[time-nuts] Re: in-ground clock room
Good point, Jared, regarding confined space protocols. When I was in
industry, the rule was “two people on any confined space job.” The second
person stays outside and watches. If the first person runs into trouble,
the second raises the alarm but does NOT enter the space until help is on
the scene.
On Mon, Sep 13, 2021 at 3:24 PM Jared Cabot via time-nuts <
time-nuts@lists.febo.com> wrote:
> Also, don't forget about ventilation if you will be entering the
> underground space.
> This sort of thing is classed as a 'confined space' and there should be
> oxygen monitoring in place while inside to prevent asphyxiation.
> Ventilation may work against the thermal isolation goals, but it's better
> than being found laying at the bottom of a pit..
>
>
> Jared.
>
>
>
>
>
>
> \ Original Message
> On Sep 9, 2021, 9:38 PM, Dana Whitlow < k8yumdoo...@gmail.com> wrote:
>
> >
> >
> >
> > Tom,
> >
> > Andy brings up good points, especially about water leaks.
> > Are you familiar with "Whitlow's 5th law" (which can be summarized
> > as "everything leaks")?
> >
> > Dana Whitlow
> >
> >
> > On Thu, Sep 9, 2021 at 7:29 AM Andy Gardner, ZL3AG via time-nuts <
> > time-nuts@lists.febo.com> wrote:
> >
> > >
> > >
> > > So the 2 things you're after are thermal insulation and vibration
> > > insulation?
> > >
> > > Digging can be expensive, and you have to worry about water table in
> many
> > > locations.
> > >
> > > How about the thickest concrete water tank you can find, plonk it in a
> > > nice location, spray layers of polyurethane foam over the top and
> sides for
> > > thermal insulation, then build a wind shield ("shed") around it. The
> shed
> > > could be an old coolstore, adding more insulation.
> > >
> > > Concrete water tanks are out of fashion these days due to plastics, so
> if
> > > you shop around you can find a cheap used one, and then it's just the
> > > trucking/crane charges.
> > >
> > >
> > >
> \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
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> send
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> > > To unsubscribe, go to and follow the instructions there.
> > >
> >
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--
Jeremy Nichols
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[time-nuts] Re: in-ground clock room
Also, don't forget about ventilation if you will be entering the underground
space.
This sort of thing is classed as a 'confined space' and there should be oxygen
monitoring in place while inside to prevent asphyxiation.
Ventilation may work against the thermal isolation goals, but it's better than
being found laying at the bottom of a pit..
Jared.
\ Original Message
On Sep 9, 2021, 9:38 PM, Dana Whitlow < k8yumdoo...@gmail.com> wrote:
>
>
>
> Tom,
>
> Andy brings up good points, especially about water leaks.
> Are you familiar with "Whitlow's 5th law" (which can be summarized
> as "everything leaks")?
>
> Dana Whitlow
>
>
> On Thu, Sep 9, 2021 at 7:29 AM Andy Gardner, ZL3AG via time-nuts <
> time-nuts@lists.febo.com> wrote:
>
> >
> >
> > So the 2 things you're after are thermal insulation and vibration
> > insulation?
> >
> > Digging can be expensive, and you have to worry about water table in many
> > locations.
> >
> > How about the thickest concrete water tank you can find, plonk it in a
> > nice location, spray layers of polyurethane foam over the top and sides for
> > thermal insulation, then build a wind shield ("shed") around it. The shed
> > could be an old coolstore, adding more insulation.
> >
> > Concrete water tanks are out of fashion these days due to plastics, so if
> > you shop around you can find a cheap used one, and then it's just the
> > trucking/crane charges.
> >
> >
> > \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
> > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send
> > an email to time-nuts-le...@lists.febo.com
> > To unsubscribe, go to and follow the instructions there.
