[Johnson] Johnson T-R Switch Receiver muting

[Harry Vaught, KT4AE]

I don't have feedback, I'm talking about the feedthrough of the 
transmitted signal to the receiver even as described in the T-R switch 
manual.  I could control the fed through signal with the audio gain, but 
I wanted an RF sensing switch to handle everything without other actions.

I have an MFJ RF-sensing T/R switch on my HT-32/SX-101A which does it 
all perfectly.  I just thought that a piece of Johnson gear with the 
Ranger would be nice but I suspect I'm trying to do something outside 
the design possibilities.

This reminds me.

Regards,

Harry, KT4AE

On 5/10/2012 11:25 AM, James M. Walker wrote:
> Well,
> I use the Johnson Pacemaker, Thunderbolt combo, with
> an SX-101A receiver! The antenna connection comes in through
> a Johnson KW Matchbox. Antenna is single wire feed to a 100 ft.
> Flat-Top antenna, works on 80 -10 meters very well, with little
> or NO SWR reading at the matchbox.
>
> The RG-8 coax from the Matchbox to the Thunderbolt is
> a single length. The cable from the Pacemaker is a three (3)
> foot length, and goes to the "T-Bolt input connector. The
> Coax from the TR-Switch to the SX-101A is Belden RG-58(A/U).
>
> That system doesn't get feedback on AM, as I control the audio
> gain manually. The system as a whole seems to work as described
> in the various equipment manuals.
> FWIW
>
> Jim
> WB2FCN/WD2XSH-22
> http://eshop1.chem.buffalo.edu/
>
>
> ----- Original Message -----
> From: "Harry Vaught, KT4AE"<kt4ae at bellsouth.net>
> To:<johnson at mailman.qth.net>
> Sent: Thursday, May 10, 2012 9:23 AM
> Subject: [Johnson] Johnson T-R Switch Receiver muting
>
>
>> Has anyone conquered the receiver muting problem with the Johnson T-R
>> switch?  It was to be used in my Ranger/SX-100 station.
>>
>> I installed the mod from the March, 2011 ER which provides a reed relay
>> for receiver muting when transmitting.  Also, the switch grounds the
>> receiver antenna connection when in transmit.
>>
>> What is needed is to disconnect the receiver antenna when transmitting.
>>   I have always done this with relay based switches I've built.  All the
>> muting relay does is to turn off external signals.  The "sidetone" from
>> the switch is still way too powerful. The front end is still overloaded,
>> AVC or not, and takes a couple of seconds to recover.
>>
>> Has anyone found a way to provide useful silencing of the receiver in
>> transmit using the Johnson switch?  These switches are very popular.  If
>> there's no solution to the muting problem, how do people live with it?
>>
>> Regards,
>>
>> Harry, KT4AE
>> Watkinsville, Georgia
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>
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