[time-nuts] need recomendation for a portable 10mhz reference oscilator
alan.melia at btinternet.com
Tue Dec 11 18:21:47 EST 2007
Hi John, Andy Talbot G4JNT developed the a Jupiter based GPSDO for just this
purpose, several are used by hill-toppers in the UK.
The idea was that it would settle and be accurate in the time it took to
seet up the microwave part of the station.
I hope that helps/
----- Original Message -----
From: "John Ackermann N8UR" <jra at febo.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Tuesday, December 11, 2007 8:56 PM
Subject: Re: [time-nuts] need recomendation for a portable 10mhz reference
> Hal Murray wrote:
> > I'm picturing an open hill top at night with clear skies so there would
> > lots of radiation cooling. Of course, with an open hill top, GPS
> > would be easy.
> As great as GPSDO are, the problem with using them in a portable
> environment is the time it takes to do a survey and then get to final
> lock; mountain-toppers may not be in one place long enough.
> One thought I've had is to use a cheap Rubidium for long term stability,
> and phase lock a good OCXO to it for short term stability and phase
> noise (ie, use a loop time constant of perhaps 100 seconds). That would
> make a portable package that would meet both the short and long term
> stability requirements.
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