> >
> \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an
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>
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[time-nuts] Re: in-ground clock room
On 9/13/21 8:05 AM, Bob kb8tq wrote: Hi The original spec was for a room roughly 3’ x 3’. You then put the clocks on the walls. Let’s say they are a foot deep on all 4 walls. You now have a 1’ x 1’ clear space for your ladder or hoist. Even if it’s 1.5 x 1.5 that seems difficult. Bob Since opening the clock vault and climbing down in there is going to perturb all the clocks anyway, why not make the whole interior lift up. You could use a winch or a chain hoist on a tripod over the hole. Or some sort of fancy lead screws elevators to raise the "floor" up to surface level. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Hi The original spec was for a room roughly 3’ x 3’. You then put the clocks on the walls. Let’s say they are a foot deep on all 4 walls. You now have a 1’ x 1’ clear space for your ladder or hoist. Even if it’s 1.5 x 1.5 that seems difficult. Bob > On Sep 13, 2021, at 10:33 AM, Joseph Gwinn wrote: > > On Mon, 13 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com > wrote: > Re: time-nuts Digest, Vol 209, Issue 11 > [snip] >> -- >> >> Message: 2 >> Date: Sun, 12 Sep 2021 09:58:32 -0400 >> From: Bob kb8tq >> Subject: [time-nuts] Re: in-ground clock room >> To: Discussion of precise time and frequency measurement >> >> > [snip] >> >> 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. > > One can use a ladder so long as there are provisions for hoisting > equipment up and down. Basically there must be a structural frame > above the access hatch from which to hang a block and tackle or the > modern equivalent. > > I installed such a setup in my attic, so I could store 100# air > conditioners in the attic over the winter. No way was anybody going > to harry that thing up and down those rickety folding starts. This > hoist has been very useful over the years. > > Joe Gwinn > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Mon, 13 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com wrote: Re: time-nuts Digest, Vol 209, Issue 11 [snip] > -- > > Message: 2 > Date: Sun, 12 Sep 2021 09:58:32 -0400 > From: Bob kb8tq > Subject: [time-nuts] Re: in-ground clock room > To: Discussion of precise time and frequency measurement > > [snip] > > 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. One can use a ladder so long as there are provisions for hoisting equipment up and down. Basically there must be a structural frame above the access hatch from which to hang a block and tackle or the modern equivalent. I installed such a setup in my attic, so I could store 100# air conditioners in the attic over the winter. No way was anybody going to harry that thing up and down those rickety folding starts. This hoist has been very useful over the years. Joe Gwinn ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
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 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 > (t...@leapsecond.com). > > Thanks, > /tvb > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
It may be that the time constant of eddy current damping would be too limited by the inavailability of sufficiently good conductors (ar room temp, anyway). To get really long time constants one basically needs superconductivity somewhere in the system. Dana On Sat, Sep 11, 2021 at 11:54 PM Tom Holmes wrote: > Which suggests a possible damping mechanism. > > From Tom Holmes, N8ZM > > > On Sep 11, 2021, at 10:08 AM, Adrian Godwin wrote: > > > > Doesn't that depend on the configuration of the fields ? > > For instance, a pair of facing like poles will repel and, as you say, > make > > a good spring. > > But a magnet falling down an aluminium tube will go slowly, because of > the > > generated eddy currents and their subsequent fading due to the lossy > > aluminium. > > > > > >> On Sat, Sep 11, 2021 at 2:02 PM Poul-Henning Kamp > >> wrote: > >> > >> > >> Gilles Clement writes: > >> > >>> Magnetic levitation, dampening external vibrations ? > >> > >> By theselves magnetic fields are just really good springs. > >> > >> To get any kind of dampening you either need to add a > >> dash-pot (=shock-absorber) as a dissipative device or > >> you need to modulate the magnitic field to emulate > >> the same result. > >> > >> I'm told the latter is much harder than it sounds. > >> > >> -- > >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > >> p...@freebsd.org | TCP/IP since RFC 956 > >> FreeBSD committer | BSD since 4.3-tahoe > >> Never attribute to malice what can adequately be explained by > incompetence. > >> ___ > >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send > >> an email to time-nuts-le...