[Elecraft] K2 with Distorted Transmit Signal: SOLVED

[John Smith]

Rick,

What you stated below is correct Rick. My original problem was an open RFC15
that Bill (NA7Y) told me to check.  Once I replaced this, I still thought
that I had a problem because I was using a small portable shortwave receiver
in close proximity to antenna and K2 that led me to believe that I still had
problems.  What I was hearing from the portable shortwave receiver was all
within it.

I got on 40M last evening and received good signal reports from everyone
including the op that I originally received the distorted signal report
from.  I asked the first contact that I made if there was any
distortion/chirps/clicks and he stated: "Sounds FB here, dont hear anything
wrong".  I also got a 559 signal report from Wayne - N6KR on 7.044.0 last
evening as well.  He was using a KX1 and putting out 4W that also sounded
great!!

Thanks to everyone for pointing me in the right direction and all the
suggestions.  The reflector is an invaluable resource with all of the
knowledgeable K owners out there.

73
John - KI7V

----- Original Message -----
  From: Rick Tavan
  To: John Smith
  Sent: Sunday, September 14, 2003 8:06 AM
  Subject: Re: [Elecraft] K2 with Distorted Transmit Signal


  A lot of the current hysteria over clicks is probably caused by artifacts
in the listening receivers. You can't build narrow filters without some
waveform deformation. There probably are some clicks in the K2, but I don't
think they are as serious as some people are saying. The folks at Elecraft
are working on better waveform shaping and I'm sure they will issue a mod to
improve it, something Yaesu never bothered with for the FT-1000MP. I think
rise times in the 1-3ms range are considered optimal but don't take my word
for it. The ARRL Handbook probably has an educated opinion. The warbling you
are hearing is almost certainly a problem in your unit. The reflector and
the Elecraft support people will help you nail it.

  Just to make sure, try 3 foot separation from your Astron. Shouldn't be
necessary, but it's always good to eliminate variables.

  GL,

  /Rick N6XI

  John Smith wrote:

Rick

Thanks for the note.  No, the closest thing around is the Astron 7 amp power
supply and that's about a foot away.  My laptop is about 8 inches from the
K2, however I tried shuting it off to see if that was it.  No luck yet.
When I listen to the K2 on a another receiver I'm getting clicking as well
as the chirp/warbling.  I'm using my oscilloscope to observe the wave form,
but I can't tell what would cause the chirping or clicks.  The clicks could
be that the rise time of the signal is to fast, but I have very limited
experience in this area and even if I saw the problem, I probably wouldn't
know it - hi.  If a had another K2, I could do signal comparisons....

John


----- Original Message -----
From: "Rick Tavan" <tavan@tibco.com>
To: "John Smith" <jlsmith5@qwest.net>
Sent: Saturday, September 13, 2003 4:40 PM
Subject: Re: [Elecraft] K2 with Distorted Transmit Signal


  Is your K2 located adjacent to a large power transformer, such as in a
linear amp? Manetic fields from them can cause symptoms like you are
describing. The amp does not have to be transmitting, just powered up.

/Rick N6XI

John Smith wrote:

    Bill,

I found that RFC15 was open on my K2 as well.  I've replaced it and it is
      a
  little improved, but the signal still sounds like it's under water.  I
didn't find a miniature one, so I used the next size up - maybe this is
      an
  issue?  There is still a pronounced warbling to it.  Seems worse on some
bands more than others.  Digging through the archives, I found someone
      that
  removed the circuit entirely and rejumpered pin 16 to the cut trace that
      is
  shown in the Erata sheet.  I tried the same, but this didn't do the trick
either.  Will keep looking through the archives etc..







--

Richard M. Tavan
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