FlightAware Discussions

Interesting Coverage Distribution

My current coverage distribution graph is interesting because it has an unexpected featue. The circular chart consists of several concentric rings that correspond to distances from the station (I assume). My current chart, from outside to inside, has 7 on the outside ring, 0 on the next ring in, 1 on the ring inside of that one, 8 on the one inside that one, and the rest full. Now why would the outside ring contain items but the next two closer ones essentially not have any? Am I picking up noise, in which case those items represent bad data?

The range rings show # of ac seen at that range in that direction. I live in a valley, to the E & W closer traffic is hidden, but distant high traffic is seen leaving an intermediate hole. And then there is that tree in the front yard.

I think there must have been an error. The outer ring is gone now, as I think it should be. So far I’m not using any special antenna or amplification. I have an antenna built, but I’m waiting for some connectors before I can attach it to the receiver.

Stats restart daily at 00:00 Zulu - 4PM PST YMMV

I just noticed that if you hover the mouse over the pie sections, you get detailed counts along with corresponding distances. I have items in the outer ring again. One of them has 7 observations at over 200 nm.

I wonder if some sort of atmospheric effect like with short wave is happening. I certainly didn’t expect to be able to receive any signals that far away with the standard antenna.

I have seen a few aircraft that report bad lat/lon data. The aircraft would plot fine, then jump hundreds/thousands of miles away and then back again to the correct position.

I send my aircraft data to my own database so I was able to see the bad lat/lons and they matched where the aircraft was jumping to.

I am sure these bad lat/lons are getting sent to FA too, thus the coverage graph is showing distances that you may not have normal coverage.


I’ve been thinking of doing that, too (sending data to my own database). I’m curious how you implemented that.

You’re not using --aggressive on dump1090 are you? (this can cause decode errors)


Nope, no aggressive option.