I would expect that at 04:10 there would not be so many aircraft around, and not much Es either.
You do not usually get me in the shack at that time either, and this sacrifice on my part for the benefit of science is something I will not let anyone forget in a hurry.
26 times I have been spotted by DK8NE since 1 May, but I have not worked or been heard by any other German station.
Not that I am paranoid, but I can see why people think that there is someone listening to their phone ...
I had one decode each from two other stations today and worked no 6m Es at all, but I still managed to be clocked by DK8NE ten times. I cannot work anyone anywhere with a beam, but DK8NE can receive me fine all day on his loop.
To say that I was spotted ten times actually means I called CQ ten times, and I was spotted ten times. The only occasions I was not spotted was when I cut the power or after 15:19.
Some things I seem to have established.
1) No contact so far after 15:19 on any day. Not yet anyway, but I know it works fine at 04:10.
2) I tried WSPR from 21:00 last night until 04:08 this morning. Although G4CPD was hearing me, and DK8NE was hearing local stations (so both stations were working), there was no result after 6 hours. The power level on WSPR was just a bit over 20 watts, the most that I felt I could comfortably run overnight. Probably not enough power for a fair test.
3) I have poured over information on radio horizons for aircraft. From the figures I have seen so far an aircraft at 30,000 feet is too low for a path of 1000km. However, at 39,000 feet it might be possible. The site conditions at each end are hard to factor in, especially with Ayton Hill cutting me off in that direction. This is not my field of expertise (what is?) so I may have got the calculations totally wrong. Let's say that any idea I had of ruling out aircraft scatter on path grounds alone is looking shaky.
4) Multiple modes have been suggested. Yes, I can see how one propagation method can feed into another. However, for this to keep happening 10 times spread over an 11 hour period is a bit of a tricky scenario for me to envisage.
Does any of this matter?
No, not really. It could be aircraft scatter, or it could be ionoscatter, troposcatter, or a combination, or something else. The odd thing is that the path exists for so much of the day, plus it does not coincide with Es or any other opening.
I think, having got this far, I should shut my investigation down for now and see how things go over the next few weeks. Either it will stop, or something will emerge which pins it down once and for all.
I am certainly not trying again at 04:10 tomorrow.