Michael:
Been there, done that! You have water in your traps, and running even a
little bit of power has zapped one or more of the insulators inside the
traps. The first time I did that on my A-4, I spent hours grinding carbon
out of the 20 meter trap internal insulator, and was able to repair it.
Even though the elements may look straight, there is no way to make them
straight enough to allow all of the water to drain out of the weep holes.
Since they are always on a slight slant, the water will collect in one end
and stay there until it evaporates, which may take a long time in cold, wet
weather. Also, moisture builds up on the coil forms, and when it
evaporates can leave a residue between the windings that can trap even more
moisture next time around. If you live near the ocean, this residue can be
mostly salt which gets conductive when wet, shorting the coil and can also
corrode the connection points.
Most of the unstable SWR readings you observed can be attributed to moisture
reacting to heat generated in the coils or by arcing. This was clearly
evident in my situation and it was no surprise that the problems disappeared
in the summer, and returned the winter.
I finally gave up and retired the beam and replaced it with a Force 12 C-4.
No traps=no problems! Not even in last year's El nino' here in Northern
California.
Ron N6AHA
-----Original Message-----
From: Michael C. Joens <joens@thecia.net>
To: 'towertalk@contesting.com' <towertalk@contesting.com>
To: <towertalk@contesting.com>
Date: Thursday, January 28, 1999 8:20 PM
Subject: [TowerTalk] A3S SWR Problem (kinda lenghty)
>
>Here's a problem that's been puzzling me for a few weeks.
[snip]
>The problem is basically that the SWR on 20 & 40 is terrible, and it
>fluctuates in an odd way. On 15, it is ok sometimes and off at others. On
>10m there seems to be no problem. Here's a detailed description of what's
>happening:
[big snip]
>Has anyone seen this kind of strange behavior before? I'd like to have some
>idea what to look for before I recruit help to get the antenna down and
>start tinkering with it. Maybe the best idea is to just buy a new A3S and
>bring the used one to a fleamarket - clearly an option if I put a price on
>aggravation.
>
>Thanks de Michael, K1JE
>
>--
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>
--
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