Hi Oliver
The plot below may be of interest to you.
It is a polar plot of dBm signal strength vs distance of aeroplane for adsb signal at my station (Toronto).
It was very kind of Martin (Flightaware Forum member G8JNJ) to do this plotting for me.
Please see Martin’s post in eHam.net for full details: http://www.eham.net/ehamforum/smf/index.php/topic,38371.msg866912.html#msg866912
Note: the dBm vs color legend is at bottom right of the image.
