profile, right?
However it is updated while using the “classic” update/upgrade command
No it isn’t showing as a warning in the profile.
I guess due to the minor changes it isn’t needed as obj stated.
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Ok, so whats the trick to finding the best gain? I read the post about optimizing gain and didn’t really come out with a solid answer as to how. I’ve slowly lowering the gain and watching the noise level and the >3dBFS on the chart. Currently the >3dBFS is under 1.
Also is there any reading on interpreting the graphs and how to put them to use?
I feel like Kylo Ren from Star Wars in the scene where hes like “MORE, MORE, MORE!” lol
Thanks!
That’s what everybody does, that and watch their signal level graph to get an idea of their signal to noise ratio (SNR.) BTW that “messages > 3dBFS” is about preventing planes that are very close from dropping off of the map because their messages are being distorted or gabled by too high a gain setting. You should look for a result of around 5-6%, but anything up to 10% is OK if you happen to live near a busy airport (or live in Seattle, the Jet City.) The main thing is your SNR: weakest signals should be stronger than your noise floor.
You make a change to your gain then watch your feeder’s map and your graphs for a few hours and see if that made it better or worse, and continue tweaking and watching until you find the sweet spot for your location and gear, then you leave it there. There’s no “trick” to it, you try things then monitor to see what happens.
Did you do anything special to get your noise low?
Not really, but I’m using an RTL-SDR Blog filtered 1090 LNA near the antenna, 12 meters (around 39 feet) of low-loss LMR240 coax and an RTL-SDR Blog v3 dongle. I don’t do UAT on 978MHz because it’s not used here. Having an LNA by the antenna usually improves SNR and linearity.
Since you’re using dongles with built-in LNAs plus a 1090 filter in the blue one the only thing I can suggest is lowering the gain in dump1090-fa and monitoring graphs1090. Its LNA is amplifying the noise along with the signals so you want to reduce that while still getting okay signal strength. Like all things RF it’s a compromise: you may have to sacrifice some range to be able to optimize the rest of the signals received.
BTW the FlightAware dongles don’t provide bias-T onto the coax because it’s blocked by their own LNAs so you wouldn’t be able to power an external LNA. You don’t need more gain anyway, you need less noise. If you have separate 1090 and 978 antennas you could put an additional filter below the 1090 one. Search the Discussions for “do I need a filter?”
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