K2: squeezing rig causing frequency change...

[Steve Kallal]

I was trying to calibrate the frequency on my K2/100 and noticed that
the received beat frequency changed when attaching the top cover (the
KPA100 option). After putting the mounting screws back in, I noticed the
frequency will again change when squeezing the top and bottom covers
towards each other with my fingers. The change is about 50 to 100 Hz or so.

Is this normal? Somewhat I don't think so, but hadn't paid attention
before. I've been monitoring WWV on 10 MHz in CW mode beating against
the spot tone. There is constant carrier to beat against, and I that's
how I noticed the beat frequency changed.

In the meanwhile I will tighten everything  down again.

73,

Steve N6VL
K2/100 #2289

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[Mike K8CN]

Steve,

If memory serves me correctly, L33 (the BFO coil on the underside of the main RF board)
has very little clearance to the bottom cover, and I found the same mild detuning when
pressing on the bottom cover.

Mike, K8CN
K2/10 #5569

Steve Kallal wrote

I was trying to calibrate the frequency on my K2/100 and noticed that
the received beat frequency changed when attaching the top cover (the
KPA100 option). After putting the mounting screws back in, I noticed the
frequency will again change when squeezing the top and bottom covers
towards each other with my fingers. The change is about 50 to 100 Hz or so.

Is this normal? Somewhat I don't think so, but hadn't paid attention
before. I've been monitoring WWV on 10 MHz in CW mode beating against
the spot tone. There is constant carrier to beat against, and I that's
how I noticed the beat frequency changed.

In the meanwhile I will tighten everything  down again.

73,

Steve N6VL
K2/100 #2289

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[Don Wilhelm-4]

Steve,

It is normal that squeezing the bottom panel will cause a BFO shift due
to the proximity of the BFO inductor to the panel.  One normally does
not squeeze th epanel during operation, so it is not usually a problem.  
The BFO may also shift during the time the KPA100 is being put into place.

Now if reasonable pressure down on the mounted KPA100 causes a BFO
shift, you either have something loose or the enclosure is being
deformed in some manner - that behavior is not normal.

73,
Don W3FPR

Steve Kallal wrote:

> I was trying to calibrate the frequency on my K2/100 and noticed that
> the received beat frequency changed when attaching the top cover (the
> KPA100 option). After putting the mounting screws back in, I noticed
> the frequency will again change when squeezing the top and bottom
> covers towards each other with my fingers. The change is about 50 to
> 100 Hz or so.
>
> Is this normal? Somewhat I don't think so, but hadn't paid attention
> before. I've been monitoring WWV on 10 MHz in CW mode beating against
> the spot tone. There is constant carrier to beat against, and I that's
> how I noticed the beat frequency changed.
>
>

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