[R-390] Product detectors for dummies

[Barry Scott]

I used to have an external product detector that used the IF output as its
input.  It worked quite well and I wish I hadn't sold it!  Perhaps you
could find something like this?

Thanks,
Barry - N4BUQ


On Sun, Sep 29, 2024 at 12:57 PM Ing. Giovanni Becattini via R-390 <
r-390 at mailman.qth.net> wrote:

> 1) why do we say that our R-390A has not a product detector? If I
> correctly understood, when we use the BFO, we practically use a product
> detector. I would prefer to say that we can implement a better product
> detector. Is this correct?
> 2) The use of BFO as is, produces a local carrier which is too low in
> relation to the IF out which contains the side band. For this, we need to
> attenuate the RF gain to get a good audio signal. Is this correct?
> 3) my 51J-4 seems to work much better than the R-390A receiving SSB
> signals. This is partly confirmed by the fact that Collins officially sold
> 51J-4 ALSO for SSB. Looking at the schematic, I could not find an
> explanation for that; the signal from the BFO is simply connected to the
> envelope rectifier diode. Was it simply designed “better”?
>
> Forgive this donkey… 😁
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