Hi,
I'm encountering something very unusual. I have no problem with the reception of my radarbox. My RB detects planes at aprox 230 nmi away. However, I've noticed something very weird: every plane that enters a circle around my radarbox (a cricle with aprox 10 km radius), it simply cannot be seen. Immediately after these planes exits this imaginary circle, the radarbox starts seeing them again. I have checked that there is nothing wrong configured on my Radarbox Software (like not showing the aircraft within a specific range). It simply doesn't receive the Mode S signal anymore for those planes being inside this "blind zone".
Have you seen this strange behavior too? Is there something wrong with my RB?
I can expect that this behavior could be due to:
1. Very strong signal. It saturates the LNA of the Radarbox.
2. Omnidirectional characteristic of the aircraft's transponder antenna. Thus, when the plane is above my head the signal would be very low.
3. Maybe the Doppler effect. Firstly, the plane is heading toward my radarbox so the signal's frequency is bigger: f_central + f_doppler. When it goes away, the frequency will rapidly decreases to f_central - f_doppler. Maybe the radarbox cannot adapt to this fast frequency changing.
If there is anyone who can explain me what is happening, I would be very grateful.
Regards!