[Elecraft] K3s - 80W on 160

[Brian Hunt]

A short story.....
I was having awful trouble with my K3 #4113 with power overshoot with band or power change on 40m especially but all bands to some degree. Also max power out on 15m was 85w. 160m unknown since I don't op there. 

As you did, I upped the PS voltage and ran a TX Gain Cal and it got better for a while but wasn't a cure. 

In "fix it or break it" mode, I updated the firmware to latest production version (was on 5.3.8) and reran the TX Gain Cal. Not much improvement. Thinking maybe I did something wrong, I redid the TX Gain Cal and for some reason, while in the K3 utility, ran the 50 watt cal a second time. Totally different gain values in the status listing AND problem cured!  No overshoot and full output on 15m. Happy camper. 

The only thing I can think is that the power of the K3 was taking longer to settle than the cal software allowed giving less than ideal results. 

OK- long story and I don't know if this will help your problem but it might be worth a try. GL!

73,
Brian, K0DTJ

> On Dec 17, 2016, at 14:54, John Kaufmann <john.kaufmann at verizon.net> wrote:
> 
> I had the same issue with my K3S.  I was seeing 80W maximum on 160 and it
> would not drive my AL1200 to full power (1500W).  Redoing the power
> calibration did not fix the issue.  
> 
> 
> 
> Elecraft Tech Support told me that my K3S was within spec but that
> increasing the power supply voltage could yield more power output.  I ended
> up increasing my supply voltage from 13.8 volts to 14.5 volts and was able
> to get 90W out, which was a bit of an improvement.  There is a trim pot
> inside my Astron RS-35M supply that adjusts the output voltage.  
> 
> 
> 
> 73, John W1FV
> 
> 
> 
> 
> 
> ------------------------------
> 
> 
> 
> Message: 10
> 
> Date: Sat, 17 Dec 2016 00:27:48 -0500
> 
> From: "Gary Smith" <Gary at ka1j.com>
> 
> To: elecraft at mailman.qth.net
> 
> Subject: [Elecraft] K3s - 80W on 160
> 
> Message-ID: <5854CCD4.7315.16D88C8 at Gary.ka1j.com>
> 
> Content-Type: text/plain; charset=US-ASCII
> 
> 
> 
> I usually don't run barefoot at 100W and 
> 
> don't drive my amp with more than around 
> 
> 50W. Tonight when I tried running at 100W 
> 
> on 160 I was surprised to find it only 
> 
> putting out 81W. It puts out incrementally 
> 
> till 81W and then even though I can adjust 
> 
> the power so it reads 100W on the K3s LCD 
> 
> bar and numerical display, the watt meter 
> 
> in the P3 and the LP-100A both show the 
> 
> wattage stopping at 81W.
> 
> 
> 
> With the ATU in or out it gives 81W out on 
> 
> 160, SWR is 1.28 
> 
> 
> 
> All other bands except 6M give around 98W, 
> 
> 6M gives 87W
> 
> 
> 
> Any ideas what might be causing the lower 
> 
> output on 160?
> 
> 
> 
> Thanks & 73,
> 
> 
> 
> Gary
> 
> KA1J
> 
> 
> 
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