[Elecraft] K2: Does QRP-Mod (T4-winding) influence linearity of PA?

[Phil Wheeler]

Thomas Martin wrote:

> Hello,
> I am in doubt if I should wind T4 as recommended for low 
> power output levels (less than 5 Watts) because this
> will be the level I'll work with.
> 
> Planning to build the SSB-Option the rig will not be a 
> CW-only one and I would rather accept less efficiency than
> less linearity. 
> 


 From the manual, page 100:

"If you plan to operate exclusively at about 5 W PEP/CW or less,
you can wind the PA transformer differently to improve efficiency
at this level. Just remove one turn from the 3-4 winding on T4
(making it 2:2 turns) to immediately improve current drain by
some 25 to 30% at 5 watts. Additional efficiency modifications
may be posted on our web site."

Phil