K3: Wattmeter calibration procedure

[Nate Bargmann]

Hi All.

My new K3 is alive and well.  One thing has me stymied and that is the
Wattmeter calibration procedure.  I believe I've followed the manual's
prodecure to the letter each time but I'm confused about which menu
entry should be adjusted as the number on the VFO A line does not change
when TUNE is active.  What I have done instead is to press XMIT to kill
the carrier after reading the value on the Wattmeter and then setting
WMTR HP to the real Wattmeter value and pressing TUNE again to see that
the K2's Wattmeter and the external meter now each read 50 Watts.  If
that is correct, could this be made a bit more clear?   This had me
running in circles last night!

73, de Nate >>

--

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

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[n7ws]

Nate,

You might want to read this thread:

http://groups.yahoo.com/group/Elecraft_K3/message/8694

and then decide that trying to calibrate the wattmeter is counterproductive.

Wes

--- On Tue, 10/12/10, Nate Bargmann <[hidden email]> wrote:

Hi All.

My new K3 is alive and well.  One thing has me stymied and that is the
Wattmeter calibration procedure.  I believe I've followed the manual's
prodecure to the letter each time but I'm confused about which menu
entry should be adjusted as the number on the VFO A line does not change
when TUNE is active.  What I have done instead is to press XMIT to kill
the carrier after reading the value on the Wattmeter and then setting
WMTR HP to the real Wattmeter value and pressing TUNE again to see that
the K2's Wattmeter and the external meter now each read 50 Watts.  If
that is correct, could this be made a bit more clear?   This had me
running in circles last night!

73, de Nate >>

--

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
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Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
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[Chris GM3WOJ]

Hello Nate

Like you I could not get this to work as described in the manual (so far this is the only thing - the rest of the manual is great).  I asked Gary at Elecraft about what I thought was a problem with my K3 (#4716) RF o/p - a '5W calibration' was reading 4.0-4.2W across all the bands on a fairly accurate external wattmeter and a '50W calibration' was between 40 and 45W - in other words the TX RF o/p was about 10% low (On CW with MCU4.1.4 etc)  Max. RF o/p was about 98W with the K3 wattmeter reading 110W.

This was Gary's very helpful reply :
-----
You may need to only do the WMTR menu calibration. It is also important to know you external wattmeter is accurate.

When in WMTR LP or WMTR HP, turning the VFO A knob counterclockwise for smaller numbers in the LCD will result in more RF output on an external wattmeter. Turning the VFO A knob the opposite way will decrease the actual RF output.   The change when turning the knob menu is small, so you may need to turn the VFO A knob quite a bit to see much change in the actual RF output on the external wattmeter. This adjustment should be done with the K3 set to the 20m band. This calibration is done while you are in the WMTR menu and you then press TUNE
-----

I found that in WMTR HP, turning VFO A to change the parameter from 50 down to 25 gave the increased RF output I wanted. This sorted my 'problem' - the internal K3 wattmeter now reads accurately and the Power control tracks accurately right up to 110W o/p, as measured externally.

73
Chris
GM3WOJ / ZL1CT