This is a sheet metal project to extend the bottom case . . .
http://nf3v.com/wp/?p=276 (http://nf3v.com/wp/?p=276)
>Ray
I saw that a few weeks ago, he did a good job, looks like it came from the factory that way. For me the minuscule power gain is not worth the penalty of the extra weight and most importantly the considerable extra bulk that this modification requires. He did execute it very well though.
Here's another method of increasing the KX1's internal battery voltage: http://wa3wsj.homestead.com/Elecraft_KX1_Battery_Modification.pdf (http://wa3wsj.homestead.com/Elecraft_KX1_Battery_Modification.pdf) It has the advantage of no increase in size but the disadvantage of having to add a charge controller PC board and being a semi-permanent modification. I think I'll leave mine the way it is but thought I'd throw it out there if any one was interested.
P.S. That site has some other cool KX1 mods, tips, tricks.