I would expect the shot noise from the random arrival of the electrons
(shot noise) on the anode would
create so much noise that you could not hear any stations at all. That is
one problem with
electronic TR switches is that on receive you have to bias off the final
otherwise the
noise is too much. Discovered this with my Johnson Challenger in the 60's.
It had
a clamp tube that limited plate current on transmit but did not cut it off.
Makes a great
white noise source.
73
Bill wa4lav
At 03:24 PM 3/6/2003 -0500, Pete Smith wrote:
>At 10:25 AM 3/6/03 -0500, W8JI wrote:
>>I was never able to get this system to work well on QSK, so I used a pair of
>>10 watt 250 volt lightbulbs as a series limiter (they lit like flashbulbs,
>>and doubled as a reminder the power was on) and a 6AL5 tube as a clamp for
>>the receiver, followed by a 6J6 to make up for gain loss.
>>
>>I'm actually serious about this, I used this system for years as an antenna
>>and TR switch. It worked quite well.
>
>There was actually a commercial TRswitch like this that a friend and I
>vaporized during an ARRL DX Contest back in the late 1950s, with a
>single-813 amplifier; if I recall correctly, it used a cathode follower of
>some sort for isolation and coupled to the tank circuit with a piece of
>RG-8 -- sometime during the night the RG-8 flashed over and totally nuked
>everything inside the little metal box the circuit was in. The miniature
>tube was reduced to powder, but to the designer's credit, the receiver was
>not harmed.
>
>
>73, Pete N4ZR
>The World HF Contest Station Database was updated 23 Feb 03.
>Are you current? www.pvrc.org/wcsd/wcsdsearch.htm
>
>
>
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