[Elecraft] Fwd: [K3] K3 #281 Perceived Output Issue

[N7FN at comcast.net]

I saw this and have been monitoring for an answer.  I have a similar problem 
also.
Hope that someone can provide some insight as to what the problem might be.

Frank Noragon
N7FN, Portland, Oregon

-----Original Message----- 
From: Ian Kahn
Sent: Monday, February 22, 2016 08:21
To: elecraft at mailman.qth.net
Subject: [Elecraft] Fwd: [K3] K3 #281 Perceived Output Issue

Reposting, since this didn't seem to get out when I originally sent it last
Friday evening. If you get this a second time, please forgive the noise.

Thanks and 73,

--Ian
Ian Kahn, KM4IK
Roswell, GA  EM74ua
km4ik.ian at gmail.com
10-10 #74624  North Georgia Chapter #2038
PODXS 070 #1962
K3 #281, P3 #688 KAT500 #860, KPA500 #1468

---------- Forwarded message ----------
From: Ian Kahn <km4ik.ian at gmail.com>
Date: Fri, Feb 19, 2016 at 10:37 PM
Subject: [Elecraft][K3] K3 #281 Perceived Output Issue
To: "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>


All,

I have what I think is an output issue with my K3 s/n 281. When set at 100W
output, I am getting the following approximate output values:

10m     ~55w
12m     ~40w
15m     ~50w
17m     ~60w
20m     ~60w
40m     ~70w
80m     ~70w
160m    ~70w

My testing methodology involved connecting the short (~12") coax out of
ANT1 to an HF power meter's input. I then connected the power meter's
output to a 300w dummy load. I then tuned to the band to test, put the rig
in CW mode, and keyed down for a few seconds. The power meter is set to
read peak output, not average output. As a self-check, I would randomly run
the test using AFSK-A RTTY, just as a double-check to ensure I was getting
100% duty cycle. The results are the same.

After discovering these power output values, I ran the TX Gain Calibration
via the K3 utility. It ran through the 5w and 50w calibration tests
successfully. After running the TX Gain Calibration, my output power
readings didn't change significantly. My readings then are:

10m     ~50w
12m     ~60w
15m     ~50w
17m     ~60w
20m     ~60w
40m     ~70w
80m     ~70w
160m    ~70w

Is there something else I should check before I plan a call back to the
Elecraft mother ship next week? If it needs to go home for repair and
testing, it will have to wait until after the Georgia QSO Party the second
weekend in April. I'm getting good signal reports when I'm on the air, but
it seems odd to me that, with the rig set for 100w out, and in a full duty
cycle mode, I'm only getting 50%-70% of my rated power.

Thank and 73,

--Ian
Ian Kahn, KM4IK
Roswell, GA  EM74ua
km4ik.ian at gmail.com
10-10 #74624  North Georgia Chapter #2038
PODXS 070 #1962
K3 #281, P3 #688 KAT500 #860, KPA500 #1468
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