[Elecraft] K2 frequency drift

[Don Wilhelm]

Adam,

You cite 70 to 80 Hz drift from a cold start.  That is within the K2 spec of
<100 Hz drift typical from a cold start at 25C (77F).  If your ambient
temperature is lower, you can expect more warm-up drift.

Once warmed up, the drift should be small.

Even my stable HP6840 takes about 2 hours to stabilize after I power it on,
and I have the MIL version, so there is a big sticker on the front warning
that it has this warm-up drift.
I just refrain from measuring anything until the warm-up drift has
subsided - so I contend that even fine lab equipment is subject to warm-up
drift and to expect that a K2 would be totally stable from a cold start at
ambient temperature is IMHO being unrealistic.  I do not know of any ham
gear that does not have some warm-up drift unless all the oscillators are
contained inside a temperature controlled ovens.  Only high-end homebrew
transcievers can achive that kind of stability, to manufacture units like
that would be too costly for the general ham market.

Or did I understand something incorrectly?

73,
Don W3FPR

> -----Original Message-----
>
> As a few people pointed out, I misspoke in my earlier email.
>
> When I calibrate C22 I immediately run CAL PLL and CAL FIL.
> True, the K2 does not directly reference C22 during normal
> operation.  My calibration of C22 and then CAL PLL and CAL
> FIL is all by-the-book.
>
> That being said, I still do notice a temperature-dependent
> frequency drift during normal usage.  The drift is
> predictable, with the zero beat on the dial I get with
> reference to WWV drifting by as much as 70-80 Hz if the
> temperature difference between ambient and the max temp the
> rig hits with the KPA100 under heavy use is large.  The
> frequency at which I can zero-beat WWV does not change
> unpredictably.  The radio consistently zero-beats low (e.g.
> WWV zero-beats at 10.000.07) when cold.
>
> Is this a really big deal?  On SSB, certainly not.  On CW I
> like to zero-beat dead-on with the narrow filters.  Perhaps
> I'm just being a perfectionist.
>
> Adam, N1KO
>
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