Topband: Daytime on 160 and Conditions

[GEORGE WALLNER]

I am out at C6AGU (FL14) with good 160 m TX and RX antennas.
Last night, around 05:00 UTC, I heard a ZS station calling me. I thought no 
way, I must have copied the call wrong: the gray-line window showed full 
daylight there. Well, not really: I just got an e-mail from him that he was 
calling me. While a contact at high noon may be very unlikely, a couple of 
hours after or before sunset, it is perfectly possible. I hear EU out here 
from about 4:30 PM local time, almost two hours before my sunset.
On Conditions
For the past three days I have been experiencing unusual conditions. Signals 
from EU are present on my EU RX antenna and SDR receiver at between -110 and 
-80 dB. (I don't know the absolute levels, it is just on the band-scope of 
the SDR.) The noise floor is around -120 dB. However, there is a fluctuating 
noise that I have not heard before: The noise floor rises in a one or two 
seconds from -120 to -85 dB, stays there for a second or two and then drops 
back to -120 dB. Through the headphones it sounds like QSB. But the signal 
levels are steady. It is the noise that has QSB, completely masking all but 
the strongest signals at its peak.
I am on a small, uninhabited island, about 10 miles from the nearest 
civilization -- if you can call a small Bahamian village that. It is 
normally very quiet here. The noise is wide-band and is at a similar level 
both on my NE and NW RX antennas. That makes me think that it may be coming 
in at a high angle, where my RX antennas do not have much directivity.
Is anybody else experiencing this noise?
TKS and 73,
George,
C6AGU/AA7JV