[Hallicrafters] Re: SX-101A standby functon with reduced volume

[kiyoinc at attglobal.net]

<barfworks at bellsouth.net> wrote:

>     maybe I am weird. I like to monitor my transmit audio off the air.
> Therefore, I don't like to "mute" the receiver during transmit.
> 
>     I am working on a T/R switching arrangement for the SX-101A receiver and
> HT-40 xmitter.  The receiver is designed to mute during transmit. When you
> put the SX-101A in STANDBY mode, an external switch across contact 1 and 4
> of the accessory plug will turn the audio on and off.  This is, of course, a
> "mute" function.  I don't want to mute, but to be able to hear my
> transmitted signal at a substantially reduced volume.
> 
>     Has anyone ever put a resistor across those contacts to allow some audio
> to pass, rather than opening the switch entirely to mute? Inside the
> circuit, there is a 330K resistor there anyway when the contacts are open.
> I'm thinking of starting with a 100K, and experimenting from there. (I'm not
> sure what wattage to try.)  Is this a workable technique to allow on air
> signal monitoring with the receiver in "mute"?

That works well.  I did that to my SX-101A 35 years ago.   I don't have 
the receiver here but I put a pot, like the RF gain pot, in an external 
box.

As I recall, I wasn't un-muting the audio, it was the RF/IF gain.  I was 
using a home made, speaker box and I added the Hallicrafters' 25 ufd 
capacitor and switch to the speaker.

Worked great, you do make the weeOOOooop-weeOOOOooop sound of zero 
beating SSB.  So be ready for that or use headphones.

de ah6gi/4