Posted by
Don Wilhelm-4 on
Oct 09, 2007; 1:31am
URL: http://elecraft.85.s1.nabble.com/HI-CUR-question-tp454370p454372.html
Larry,
The bare K2 (no KAT2, no KPA100, no KAT100) will respond like that if
the antenna load has an impedance less than 50 ohms - it is not likely
to happen when the antenna feedpoint impedance is higher than 50 ohms.
It all has to do with the way the basic K2 handles its power control -
it assumes that the load is 50 ohms and measures the RF Voltage at its
output and adjusts the power until it is correct (or runs out of gain).
When the impedance at the K2 output is lower than 50 ohms, it takes more
power to produce the required RF voltage, so your K2 puts out more power
- however the K2 does not know it is producing more power because the RF
voltage is still low.
Your Hi Cur messages are the result the K2 producing this higher power
level.
Conversely, if your antenna feedpoint impedance were higher than 50
ohms, the K2 would not actually be producing as much power as it thinks
it is, and you would see a lower current.
This condition is not likely to damage the K2, but if you want real
power output indication you will have to use a tuner of some sort to
produce a 50 ohm resistive load for the K2. The KAT2 or KAT100 will do
that, and also have a real wattmeter included so the K2 power control
circuits will not be dependent on the SWR.
73,
Don W3FPR
Larry Naumann wrote:
> I sometimes get a HI CUR warning on my new K2. I have the high current set at 2.5 amps. My power supply is steady but on 40 meters when the SWR is slightly high but below 2:1, I get a HI CUR when running 10 watts out. Into a good 50 ohm dummy load I get 2.02 amps on 40 meters.
> I've double checked my output filter tuning and all is good.
> Is this something to be concerned about or is this in the normal range of xmit current at 10 watts?
>
>
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