Sunday, September 27, 2009

Aircraft scatter on 2m

Whenever I see reports of tropospheric propagation on 144MHz I tune my receiver to the GB3VHF beacon in Kent to see if I can receive it any better than normal. I am always disappointed, because it appears that the mountains of the Lake District block all signals from the south round to the east, except for Sporadic-E which is presumably reflected in at a higher angle.

However, when I monitor the beacon using WSJT in JT65B mode I very often see traces like the one on the right, showing a strong doppler shift on the signal. The traces normally last for no longer than two or three minutes, then it's back to band noise again.

At this QTH when the sky is clear you can always see aircraft trails heading north-south on their way down to London. So I presume that the effect I am seeing is due to aircraft scatter?

I don't suppose it is of much interest to most 2m DX enthusiasts to spend some time trying to work a relatively QRP station in IO84hp square, but from my point of view it would be interesting to try a couple of skeds with other UK stations using, I guess, JT6M, just to see if it is possible to make a contact by bouncing RF off an airliner.
Post a Comment