[R-390] 60 Hz on Audio

[w9ya]

I am going to go out on a limb here and answer your question: "
If not acceptable, what could be causing the distinct difference of
60 Hz level just by changing the BW setting? " <- The filter.

Not So Anonymous



On Tue, Jun 9, 2009 at 1:30 PM, Jon Schlegel <ews265 at rochester.rr.com>wrote:

> All,
>
> Please check out these photos of the output of my R-390A IF Module.
>
> This first image shows the audio output from the Diode Load signal
> line.  Input to the IF module is 455 kHz modulated 30% with a 1 kHz
> tone.  The 16 kHz mechanical filter is selected in this image.  The
> audio looks pretty clean.  Any 60 Hz that might be there really isn't
> visible.
>
> http://www.vecnav.com/R-390A_IFmodule/DiodeLoadOut_16kHzMechFilter.jpg
>
>
>
> This second image was made with the identical conditions as above
> except that the selected mechanical filter is now 8 kHz.  A 60 Hz
> component is now easily visible.  In fact it's about 25 dB or a
> factor of about 18 times worse than with the 16 kHz setting.
>
> http://www.vecnav.com/R-390A_IFmodule/DiodeLoadOut_8kHzMechFilter.jpg
>
>
>
> Is this kind of behavior acceptable for these receivers?
>
> 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
>
>
> ______________________________________________________________
> 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
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>