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Re: LF: 500 QSB

To: [email protected]
Subject: Re: LF: 500 QSB
From: [email protected]
Date: Thu, 13 Sep 2007 21:50:28 EDT
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Hi John / LF
 
That's a very interesting comment.  Not because of the 2-3 minute period that you have observed, but because you think it's unusual.
 
Having monitored my beacon for a fair time now I've noticed that after sunset the typical period for a cycle of QSB seems to be 3 minutes. That's at a range of 150km and 700km (thanks to Dave 'YXM and Hartmut)
 
I'm intrigued as to the conditions you normally experience with Finbar at 22.00 local over a sea path. Is that consistent propagation or do you have less destructive QSB over a shorter or longer period?
 
I notice in this months Rad Com, which fell through the door today, That Pat Hawker devotes a couple of pages to 500kHz. While suitcase transmitters are thankfully absent, he does quote extensively from a recent QEX article which makes some interesting observations about short vertical vs loop antennas and how 500kHz can produce optimal ground wave in terms of S:N per Watt over 60 to 200 miles.
 
Sadly, he also says that as yet, he hasn't heard a single UK station on 500k yet.
 
Still, all publicity is good publicity.
 
73
 
David
 
 
Hello LF Group,

Finbar and I moved our sked forward tonight to 9pm local (20:00UTC) and
noticed some rather rapid, deep fading. I'm not sure if this was time
related due to being closer to our sunset time, or condition related.
I'm sure the fading is generally slower and less catastrophic in the
dips.

The QSB on Finbar's signal went from RST 579 to NIL and back over a
period of around 2-3 minutes.

Some periods were much shorter, some longer, but in the 20 minute QSO
there must have been 5 or 6 complete cycles. The QRN made it a bit
difficult to tell if the signal was fading or the noise increasing at
times!
 
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