P3/K3 spurry

[stephen pearce]

Hi

My P3/K3 combination (with pa and atu) seems to have developed a big spurry
on the spectral display of the P3 which sits around
the mid point of the display (the tuned frequency) .. it is initially (on
turn on) worse and gradually subsides as things warm up (I presume)
though never goes away entirely. It didn't used to be there .. and I wonder
if it has been observed and trouble shotted in another system.
It doesn't seem to produce any noticable interference on the audio but it
does make it difficult to id signal on the spectral display.

73s
de
zl1any

--
Stephen Pearce
Critical Care
Whangarei
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[Phil Wheeler-2]

No such thing here with same equipment.

Best take a digital shot of the screen and send it
to Elecraft.

73, Phil W7OX

On 4/7/14, 4:55 PM, stephen pearce wrote:

> Hi
>
> My P3/K3 combination (with pa and atu) seems to have developed a big spurry
> on the spectral display of the P3 which sits around
> the mid point of the display (the tuned frequency) .. it is initially (on
> turn on) worse and gradually subsides as things warm up (I presume)
> though never goes away entirely. It didn't used to be there .. and I wonder
> if it has been observed and trouble shotted in another system.
> It doesn't seem to produce any noticable interference on the audio but it
> does make it difficult to id signal on the spectral display.
>
> 73s
> de
> zl1any
>

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[Jim Brown-10]

On 4/7/2014 4:55 PM, stephen pearce wrote:
> My P3/K3 combination (with pa and atu) seems to have developed a big spurry
> on the spectral display of the P3 which sits around
> the mid point of the display (the tuned frequency)

One possible cause is bad coax between the P3 and K3.

73, Jim K9YC
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[Bill-3]

I had problems similar to what you describe when I first got the P3. The
story is simple: Use a mil-spec RF patch cable between the K3 and the
P3. The long story: I tried grounding straps, redoing the station ground
system, checking all antenna connections, was sent a couple of
replacement cables - and in general wasted a lot of time over a period
of a couple of weeks trying to rid my P3 of the odd signals it was
displaying. Each replacement cable did improve or change the display.
This clued me in that the cable had a direct effect - so I put on my own
mil-spec cable - and immediately the P3 was fixed and remains to today.

Try replacing the cable with a known quality cable and see if that fixes
your problem - before you jump through any additional hoops. Let me know
if it does - I would be interested if my solution helps anyone. Use a
mil-spec cable if possible - not something of unknown quality.

Bill K-Line



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[k6dgw]

Somewhere, not too far after the introduction of the P3, Elecraft seems
to have received some inferior RG-58 patch cables with BNC connectors
from a supplier and the problems were several.  In my case, at narrow
spans [20 KHz or so], the baseline would just drift up.  Putting my hand
on top of the P3 sent it back down where it belonged.  At wider spanss
[~100 KHz, I could see that it looked like a very broad spur of variable
amplitude.

Elecraft sent me a new cable with explicit instructions to cut the old
one into small pieces so it didn't show up at a flea market. :-)  I did,
the new cable solved the problem.  Anyone who has worked in
manufacturing engineering knows the problem, sometimes it's 2nd or 3rd
generation ... your supplier got some bad stuff from their supplier and
didn't know about it.

It is very important that the case of the P3 be electrically intact ...
any overspray on contact surfaces be removed and *all* screws tight.
Also, if you have an early K3 [mine is #642], there is a simple mod to
increase the first IF output.  Just destroy one SMT resistor ... you
don't have to unsolder it, just break it with needle nose pliers ... and
replace it with a "regular" resistor.  Results in less gain requirement
in the P3, and got rid of a lot of "grass" for me.
73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 4/8/2014 11:09 AM, Bill W2BLC wrote:
> I had problems similar to what you describe when I first got the P3. The
> story is simple: Use a mil-spec RF patch cable between the K3 and the
> P3.

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