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

[Bob kb8tq]

Hi

So you build the buried clock vault out in the yard. My guess is that 
simply in order to get in and out of it, the size will grow to something
like 2 x 2 x 2 m. ( how do you, a ladder, and a bunch of clocks get into 
a 1x1M square without crashing into stuff all the time? ). I’d put a raised
floor in it simply so the slope to the drain doesn’t drive you crazy. Some
space at the top for lighting might be nice. Now it’s up to maybe 2 x 2 x 3 m.

None of this helps the budget any, but it does increase the mass. It also
lets you space things out a bit more. Injection locking is probably not 
what you want between the clocks. 

If the top / roof is simply sitting there at ground level, the sun comes along
and does this or that to it on a daily basis. Either you sink it another meter
and put a dirt layer over the top or you build a hill over it. You might put
in a small building over the top. 

No matter what’s on top, you still need to get in and out of your vault. 
A ladder might work. I *know* that bringing the sort of stuff you are talking
about down a ladder would not be anything I would even remotely want
to try. Stairs and multiple doors would work, but you just > doubled the 
size of the hole. It’s not quite clear how you deal with the “thermal leak”
that the stairs create. The door to the stairs also uses up valuable wall
space. Even a trap door to get to a ladder would require a bit of thought.

Unless you have a really ideal area for drainage, there will be some sort
of sump pump down at the bottom of the beast somewhere. Yes, I have
one here, despite the issues the neighbors have, mine has never turned
on. Still glad it’s there. You don’t know if you need it until a couple of
years have gone by. 

One approach to this I actually have seen done is to go to a basement 
below the basement. The objective in that house was a sizable wine 
cellar. The claim made was that the cost of putting it in (on that property)
paid back in cooling costs fairly quickly. I never asked to see the math
that backed up that claim …. The wine inventory *was* impressive ….
One might note that the house was on a pretty steep hill. 

The family may or may not be up for dynamite being used just outside
the kitchen window. This vault sounds like a “not going to spend a lot
of time in there” kind of thing. How about a vault under that summer 
cabin in the woods you didn’t know you needed until about 3 seconds
ago? 

Bob

> On Sep 8, 2021, at 9:54 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
> 
> 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 (tvb at leapsecond.com).
> 
> Thanks,
> /tvb
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