Message-ID: <3A5B300E.923DB252@alg.demon.co.uk>
Date: Tue, 09 Jan 2001 15:36:46 +0000
From: "Steve Rawlings" <steve@alg.demon.co.uk>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Loading coil Q
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Urban SM5EUF wrote:

> Measuring the coil Q revealed that having the coil elevated
> about 70cm above the floor (concrete) resulted in a Q of 300
> and when putting the coil directly on the floor with the lowest
> turn about 5cm above the floor the Q was reduced to 220. The
> first 30 cm seemed to make a big difference.  From 30 up to
> 70cm did not make much change . . . .  Having seen on homepages
> that some of you have the coil standing quite close to ground it
> might be wise to elevate it somewhat.

Thank you, Urban, for your observations.  The base of my loading
coil is only about 15 cm above ground.  So it seems that I should
be able to make some improvements when I rebuild the loading coil
later this year.

By the way, as at G3KEV, I have also designed all my equipment to
match to 50 ohms, and tune for minimum SWR.  I find that
continuous monitoring of SWR provides a very sensitive indication
of what's happening at the hot end.

Regards to all,
Steve GW4ALG