On Thu, 09 Sep 2021 03:30:35 -0400, [email protected] wrote: Re: time-nuts Digest, Vol 209, Issue 6
> ------------------------------ > > Date: Wed, 8 Sep 2021 18:54:03 -0700 > From: Tom Van Baak <[email protected]> > Subject: [time-nuts] in-ground clock room > To: Discussion of precise time and frequency measurement > <[email protected]> > Message-ID: <[email protected]> > Content-Type: text/plain; charset=utf-8; format=flowed > > I am considering a below ground "clock room" away from the house. This > will be for some low-drift quartz oscillators and also a couple of > precision pendulum clocks. The goal is long-term, unattended, and very > undisturbed operation. > > For scale, assume the room is 1 meter × 1 meter × 2 meters deep. So > that's vastly smaller than digging a basement, but much larger than > drilling a 8 inch round pipe. Digging down gives some natural isolation > and temperature regulation. A couple tons of concrete gives high > stability vertical walls for the pendulum clocks. > > If any of you have personal or professional experience with the design > or construction of this sort of thing, especially experience with > precast (utility) vaults or poured concrete, please let me know. > > In case this gets too off-topic for time-nuts, off-list email to me is > fine ([email protected]). As others have said, it may not be economically practical to build an underground clock room. Assuming that you have a basement of other suitable room in your house, I'd suggest an insulated box or room containing a big lump of iron riding on an inner-tube suspension of some kind. The big lump of iron can be a 500-pound truck engine head or block from a junkyard, steam cleaned (to remove oil) and painted (to keep the rust under control). Drill and tap holes as needed for mounting. This box/room plus block can be set up as a temperature-controlled oven with a few extra components, including a PID controller. Bolt a thick plywood floor to the top of the iron hunk, and attach the clocks to this floor. Joe Gwinn _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
