[Elecraft] [K3S] K3S High SWR Shutdown on FT8?

[Don Wilhelm]

Bret,

As far as I know, the K3S does not have any audible alarm.
So that leaves 2 elements in your setup that could be producing that 
alarm - the remote ATU control unit, or the computer you are using.
The "alarm" could also be the result of some sort of feedback and is 
'just something that happens' but is not really intended to be an alarm.

If you find your remote ATU is causing the problem, check all 
connections at the antenna.  It is quite common for a connection to be 
OK at lower powers, but when the power is increased, something breaks 
down causing the problem.  If you can verify that it is an SWR problem, 
then look carefully at the antenna for the solution.

73,
Don W3FPR

On 7/30/2017 9:16 AM, MaverickNH wrote:
> I'm using a K3S/100 with ATU to drive a 43ft vertical with remote ATU at
> base. To operate, I typically bypass the K3S ATU, tune the remote ATU to 1:1
> on 20m, then turn the K3S ATU to auto and tune again to 1:1 reading on the
> K3S. Running WSJT-X FT8 digital mode at 63W, all is fine, but if I run 100W
> too long I sometimes hear an alarm and turn power back to 63W (the alarm
> stops) or the K3S just shuts down. I'm not sure where the high-pitch alarm
> is coming from - I have a nearby Yaesu FP3010A Linear PSU but the manual
> mentions nothing about an alarm. Nor does the K3S mention an alarm. I see no
> High SWR warning on the K3S display. The PSU does not turn off.