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" <[email protected]>
To: "LF Group (E-mail)" <[email protected]>
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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