Putting my 1090Mhz FA Antenna on the roof changed everything! For the worst

FlightAware ADS-B Flight Tracking
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Hello! I received my Pro Stick Plus, 10 meters of Low Loss RF Communication 50Ohms Impedance Cable, and my 1090 MHz FA antenna from the FlightAware store just a few days ago. Hooked everything up and threw the antenna in the window and tracked about 430 flights that day from distances as far as 80 nm away. I just had the cable coiled up on the floor. I was excited to mount my antenna on the roof to hopefully get more range. So next day I mounted the antenna on my roof eave with a j pole mount. Routed the cable down to my office and hooked up the piaware rig only to find that I can now only see some airplanes at most 4 miles away from my antenna. UGH!!! To do a test, I connected a simple 6’ piece of wire going up vertically to the Pro Stick and saw more airplanes. The simple wire is in my closet even, so I had low expectations of seeing anything - but I can see more planes that way. I verified that the antenna isn’t shorted to ground and that everything is hand tightened at the antenna and on the pro stick. But no luck.

I’m really reaching out to see if anyone might have experienced this and what you can do to improve things.

2

I ran the command:

sudo systemctl status dump1090-fa -l

The response was:

 dump1090-fa.service - dump1090 ADS-B receiver (FlightAware customization)
     Loaded: loaded (/lib/systemd/system/dump1090-fa.service; enabled; vendor preset: enabled)
     Active: active (running) since Fri 2022-07-29 16:19:29 UTC; 1h 2min ago
       Docs: https://flightaware.com/adsb/piaware/
   Main PID: 450 (dump1090-fa)
      Tasks: 3 (limit: 2059)
        CPU: 16min 44.240s
     CGroup: /system.slice/dump1090-fa.service
             └─450 /usr/bin/dump1090-fa --quiet --device-type rtlsdr --device-index 0 --gain 60 --adaptive-range --fix 
			 --lat 44.02823 --lon -121.32573 --max-range 360 --net-ro-port 30002 --net-sbs-port 30003 --net-bi-port 30004,30104 
			 --net-bo-port 30005 --json-location-accuracy 2 --write-json /run/dump1090-fa

Jul 29 16:23:22 piaware dump1090-fa[450]: adaptive: changing gain from 14.4dB (step 8) to 12.5dB (step 7) because: probing dynamic 
    range gain lower bound
Jul 29 16:23:22 piaware dump1090-fa[450]: rtlsdr: tuner gain set to 12.5 dB (gain step 7)
Jul 29 16:23:32 piaware dump1090-fa[450]: adaptive: available dynamic range (29.9dB) < required dynamic range (30.0dB), continuing 
    downwards scan
Jul 29 16:23:32 piaware dump1090-fa[450]: adaptive: changing gain from 12.5dB (step 7) to 8.7dB (step 6) because: probing dynamic 
    range gain lower bound
Jul 29 16:23:32 piaware dump1090-fa[450]: rtlsdr: tuner gain set to 8.7 dB (gain step 6)
Jul 29 16:23:42 piaware dump1090-fa[450]: adaptive: available dynamic range (44.3dB) >= required dynamic range (30.0dB), stopping 
    downwards scan here
Jul 29 16:32:04 piaware dump1090-fa[450]: adaptive: available dynamic range (29.3dB) + half gain step down (30.0dB) < required 
    dynamic range (1.0dB), starting downward scan
Jul 29 16:32:04 piaware dump1090-fa[450]: adaptive: changing gain from 8.7dB (step 6) to 7.7dB (step 5) because: dynamic range 
    fell below target value
Jul 29 16:32:04 piaware dump1090-fa[450]: rtlsdr: tuner gain set to 7.7 dB (gain step 5)
Jul 29 16:32:14 piaware dump1090-fa[450]: adaptive: available dynamic range (30.6dB) >= required dynamic range (30.0dB), stopping 
    downwards scan here
3

Jul 29 16:32:04 piaware dump1090-fa[450]: rtlsdr: tuner gain set to 7.7 dB (gain step 5)

Gain is set too low (7.7 db) by adaptive gain control. Better disable adaptive gain control, and manually set gain to 49

3 Likes
4

That is weird indeed. Probably local interferences?

1 Like
5

If it’s interference, you’ll need a filter. (no the builtin filter doesn’t help it’s after the LNA)

4 Likes
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Well darn, the gain setting in the piaware-config.txt file was set to the string “max”, I set it to 49 instead. And it’s sitting at 49 now, but no luck in getting any better range. I ordered the FA filter. I hope that does something because this is depressing.

7

I faced the same situation when I purchased Flightaware antenna. I changed connectors and coax cable, but no luck. Then I ordered and installed FA Filter and it played magic.

 

 

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Woah! I got my new dual band bypass filter from the FlightAware store today and MAN!!! What a difference! Thanks for everyone who recommended I get the filter even though I got the Pro Stick. I am now picking up planes up to 140 miles away. I was only getting like 5 planes a day, and after I connected that filter I instantly started seeing 30+ on my SkyAware screen. Next, I’ll start fiddling with gain to tune in my rig. Thanks again!

3 Likes
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