Nick. The overall timing was irregular, but the slope of QSB took a couple of
seconds.
This was at local noon time, so had not considered other stations.
We do not have high power BCB stations here in Maine. Only a little over 1
million residents that widely placed.
Some 1 KW, 5 KW BCB stations. It is however possible in mid-coast Maine to
hear WBZ 1030 KHZ in Boston, at mid-day...
Thanks for the heads up. Appreciate your input. Will do more testing
73
Bruce-K1FZ
On Thu, 16 Jun 2016 05:41:41 +0000, Nick Hall-Patch wrote:
Hi Bruce,
Does the QSB vary regularly at say a 0.5Hz or 1Hz rate? Could it be
another station on the channel that is not exactly the same
frequency, not strong enough to deliver audio, but strong enough to
create a sub-audible beat note?
If it is irregular, shouldn't the traditional explanation of a
touch of high angle skywave interfering with the small amount of
ground wave remaining after nulling the station be sufficient to
explain the QSB?
73,
Nick
VE7DXR
At 15:20 15-06-16, K1FZ-Bruce wrote:
Been working to optimize the F/B on some antennas, using ground
wave stations in the upper BCB band. Noticed that some weaker ~20
mile distant 5 KW stations that the back (reverse) signal
has QSB on them. Think we used to call it back scatter years ago.
Some are down in the noise and QSB up to about 1 S unit.
We used to think back scatter was reflective variations in the
ionosphere. Is there any more recent information ? Maybe carbon in
varying cloud layers ?
73
Bruce-k1fz
http://www.qsl.net/k1fz/beverage_antenna.html
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