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From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <4E7275A5.7040204@iup.uni-heidelberg.de> <E1R4KSt-0002Od-2X@post.thorcom.com> <4E729468.3090908@iup.uni-heidelberg.de> <4E732BAC.4060204@toya.net.pl>
Date: Fri, 16 Sep 2011 12:27:39 +0100
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Subject: Re: LF: QRN in the west?
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Hi Piotr yes long term monitoring does suggest that the best times are often
just after sunset and just before dawn at mid-path.

I think the before dawn period can be good after a geomagnetic event because
the precipitated electons which increase the absorbtion of LF signals are
slowly decaying during the darkness period. However it also depends on where
you are located. In the UK we have no QRM sources to the west (The Atlantic
:-))  ) but we have land stretching to the east. So for us the dawn period
has the lowest QRM because the propagation of QRM from the East is cut off
by the dawn. The East Coast American stations often see the opposite....mid
west states QRM starts to appear later in the night. Even then odd periods
of enhanced signal can pop up at any time.  I always found a general dip in
signal levels here around roughly 0230 to 0400 in winter when the darkness
was longest.

Fascinating stuff.

Alan G3NYK



----- Original Message ----- 
From: "Piotr Mlynarski" <sq7mpj@toya.net.pl>
To: <rsgb_lf_group@blacksheep.org>
Sent: Friday, September 16, 2011 11:57 AM
Subject: Re: LF: QRN in the west?


W dniu 2011-09-16 02:12, Stefan Schäfer pisze:
> Bill, Dex,
>
> Decided to TX anyway, starting at 3 UTC, repeating 2x my call. That
> was arround the best time during Bill's last reception of my signal.
> For Dex it may be a bit later (?), thus 2x.
>
Hi Stefan, LF Group

last night i had my radio gear  off but  the previous night my grabber
at 136.172 kHz has been switched  on and i also made some  auto screen
saves.
  Two of them in a sequence:

http://www.toya.net.pl/~mlynarski/capt05.jpg
http://www.toya.net.pl/~mlynarski/capt06.jpg

show that, indeed, the best time for RX ( read: possible qso) was
betwwen   03 - 04 UTC
Of course, it is my   "one -time" observation , however, it fully
confirms the long terrm  observations made by Mal, g3kev and stated in
one of his recent mails that this
part of european night is a good one for possible dx operation at LF
Also , the relatively high S/N at qrss-60 speed indicates that it can be
changed into higher speeds , say "30' or even '10' -  sure, it will
decrease S/N but not that much making
decoding impossible but , at the same time, allowing for full exchange
of callsigns  etc... assuming it must be fitted in , say,one hour,
timeslot.


73, Piotr, sq7mpj