Aircraft Scatter

I put up a 4 element beam for 144 MHz in September 2025, and was suprised that I could hear just in the noise, F6ZAQ 225 miles away. It was difficult to pinpoint exactly where the maximum of the signal was coming from. I increased the number of FFT bins in GQRX to the maximum possible, and zoomed in on the signal.

There was clear doppler shift on the signal inducating aircraft scatter (AS). The signal is coming via tropposcatter and being enhanced by scattering off aeroplanes between us. It was the first time I'd looked!

I then looked at some of the less exotic beacons that I can usually hear at M0CWX. Both

GB3MCB

and GB3NGI both show some doppler on their signals. Although these plots were taken later in the day when there was less air activity.