[Elecraft] K3 - External RX Mute

[Joe Subich, W4TV]

Dave,

How is the signal reaching the "spotting" K3 during transmit from
the "run" radio?  Have you checked the signal level with the antenna
completely disconnected from the run radio?

If the problem is coupling through the 2S1 and primary antenna
input you could build a pin diode operated attenuator (or even
reed relay switched attenuator),  install it in the RF IN/OUT
loop of the spotting radio and control it with PTT from the run
radio.

73,

    ... Joe, W4TV

On 8/17/2010 8:37 PM, Dave Hawes wrote:
> In the recent WAE CW Contest, we had two K3s on the same band, one as
> the live transmitter, and the other either tuning the band or listening on the
> running frequency to assist the run operator.
>
> While listening on the run station's frequency, even though we used an Acom
> 2S1 to ground the antenna line and thus protect the RX front end, the run
> station's signal was very loud in the spot radio's RX.
>
> Is there a way to configure the K3 for variable muting during PTT active times
> on the other K3?  I'm wondering if the run station's PTT line could be used to
> variably mute the spot RX somehow.  Full muting is not the goal, but rather a
> way to keep the RX "on" but keep the S meter down to S9 or thereabouts, to
> allow the RX to recover very quickly.  Even with AGC-F, often the first
> character of the caller's callsign would be missed due to the recovery time.
> Plus it hurt my ears!
>
> OTs may remember that the Collins 75S3B had a "Mute" jack on the back, to
> be used with the 32S3 transmitter.  In those days, we could accomplish a
> variable mute of the RX by putting a large resistance pot (50K maybe) across
> that jack, and switch it in and out with a reed relay following keying.  Can this
> be done with the K3?
>
> 73 - Dave N3RD
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