My last blog entry covered an experiment to prove that it is possible to get a straight line reflection from an Aircraft travelling away from both the originating, TX, station and the receiving station.
The Aircraft needs to be, I believe on the same bearing as that of the path between the two stations.
At my QTH this is merely a waiting game, there are so many aircraft on the S/N corridor that finally one will fit the equation.
Previous tests with G6AVK did not achieve the desired result. I think that, while his omni directional signal reached me fine, by the time it got to Aircraft sufficiently North of me it had run out of ‘steam’.
The addition at G6AVK of a mast and rotatable 6m Beam means that strong Aircraft reflections from the North are now possible.
I pointed my beam in line with the S/N UK Air Corridor G6AVK beamed toward me.
Note the trace at 19.32. There is the direct signal from AVK. A long descending trace from an Aircraft, which has passed me and is heading North, on a track at a tangent to the path between AVK and ZJO. Third a parallel trace, classic 61Hz shift equating to an air speed of c.600Km Hour.
This produced 2 decodes of WSPR on the two frequencies.
2009-05-29 19:32 G6AVK 50.294482 -18 1 JO01ho 5 G3ZJO IO92ng 127 306
2009-05-29 19:32 G6AVK 50.294421 -25 0 JO01ho 5 G3ZJO IO92ng 127 306
I think we can now say that this is the definitive explanation of the phenomena. Repeatable by experiment, using 3 different signal sources.