[time-nuts] Disciplining Rubidium

wa1zms at att.net wa1zms at att.net
Thu Apr 24 09:29:37 EDT 2008

In talking to Charles Wenzel some years back, he mentioned what he called
the "quartz-to-crud" ratio.  i.e.: How much contamination you get while
a quartz crystal vs. the Q of the quartz blank itself.

It seems that through either luck/design or just demands of the industry
5MHz is the sweet spot for lowest close-in phase noise of an XO.

Other technologies may very well change that in future, but for best
close-in noise a 5MHz XO seems to be the best today.

-Brian, WA1ZMS

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of John Ackermann N8UR
Sent: Thursday, April 24, 2008 7:21 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Disciplining Rubidium

John Miles wrote:
> Phase noise generally gets better with the higher-frequency OCXOs, though.
> I think the best of all possible worlds would be a 5-MHz OCXO like the one
> you describe, being used to discipline a 10 MHz or higher-frequency part.
> -- john, KE5FX

I'm not sure about that -- at least, the Wenzel ULNs show better noise
at small offsets for the 5 MHz than the 10 MHz versions (though the
floor is the same).

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