Overnight WSPR report, 18-19/02/2019.

Overnight, geomagnetic conditions were as flat as the proverbial pancake - probably the most undisturbed I've seen for a long time.  Kp was never above 1 throughout much of the preceding 24 hours.

This didn't stop an unusual series of spots of 4Z1DZ, who initially disappeared into the noise after my greline period, then came back strongly and repeatedly for a couple of hours around UT midnight.

There is no obvious geomagnetic explanation for the fact of and variation in 4Z1DZ's signal, except perhaps for the drift of ionisation patches across the north pole from the midday to the midnight sector.