[LEAPSECS] New time scale name
ashtongj at comcast.net
Fri Aug 13 07:19:15 EDT 2010
If, for sake of discussion, we view TAI as correct, then according to HP
Application Note 1289, The Science of Timekeeping, D. W. Allen, N.
Ashby, and C. C. Hodge, the irregularities in the rotation of the earth
are at the level of 1.5 × 10^-9 (page 20). Frequency transfer using HF
radio broadcasts can be performed at the level of 10^-6 to 10^-8, and
with LF radio broadcasts, the level is 10^-10 to 10^-11 (pg. 73).
Currently, the FCC requires base stations for some public safety radios
to have a frequency stability of 1^10-7 (47 CFR section 90.213) which
radio technicians who do not necessarily have a university degree will
have to be able to verify compliance to this level. So we see everyday
needs and capabilities are bumping up against the fundamental frequency
stability of UT1 right now. One supposes the requirements will only
become tighter in the future. For several decades now, the frequency of
the radio broadcasts has agreed with the time ticks (or at least, that
is supposed to happen). If the ticks were instead providing UT1 while
the carrier frequency continued to be calibrated to the SI second, this
could cause widespread effects that have not been examined.
On 2010-08-13 5:00 AM, p at 2038bug.com wrote:
>> UTC cannot exist without [...]
> All this talk of GMT/UTC/Legislature makes me ask how the world
> currently syncs their time.
> In the case of SMS networks - they use NTP or nothing.
> In the case of in-house business systems - they use NTP or nothing.
> In the case of Internet hosts - DNS/SMTP servers - they use NTP or nothing.
> Then there are many embedded devices that use the radio time signal.
> Then there are a few atomic time clocks for specialized cases not
> part of the NTP network.
> What else?
> The point is that there is *small* number of time syncronization
> "networks" used by *everybody*.
> When you talk about changing this or that standard, it is meaningless
> unless you ask also how these systems are going to deal with it.
> This is analogous to the IPv6 upgrade debate.
> There is no point defining new standards unless you also have a:
> 1. VIABLE UPGRADE PATH
> 2. REASON TO UPGRADE
> 3. COMPATIBILITY BETWEEN SYSTEMS THROUGH AND AFTER THE UPGRADE
> These other conversations would have made sense before the age of the
> From all I've heard it seems best to make UTC and UT1 identical,
> and to start broadcasting UT1 over the radio and NTP networks.
> And drop further leap seconds of course. I have tried, but can't
> find a system that would break because of this.
> 2nd option is to keep leap seconds but upgrade the NTP and radio
> protocols to give more warning - not 10 years warning, just *more*
> 3rd (worst) option is to just stop announcing leap seconds.
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