[ARC5] CW/MCW

[Fuqua, Bill L]

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From: Kenneth G. Gordon [kgordon2006 at frontier.com]
Sent: Monday, November 11, 2013 3:43 PM
To: Fuqua, Bill L; ARC-5 List
Subject: Re: [ARC5] CW/MCW


>    Other good options were to use pentagrid converters for product
>    detectors.

Yes. 6BE6 was commonly used for such. I never liked that particular kind of
PD though. The 6BE6 is a very noisy mixer and doesn't make a particularly
stable BFO either.
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  Noise is not an issue after several stages of amplification
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> Some Hammarlunds use the last IF (pentode) as a product detector.

Yes. HQ-110 and possibly the HQ-160. To me, that whole idea was a waste
of a good IF amp stage. :-)

I have always thought it was somewhat of a kludge.
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 The last IF transformer is usually broadband anyway since it is driving
the heavy load of a diode detector in AM or CW without a PD.
  The audio bandpass filter after the PD can enhance the selectivity and
the stage will provide just about as much amplification as a product detector
as it would has a heavily loaded last IF driving a diode detector. It is 
a cleaver solution and worked very well.

Ken W7EKB