FlightAware Discussions

Why different number of aircraft VRS and local FlightAware feeder web page

Hello everybody,

My name is Stephan, I come from northern Germany and have only been running a feeder for a few weeks.

The problem I have is that the aircraft displayed in the local FlightAware web page of the local feeder do not match what I see in the Virtual Radar Server Website. When I see about 30 aircraft on the feeder website, I see 2-4 on the Virtual Radar Server website.

I installed the server according to the instructions found here in the forum: GitHub - mypiaware/virtual-radar-server-installation: A Linux installation script to easily install and enhance Virtual Radar Server.

There were no errors during the installation.

My goal is to get an overview of how far the range will change when I replace the antenna cable in the next few weeks. I would like to create polar plots and compare them with each other.

I think I have certainly configured something incorrectly on the VRS and hope to get help here.

I run the following setup:


  • RaspberryPi 4 with 4 GB RAM
  • AirNav ADS-B 1090 MHz external antenna
  • Flightaware Pro Stick Plus
  • A still too long cable with poor attenuation


  • PiAware 5.0
  • dump1090-fa
  • Grafana
  • Virtual Radar Server

In addition, I make my data available for the following services:

  • FlightAware
  • ADSBExchnge
  • AirNav RadarBox
  • Planefinder
  • Flightradar24

Greetings Stephan

Hi Stephan,

I suspect you only have VRS making one single connection to dump1090-fa on port=30105. That port does provide mlat, but it does NOT provide the normal ads-b traffic. To display everything in VRS you will want to set up two separate “receiver” connections in VRS, one for port=30005 and the second for port=30105. Then use the VRS “Merged Feeds” section to combine the two feeds. Finally, in the web view you can select either a single feed or the merged feed.

Be careful with the polar plots. If you want an accurate plot of actual positions that you are receiving you might want to rely on the polar plot for the 30005 port. The merged feed will exaggerate your range.

The VRS documentation covers the merged feed options very well. It’s a very easy fix.

I rarely post here to FA, but you will probably have better luck in the FA “ADS-B Flight Tracking” section and not the General section.

Good luck,


30105 is where you get the FA MLAT results from piaware (fa-mlat-client).
Not a connection to dump1090-fa.

But that’s just nitpicking, well explained.


Thank you for the answers, they have already helped me. Now I just have to deal with the topic of polar plots.

Greetings Stephan

Have you taken a look at:
GitHub - wiedehopf/tar1090: Provides an improved webinterface for use with ADS-B decoders readsb / dump1090-fa
GitHub - wiedehopf/tar1090: Provides an improved webinterface for use with ADS-B decoders readsb / dump1090-fa

It’s not quite a polar plot but i like it even better to be honest.
You can filter for altitude if you like and it will not show parts of the traces that aren’t in the altitude range.
Also you have a comparison to the heywhatsthat estimated radio horizon for 1090 MHz.

This might also be useful: GitHub - wiedehopf/graphs1090: Graphs for dump1090 (based on dump1090-tools by mutability)