Message-ID: <00d401c4cc90$8203f1b0$7900a8c0@athlon1200>
From: "Dave Brown" <tractorb@ihug.co.nz>
To: rsgb_lf_group@blacksheep.org
References: <B333AB0EF6D4D4118BAF00508BAED8EA088D9ECA@mms12014.stv.uk.astrium.corp>
Date: Wed, 17 Nov 2004 23:30:50 +1300
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Subject: LF: Re: Loading Coils
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Chris

 Most of your losses will normally be in your ground system - not the 
loading coil.  Amateur LF vertical antenna systems of necessity have 
severely constrained (size/efficiency) ground systems. So 
contributions from any half-decent loading coil will be way down, 
compared to the ground system losses.

Dave, ZL3FJ

----- Original Message ----- 
From: "OSBORN, Chris" <Chris.OSBORN@astrium.eads.net>
To: "LF Group (E-mail)" <rsgb_lf_group@blacksheep.org>
Sent: Wednesday, November 17, 2004 10:19 PM
Subject: LF: Loading Coils


>
>
>
> Hello LF Group
>
> Many thanks for all comments and advice - most interesting.
>
> I drilled out the wooden dowels on the loading coil and replaced
> them with lengths of 15 mm plastic water pipe.
> I was unable to obtain plastic rod at short notice and my XYL
> wouldn't let me have her knitting needles !
> The pipe was not really rigid enough and bent slightly but was
> sufficient to prove the experiment.
> 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.
>
> I share my office with some young electronics engineers and was
> surprised that they know very little about RF inductors or Q factor.
> It must be a dying art !
>
> My next improvement will be to raise the 'droopy' end of my aerial,
> presently at a height of about 5 metres
> 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 ?
> Presumably I can't get the phone company to move their wires !!
>
> 73 Chris G3XIZ
>
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