Message-ID: <000001c41e1b$cfebbda0$6507a8c0@Main>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: "LF-Group" <rsgb_lf_group@blacksheep.org>
Date: Fri, 9 Apr 2004 10:42:42 +0100
MIME-Version: 1.0
Subject: LF: DCF39 in ZL again
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Hi again Mike, there seems to be a concensus that you have a trace of
DCF39.....well done !! It is not absolutely necessary for both ends to be in
darkness for the path to exist. First it is the position of darkness at
100kms altitude that seems to be important. Then the path will probably
exist if the darkness line is not more than 1000kms away (approximately the
length of a "half hop"). I have received traces from Joe VO1NA when the
night-time shadow was only in mid-Atlantic, suggesting that a daytime
D-layer hop (or maybe two) was responsible for the first stage of the path.
Signals were much weaker in this period, than later when the darkness
covered the path. The path normally opens around the time that the ground
shadow reaches Newfoundland and closes about an hour after (ground)dawn in
the UK., though an east to west path can linger longer in winter. Conditions
whilst not "very-good" at the moment, are not too bad ...a bit of a
"curate's egg" There should be better nights in the coming few years.

This puts up a challenge to amateurs, though it must be remembered that
DCF39 has around a 36dB advantage over most stations.

Cheers de Alan G3NYK
alan.melia@btinternet.com