[time-nuts] How did they distribute time in the old days?
bownes at gmail.com
Wed Oct 14 14:29:25 EDT 2015
Precise time (and time zones) and the relationship with the telegraph were
a side effect of the railroads. You need to keep time (and keep on time) in
order to avoid collisions on single tracked main lines.
On Wed, Oct 14, 2015 at 12:42 PM, Nick Sayer via time-nuts <
time-nuts at febo.com> wrote:
> > On Oct 14, 2015, at 4:42 AM, billriches <bill.riches at verizon.net> wrote:
> > Not milisecond time distribution but time related!
> > In the early half of the 1900s Western Union was in the time business.
> > would rent businesses such as banks, office buildings, etc clocks for a
> > dollars a month. These were pendulum wall clocks that had 2 #6 dry cell
> > batteries inside that would wind them every hour or so. The clocks were
> > connected to the WU telegraph line and for a minute before and after the
> > top of the hour all traffic on the circuit would stop. Exactly at the
> > of the hour they would push a pulse of 50 ? volts or so over the line
> and it
> > would reset the clock to the top of the hour.
> The WU standard time service goes back further than the turn of the 20th
> century. It started in 1870.
> I’ve always wanted to get my hands on one of those clocks and come up with
> a circuit to recreate the synchronization signal for it, probably with a
> Raspberry Pi running ntpd and a big ol’ MOSFET. The problem is that at this
> point, those clocks are quite expensive once they’re reconditioned.
> My understanding (perhaps incorrect) was that the sync pulse was once
> daily and, as you said, would cause the hands to “snap” to 12. The trailing
> edge of the pulse was synchronized and would release the clock to operate
> That they had something as accurate and widespread as it was so early is
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