Topband: Strange conditions Sunday night

[K8LV1 at aol.com]

As a newcomer to 160M dxing, I am near the bottom of the learning curve 
relative to propagation on this interesting and perplexing band. Last night I 
witnessed an anomaly that is maybe fairly common to veterans, and I would like to 
know if there is an explanation which utilizes minimum quantities of snake oil.

I went on at about 0500Z and found a moderate amount of EU activity, with 
signals mediocre to weak. I easily worked everything I heard and was considering 
QRT when at about 0700 there were, fairly suddenly, several very strong EU 
signals (I recall F5IN, I2Z??, and the ubiquitous DF2PY). F5IN was CQing 
relentlessly, with only an occassional W6 QSO.I could not get a whisper from any of 
them and they were all working West coast only, giving out 449's and 559's only 
to them. I heard other midwest and some eastern stations having the same 
experience, some of whom I recognized as veteran DXers.

After making sure that the TX and antenna were still intact, I just sat there 
scratching my head. This lasted for maybe 15-30 minutes. Then these stations 
disappeared, or QRT'd (???) and there were a few normal (i.e. medium/weak) EU 
signals which I worked with no problems.

Some real interesting non-reciprocal propagation going on here.

73
Eric K8LV