[Elecraft] [KX1] 20m Power Out Question

[Don Wilhelm]

Clark,

Spreading or compressing the turns on the L1 and L2 toroids is the way 
to do it.  So, do whatever you need to to accomplish that. Actually, you 
do not have to adjust all the turns, just move the end turns closer 
together or further apart.

Yes, you should be able to achieve a bit more power on 20 meters, but 
remember that the KX1 LPF is a compromise - play with the toroids a bit 
to see what you can accomplish.
Actually, you may be better off rewinding L2 on a new core (assuming you 
have one).  I have found that some of those yellow cores vary in 
permeability, and if the one you have installed has a greater 
permeability than normal, the cutoff frequency of the LPF may be too low 
and shunt some of the 20 meter RF energy to ground.

73,
Don W3FPR

On 3/29/2015 1:55 PM, engineercm wrote:
> Hi, all.
>
> I recently uncovered a bad solder on C41 that had been there from my initial
> build some years ago.  Now I get 4.1w on 40m and 2.7w on 20m--both much
> higher than I've ever seen.  I'd like to get more power out on 20m even if
> it takes away from 40m.  L2 is wound pretty tight so there isn't much
> movement in spreading the windings.  In searching the mail list for ideas,
> it does seem as if 20m should be closer to 40m.  Should I rewind L2 loosely
> so it is easier to move around?  Or leave it alone?  And, yes, I've checked
> the number of turns on L1 and L2 as well as the capacitor values multiple
> times.  These measurements are with the ATU out of the circuit.
>
>