[Elecraft] K2 low power and SWR problems

[Don Wilhelm]

Chris,

That is very strange, but if the K2 operates properly into a dummy load, but
not into the tuner, then the problem is not in the K2, but either in the
tuner or in the coax between the K2 and the tuner.

If your tuner is adjusted for a perfect match, that alone tells us that it
should be exactly a 50 ohm non-reactive load - just the same as your dummy
load.  How are you determining that your tuner is set to a 'perfect match'?

The only other reason that I can think of is that you may have a significant
amount of RF in the shack if the RF return path is different when you have
the K2 connected to the tuner input vs. the RF return path created when you
use the device (whatever instrument) that indicates your tuner is adjusted
for a perfect match.  If you are not using a balanced antenna, this is quite
likely.  You may wish to experiment with some quarterwavelength counterpoise
wires.

73,
Don W3FPR

> -----Original Message-----
>
> I built my K2 in late 1999 and it has behaved the same way ever since.
> Gary has been very helpful and once his advice was correct (bad soldered
> antenna connection) but it did not improve my K2. I did not want to
> bother Elecraft anymore so I have learned to live with my rig. However
> now I have decided to do something to cure my K2.
>
> When I change band I first have to tune into a 50 ohm dummy load before
> I switch to the antenna. If I first connect K2 to my antenna tuner
> (perfect match) the power is significantly reduced and my cross needle
> SWR meter shows high SWR.
>
> If I have tuned via dummy load, then connected to the ATU (with good
> match) and start reducing output from K2 the SWR meter will show a great
> mismatch when having decreased to about 2 watts. The "low power
> hostility" is most outspoken on 80 m.
>
> This I guess is also why I can not use K2 on SSB.
>
> Chris, SM7KJH
>