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From: "Dave G3WCB" <ganymede444@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Date: Wed, 5 Jul 2006 22:33:41 +0100
Message-ID: <PAEFLMFGBDKKCONLMLBICECFCHAA.ganymede444@btopenworld.com>
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Subject: LF: LF loading coils <Litz>
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Dear Gary, LF.

I have just finished rewinding my loading coil. The original 3.2mH coil was
wound with 150 turns of 2.5mm cross-sectional area pvc covered solid copper
wire,(i.e. mains cable inner) The coil is 300mm dia and 500mm high, and the
antenna is a "Tee" at 6m with a 60m top. The antenna capacity to ground is
about 390 pF.

I rewound it with Litz wire of about the same cross-sectional area, and got
an antenna current increase of 15%. Not much, but every little helps.

I haven't tried a short, fat loading coil yet, but the indications are that
short fat coils have lower losses.

73, Dave G3WCB IO91RM

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of James Moritz
Sent: 05 July 2006 22:09
To: rsgb_lf_group@blacksheep.org
Subject: LF: Re: LF loading coils


Dear Gary, LF group,

...But there is another justification for making a high-Q loading coil, and
that is power dissipation. If you are trying to run 1kW into a small
antenna, it isn't hard to end up with a few hundred watts dissipated in the
loading coil if this has mediocre Q. This would only reduce the radiated
signal by about 1dB or so compared to a perfect, zero-loss loading coil, but
it would certainly make the coil get warm! A big, high Q coil dissipates
less power in the first place, and has more surface area to dissipate the
heat, too.

Cheers, Jim Moritz
73 de M0BMU

----- Original Message -----
From: Gary - G4WGT <g4wgt@tiscali.co.uk>
To: <rsgb_lf_group@blacksheep.org>
Cc: LW Wave <lowfer@lwca.org>
Sent: Wednesday, July 05, 2006 8:11 PM
Subject: LF: RE: Re: LF loading coils


> Hi Alan & Steve,
>
> You made almost identical comments.
>
*****************
>
> So I will give that idea a "MISS"
>
> Thanks to you both for your comments.
>
> 73
>
> Gary - G4WGT.
>
>
>