Message-ID: <000b01cc6a61$f7fff320$0401a8c0@xphd97xgq27nyf>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <001201cc6a48$c8123dd0$0401a8c0@xphd97xgq27nyf> <20110903152500.2cbf2a9e@svr1> <9443BF673E7A4E51BBF052ADEA904B4C@JimPC>
Date: Sat, 3 Sep 2011 18:49:15 +0100
MIME-Version: 1.0
Subject: LF: Re: Re: 500 Khz - QSO
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-AOL-SCOLL-URL_COUNT: 0  
x-aol-sid: 3039ac1d41174e62693b49c1
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none


Jim es Co
There could be some merit in what you say.
The most difficult station for me is GW3EUP, rough terrain between us over
the Pennines. I do not know what ERP he is using but he is up es down in
severe qsb most of the time and fades out also, but EI0CF has the same
terrain  between us and he is always a good signal all day long.
One consideration is the launch SITE  regardless of in between,  I am only a
couple of miles from the sea and EI0CF is likewise on the Atlantic shore.
maybe that makes all the difference.
de mal/g3kev

----- Original Message -----
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, September 03, 2011 5:33 PM
Subject: LF: Re: 500 Khz - QSO


> Dear John, LF Group,
>
> > Good signals in daytime - steady with little QSB, but some QRN just
> > starting to build. The sea-path down the East Coast must help
> > enormously!
>
> Looking at the map, the path Shetland - Scarborough is almost entirely
over
> the sea, while Shetland - Lancashire/Cheshire is about 50% over the rocky
> ground of Scotland and NW England. Looking at the ITU ground loss curves
for
> 500kHz, and applying the "Millington Method" for the appropriate distances
> and ground conductivities comes up with something like 30dB less signal at
> G0NBD/G4WGT compared with G3KEV, even though the distance is similar. This
> is easily enough to make the difference between an audible signal and one
> that would require long integration periods on a spectrogram to detect. It
> might be interesting one day for you to try transmitting slow QRSS signals
> during daytime ground-wave conditions, and see if your signals are
> detectable at inland and western UK locations to make a comparison with
> east-coast locations.
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
>