[ARC5] CW/MCW

[Kenneth G. Gordon]

On 11 Nov 2013 at 20:17, Fuqua, Bill L wrote:

>    Well, the puzzling part is that they knew very well those days that
>    a mixer and product detector were the same thing.

Yes, but to implement a PD when it wasn't really necessary would have 
necessitated a much more complex receiver, thus a higher-cost receiver. 
Since the only two methods of communication most commonly used at that 
time were CW and AM, there was no need for a PD, nor to implement an 
AVC that wasn't effected by the BFO, either.

> The only difference is the output frequency range. Even a diode
> detector worked well as a product detector just as long as the BFO
> injection voltage was much greater than the signal to be detected.

True.

> Just as a single triode detector. In both cases you are relying on the
> non-linearity of the device to achieve frequency mixing. If the device
> is driven so hard that it works as a switch, more or less, you have a
> reasonably good product detector. 

Yes. "Reasonably" :-)

>    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.
 
> 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.

Ken W7EKB