472kHz WSPR puzzle

Last night and overnight more stations copied me than I copied. Since 1030z today I have copied lots of WSPR stations on 472kHz but no-one has copied me!

About 20 minutes ago I re-set the clock to internet time and changed frequency about 20Hz lower. I also closed and re-opened the WSPR software. Still I am copying plenty but no-one has so far copied me still since 1030z.

The 5mW ERP TX to the earth-electrodes will remain on overnight.

I checked frequencies and power into the ground loop.  All looks the same as yesterday. Odd.

UPDATE 2237z:  Panic over: G6AVK (78km) is copying me at -20dB S/N.