Steve Allen
Thu, 30 Jan 2003 12:58:01 -0800
On Thu 2003-01-30T12:54:09 +0000, Markus Kuhn hath writ: > VERDIN phase tracking is perhaps a somewhat pathological case.
True, but I know of someone who built a household clock to use it, and for someone living in a Navy base town during the early years of the Reagan era that seemed like a prudent harbinger. > The UCPTE > specification says that the grid phase vectors have to rotate on > long-term average exactly 50 * 60 * 60 * 24 times per UTC day. Obviously the grid frequency shift after leap seconds is annoying, and it is undoubtedly one of the reasons contributing to the notion of stopping leap seconds. But the question arises as to why the spec can't easily be changed to indicate that it is per TAI day. My power company cannot supply me with a reliability of 0.99999997, so I can never see leap seconds from my household clocks. I don't really believe that other power companies achieve it either, so what is the value obtained by a specification like this? My power reliability is more like 0.999, and various folks in my region recently experienced outages lasting from hours to weeks. My recent outage was 8 hours. In order for a household device with battery backup and internal clock to keep phase with the grid while it was offline it would have needed an oscillator which would drift only 1 second in 20 days. Are there any battery-backed devices, let alone household ones, with internal clocks of this caliber which rely solely on power grid phase locks to keep SI time? -- Steve Allen UCO/Lick Observatory Santa Cruz, CA 95064 [EMAIL PROTECTED] Voice: +1 831 459 3046 http://www.ucolick.org/~sla PGP: 1024/E46978C5 F6 78 D1 10 62 94 8F 2E 49 89 0E FE 26 B4 14 93