Hi The aircraft in question is TGW572 - VH-VNF - 7C6C29
It passed through my no go zone at time 17.37.35
Attached is a txt file
OK - I have good news and bad news.
First the good news, you
aren't losing the signals from aircraft above you - they are still being received, so there's nothing wrong with your RadarBox hardware or aerial.
Now the bad news, there is a position encoding/decoding bug which means that aircraft latitudes and longitudes aren't being shown correctly. My money is on a decoding bug in RB, simply because if it were an encoding bug on board the aircraft I think we'd have heard about it before now (it affects several aircraft in your sample, not just VH-VNF, and not all the time either).
What is happening is that, at a certain point in their trajectory, RadarBox starts outputting longitudes with a minus 360 degree offset so that, for example 146 degrees E (+146) becomes
minus 214 degrees W (-214). Obviously that means the resulting position can't be plotted on the map, so the aircraft symbol disappears from your screen.
I have no doubt that AirNav Development and Support are monitoring this thread too, so we'll leave it in their capable hands.