[Boatanchors] DOW KEY info

Tue, 11 Feb 2003 05:22:12 -0600

Hi Ed & Dave & Gang,

I have used an electronic T/R switch for everything, CW, SSB, etc....for
years....
No Problem!....
Good luck Dave....

Ken....N5CM....NNN0FKQ....

----- Original Message -----
From: "Ed Tanton" <[email protected]>
To: <[email protected]>
Sent: Monday, February 10, 2003 9:53 PM
Subject: Re: [Boatanchors] DOW KEY info

>
> ///snip At 09:44 PM 2003-02-10, Dave Roscoe wrote:
> >Can someone fill me in on info  re:  a Dow Key TRM-1 changeover relay. It
> >uses a 6EH5 tube.  I think they use the same scheme as the EF
> >Johnson  model  but not sure.
> >
> >1. What are the power supply requirements for the tube ?
> >2.  Which are the RX and TX terminals?   Since there is no "hard"
> >contact  (as from a relay) , I am not sure how to pin down which is
> >which.  A schematic would help too.
> >
> >Thanks in advance from:
> >    Dave W1DWZ
> >///snip
>
> Hi Dave... MY DKC-TRM-1 uses a 6CB6 Sharp Cutoff Pentode. I'd BET the
power
> connections/etc. are the same. There were several variations... and the
way
> you connect a T/R SW with only two connectors is: use a coaxial T
connector
> right at the transmitter (attach a double-male connector to the TX, then
to
> one side of the T connector.) Connect the ANT to one side of the T... and
> you have connected the other side to the transmitter. The 3rd (bottom of
> the T-so to speak) connector goes to the INPUT of the T/R SW. Your
receiver
> then connects to the output. If this isn't clear... let me know, and I'll
> draw it. You can also take a look at the connection instructions I have
> written on one of my web pages:
<http://www.qsl.net/n4xy/accessories-2.html> .
>
> There should be a 3 conductor cable for power: RED is B+; Black is GND;
and
> the other (white? I forget) is the filament. Double check this by
measuring
> it out with your ohmmeter: The filament wire will look like a short... but
> have SOME resistance to GND. Obviously, GND ought to be zero ohms. The
> other wire is your B+.
>
> If you need to identify which RF connector is the receiver output, find
the
> coil, and note where the capacitor goes that taps from it. The other
> connector goes to the T-connector connection you have at the transmitter.
>
> Now, if it's a THREE connector T/R SW, the ANT and TX connector center
> connectors are simply wired through the unit-as shown in the drawing. Zero
> ohms from one to the other, but infinite to ground. The 3rd connector is
> the receiver output.
>
> I love using a T/R SW... the breakin is terrific! I use the B&W 380-B
which
> is a 2-terminal unit. One thing to be CERTAIN of: ALWAYS use a Low Pass
> Filter AFTER a T/R SW, BETWEEN it and the ANTENNA.
>
> By the way... T/R SW are CW ONLY.
>
>
>
> 73 Ed Tanton N4XY <[email protected]>
>
> Ed Tanton N4XY
> 189 Pioneer Trail
> Marietta, GA 30068-3466
>
> website: http://www.n4xy.com
>
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>
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