[Boatanchors] Antenna Relays & T-R Switches

[Bob Macklin]

And you can get the Johnson T/R switch at BAMA!

Bob Macklin
K5MYJ
Kent (Seattle), Wa,
"Real Radios Glow in the Dark"

----- Original Message ----- 
From: "Peter Markavage" <manualman at juno.com>
To: <boatanchors at mailman.qth.net>
Sent: Tuesday, November 04, 2008 9:30 AM
Subject: Re: [Boatanchors] Antenna Relays & T-R Switches


> 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
> > _______________________________________________
> > 
> > 
> _______________________________________________
>