[Elecraft] K2 fine carrier balance

[w2bvh]

Well it only took 10 years but I finally did the "fine carrier balance" 
adjustment on my K2. I never did it when I built my K2 in 1999, since 
the "dead zone" in R1 on the ssb board seemed to be 0 during the coarse 
balance adjustment. In addition I've gotten several unsolicited 
compliments on my audio over the years. So what prompted me to finally 
do the adjustment? 

About a year ago I installed the  Elecraft  "bandwidth modification 
kit", to the SSB board, mainly to get a few more hz  view in digital 
modes (WSJT in particular). When I did the mod, I re did the coarse 
carrier balance and noted the same lack of a "dead zone" in R1. So I was 
satisfied all was well.

But a few weeks ago I got a negative comment on the audio from one (out 
of 181 qso's) during the ARRL VHF sweepstakes.  I noted it, but ascribed 
the comment to the $0.50 mic element in the homebrew boom mic I built 
just prior to the contest (a boom mic and a foot switch make life easier 
during a contest).

But yesterday I worked K5D with ssb using my usual mic (a D-104) and he 
made a comment on the audio too (though he also said he or I was 
mistuned). Well that motivated some action on my part.  It took about 
20-30 minutes to dig my old SX-117 out of the bowels of my son's closet, 
and for the first time ever, performed the fine carrier balance on the 
K2 ssb board using the SX-117 as a monitor.

I was surprised to find that I could easily suppress the carrier by an 
additional s-unit inside that "missing dead zone" on the pot.  But self 
monitoring of my audio using the SX-117 before and after the balance 
adjustment, using both the boom mic and the D-104 made no difference in 
the audio. To my ear it sounds fine, with little if any distortion. 
Maybe the poor audio reports were just a fluke, from two stations 
operating in "contest mode", not looking to make any receiver 
adjustments at their end.

Anyway, I learned something: the fine carrier balance adjustment 
actually can improve carrier supression, which may benefit me if I ever 
upgrade to a high power K2. And now after 10 years, all the alignment 
steps of the K2 have been completed!

73,
Lenny W2BVH