[time-nuts] Re: [time nuts] Re: in-ground clock room

[Bill Beam]

--Original Message Text---
From: Tom Van Baak
Date: Thu, 9 Sep 2021 04:44:22 -0700



Hi Bill, 

I'd like undisturbed on the order of several months or years. Yes, earthquakes are possible but they are rare here and interesting so that's 
ok. Here's a once-in-a-decade one that I captured a few years ago: 

http://leapsecond.com/pend/synchronome/quake.htm 

The main thing is to avoid "cultural noise" -- local seismic activity caused by cars, trucks, doors opening and closing, people walking, A/C or 
mechanical appliances going on and off, etc. This is best done by locating the clocks away from roads, away from the house, in a solid 
compartment weighing many tons, underground in virgin soil or bedrock.

Hi Tom,

A "compartment weighing many tons" is a low pass filter good against "cultural noise" but not so good against earth quake or earth tide
noise. A "compartment weighing many tons" is strongly coupled to the earth. The opposite approach is to uncouple from the earth as
much as possible. Your earthquake enviornment in the Pacific northwest is similar to here in Alaska. Your precision pendulum clock
is good enough to respond to monthly/daily earth tides. There is a 'catch 22' in trying to protect a pendulum clock. The pendulum
depends on constant acceleration of gravity. It ain't constant. If g varies or is noisy by one part in N then that sets the point of diminishing
return in your protection efforts.

Bill

/tvb 
On 9/8/2021 7:36 PM, Bill Beam wrote:

Tom,

How long do you expect your proposed voult to go undisturbed?
I have several pendulum clocks. They are disturbed every couple of months
by earth quakes. By disturbed, I mean pendulum banging against the case walls....
Any ground motion that can be felt will upset the clocks. Often the clocks will
signal an earth quake that is not felt.

Good luck.




Bill Beam
NL7F




Bill Beam
NL7F