-----Original Message-----
From: James Moritz <[email protected]>
To: [email protected] <[email protected]>
Date: 08 January 2001 18:14
Subject: LF: Loading coils / Measuring receivers
Dear LF group,
OK on the loading coils - my current loading coil is over 500mm
diameter, so ready-made containers to fit it are hard to come by.
I'm suprised that people have had success with coils exposed to
the rain, I found with mine that this drastically reduced the Q once
water got in between the turns.
Hello Jim.
My loading coils are outside and I do not suffer from any detrimental
affects in hot sun, rain, frost or snow or rain of any sort. The swr meter
shows virtually no change in changing wx conditions. I do have a fairly high
mast at 120 feet supporting 3 x inv L antennas with 250 feet horizontal top
sections. The coils are wound with 2.5 mm multi strand plastic insulated
wire. My coils are 6 feet above ground and vertically orintated and I have
never noticed any water or snow etc in between turns. The coils also run
cool, not even warm. I have a fairly elaborate insulated ground system. I
can run around 1w erp. The coils at the base of the antenna vertical are
matched to the 50 ohm coax feed and are about 90 feet away from the shack.
Not much chance of my shack catching fire. Ever since I started on LF some 3
years ago I never had any problems with the installation, no fet, insulator,
wire etc failures. I have built the installation to match 50 ohms and always
tune for minimum swr, this always coincides with max rf output. I NEVER tune
for max SMOKE!!!!!!!!!!! This could be a recipe for disaster.
I do not have any PA protection. I monitor SWR for any change and so far no
problems.
73 de Mal/G3KEV
Cheers, Jim Moritz
73 de M0BMU
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