[time-nuts] rapid startup GPSDO

David C. Partridge david.partridge at perdrix.co.uk
Wed Jul 14 10:21:44 EDT 2010

After a forced cold start in an unknown location, the TB will still be searching for satellites after five minutes.

If you move it and don't clear the incorrect location, I don't know how long it will take to realise it is wrong (if it ever does).


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of jimlux
Sent: 14 July 2010 14:43
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] rapid startup GPSDO

Is there some (inexpensive) GPSDO that has a "time from power on in an unknown location to reasonably stable" in the <5 minute category?

Frequency accuracy in the 1E-9 range would be fine.

A regular old GPS has a Time to First Fix well under that, and it should be cranking out 1pps pulses with 1E-7 or 1E-8  precision pretty quickly.. Would it be fair to say that after 100 seconds, one could theoretically have driven that down another factor of 10?

As I understand it, a thunderbolt needs some number of hours after turn on to stabilize, but just how bad is it after, say, 5 minutes.

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