Asymmetrical Reflections on Aircraft Scatter

June 8th, 2015

A long time monitoring of the beacon F1ZMT in JN07CX via Aircraft Scatter on 1296.872 MHz shows asymmetrical reflections on most of the crossing planes.

As the distance to the beacon is 624 km and it´s ERP of just 10 W (a panel antenna to the south combined with an omnidirectional big wheel) is rather QRP, only weak reflections can be detected from time to time. This ensures, that received signals were reflected on single airplanes. In this example can be seen, that the reception starts shortly before the plane crosses the path between DJ5AR in Mainz and F1ZMT in LeMans. Unexpectetly the signal can be seen for quite a while after crossing. There is a continuous variation of the doppler shift and no spread of the signal, as is usual for a moving solid reflector.