[Elecraft] PX3 Spike won't go away

[Brian Waterworth]

Hi Phil,

It is a Stealth.  I picked it up used at a flea market.  Mine is an older
model no longer supported, but it works really well.  Perfect pairing for
the KX3/PX3 due to its size and ability to run off of 12V.

https://www.stealth.com/littlepcs/fanless-mini-pcs/

regards,
Brian
VE3IBW

On Thu, Jun 23, 2016 at 10:37 PM, Phil Wheeler <w7ox at socal.rr.com> wrote:

> What sort of "small computer", Brian?
>
> Phil W7OX
>
>
> On 6/23/16 4:31 PM, Brian Waterworth wrote:
>
>> In prep for field day, I decided to stage everything last night and also
>> ran into the same problem as you describe.  I re-seated all the cables.
>> No
>> effect.  I turned on the rx shft on the kx3 and the nasty noise shifted
>> away.  Ok, that's good.  But not what I wanted.
>>
>> I disconnected the USB acc1 cable from the small computer I was planning
>> to
>> take with me to FD and the noise vanished.  Each of the computer, the kx3,
>> px3, external power supply, external antenna tuner are all grounded to a
>> common point.  The exception is the monitor and fan (it's going to be hot
>> :-).
>>
>> I connected the same setup using a raspberry pi instead of the small
>> computer and no noise observed at the tuned frequency.  Drat.
>>
>> So, I am thinking of buying a powered USB hub to try and isolate the USB
>> acc1 cable plugged into the PX3.  Seems as thought the small computer I
>> was
>> going to use is picking up the internal IF and bringing it back into the
>> PX3, KX3 via the USB acc1 cable.
>>
>> regards,
>> Brian
>> VE3IBW
>>
>> On Thu, Jun 23, 2016 at 10:58 AM, Sanger, Joseph <Joseph.Sanger at nyumc.org
>> >
>> wrote:
>>
>> I have developed a new problem with my PX3, which has been quietly sitting
>>> in a case for the past 6 months.
>>>
>>> Whenever I tune across the display, there is a slowly rising spike at the
>>> base frequency (for instance, in USB mode this spike adheres to the left
>>> hand edge of the bandpass indicator on PX3 screeen), takes about 2-3
>>> seconds or so to increase in intensity, and then dwarfs any of the
>>> signals
>>> on the band.  This spike tracks across as I tune; it is there whether or
>>> not the antenna is connected.  I can tune to stations and hear them fine,
>>> but the display is barely usable because of this very tall spike that
>>> won't
>>> go away.  I reseated my cables connecting the PX3 to KX3, with no change
>>> in
>>> behavior.  I have no other cables here to swap them out, and am kind of
>>> stuck
>>>
>>> I have updated b both KX3 and PX3 to latest firmware, with no change in
>>> behavior.
>>>
>>> Any thoughts would be GREATLY appreciated.
>>>
>>> --Joe
>>> --WB2SSB
>>>
>>
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