[Elecraft] KAT500 TUNER WOES

[David Inger]

I have a fairly early KAT500 tuner  (#275).  I am using it to tune several
antennas.  Recently it has stopped finding acceptable matches to a
ladderline-fed 110 ft. dipole.   This problem is only on 40-meters.  The SWR
anywhere in that band is around 8:1.  The tuner works great on all other
bands (well, not so much on 160, but that's the antenna's problem).  I also
have a 43-ft vertical and the tuner matches fine on that antenna.  I
replaced all intervening coax jumpers and even the 1:1 current balun at the
transition of the ladderline to the coax in the shack.  None of the above
help.

 

Interestingly, when I bypass the KAT500 and enable the internal tuner in the
K3, everything works fine, including matching 40-meters.  I have also done a
reset using the KAT500 utility program; still no help.

 

Before, I tear into things or stop bothering the good people at Elecraft, I
wonder if any in the group has any suggestions.

 

73 de K6SBA

David in Santa Barbara, CA