[Boatanchors] Antenna Relays & T-R Switches

[Peter Markavage]

There are several articles on simple electronic T-R Switches listed in
the QST archives on the ARRL web site  that can be downloaded or just
build the circuit from the Johnson T-R switch. No mystery parts in there.

Pete, wa2cwa

On Tue, 04 Nov 2008 11:09:27 -0600 "Michael D. Harmon" <mharmon at att.net>
writes:
> Hi,
> 
> I know most of the original stations operated back in the Fifties 
> and 
> Sixties used the venerable Dow-Key antenna relay, connected to the 
> 110VAC line from the internal PTT relay.  However, back when I was a 
> 
> Novice (late Sixties), I built an electronic T-R switch to use with 
> my 
> DX-40 and HQ-110.  I was a poor college student and couldn't afford 
> to 
> buy a real Dow-Key!  I seem to remember that I was one of a very few 
> 
> guys to actually have QSK capabilities back then.  Granted, the 
> DX-40 
> input was only 75 watts (with a good 6146), but it worked fine.
> 
> Now after all these years later, I've gotten the boatanchor bug, and 
> 
> have a National NC-300 receiver and a Viking Valiant transmitter I'm 
> 
> rebuilding for the "ultimate" boatanchor station I would have given 
> an 
> arm and leg for back when I was a teenager.  After looking at the 
> prices 
> and availability for the Dow-Key relays, I'm very interested in 
> (once 
> again) pursuing the electronic T-R switch alternative.
> 
> Have any of you had success using an electronic T-R switch with a 
> transmitter having the power of a Valiant?  Can I get enough 
> isolation 
> in a vacuum-tube design to allow me to monitor the receiver output 
> between dits with headphones without destroying my eardrums with 
> switching transients?  I'm open for any suggestions, tips, or 
> advice, 
> since I haven't tried this since 1968!  (Wow ... forty years 
> ago!!).
> 
> Anyway, if any of you have ideas, designs, etc., send them along.  
> I'm 
> interested.
> 
> Thanks!
> Mike, WB0LDJ
> mharmon at att dot net
> _______________________________________________
> 
>