There were quite a few 'Electronic T/R switches' available in the late
50's and early 60's, the most 'famous' of which was the B&W T/R switch.
Most used a cathode-follower circuit to isolate the transmit coax from
the receiver input and a broadband amplifier to regain the signal level
[cathode-follower circuit has gain <1 ]. Not sure if any of the
commercial versions would handle legal limit power, but the ones I built
back then did an excellent job with 150 watts CW.
Still have one or two of these in my junk-box somewhere [don't ask!].
Don
N8DE
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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