Overnight WSPR Diary, 11-12/01/2018

Geomagnetic conditions were very quiet overnight, although pulses of very slight field increases did occur from around 03:15UT.

IRF/Kiruna magnetogram.

Statistical aurora 2 minutesbefore first VK spot.  NOAA/SWPC.

Propagation at 14MHZ was different from previous evenings, in that spots from the eastern US were being heard until 21:54UT, much later than usual.  The last DX spot was of W7YLQ at 23:06UT (-27dB from 5W).

The anomalous receptions were restricted to one of PD0OKP at 03:08UT (-23dB from 0.01W), and  two of VK2ALR (04:32UT, -24dB and 05:24UT, -28dB from 5W).

Consulting the WSPR database, other than Asian stations and a couple of western US stations, I was the only one to hear VK2ALR, as the 23:30 - 05:30UT plot shows:

Clearly, something unusual there.

I was also the only one to hear PD0OKP all night, as the last 12 hour database record shows:

Ever-more curiously, I was also the only one to hear W7YLQ for the whole overnight period (database consulted 20:42-08:42UT):

Comment.

The story gets ever more intuguing!  The VK spot at those times is unusual, as is the fact that only I heard him in this broad part of the world. 

The PD0 spot, from a very tiny, 10mW signal, was also unique and clearly subject to some transient phenomenon. 

One might conclude that this QTH really is especially electrically quiet as at least a partial explanation.  But as I keep saying, stations in many other parts across Europe must have equally good or better receiving conditions.

The only other factor that could make this QTH unusually sensitive is the very highly-mineralised ground.  Les Moxon discussed that kind of thing in relation to VK3MO's signals way back in the 1980s, and put the anomalously strong signals (claimed to be up to +12dB over other VK stations), down to 'ray bending' in inhomogenous ground - see 'HF Antennas For All Locations', RSGB publications (still in print), p.168. The ground here consists of multiple layers, sandwiched on top of one another and tilted over.  A lot of it is a massive sulphide deposit caused by an ancient hydrothermal vent.

There are no real answers yet, just more and more questions!