K3 - 'Unwanted' TX Gain calibrations?

[GW0ETF]

Been wondering just how the TX Gain calibration works. To quote from the manual -

"The gain constant is updated whenever the TUNE function is activated on a given
band at one of three specific power levels: 5.0W, 50W, and 1.00 milliwatt."

So if I'm adjusting my external ATU by TUNE(ing) at say 5watts, will the (LP)Tx gain constant be updated while feeding into an unspecified load. The described procedure requires the use of a dummy load to set the gain constant; if the load isn't 50 ohm resistive will the constant be set to some anomalous figure which may not be updated when the atu eventually presents (hopefully) 50R to the K3??

Just curious........

Stewart Rolfe, GW0ETF (K3 #145 with latest everything)

[AD6XY]

I hope not - though it could explain a few things. Surely the radio needs to be in TECH mode. Tuning up an ATU would reset all the calibrations otherwise. My amplifier needs about 50W of drive and my transverter about 1mW.

Mike

GW0ETF wrote

Been wondering just how the TX Gain calibration works. To quote from the manual -

"The gain constant is updated whenever the TUNE function is activated on a given
band at one of three specific power levels: 5.0W, 50W, and 1.00 milliwatt."

So if I'm adjusting my external ATU by TUNE(ing) at say 5watts, will the (LP)Tx gain constant be updated while feeding into an unspecified load. The described procedure requires the use of a dummy load to set the gain constant; if the load isn't 50 ohm resistive will the constant be set to some anomalous figure which may not be updated when the atu eventually presents (hopefully) 50R to the K3??

Just curious........

Stewart Rolfe, GW0ETF (K3 #145 with latest everything)

[P.B. Christensen]

> Been wondering just how the TX Gain calibration works. To quote from the
> manual - "The gain constant is updated whenever the TUNE function is
> activated on a
> given band at one of three specific power levels: 5.0W, 50W, and 1.00
> milliwatt."

I'm surprised there have not been any comments on this matter as it's an
excellent question.

To Stewart's point, does the gain of the K3 recalibrate every time TUNE is
depressed at one of the three stated power levels when the CONFIG menu is
set as instructed in the alignment section of the owner's manual for "PWR
Set = nor?"

Does the K3's display need to reflect "PWR Set" simultaneously for the
calibration to occur, or can we exit from the CONFIG menu prior to the gain
alignment so long as "PWR SET - nor"?

Finally, what prevents the re-loading of new gain data if as Stewart
suggest, he sets the K3 power to exactly 5 watts or 50-watts and depresses
TUNE for external ATU tuning purposes?  Should he instead stay away from
those two values and use perhaps 49 or 51 watts?

I am running into the same issue as my K3's 10M output power appears to be
substantially less (~ 75W) than on lower HF bands.  I would like to ensure
that I have calibrated gain for 10M and 6M and know that the routine was
invoked as expected.

Paul, W9AC


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