Subject: Re: Installed K3EXREF

[Edward R Cole]

Dan,

Sorry for delay in reply, I get the Elecraft reflector by digest.

I believe it will work with the standard TCXO but there was a note
from Elecraft recommending that the TCXO-3 be installed for use with
the K3EXREF.  Perhaps that e-mail can be retrieved from the digest,
Napple, etc.

I ordered the TCXO-3 with my K3 so all testing was done with it installed.

The K3EXREF corrects the TCXO error periodically but The TCXO drift
is not affected in between times so probably one would experience
more drift with the TCXO vs the TCXO-3.  I suppose this could cause
(?) a more abrupt freq. shift when the EXREF performs the
correction.  This is really a question to ask the Elecraft guys.

My experience with the TCXO-3 + K3EXREF is the drift is minimal and
often does not amount to even 1-Hz between times the K3EXREF samples
the freq. (so I do not see a change in the TCXO-3 that often - after
the initial 20-30 minutes warm-up).  During warm up the K3EXREF
generates repeated corrections to the TCXO-3 frequency stabilizing at
about 49.380.070.  This is supposedly due in part to xtal aging in my
TCXO-3 (now over a year old).  But checking actual radio frequency
accuracy (say on 14-MHz) during the warm-up period the frequency
error is never more than 2-Hz with my frequency counter (locked to a
rubidium).

With the K3EXREF installed you can monitor the offset on CONFIG:
REF*CAL  (the asterisk blinks when the EXREF is running).  Without
the K3EXREF CONFIG: REF CAL permits entry of a fixed offset (useful
for running a transverter that may not be exact in frequency) or for
those that like to tweak such things ;-)  The manual offset feature
is defeated when running the K3EXREF.

73, Ed - KL7uW

------------------------------

Message: 8
Date: Fri, 20 May 2011 19:47:33 -0700 (PDT)
From: Dan AE9K <[hidden email]>
Subject: Re: [Elecraft] Installed K3EXREF
To: [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=us-ascii

Ed,

Thanks for the response.  Let me clarify my question.  I'm wondering if the
KTCXO3 0.5 ppm oscillator can be omitted and still get great results with
the K3EXREF and the standard 5 ppm oscillator.  This is of interest because
I intend to acquire the K3EXREF but do not have the KTCXO3 and would prefer
not to buy it if it doesn't add any benefit.

My logic: If the K3EXREF adjusts the TCXO (via REF CAL) every 4 seconds,
then why not let it adjust the standard K3 TCXO instead of having it adjust
the optional KTCXO3 oscillator?

Even though the two oscillators differ by an order of magnitude in their
error, does that error make a difference when the K3EXREF adjustments are
every four seconds?

ps - During your beta testing were you using the standard K3 5 ppm
oscillator or the KTCXO3 0.5 ppm oscillator?  I didn't find mention of that
on your web site.

Dan
AE9K




73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-testing*, 3400-?
DUBUS Magazine USA Rep [hidden email]
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