[Elecraft] KAT100-1 tweak for 40mtrs?

[Don Wilhelm]

Eddy,

I would not advocate doing anything.  The KAT100 firmware quits tuning 
when it determines that the SWR is "low enough", and less than 1.5 is 
generally deemed low enough.
The next time you do a TUNE into a dummy load on 40 meters, it may (or 
may not) be lower.
There are stray inductances and capacitances in the tuner that cannot be 
compensated out by any combination of L and C, or 40 meters may require 
one of those "in-between" steps - the minimum step size in the KAT100 is 
0.08 uHy inductive and 12 pF capacitive, and those may not be small 
enough to cancel out the stray reactance in the tuner.

An SWR of 1.5 or less at 40 meters is not significant and will not 
produce significant loss.

73,
Don W3FPR

On 7/21/2013 8:44 PM, Eddy wrote:
> My newly-built KAT100-1 has been working FB .... very impressed.
>
> However, tuning up into a 50-ohm dummyload I get a 1.2 swr reading on 40 meters while perfect readings from 160 to 10 meters!! This doesn't seem right, I rechecked the dummyload into a different rig and my ICOM 746pro shows .1.0 swr using its internal tuner.
>
> So, I'm thinking I may need to "tweak" one the the KAT100-1 inductors....does this make sense to the K2 experts in the crowd and if so, which inductor? I notice that if I tune down to 6980khz I get the 1.0 reading.
>