[Elecraft] KX-1 ATU question

[Don Wilhelm]

Jean-Francios,

That is a normal occurrance, and is not unique to the KX1 and its tuner.
The wattmeter reads forward power (only) as measured on the transmission
line (or more specifically at the transmitter/ATU junction, and it should be
calibrated for 50 ohms.  The same thing happens with many amateur wattmeters
although there are a few (such as the Tandem Match) that calculate the net
power output.

The actual power being developed is the forward power minus the reflected
power, when the SWR increases, the forward power required to maintain the
same actual output power must also increase.

In my KX1 work when calibrating the wattmeter in the tuner, I use both a 100
ohm dummy load and a 25 ohm dummy load to determine the 2:1 SWR points, and
I find that the net KX1 power does not ddecrease significantly with the 100
ohm load, but it does drop with the 25 ohm load.  From that experience, I
would say that your increase in SWR is due to an increase in the load
impedance rather than a reduction.

73,
Don W3FPR


> -----Original Message-----
>
> I found something strange with my KX1.... everything works fine, I did a
> many QSO... but I found something that when I use the ATU.
>
> When I start tuning with the KX1, everything is OK, it tunes normally
> then show me POWER and after a push of a button show me SWR.
>
> Example: I get 2.3W on 40M with a SWR of 1.1:1, but  higher in the band,
> I have 4.3W power and 1.9:1 SWR..... When I get an higher SWR, power
> rise..... SWR drop, power drop.....
>
> That is what my ATU give me.... Something sounds to be installed reverse
> !?!?!?!?
>
> Any explanation ?
>
> J-F VA2VYZ
>