TX current on the Elecraft K2

[stephen Farthing]

Gentlefolk,

I could do with some advice. I am at Page 72 in the K2 MANUAL aligning
the TX for 40 Meters.

At 5 watts output the current drain is supposed to be 1.3-1.6 amps. The
book says if it is *much* higher than this, or the Voltage drops more
that 1 Volt I may have a problem with the TX, load or PSU.

The figures I get are: -

Tx Off...13.8 Volts 200ma

Tx on...13.1 Volts 2.16 amps 5 watts out according to the K2 internal
meter, 6.1 watts out according to Motorola R200D comms analyser....which
contains the dummy load...the PSU is a large Palstar 30 ampere gizmo
thus oodles of spare umph.

Setting the power at 10 watts I get the following.....

Tx on 13.0 volts,  - High Current warning then 2.44 amps 10 watts out
according to the K2, 7.87 watts according to the R200D,

the manual says "if the current is *much* higher than 2 amps see
troubleshooting....."

The R200D tells me the output frequency is very stable...and after a
short warm up that the power out of the K2 is not fluctuating .and I am
assuming that its dummy load is good...the interconnecting lead looks
fine though it is rather (i.e. 10 meters) long.. And I am using a bnc to
ntype adaptor at the R200D end. The K2 current meter tells me that after
about 30 seconds the current is stable at the values I have quoted above...

So the 64,000$ (£37,647) question is......do I have a problem or
not...normally I would go through the trouble shooting stuff but the
shack is as cold as heck at the moment and I have some other things to
do......and M0PUB wants a sked when its finished and I have the ATU,
Sideband and 160 meter options to build and the battery option and I
want to get it all finished in time for the winter sports.....

Greatful for any advice,

Steve G0XAR


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[Don Wilhelm-3]

Stephen,

Yes, that current is too high - you should not get Hi-Cur warnings at max
power with CAL CUR set to 2.5 amps.

First thing to check is the Low Pass Filter - check the capacitors for
proper values and the toroids for the correct color core and proper number
of turns (count each turn as it passes through the center of the core,
otherwise you can end up 1 turn off).

If the Low pass filter is OK, then check the winding of T4.

If all seems well for each of the above items, build the RF Probe if you
haven't already and turn to Appendix E of the manual - on page 12 you will
find the steps for Transmitter Signal Tracing - follow those steps and find
the stage where the RF Voltage differs substantially from the indicated
expected voltages.

73,
Don W3FPR

> -----Original Message-----
>
> I could do with some advice. I am at Page 72 in the K2 MANUAL aligning
> the TX for 40 Meters.
>
> At 5 watts output the current drain is supposed to be 1.3-1.6 amps. The
> book says if it is *much* higher than this, or the Voltage drops more
> that 1 Volt I may have a problem with the TX, load or PSU.
>
> The figures I get are: -
>
> Tx Off...13.8 Volts 200ma
>
> Tx on...13.1 Volts 2.16 amps 5 watts out according to the K2 internal
> meter, 6.1 watts out according to Motorola R200D comms analyser....which
> contains the dummy load...the PSU is a large Palstar 30 ampere gizmo
> thus oodles of spare umph.
>
> Setting the power at 10 watts I get the following.....
>
> Tx on 13.0 volts,  - High Current warning then 2.44 amps 10 watts out
> according to the K2, 7.87 watts according to the R200D,
>
> the manual says "if the current is *much* higher than 2 amps see
> troubleshooting....."
>
>

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