Overnight WSPR report, 2019 January 09-10

Extremely quiet geomagnetic conditions overnight, with only the slightest field deviations, even at very high latitudes.

No unusual spots came in overnight, propagation ending for very short skip signals (e.g. ON) just after 01:00UT.  Models, using the correct antenna types at both TX and RX, predict the MUF between LU8 (TX) and Wales (RX) at 23:00UT was about 9MHz:

Image: www.predtest.uk

Raul, LU8ADV, had kindly offered to send WSPR at 37dBm with his 3-element Yagi pointing at northern Europe for an extended period.

The results are interesting in light of the quiet field, in that it all looks much less anomalous and easier to comprehend.

Peak reception strength comes (between ~20:30 and 21:30UT) when the grey line is passing half way between our respective stations, though the distance to that area is still about 6000km.  It therefore seems simply a case of very low angle radiation making it to the grey line zone in mid-Atlantic, and a rapidly vanishing D layer allowing Raul's signals to the F2 region, where they continue to Wales.

Of course, that is not the whole story, because Raul's signal keeps on coming to MW until the last spot of 23:58UT, when everyone else in Europe has lost him, too.

Then, a surprise! TF1VHF received LU8ADV at 01:06UT (-26dB), where the path is rather difficult to explain.

Looking at the azimuthal projection of the terminator with DX Atlas, one can see the path is about 11,800km if it is along a great circle path.

But also, the grey line area is within F2 line-of-sight of Iceland from his north west to the south east.  I initially thought the signal could be undergoing 'semi-antipodal' focusing (signals reaching TF from many directions), until I remembered Raul's Yagi, with something like 25dB front-to-back, is ensuring practically no signal is being sent to the south.  So focusing is not the answer!

Azimuthal projection of the grey line at 01:06UT, when LU8ADV was heard (once) in

 TF.

So I am wondering if the path is to Raul's west of north, perhaps along ionisation patches drifting from the far eastern Pacific region day side in the F2 layer, allowing continued, if weak propagation into the late (UK) evening.

Raul is not recovered in Europe until 08:46UT, when DK8FT/GPS hears him at -24dB along the immediate-post sunrise line, currently running directly between LU8 and Europe.


When Raul is able, it would be interesting to point his antenna about 335 degrees, to see if we still get any spots from northern Europe, and what their strength might be.

Interesting to note the signal from DL8ULF (TX: 27dBm), as this vanished in the early evening, reappearing much later in a strong peak centred on 00:00UT.  Again, I am not sure as to the mechanism involved, but it may be electrons precipitating from the dayside into the night side, across the north pole.

DL8ULF, WSPR (0.5W), received at MW1CFN 09-10/01/2019