[Elecraft] K3 false SWR indication with SSB

[Guy Olinger K2AV]

Peak SSB power can exceed the 100 watts if all the calibrations are
not current. You should very carefully make sure that the actual peak
power and the steady CW power are the same. Make sure that all the
manual's calibrations have been run.  In order to run right, the
firmware needs to know a small pile of things about your particular K3
to make performance standard. "Recently" does not give me warm fuzzies
about being adjusted to spec.

I have found that sometimes doing a firmware update will unglue some
of the stored data in the K3, both calibration and others, despite
Elecraft's protestations that shouldn't happen. Doesn't hurt to rerun
the ENTIRE set of calibration exercises every couple of years.  Not
with every firmware update for sure, but whenever an update is
followed by some previously unnoticed quirkiness I'll run them. That
way I'm on the clean side of things if I report a quirk to be related
to an update.  If the quirk was cleaned up by a calibration, one can
be assured that Big E will never be able to duplicate it and figure
out what was going on if I reported it without recalibration. I really
don't want to waste any of their time. They're more interesting when
they're working on their projects.

73, Guy K2AV


On Tue, Aug 19, 2014 at 3:33 PM, Fred Townsend <fptownsend at earthlink.net> wrote:
>
> Mark I have not seen your problem so I tend to discount your explanation. It sounds like something is breaking down. Perhaps bad coax, antenna, insulator, or lightning arrestor. You could test with a TDR (Time Domain Reflectometer) or Hipot tester. If you lack the equipment connect a dummy load to the K3 and test. If that passes your problem is not in the K3.
> 73
> Fred, AE6QL
>
> -----Original Message-----
>>From: Mark N2QT via Elecraft <elecraft at mailman.qth.net>
>>Sent: Aug 19, 2014 12:15 PM
>>To: "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>
>>Subject: [Elecraft] K3 false SWR indication with SSB
>>
>>My k3 flashes a higher swr indication with ssb voice peaks than with a steady carrier.
>>
>>If using an antenna with 1:1 SWR the bar graph flashes the first segment.  If swr is 1.5:1
>>all the segments illuminate on voice peaks, as if swr was greater than 3:1.  To reduce the
>>uncertainty introduced by my antennas,  I connected a 50 ohm load after an external tuner
>>so I could create the 1.5:1 SWR, and got the same results.
>>
>>I assume this is a benign problem and likely caused by the non simultaneous sampling
>>of FWD and REV power by the CPU.
>>
>>However, if no one else sees this I'll do some more checking.
>>
>>FW 4.81/2.83 and TX Gain Cal done recently.
>>
>>Mark. N2QT
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to k2av.guy at gmail.com