[R-390] Filter Bandwidth Question

[Larry H]

Hi Ed,  You are right that the .1, 1, and 2 kc bandwidths use the 2 kc
filter.  Sometimes getting the vfo on the center using the .1 b/w is
difficult, so try adjusting the kc knob carefully.  What can happen is the
455 kc crystal filter in Z501 will drift over time and nolonger be on 455
kc.  That's why the 1st part of the IF alignment procedure is to set the kc
knob on the strongest signal point when in the .1 kc position and set the
bfo to 0 there.  The crystal should be ok as you said that the signal
strength was ok on the 1 kc position.  The Z501 alignment procedure may
need to be done to get the .1 and 1 kc signal levels equal.

Regards, Larry

On Mon, May 11, 2020 at 2:01 PM Ed G <ed.n3cw at gmail.com> wrote:

> Hi Folks,
>      My Capehart 390A is working mostly FB, but I do notice what would
> appear to be filter loss when I switch down to the .1 filter bandwidth.
> All other filter positions seem to be fine with no difference in
> signal/S-meter readings when going from 16 KC down to 1 KC.  But when I go
> to .1 KC signal level does drop down noticeably. I thought the 1 and .1
> positions used the same mechanical filter, so perhaps the problem is
> something else (load resistor)?  Any suggestions on what to check?  Thanks!
> --Ed—
>
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