Date: Mon, 23 Aug 2010 19:41:14 -0700
From: "Hardy Landskov" <n7rt@cox.net>
Subject: Re: [Amps] Can I cool too much the tubes or ants?
To all :
Melting antennas is a very good sign since I am the last one to relate this
story.
Circa 1957. San Fernando Valley, CA
W6HX, Ted Gillete builds a 20 meter amplifier for W6YMD using 2-- 4-1000D
tubes. They run 7000VDC on the plate at 2 Amps. This causes the driven
element to glow at the ends as neighbors knock on Bill's door to tell him
there are invaders from outer space. Actually they worked many AP, VU, & 3B8
that night. The antenna did not survive.
Anyway that's what was relayed to me.....
73 Hardy N7RT
## That's called ...'corona' and it's an easy problem to fix. With corona,
you
are just stripping electrons right out of the air. A few methods that been
used on the
tips of DE's is to use AL corona balls. Another method is anti-vibration
loops. Another
method is to use insert machined solid AL cylinders in the tips... with the
ends of the
cylinders ground off, and rounded..sorta phallic looking. Another method is to
grind and round off
the sharp edges of the DE tips. HV acrylic spray...or corona dope can also be
used on the last 6"
of the DE tips. Plane silicone rubber rtv will also work. The idea here is...
if you put a barrier between
the HV points and the air... you can't strip electrons from the surrounding
air... since the al tips
are surrounded by corona dope/rtv/ge spray, etc. Being at high altitudes
just makes the corona problem
worse.
## Ted, W6HX was a nice fellow. I use to hear his station during the Nov SS
phone contest all the
time during the mid-late 70's. I think it was WB6OLD/6 that used to operate
Ted's station, during the contests.
Dunno what happened to WB6OLD/6 .
later... Jim VE7RF
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