Message-ID: <000401c2c536$e8a79d80$e6e086d4@erica>
From: "g3ldo" <g3ldo@ukonline.co.uk>
To: rsgb_lf_group@blacksheep.org
References: <000001c2c4cf$96331640$6507a8c0@Main>
Date: Sun, 26 Jan 2003 12:29:37 -0000
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Subject: LF: Re: re Tx with loop
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Regarding ON4ND's horizontal loop Alan G3NYK said:

> . My estimation is that he was about 2 S points
> down on the strength I normally hear him. Thus 559 against his usual 579
on
> the vertical. This report seems to be confirmed by Dave G3YXMs comments.

The EZNEC model gave it about -40dBi in free space. Above ground it was
worse at -50dBi, - so bad that I suspected the model.
80m of wire 12m high is a lot of wire in the air. If configured as a Marconi
we get -30dBi even with poor ground.

> To Peter
> A take off at 45 degrees is not actually too clever, as it then puts the
> signal back down again just 100kms further on !! (Check the geometry with
a
> 50km reflecting D-Layer.) In fact it is likely to give fading in the 300
to
> 400kms region. The fact that there was no sign (as far as I could tell) of
> fading on Werner suggests that the high angle radiation was just totally
> lost in absorption in the D-layer. To use "skywave" effectively one has to
> "aim" at the horizon. (see the Simple Geometry page on my web site) as
only
> grazing incidence waves are returned in daytime.

Yes Alan, you are right. In fact the marconi antenna over poor ground has a
maximum gain elevation angle of 15 degrees. Over good ground it is 12
degrees with the above antenna having a gain of -24dBi. These figures do not
take into account electromagnetic obstructions or other enviomental
absorbsion.

Regards,
Peter, G3LDO

e-mail <g3ldo@ukonline.co.uk>

Web <http://web.ukonline.co.uk/g3ldo>