Last night, Oct 8, 2009 about 8pm (local) I checked my WSPR receiver for activity - there was NONE!
It was like the receiver was disconnected from the antenna - in fact, I checked all of the antenna connections looking for a problem. The S meter was indicating near zero for background noise. Only the "heart beat" of my electric fence charger moved the needle off of zero, I unpluged the charger and then, . . . Nothing, Nada, Zip - S Zero!
At intervals, only one station, a friend, Doug W7RDP (about 21 miles away) was being Heard and Reported via WSPR. Which was also unusual in itself, as we do not often report each others WSPR signals. Doug was also not being Heard or Reporting any other WSPR stations.
Also, there were no QRSS signals being heard. My QRSS Grabber was blank - it looked like an off-station TV screen.
I must have been in "A 30m Signal Black Hole"!
This was very unusual, normally about 8pm, 30m is HOT.
The only thing that I suspect, for the lack of signals in-or-out of my QRH, was the strange weather. It had been a clear all day, followed by a very dense low overcast evening.
Could contrasting weather layers trap signals in, and prevent outside signals from reaching my antenna?
I wonder if anyone has ever report this type of signal or weather related condition?
It would be interesting to review the WSPR data base for when the "Black Hole" effect started, how long it lasted, and how large an area was affected.