Message-ID: <000201bfe152$05be7900$22bc01d5@default>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: "rsgb_lf_group" <rsgb_lf_group@blacksheep.org>
Subject: LF: Antenna wire materials
Date: Wed, 28 Jun 2000 20:26:24 +0100
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Hi Larry, I will fly this through the reflector so it can generate some
Flak. It occurs to me that you are having separate TX and RX sites......so
presumably separate aerials.
I would not think that you want to transmit into a very long wire (though
several do quite successfully) but that your main interest in this would be
in receive as a Beverage format. My reason for saying this is that I suspect
that wire resistance is not quite so much an issue on a receive aerial, so
you could probably use a steel/copper stranded mix for a long span. You do
not want to put a lot of effort into the erection of many support masts for
such a short period.  I am aware that a good TX antenna is usually a good RX
antenna, but the reverse is not necessarily true (e.g. small loop)

Now, at the risk of creating a furore, in the case on an 'L' or a 'T'
antenna for TX, the current flowing in the vertical section is all important
so this needs to be thick and low resistance, but when it gets up into the
top section it doesn't matter so much as this is all 'top loading' so
several smaller lighter wires would do. You could even use telephone
'drop-wire' (steel/copper stranded mix, you can see my upbringing, but I
don't know whether your telcos have a different name for it ) the current in
these wires is supposed to be lost to radiation so what matter if a bit is
lost in resistance?.  That is a challenge to the modellers to calculate how
many tenths of a dB you will loose with resistive top wires.  I am assuming
you will not want to transit on a low horizontal dipole, because too much of
the power would be lost straight up in the air.

On top of these you will need to consider the kind of wire for kite use (I
think you said you had found a kite specialist)  Dave and Mike are better
sources on that topic.

Hopefully my misconceptions can be corrected with experimental experience,
but I do like to look at problems from strange angles, if not quite
laterally.

Cheers de Alan G3NYK
Alan.Melia@btinternet.com