Message-ID: <000401c3fd43$8b7f0760$6507a8c0@Main>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
References: <8840D182F8BB7540B173D2B1FA0CA9AB018AE3C5@argos.clb.tcfr.thales>
Date: Fri, 27 Feb 2004 15:08:15 -0000
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Subject: Re: LF: Propagation...reply
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Hi again Jean-Louis...a very good question !! I am not sure I know the
answer, but it sure is not a "skip zone" I dont think there should be any of
these on LF.

My crude geometry suggests that about 2000kms is the distance for a single
night-time "hop" ("reflection" height about 90-100kms) ....this means that
Uwe is 2 hops and Sam is 3 hops. I think as conditions are not too bad at
the moment that there may be interference between paths of different numbers
of "hops". It is possible that Sam is getting constructive interference
whilst Uwe is seeing destructive interference.

Steve Dove W3EEE has a real-time plot of DCF39 and he shows very deep fading
nulls. The peak levels which were good were only maintained for a few
minutes. It may also be the case that Uwe's noise levels are quite high. He
has the Sylt Loran-C chain and various utility high power stations to
contend with. I have often seen difference in reception across the width of
the UK but nothing as dramatic as these reports.

Joe is transmitting on 137.777kHz using around 20sec dot QRSS. He uses a
keyer clocked by a free running 555 rather than a computer driven system
hence the "odd" (and sometimes different) value

Cheers de Alan G3NYK
alan.melia@btinternet.com

----- Original Message -----
From: <Jean-Louis.RAULT@fr.thalesgroup.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: 27 February 2004 13:59
Subject: RE: LF: Propagation


> > Hi Alan and group,
> > the propagation for 6600km distance was good, but for 4300km,
> > the distance
> > between Joes and my QTH, was not. all nights I have had VO1NA
> > on the screen.
> > last night: nothing.
> >
> > regards
> > Uwe/dj8wx
>
>
>
> And now, ladies and gentlemen, a newbie question: could this be explained
by
> a propagation phenomenon (silent zone between 2 hops ??) or rather by an
> important noise floor at Uwe QTH ?
>
> (Another newbie question: please what is (again !) the xmitting frequency
of
> VO1NA ?)
>
> 73 de Jean-Louis F6AGR
> Loc JN18DQ
>