[Collins] 32S-1 unknown mod

[Dr. Gerald N. Johnson]

I was just loaned a copy of W5USI's book on the KWM-2A. On page 60 he 
describes that mod for both KWM-2 and S-line. Its quasi AM, only one 
sideband. He doesn't list a source or reference. He does suggest that 
the output must be limited to approximately 50 watts. Limit tuning and 
loading 100-125 ma maximum. Adjust carrier reinsert pot for no more than 
100ma in USB mode, mic. gain to minimum (not off). Raise mic gain until 
a slight plate current variation is noted on the plate current meter 
with modulation.

I'd watch the output envelope with a scope and make sure any peaks 
didn't get clipped. When the PA is designed for linear operation on SSB 
or on off keying on CW it may not have enough cooling for full tilt or 
enough peak capability for full FM. Most rigs running both sidebands 
these days run a maximum carrier of 1/4 the PEP power because full AM 
peaks are twice voltage, so 4 times the carrier power.

Its not a Collins company mod. That knob was and may be still a common 
knob, not a Collins special. A standard distributor product.

73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.

On 3/8/2014 3:12 PM, Bill Riches wrote:
> Just obtained a clean 32s-1 that has a mod in it that I have not seen.  I
> have not fired up the unit yet.  Pin 6 of v2 plate of BFO  osc is connected
> to a 100 k pot thru a 51 pf cap.  The wiper of the pot is connected to p7 of
> V4 first mixer through a 100 pf cap in series with a 22k resistor.  The 100
> k pot is mounted on the same type of add-on bracket that is used for the vox
> time const control mod. The knob on this control is identical to the other
> knobs on the other three controls.  Workmanship is first class.  Is this a
> Collins mod?  What is it for?  Inquiring mimes want to know!
>
>
>
> 73,
>
> Bill, WA2DVU
>
> Cape May, NJ
>
>
>
> .
>
>
>
> ______________________________________________________________
> Collins mailing list
> Home: http://mailman.qth.net/mailman/listinfo/collins
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Collins at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>