Message-Id: <5.1.0.14.0.20041117111955.020e7d70@u0019445.kuleuven.be>
Date: Wed, 17 Nov 2004 11:32:50 +0100
To: rsgb_lf_group@blacksheep.org
From: Rik Strobbe <rik.strobbe@fys.kuleuven.ac.be>
In-Reply-To: <B333AB0EF6D4D4118BAF00508BAED8EA088D9ECA@mms12014.stv.uk.a
 strium.corp>
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Subject: Re: LF: Loading Coils
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Hello Chris,

>With this new arrangement I obtained my personal best Q of about 250..
>
>Placing the new coil in the aerial circuit made a slight improvement
>to the aerial current - from about 1.2 A to 1.5 A
>I would have thought that as most of the losses were in the coil a
>bigger current improvement would have been achieved.
The loss in the loading coil rarely exceeds 10 .. 20 Ohm, unless Q is very low.
Other losses (ground, greenery, buildings)  are typical 50 .. 100 Ohm, 
unless you live close to the sea
So once you have the coil losses below 10 Ohm don't expect too much from 
further coil improvement.
About your "slight improvement" : increasing the current from 1.2 to 1.5 A 
increases the ERP by 56 % (2 dB), that's not so "slight"

>Unfortunately two neighbours' telephone wires pass over my garden
>where the mast was to be situated.
>Any suggestions - should I go over the wires or keep well clear of
>them and cut a length off the aerial ?
I wouldn't be too keen to get the antenna wire over the phone lines.
In the event that the wire breaks and drops on the phone line during 
transmission  (can happen if you burn some ropes or isolators due to 
arcing)  you might put several kV on the phone line and cause a lot of damage.

73, Rik  ON7YD