The military can get away with anything they want.
In 1960 I was at NAS Olathe KS were a ham station was set up in a small
section of a former WW2 hangar. The normally used equipment was a 75A3, 32V3
and a modified BC-610. The antennas were a 6 eL 20 and 15M Telrex on a
platform above the hangar, about 90' AGL.
Since this was an all services facility we did a lot of phone patch traffic
and this was still at the Cycle 19 peak years. SSB was starting to gain
serious traction on 20M and at times deliberate QRM happened. When that
happened it took about 5 minutes to fire up and interconnect the 5KW surplus
amp, a pair of 1500T's modulated by 1000T's; this resulted in a clear
frequency (-;
At the other end the military station in Libya would often be running
traffic to us running about 750W (T-368 maybe?) into a rhombic and
sometimes kicking in the 5000W amp. When that didnt clear a hole the 50KW
stage was kicked in.It didnt take long for the QRMers to realize that when
that station was on they didnt stand a chance.
A year or so later I got a chance to visit and operate the MARS facility
there whenever the ship pulled into Tripoli, it was S Line SSB then and no
longer shared the "big rig" used by military comms, CIA, etc.
Carl
KM1H
----- Original Message -----
From: "Glen Zook" <gzook@yahoo.com>
To: <amps@contesting.com>; "Jim Thomson" <jim.thom@telus.net>
Sent: Tuesday, August 24, 2010 11:44 AM
Subject: Re: [Amps] Can I cool too much the tubes or ants?
> Back in the late 1960s some of the technicians at the Collins Radio plant
> here in Richardson, Texas, were testing one of the military amplifiers,
> 308-U20, that put out at least 20 kW. This particular amplifier has an
> auto-tune that can definitely match a very wide range of input impedance.
>
> The technicians placed about 100 feet of wire across the parking lot and
> then activated the amplifier. They soon noticed that the end of the wire
> was burning. Someone got the idea to just let the amplifier operate and
> see how long the auto-tune would function before shutting down the
> amplifier. The wire continued burning until it was less than 3 feet long
> when the safety circuits shut down the amplifier.
>
> Those same technicians liked to check out the 3 MHz to 30 MHz Collins
> built log periodic antennas using the "CB" channel 19. Since Collins was
> building antennas for the military the technicians were authorized to
> operate on any frequency within the range of the antenna. So, CB channel
> 19 was one of the frequencies that they liked to use. The system
> consisted of a KWM-2A and one of the 20,000 watt amplifiers into the
> antenna. This resulted in an e.r.p. of around 200,000 watts.
>
> A test transmission involving both a carrier then some voice would be
> made. Then the technicians would just listen for a minute, or two.
> Virtually every time the frequency would be silent for several seconds.
> Then, someone would come on the frequency asking "WHAT WAS THAT"! The
> technicians would then make more test transmissions on Channel 19 which
> "stirred the pot" even more. Finally, the technicians would change to
> other frequencies within the range of the antennas.
>
> Glen, K9STH
>
> Website: http://k9sth.com
>
>
> --- On Mon, 8/23/10, Jim Thomson <jim.thom@telus.net> wrote:
>
> 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.....
>
>
>
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