[Elecraft] Re: Elecraft K2 Temperature-Compensated PLL Reference Upgrade

[Wayne Burdick]

"David A. Belsley" wrote:
> 
> Eric:
>   I know when John first did some of the drift tests, there were
> substantial variations in how badly different K2s were affected by the
> problem.  How does "one size fits all" work for this mod?

Hi David,

I'll take this question. I think Eric is already in bed  ;)

The degree to which an individual K2 will benefit from this mod depends on:

  - whether a KPA100 is installed (this heats the enclosure a lot faster)

  - whether the rig is used in temperature extremes

  - if it has had the BFO modification installed (p/n BFOMDKT,
    already present in the revision B K2)

  - the pre-modification temperature coefficients of various
    components in the PLL reference and BFO

The overall TC (temperature coefficient) of a given K2, pre-modification, can
vary over a wide range. If the operator perceives that the TC is already low,
the PLL upgrade may not offer any advantage. 

What we know for sure is that the combination of the BFO modification (using the
new, highly stable toroidal inductor) and the PLL upgrade (using thermistor
compensation) produces truly excellent results. In fact we considered simply
calling this the K2 TCXO modification, but it's really a "VCTCXO" (voltage
controlled, temperature compensated crystal oscillator), which is a less
well-known acronym ;)

73,
Wayne
N6KR