@lists.febo.com > >> To unsubscribe, go to and follow the instructions there. > >> > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-le...@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Which suggests a possible damping mechanism. From Tom Holmes, N8ZM > On Sep 11, 2021, at 10:08 AM, Adrian Godwin wrote: > > Doesn't that depend on the configuration of the fields ? > For instance, a pair of facing like poles will repel and, as you say, make > a good spring. > But a magnet falling down an aluminium tube will go slowly, because of the > generated eddy currents and their subsequent fading due to the lossy > aluminium. > > >> On Sat, Sep 11, 2021 at 2:02 PM Poul-Henning Kamp >> wrote: >> >> >> Gilles Clement writes: >> >>> Magnetic levitation, dampening external vibrations ? >> >> By theselves magnetic fields are just really good springs. >> >> To get any kind of dampening you either need to add a >> dash-pot (=shock-absorber) as a dissipative device or >> you need to modulate the magnitic field to emulate >> the same result. >> >> I'm told the latter is much harder than it sounds. >> >> -- >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 >> p...@freebsd.org | TCP/IP since RFC 956 >> FreeBSD committer | BSD since 4.3-tahoe >> Never attribute to malice what can adequately be explained by incompetence. >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send >> an email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Doesn't that depend on the configuration of the fields ? For instance, a pair of facing like poles will repel and, as you say, make a good spring. But a magnet falling down an aluminium tube will go slowly, because of the generated eddy currents and their subsequent fading due to the lossy aluminium. On Sat, Sep 11, 2021 at 2:02 PM Poul-Henning Kamp wrote: > > Gilles Clement writes: > > > Magnetic levitation, dampening external vibrations ? > > By theselves magnetic fields are just really good springs. > > To get any kind of dampening you either need to add a > dash-pot (=shock-absorber) as a dissipative device or > you need to modulate the magnitic field to emulate > the same result. > > I'm told the latter is much harder than it sounds. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room - geophones
Poul-Henning Kamp writes: "There are a number of footnotes about geophones, the primary one being that they have a resonance frequency in the 4-7 Hz range and therefore provide no usable information below that. The second is that it is anyones guess what their sensitivity is, in particular if you buy it on eBay from somebody who found it lying in a field after percussive oil-exploration, so buy more than one." For something a little more reliable and trustworthy than an eBay gamble, albeit probably more expensive, there is an organisation that caters for people nuts about vibrations - https://raspberryshake.org/ They offer some very nice products and would allow correlation of time glitches from pendulums (an interest of mine), and other clocks, with earthquakes and other such disturbances. John ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Gilles Clement writes: > Magnetic levitation, dampening external vibrations ? By theselves magnetic fields are just really good springs. To get any kind of dampening you either need to add a dash-pot (=shock-absorber) as a dissipative device or you need to modulate the magnitic field to emulate the same result. I'm told the latter is much harder than it sounds. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Magnetic levitation, dampening external vibrations ? GC > Le 10 sept. 2021 à 23:03, Jerome Blaha a écrit : > > Would the use of a partial vacuum in a sealed chamber or even the septic > tank to reach a somewhat steady-state temperature be out of the question, as > only radiation would dominate the temperature? > > Bill's idea of a 0C water bath also sounds kind of cool and perhaps it might > be attainable with a double or triple stacked pettier cooler (reversible in > voltage if your outdoor temps get below 0C) with very small tubing with > coolant and two tiny DC powered pumps for redundancy with check valves to a > small radiator inside the crypt water/ice bath with an RTD temperature > sensor. Throw in an above-ground solar and battery backup, and the > solid-state refrigeration unit could be fully self-contained and located far > enough from the time crypt to not influence gravity, magnetism, quantum > physics, etc. > > -Jerome Blaha Jr > > > > -Original Message- > From: time-nuts-requ...@lists.febo.com > [mailto:time-nuts-requ...