[Elecraft] Could the be the basis for the KPA-1500?

[Edward R. Cole]

Ron,

Excellent advice.  Many years ago I built a 832A high-level tripler 
for 432 to drive with my 2m transmitter.  The output was not that 
high probably only a couple watts at 432.  I was adjusting the plate 
tuning and got zapped with RF which punched a tiny hole thru one of 
my fingers.  At first I thought it was HV but the metal I was 
handling  was grounded.  It hurt for three weeks.  Felt like a hot 
number-22 wire had punched thru.

73, Ed
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Message: 23
Date: Sun, 24 Jul 2011 14:53:16 -0700
From: "Ron D'Eau Claire" <ron at cobi.biz>
Subject: Re: [Elecraft] Could the be the basis for the KPA-1500?
To: <elecraft at mailman.qth.net>
Message-ID: <005201cc4a4c$18c8bb40$4a5a31c0$@biz>
Content-Type: text/plain;       charset="us-ascii"

Nice demos and a reminder of just how dangerous QRO RF can be - to people
and to property.

In my commercial work I learned to be as careful around RF as I am around
any high voltage - especially after accidentally drawing a small arc from an
RF source. Messing with 50 or 100 watt Ham rigs from which we often "drew an
arc" with a pencil from a high-impedance point made me careless. My QRO burn
only made a small black patch on my skin, but it felt exactly like a nail
had been shoved through my flesh - and it felt like the nail was still there
for days! RF burns are deep burns that injure a lot of tissue and nerves.

If I had been doing that YouTube demo, I'd certainly have worn the welding
mask and more than that T-shirt in case some hot metal bounced around.

Until now, a solid state amp could do limited damage because it would fail
in milliseconds. The demos show these solid state amps are as robust as
vacuum tube amps, and so they are just as dangerous.

And we all should remember that one doesn't have to draw an arc or get a
surface burn to do deep tissue damage from an RF field. That's why there are
firm guidelines for RF field exposure.

RF can set fires too. G3BDQ tells the story of the Ham whose end-fed wire
ran through a hole drilled in his wooden window frame. Every time he held
the key down a curl of smoke would come out of the hole.

Ron AC7AC



73, Ed - KL7UW, WD2XSH/45
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