[time-nuts] Holdover

Bob Stewart bob at evoria.net
Wed Aug 17 00:30:44 EDT 2016

Thanks Chris.  Those are more considerations that I hadn't thought of.  I begin to see why there's no "standard".



      From: Chris Albertson <albertson.chris at gmail.com>
 To: Bob Stewart <bob at evoria.net>; Discussion of precise time and frequency measurement <time-nuts at febo.com> 
 Sent: Tuesday, August 16, 2016 7:59 PM
 Subject: Re: [time-nuts] Holdover

What to do during and right after holdover depends on the reason you have a time standard.  If it is for maintaining a lab standard, then just shut down as you can't perform your primary function.  It you have this standard because you are required to time stamp financial transactions then you have to keep going until you estimate some error threshold then stop.  If you are using it to aim a telescope then again, stop using it the estimated error is enough that you'd miss your targets.    It depends on the use case.
I remember aiming a telescope when our best source of time was NTP over a dial-up phone modem in the days before always-on Internet  This was in the 1980's and it worked well enough.  The normal case was "outage" as the modem connection was short and only a few times per day.  But was good enough to re-calibrate a local  clock Chris Albertson
Redondo Beach, California


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