@lists.febo.com] > Sent: Friday, September 10, 2021 12:30 AM > To: time-nuts@lists.febo.com > Subject: time-nuts Digest, Vol 209, Issue 7 > > Send time-nuts mailing list submissions to >time-nuts@lists.febo.com > > To subscribe or unsubscribe via email, send a message with subject or > body 'help' to >time-nuts-requ...@lists.febo.com > > You can reach the person managing the list at >time-nuts-ow...@lists.febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > Today's Topics: > > 1. Re: in-ground clock room (B Riches) > 2. Re: in-ground clock room (Dana Whitlow) > 3. Re: in-ground clock room (Andy Gardner, ZL3AG) > 4. Re: in-ground clock room (Dana Whitlow) > 5. Re: in-ground clock room (Bob kb8tq) > 6. Re: in-ground clock room (Brent) > 7. Re: in-ground clock room (Joseph Gwinn) > 8. Re: in-ground clock room (Steve Allen) > 9. Re: in-ground clock room (Scott McGrath) > 10. Re: in-ground clock room (Dana Whitlow) > 11. Re: in-ground clock room (Gilles Clement) > 12. Re: in-ground clock room (John Marvin) > 13. Re: [time nuts] Re: in-ground clock room (Bill Beam) > 14. Re: in-ground clock room (Lux, Jim) > 15. Re: in-ground clock room (Graham / KE9H) > 16. Re: in-ground clock room (Ben Bradley) > > > -- > > Message: 1 > Date: Thu, 9 Sep 2021 11:17:02 + (UTC) > From: B Riches > Subject: [time-nuts] Re: in-ground clock room > To: Discussion of precise time and frequency measurement >,Tom Van Baak > Message-ID: <376021411.3362644.1631186222...@mail.yahoo.com> > Content-Type: text/plain; charset=UTF-8 > > How about using a round septic tank. Mine is about 5 feet wide and 6 feet > deep Large hole in the top - put ladder for entry. > 73, > Bill, WA2DVUCape May, NJ >On Thursday, September 9, 2021, 02:29:40 AM EDT, Bill Beam > wrote: > >> On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: >> >> On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). > >>> Thanks, >>> /tvb > >> 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 tha
[time-nuts] Re: in-ground clock room - Random Thoughts
Tom When I added a machine shop to my home I devoted a part of it to set up and run a number of precision clocks which at the time consisted of a Fedchenko, two Shortt clocks and a tank Riefler. Of course the room was above ground and all of the problems regarding temperature and vibration had to be considered. The concrete floor of the room was particularly deep and I had arranged to have two large square holes made (when the floor was poured) in the floor into which I mounted two 3000 pound square freestanding concrete blocks that were floor height. The blocks were mounted on vibration isolators (used to mitigate the effects of earthquakes in California buildiings) which I had made. Although it wasn't perfect it did help with the local road noise and random vibrations. What I hadn’t counted on was the change of seasons and heavy rain. When I set up the clocks (Fedchenko on one of the isolation blocks and an Englsh Shortt on the other) I mounted a very sensitive tiltmeter on the floor of the room and found that when we had a long duration rainfall in the summer, the entire floor tilted slightly. It did the same when the seasons changed from Winter to Summer. Keeping a steady temperature also proved to be difficult. The tiltmeter was of the type used on bridges to check for beam flexing and was made by Sperry. My house was built in the 50's and I believe a good deal of fill was used to level the site. This most likely caused the problem. Neverthess I had quite good results with the clocks. Bill S www.precisionclocks.com On 9/8/2021 9:54 PM, Tom Van Baak 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 (t...@leapsecond.com). Thanks, /tvb ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Bill Beam writes: > >Bill's idea of a 0C water bath also sounds kind of cool and perhaps it might > be attainable with a double or triple stacked pettier cooler [...] There are excellent and cheap, widely available cabinets for this kind of experiment: Buy a fridge or a freezer and dont plug it in. If you want to, you can use the plumbing to run your own cooleant. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Fri, 10 Sep 2021 21:03:05 +, Jerome Blaha wrote: >Would the use of a partial vacuum in a sealed chamber or even the septic tank >to reach a somewhat steady-state temperature be out of the question, as only radiation would dominate the temperature? >Bill's idea of a 0C water bath also sounds kind of cool and perhaps it might >be attainable with a double or triple stacked pettier cooler (reversible in voltage if your outdoor temps get below 0C) with very small tubing with coolant and two tiny DC powered pumps for redundancy with check valves to a small radiator inside the crypt water/ice bath with an RTD temperature sensor. Throw in an above-ground solar and battery backup, and the solid-state refrigeration unit could be fully self-contained and located far enough from the time crypt to not influence gravity, magnetism, quantum physics, etc. My suggestion of floating the clock in a water/ice bath raises a not so obvious mechanical issue: The clock is now no longer constrained against side-to-side motion. As the pendulum swings to and fro the clock case will move/rock fro and to. Expect large phase noise from turbulence in the bath. A 'simple' pendulum exists only in theory. A real 'simple' pendulum does not exist in any ones clock lab. