[R-390] Product detectors for dummies

[Ing. Giovanni Becattini]

Thanks for replying, but my doubts are more philosophical than practical…. I mean, I would understand….

> Il giorno 29 set 2024, alle ore 20:01, Barry Scott <72volkswagon at gmail.com> ha scritto:
> 
> 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 <mailto: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… 😁
>> ______________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:R-390 at mailman.qth.net <mailto:R-390 at mailman.qth.net>
>> 
>> This list hosted by: http://www.qsl.net <http://www.qsl.net/>
>> Please help support this email list: http://www.qsl.net/donate.html