[Elecraft] K3 deaf when narrow filter engaged

Sat Jul 9 00:44:33 EDT 2011

Problem solved -- I think....

I ended up doing a factory reset (power-up while pressing/holding Shift knob
in until power up completed), EE INIT. And I just read through the rest of
your note and now see that's what you suggested!

I then went through the entire setup process.

What I did differently this time was during the reference oscillator
calibration, I found that much less of an adjustment was needed than what I
did before.  In fact it was fine as-is.  I'm not sure what prompted me to
adjust the oscillator before (I used WWV as an on-air reference), but this
time around, everything came out fine.

I suspect my incorrect reference oscillator adjustment explains why all
three filters appeared to have incorrect offsets.

Now the only remaining problem is getting the rig to show S9 with a 50 uV
source.  The adjustment range doesn't go far enough to produce S9 on the
display. I put a new battery in the XG2 signal source, same problem.  I'm
not too concerned about this one -- only mildly annoyed.  This is a very
minor problem compared to what I *thought* was wrong with my filters!

Thanks for your detailed response -- appreciated.

--Andrew, NV1B

On Sat, Jul 9, 2011 at 12:33 AM, Matt Zilmer <mzilmer at verizon.net> wrote:

> The chances of that are negligible.  You should send your original
> email and all follow-ups to k3support at elecraft.com.
>
> I have heard of a lot of strange K3 symptoms, but this one is beyond
> the pale.  It sounds like one of the pre- or post-roofing filter
> components is somehow shifting the resonance, and looking at the
> schematic I just don't see how that's possible unless there is a
> bypass-value in place of a regular cap.  Conventional SMT assembly -
> that would not happen.
>
> I'm no expert, but this probably is not some trouble that can be shot
> over email.  One of the Elecraft gang can help you narrow it down, but
> it should probably be done interactively over the phone or Skype or
> whatever.
>
> You *may* be able to avoid the additional hassle by running the EE
> INIT procedure on your K3 and starting over.  This will only work if
> there isn't some defect in the hardware, but that is so unlikely that
> running EE INIT is your best bet.  See p66 of the Owner's Manual (rev
> D7), or use Adobe to search for "Parameter Initialization".  If you
> dorked a setting, then EE INIT will solve that problem and put your K3
> into its factory default settings.
>
> Good Luck.  No matter what you can or can't get done in short order,
> Elecraft will assist you with any problem.
>
> 73,
>
> matt W6NIA
> K3 #24
>
> ==
>
>
> On Fri, 08 Jul 2011 23:40:40 -0400, you wrote:
>
> >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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