Strange issue. Performance degradation

FlightAware ADS-B Flight Tracking
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I’ve been noticing a weird switch-up during the day [and now night]. My range decreases quite a bit, and so do messages. Additionally, I get aircraft that do not track well, and not in the ‘something is obstructing the view’ kind of way. It seems to only happen during the day, and only recently.

My setup is DPD Antenna > 25ft LMR600 > Uputronics LNA > 1090 Bandpass filter > Airspy Mini > Pi4 OC’d 2ghz. Need to move the LNA probably, but it is winter :frowning:

Anyway, swapping everything out to an ADSBx Pro stick or FA Pro/regular does nothing; arguably it reduces range and m/sec further. What’s odd is my somewhat generic SignalPlus Antenna does not exhibit the same behavior. It picks up more than my Airspy/DPD during the day now on an RTL V3, and it is at ground level while the DPD is about ~20’ above.

Below are 24hr Graphs. Small interruption in graph data as I tried to troubleshoot with a different pi4.

Graphs

Note: I live about .1 mile from a blasting Cell tower and about a ~mile from another.

This has been happening for a few days now, but never before.

OPTIONS= -v -t 90 -f 1 -w 5 -e 4 -C 25 -P 5 -E 15 - pretty stable and was solid. Changing settings does not seem to change a ton for me. Gain is 21; changing gain always reduces range and m/sec for me, though ~19 works fine, but does not change this behavior.

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It would seem it is not isolated to daytime. Not sure what to make of this or these graphs.

airspy-localhost-snr-8h

8hrGraphs

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Other users have reported that the Uputronics can get overwhelmed by strong nearby signals (you mention strong mobile towers in your view). Try moving the bandpass filter before the Uputronics or right atfter the antenna.

1 Like
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Thanks for the suggestion! Turns out the biggest problem was water in the DPD > LMR600 connection. I had checked earlier and nothing seemed present, but a can of air later in the day took out quite a bit of water.

I’ve since wrapped it better in Temflex and some Butyl masking tape/putty. Then Temflex again. Hopefully no more water :slight_smile: – although I’ve heard of this issue with DPD antennas… kinda wish they didn’t pigtail it and just had a direct-to-antenna connector, but I digress. Great antenna otherwise!

Gonna pop the Bandpass filter in before the LNA and see what happens anyway :slight_smile:

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