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

[David A. Belsley]

Wayne:
  Thanks for the reply.  One further point, if I may.  Suppose one's K2 
does indeed have low TC.  Will the addition of the thermistor mod now cause 
over compensation, perhaps even producing negative temperature compensation 
(in the opposite direction)?

thanks,

dave belsley, w1euy

--On Friday, April 25, 2003 8:58 PM -0700 Wayne Burdick <n6kr@elecraft.com> 
wrote:

> "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



----------------------------------
David A. Belsley
Professor of Economics