[Elecraft] 160M Receive and Transmit Antenna Switching help

[Mel Farrer via Elecraft]

Any RF horse race is a bad choice.  I prefer to do the simple sequence switching.   A single relay that is keyed by the PTT line with one set switching the loop off and the Tx antenna ON and the other set of  NO contacts on that relay keys the KX3 and Amp.  I built a little TR cast AL box that has the KX3 mike plugged into it and a short cable with the 4 conductor cable to the KX3. The box has the cable from each antenna and the plugged into it.   I use a 12 VDC jumper into the box to supply the relay  . Simple DPDT crystal can relay on a perf board is enough to handle a couple of hundred HF watts.  The third RF cable goes the the output of the KXPA100.    I love KISS,
Mel, K6KBE

      From: Don Wilhelm <w3fpr at embarqmail.com>
 To: Jim GM <jim.gmforum at gmail.com>; Elecraft <elecraft at mailman.qth.net> 
 Sent: Saturday, November 22, 2014 12:55 PM
 Subject: Re: [Elecraft] 160M Receive and Transmit Antenna Switching help
   
Jim,

Since the KX3/KXPA100 combination has no RX ANT input, you will have to 
devise some kind of external T/R switching to connect the receiving loop 
during non-transmit times.
There is a PA Keying output from the KXPA100 that you could use to 
activate the T/R switch for transmit times.

If you use a relay, it must be fast enough to avoid hot-switching or you 
will be seeing the KXPA100 go into a fault condition.

73,
Don W3FPR

On 11/22/2014 1:59 PM, Jim GM wrote:
> I have a KX3 and KXPA100.  I want to put up a receiving loop antenna for
> 160M and transmit with my short marconi 160M antenna.  What do I need to do
> to accomplish this?
>
> Switching things the way they are now takes too long and too many
> operations so I pretty much gave up on the project.
>
>

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