[Elecraft] K3 Frequency Shift

[Mike Harris]

Quite so.  The calibration against WWV is not a one time event, I do it 
at least a couple of times a year.  Actually it can vary a few counts in 
a day, mainly dependent upon heat soak of the front panel.  Mine 
regularly runs at 37C.

If my understanding is correct the REF CAL number is a stored number not 
a direct measurement of the TCXO frequency, though it might look like 
that.  Therefore it will not change, ever, unless manually done so or 
the EXTREF board is installed and running.

It would be interesting if someone with an EXTREF board installed would 
post the change in REF CAL number from cold to hot and extended run.

I used to drive the local Intelsat Std. B earth station and our uplinks 
at 6GHz were locked to an approximately 4MHz precision TCXO which locked 
a 100MHz osc, which locked the final SHF osc.  It was not unusual to see 
a couple of Hz/month wander (at 4MHz).

Not done like that in the new station.  Neither does it have two stage 
parametric RX preamps that need de-icing twice a year at the feed 
assembly, but that is another story.

Regards,

Mike VP8NO

On 29/04/2012 06:06, Oliver Dröse wrote:
> Aging of components?
>
> Vy 73, Olli - DH8BQA
> http://www.dh8bqa.de/
>
>
>
> ----- Original Message -----
> From: "w0ih"<mfroster at msn.com>
> To:<elecraft at mailman.qth.net>
> Sent: Sunday, April 29, 2012 4:52 AM
> Subject: [Elecraft] K3 Frequency Shift
>
>
>> A couple weeks ago, I was on 40 meters with a group of friends, and one of
>> the guys (likes everyone on frequency ;-) suggested that I was off.
>>
>> I finally got around to checking the K3 last week and found that it was
>> off
>> by about 260 Hz from what it should have been.  I rechecked the
>> calibration
>> (against WWV, per the manual instructions) and the reference oscillator
>> had
>> not changed from the original setting (I had it marked down in the manual
>> from when I first calibrated it).  I had to move it by 260 Hz to get it to
>> zero beat WWV.
>>
>> Anyone have any idea why it should shift frequency?   I can't say that I'm
>> terribly concerned, more curious about it.
>>
>> Mike
>>
>
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