[R-390] 60 Hz on Audio

[Jon Schlegel]

Hi Tony,

I get the same behavior regardless of gain settings, AGC, MGC.  When 
I switch OUT of AGC, I set the generator signal level appearing at 
the IF test point (J514) so that it is the same as when the receiver 
is into AGC (about -15 dBm).

I can now also say that if I remove V502 and inject a 455 kHz signal 
at pin 5 on the socket (plate) I get a very clean audio signal out 
with virtually no 60 Hz present.  It would seem then that it's 
getting in previous to that.  Time to inject at pin 5 on V501.

Jon


At 02:24 PM 6/9/2009 -0600, ANTHONY CASORSO wrote:

>If you have already mentioned it, my apologies. Are you in MGC or 
>AGC mode? If AGC, what happens in MGC mode? I am thinking that the 
>broader filter lets more noise through which generates more AGC, 
>reducing the IF gain. If in MGC mode, then this is obviously not the case.
>
>
>
>Tony Casorso
>
> >
> > If not acceptable, what could be causing the distinct difference of
> > 60 Hz level just by changing the BW setting?
> >
> >
> > Thanks and regards,
> > Jon Schlegel WA3MVM
> >
> >
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