[Collins] AADE digital dial on the KWS-1?

[Dennis Petrich]

Hi Jerry,

AADE sells this thing as a plug-n-play for the KWS-1 so I thought I would 
give him the benefit of the doubt...   After it didn't work I looked at the 
schematic and saw exactly what you saw, too much shunt cap so the wires are 
killing the signal.  I will need to design my own interface, just what I 
don't have the time to do....

Ciao, Dennis, k0eoo


----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj at storm.weather.net>
To: <collins at mailman.qth.net>
Sent: Saturday, April 18, 2009 12:20 PM
Subject: Re: [Collins] AADE digital dial on the KWS-1?


> On Sat, 2009-04-18 at 11:47 -0500, Dennis Petrich wrote:
>> I am installing the AADE C75 digital dial on my KWS-1 and notice it's 
>> loading down the VFO and HFO injection points so the KWS-1 doesn't want 
>> to output any signal.  The AADE digital dial works just great indicating 
>> the signals are always present.  When I remove those two connections the 
>> KWS-1 works just great.
>>
>> Has anyone on the Collins reflector had this experience?  I don't want to 
>> make any adjustments to correct for the coax load if I don't have to?
>>
>> Dennis, k0eoo
>
> The outputs of the crystal oscillator and PTO are very high impedance
> points. 100K grid resistor on the mixer for load. A coax connected
> counter is a killer on that high impedance. Not at all like the
> oscillator outputs in a 75S or 32S that are low impedance and stand
> extra loads.
>
> The coupling capacitor from the PTO is 24 pf, less than the capacitance
> of one FOOT of coax. The coupling capacitor from the crystal oscillator
> is 5 pf. Way less than the capacitance of a foot of coax. If the counter
> is sensitive enough, you can try a small coupling capacitor at the coax
> connector in the KWS-1, like 5 pf for the PTO and 1 pf for the crystal.
> Else you may have to build follower circuits to match the coax to the
> high impedance oscillator circuits.
> -- 
> 73, Jerry, K0CQ, Technical Advisor to the CRA
> All content copyright Dr. Gerald N. Johnson, electrical engineer
>
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