FlightAware Discussions

Trying to make sense of it all. Antenna, ProStick, and Filters

It’s been a while that I’ve taken a hard look into not only the initial setup, but the geekier details behind ADS-B. A failed SD card and a year of putting off bringing my setup back online, things have changed.
We now have things like Graphs1090 etc.

My Setup is/was:

  • Raspberry Pi 3B
  • ProStick Plus w/ AGC -10
  • SMA to RG6
  • 25’ RG6
  • Cantenna Indoors

What can I do to improve?
1090Mhz Filter due to interference? If so, suggestions?

I do know that the RG6, RG6 adapter, and Cantenna are the biggest factors. Just looking to improve what I have currently.

Get an outdoor antenna even if you leave it indoors.
For indoors you actually have very good range, don’t think filter is necessary.

You can run this, at least me personally i find local traffic more interesting than far away traffic, so i’d reduce gain.
Automatic gain optimization for readsb and dump1090 fa · wiedehopf/adsb-scripts Wiki · GitHub

If you lose any range it’ll not be much but should improve reception for low flights close by.

Setting it manually to 49.6 might be all you need actually.
Your choice.

In my case, I removed “–fix” from /etc/default/dump1090-fa DECODER_OPTIONS and that got rid of a lot of tracks with single message. Also, if you add the FlightAware blue filter you may get rid of the noise you’re seeing in ADS-B Signal Level.

Edit: I see you have the Prostick Plus, so you probably don’t need to add the filter. But when I added the blue filter the noise completely disappeared.

Too high. You can see this in the first graph of the charts.
A general recommendation is to aim for <5% of messages > -3dbFS
Yours is with 18% too high.

The suggestion of wiedehopt should be followed. You might go even lower to 44.5 or 43.4

Even with the blue stick the dark blue filter does not hurt.
These are my graphs, using a good antenna, blue FA stick and dark blue filter, but antenna indoor. Gain set to 49.6 as the messages > -3dBFS are low enough.


Thank you and I appreciate the hard work you’ve put into the community!

I have a dedicated 1090Mhz Antenna and Low-Loss LMR cabling in the pipeline. It all came down to what cost I was willing to put into the hobby in the beginning. Not to mention not much talk/discussion then regarding lightning mitigation / reduction etc. etc. So my setup has remained in the attic indoors.

When I was reading the other threads, reducing single message was the goal. From my understanding, this is errored/corrupted data? I can add --no-fix and achieve the same iirc?

Thank you! I used some of the advice from the Github but did not know what number we were aiming for.

  • uses strong signals (messages >-3dB) to determine if gain should be changed
  • if the percentage of strong signals is greater than 7 percent → gain is reduced
  • if the percentage of strong signals is less than 0.5 percent → gain is increased

I was trying to interpret the scan data which @abcd567 mentioned the 850Mhz overload was cellular. I wasn’t 100% sure if an additional 1090Mhz filter would assist since the Prostick Plus included one but was probably overloaded.

1 Like

It’s a general value which fits most of the times. However there are environments where a higher value is applicable.

The suggestion of wiedehopf with the script is a very comfortable way.
My scan look similar. With the filter, the noise below 1090 is a lot lower, but for me it does not improve a lot.

But again, it depends on the individual location, the environment, what’s in your way and other frequencies including their strength

It is pretty often try and error.

1 Like

Don’t worry so much about the single messages, it’s futile.
Using --no-fix is a bad idea.

–fix is the default option for dump1090-fa, removing it from the config will do nothing.

At some point it could be in there twice meaning 2 bit fixes which do lead to some more bogus stuff. But i believe that has been changed.

It’s for example in the graphs.