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Hi I think that if you are looking at something this size, a compressor based heat / cool setup will do much better than a solid state approach. Way less power due to the much better efficiency . You can get pretty small systems that will hold < 0.05 C on the “coolant line". Bob > On Sep 10, 2021, at 5:03 PM, Jerome Blaha wrote: > > Would the use of a partial vacuum in a sealed chamber or even the septic tank > to reach a somewhat steady-state temperature be out of the question, as only > radiation would dominate the temperature? > > Bill's idea of a 0C water bath also sounds kind of cool and perhaps it might > be attainable with a double or triple stacked pettier cooler (reversible in > voltage if your outdoor temps get below 0C) with very small tubing with > coolant and two tiny DC powered pumps for redundancy with check valves to a > small radiator inside the crypt water/ice bath with an RTD temperature > sensor. Throw in an above-ground solar and battery backup, and the > solid-state refrigeration unit could be fully self-contained and located far > enough from the time crypt to not influence gravity, magnetism, quantum > physics, etc. > > -Jerome Blaha Jr > > > > -Original Message- > From: time-nuts-requ...@lists.febo.com > [mailto:time-nuts-requ...@lists.febo.com] > Sent: Friday, September 10, 2021 12:30 AM > To: time-nuts@lists.febo.com > Subject: time-nuts Digest, Vol 209, Issue 7 > > Send time-nuts mailing list submissions to > time-nuts@lists.febo.com > > To subscribe or unsubscribe via email, send a message with subject or > body 'help' to > time-nuts-requ...@lists.febo.com > > You can reach the person managing the list at > time-nuts-ow...@lists.febo.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > Today's Topics: > > 1. Re: in-ground clock room (B Riches) > 2. Re: in-ground clock room (Dana Whitlow) > 3. Re: in-ground clock room (Andy Gardner, ZL3AG) > 4. Re: in-ground clock room (Dana Whitlow) > 5. Re: in-ground clock room (Bob kb8tq) > 6. Re: in-ground clock room (Brent) > 7. Re: in-ground clock room (Joseph Gwinn) > 8. Re: in-ground clock room (Steve Allen) > 9. Re: in-ground clock room (Scott McGrath) > 10. Re: in-ground clock room (Dana Whitlow) > 11. Re: in-ground clock room (Gilles Clement) > 12. Re: in-ground clock room (John Marvin) > 13. Re: [time nuts] Re: in-ground clock room (Bill Beam) > 14. Re: in-ground clock room (Lux, Jim) > 15. Re: in-ground clock room (Graham / KE9H) > 16. Re: in-ground clock room (Ben Bradley) > > > -- > > Message: 1 > Date: Thu, 9 Sep 2021 11:17:02 + (UTC) > From: B Riches > Subject: [time-nuts] Re: in-ground clock room > To: Discussion of precise time and frequency measurement > ,Tom Van Baak > Message-ID: <376021411.3362644.1631186222...@mail.yahoo.com> > Content-Type: text/plain; charset=UTF-8 > > How about using a round septic tank. Mine is about 5 feet wide and 6 feet > deep Large hole in the top - put ladder for entry. > 73, > Bill, WA2DVUCape May, NJ >On Thursday, September 9, 2021, 02:29:40 AM EDT, Bill Beam > wrote: > > On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: > >> On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). > >>> Thanks, >>> /tvb > >> Tom, > >> How long do you expect your proposed voult to go undisturbed? >> I have several pendulum clocks. They are disturbed every couple of
[time-nuts] Re: in-ground clock room
Would the use of a partial vacuum in a sealed chamber or even the septic tank to reach a somewhat steady-state temperature be out of the question, as only radiation would dominate the temperature? Bill's idea of a 0C water bath also sounds kind of cool and perhaps it might be attainable with a double or triple stacked pettier cooler (reversible in voltage if your outdoor temps get below 0C) with very small tubing with coolant and two tiny DC powered pumps for redundancy with check valves to a small radiator inside the crypt water/ice bath with an RTD temperature sensor. Throw in an above-ground solar and battery backup, and the solid-state refrigeration unit could be fully self-contained and located far enough from the time crypt to not influence gravity, magnetism, quantum physics, etc. -Jerome Blaha Jr -Original Message- From: time-nuts-requ...