[Milsurplus] Re: 6m "Golden Era" Radios with Squelch

[David Stinson]

> ----- Original Message ----- 
> From: "David M. Upton" <david at wb1cmg.mv.com>
>>I would like to know if any of the classic AM 6m rigs were equipped with 
>>carrier squelch.  My recollection is very few if any.  This is a 
>>consideration in setting up a monitoring capability on 50.4 MHz ....

I had an idea- though I haven't done it yet-
of how to put those little 75 MC "marker beacon" 
receivers to use as band-opening alerts.  
A little NE602 converter would provide
both gain and conversion.   
They're wide enough that signals on both 50.400 and 50.125 
would be detected.  Or you could use the old 
40-something MC paging channels 
(don't know if they are still as active as they used to be), 
or channel 2 television carriers, etc.
Put a whip antenna on the converter and 
24 volts to the little unit, set the "trip level" and forget it.
When there's an opening, you'll get a relay closure
to connect a speaker, flash a light or blare a siren, as you see fit.
I have a circuit for the converter, which takes 10 parts and a perf board.
The only slightly-expensive part might be the crystal.
Tuning the set freq of the receiver around
might allow a surplus xtal to work; the 602 will do 3rd overtones 
or fundamentals, and several harmonics of the xtal freq as well.
If you're really good and use quality parts, you can wire the 
602 with a VFO local osc. and skip the crystal.

73 Dave S.