[Elecraft] K3 deaf when narrow filter engaged

[Andrew Moore]

Filter placements are correct, and no empty slots are enabled -- I've done
the setup both ways: manually via CONFIG on the K3 itself, and via the K3
utility.  Done it many times now.

Here's the odd part:

If I change the frequency offsets in the K3 (via CONFIG menu), I can dial
across the range of value offsets and peak a signal almost to the point at
which things sound like they're operating properly.  Same thing happens for
3 of my filters -- the 2.7k, 400 Hz and 200 Hz.  In all cases the specified
offset is not the one value that gives the strongest signal.  Using the
specified offsets, it seems like the signal is not properly centered in the
passband.

What are the chances all three of my filters have the wrong offsets?
 Possible but doubtful.

Is there some other setting on the K3 that I may have inadvertently tweaked
during calibration that would have thrown off all filters?

I'm stumped.

--Andrew, NV1B
..





On Fri, Jul 8, 2011 at 9:35 PM, Guy Olinger K2AV <olinger at bellsouth.net>wrote:

> The most likely cause of your problem is that the filter placements as
> viewed in the K3 utility and as actually installed on the main board
> do not actually match.  Next is that you have left an empty slot
> ENABLED in the K3 utility.  After that, a filter not plugged all the
> way in or defective.
>
> 73, Guy.
>
> On Fri, Jul 8, 2011 at 8:06 PM, Andrew Moore <andrew.nv1b at gmail.com>
> wrote:
> > New K3 with 3 filters:
> >
> > FL1 - empty
> > FL2 - 2700 Hz
> > FL3 - empty
> > FL4 - 400 Hz
> > FL5 - 200 Hz
> >
> > FL2,4,5 enabled, offsets and bandwidths entered, and filters plugged into
> > right slots (FL1 can remain empty right?)
> >
> > When I turn the bandwidth encoder CCW, everything's fine until I hit 400
> Hz.
> >  At 450, I hear signal. At 400, when FL4 kicks in, receiver goes quiet
> from
> > then on.
> >
> > Ideas?
> >
> > Also - RF calibration - I'm using an XG2 to feed the K3 a 50 uV signal.
>  The
> > K3 hears it at about S5 max, not even close to S9.  Followed the
> calibration
> > instructions.
> >
> > --Andrew, NV1B
> > ..
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