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LF: Re: re Tx with loop

To: [email protected]
Subject: LF: Re: re Tx with loop
From: "g3ldo" <[email protected]>
Date: Sun, 26 Jan 2003 12:29:37 -0000
References: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
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 <[email protected]>

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





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