I had this happen when I got my KPA-1500 a few years ago. When using my old
IC-7000 it was fine, using 100W from my K3s was good but QRO, at any level,
and it went to heck. I was advised by several folks that the matching
network on my antenna (M-Squared 6M5) was known to be problematic at high
power.
To rule everything else out I went with a straight run from the amp to the
antenna and the same thing was occurring. That's what prompted me to change
antennas. I bought a 6-el LFA from InnovAntennas two years ago and not a
hint of a worry ever since. 1400W all day on FT8 and other than the noise of
fan level 3, it's all good.
Now with all that said, I'd definitely check your balun and feedline first
and foremost.
- pjd
-----Original Message-----
From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On
Behalf Of N4ST - Jim
Sent: Tuesday, June 14, 2022 2:05 AM
To: 'Joe Subich, W4TV' <li...@subich.com>; elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S - High SWR on 6 Meters
SWR is fine with CW, problem only occurs with FT8. Same antenna, same coax,
same frequency.
Only occurs on 6M.
___________
73,
Jim - N4ST
-----Original Message-----
From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On
Behalf Of Joe Subich, W4TV
Sent: Monday, June 13, 2022 14:50
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] K3S - High SWR on 6 Meters
> Any advice?
> A spur/oscillation in the KPA3A?
> A relay stuck/not switching?
Are you sure there is no breakdown in your antenna, feedline or external
antenna switch? Infinite SWR on the external meter would indicate an issue
beyond it.
Are you seeing the problem on any other band? with any other antenna?
I recently went through a "High SWR" issue with my K3 that turned out to be
a bad coaxial jumper (between rig and switch that allows me to switch rigs)
even though the jumper does not test bad with an ohm meter (no shorts, opens
or intermittents as either connector is flexed or twisted).
73,
... Joe, W4TV
On 2022-06-13 4:07 PM, N4ST wrote:
> So, received a new KLPA3A & KPA3A from Elecraft in exchange for my old
ones
> plus $$.
> Installed the new KLPA3A & KPA3A and passed LP and HP TX Calibration.
> My 6M beam measures 1.06 SWR on analyzer.
> CW Key down, 100W, I get 1.2 on external SWR meter and 1 bar on K3S
> SWR meter.
> With FT8 I'm OK for 1 or 2 transmits and then I get infinity on
> external
SWR
> meter and full scale on K3S SWR meter, but full power out.
> If I switch to a dummy load, I get zero power out (fold back?) If I
> operate FT8 at 8 watts with the beam, I get 1.2 on external SWR meter
> and 1 bar on K3S SWR meter and 8 watts out.
> Going back to CW full power seems to perform a reset. Everything
> still
fine
> in CW, but now FT8 is OK for 1 or 2 transmits and then high SWR returns.
>
> Any advice?
> A spur/oscillation in the KPA3A?
> A relay stuck/not switching?
>
> My TenTec Eagle is carrying the load for me during these 6M openings.
> (46 states worked in last few weeks)
>
>
> ___________
> 73,
> Jim - N4ST
>
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