Posted by
Charles Greene-2 on
May 25, 2005; 2:43pm
URL: http://elecraft.85.s1.nabble.com/SWR-and-Power-readings-RE-K2-tp378727.html
Hi,
I have a question concerning antenna power and SWR. I am setting my K2
power at 5 watts via CAT. The K2 display reads 4.3 F, 0.0r. An external
watt/SWR dual meter reads 5.9 +/- 0.2 Fwd and a small value which can't be
read accurately, Rev. A Tandem SWR/Power meter reads 7.2 +/- 0.2 watts
and a SWR of 1.2 +/- 0.1.
The question is, if the SWR is not 1:1, does the power reading which is
based on the voltage in a 50 ohms load read high or low? I don't think
any of my meters have SWR compensation in the power level reading, if
there is any. The Tandem has compensation for diode nonlinearity in low
power readings.
I had measured the following on the antenna a few days ago using a AIM430
antenna analyzer:
http://w5big.home.comcast.net/sitemap.htm SWR 1.1:1 +/-
0.1, Zmag 48.5 +/- 0.5 ohms, Theta +5 +/- 2 degrees, Xs, a small + value,
can't read it accurately. I am using the KAT2 so what the K2 display reads
on r is probably correct or it is less than 0.1 which is the LSD.
Also, if the power level is set by the K2 CAT at 5.0 watts, why is the K2
display reading 4.3 watts? If I have a very accurate wattmeter, can I
calibrate the K2 wattmeter? How about calibrating the CAT setting? I
probably can get a more accurate reading on the Tandem by using a DVM set
on current in series with its meter(s).
73, Chas, W1CG
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