@lists.febo.com [mailto:time-nuts-requ...@lists.febo.com] Sent: Friday, September 10, 2021 12:30 AM To: time-nuts@lists.febo.com Subject: time-nuts Digest, Vol 209, Issue 7 Send time-nuts mailing list submissions to time-nuts@lists.febo.com To subscribe or unsubscribe via email, send a message with subject or body 'help' to time-nuts-requ...@lists.febo.com You can reach the person managing the list at time-nuts-ow...@lists.febo.com When replying, please edit your Subject line so it is more specific than "Re: Contents of time-nuts digest..." Today's Topics: 1. Re: in-ground clock room (B Riches) 2. Re: in-ground clock room (Dana Whitlow) 3. Re: in-ground clock room (Andy Gardner, ZL3AG) 4. Re: in-ground clock room (Dana Whitlow) 5. Re: in-ground clock room (Bob kb8tq) 6. Re: in-ground clock room (Brent) 7. Re: in-ground clock room (Joseph Gwinn) 8. Re: in-ground clock room (Steve Allen) 9. Re: in-ground clock room (Scott McGrath) 10. Re: in-ground clock room (Dana Whitlow) 11. Re: in-ground clock room (Gilles Clement) 12. Re: in-ground clock room (John Marvin) 13. Re: [time nuts] Re: in-ground clock room (Bill Beam) 14. Re: in-ground clock room (Lux, Jim) 15. Re: in-ground clock room (Graham / KE9H) 16. Re: in-ground clock room (Ben Bradley) -- Message: 1 Date: Thu, 9 Sep 2021 11:17:02 + (UTC) From: B Riches Subject: [time-nuts] Re: in-ground clock room To: Discussion of precise time and frequency measurement ,Tom Van Baak Message-ID: <376021411.3362644.1631186222...@mail.yahoo.com> Content-Type: text/plain; charset=UTF-8 How about using a round septic tank. Mine is about 5 feet wide and 6 feet deep Large hole in the top - put ladder for entry. 73, Bill, WA2DVUCape May, NJ On Thursday, September 9, 2021, 02:29:40 AM EDT, Bill Beam wrote: On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: >On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). >>Thanks, >>/tvb >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. I spent a few years as a geotechnic/soils engineer and learned as others have pointed out that a thermal wave of period one year and wave length of several meters propagates downward thru the soil. Peak amplitude of a few degrees can be expected near the surface. Consider building an "oven" with the clock vault freely floating in a water-ice mixture. This will provide constant temperature (0C) and limited mechanical isolation from earth quakes. But of course this will be expensive to operate. As you know 'good' clocks require a lot of energy and generate a lot of entropy. Pro
[time-nuts] Re: in-ground clock room
Or Better yet... Time-lapse! Preferably, timestamped. On 9/10/2021 3:30 AM, time-nuts-requ...@lists.febo.com wrote: Message: 15 Date: Thu, 9 Sep 2021 18:03:08 -0500 From: "Graham / KE9H" Subject: [time-nuts] Re: in-ground clock room To: Discussion of precise time and frequency measurement Message-ID: Content-Type: text/plain; charset="UTF-8" Sounds like we need a volunteer time-nut with motion picture camera capability to document this event. --- Graham ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Hendrik writes: > go to ebay and get a cheap geophone. [...] I did that prior to building our house, because we built about 60m from the main rail-road through Denmark, and I needed vibration data to design of the house. There are a number of footnotes about geophones, the primary one being that they have a resonance frequency in the 4-7 Hz range and therefore provide no usable information below that. The second is that it is anyones guess what their sensitivity is, in particular if you buy it on eBay from somebody who found it lying in a field after percussive oil-exploration, so buy more than one. The good news is that it is easy to calibrated a geophone for absolute response using common T kit. I feed the geophone directly into a TI ADS1282 evaluation board, that ADC is built specifically for geophones and it works great. It is now bolted to the foundation of our house, and here is a recent plot: http://phk.freebsd.dk/misc/_.18856.pdf The 50 & 100 Hz lines are electical noise. The vertical red impulses at night are typical of passing trains, around 5Z construction work on the rails started. See if you can guess when they used the huge vibration compactor :-/ I have no data from any other building to compare with, and we did succeed in building a very quiet house: You really have to pay attention to hear the train-traffic. Amongst the many faint domestic signals I can identify in these plots are our ground-circuit heat-pump, the "GenVex" ventilation, the cooling in my lab, the fans in my Dell-server, the freezer, the washer, the dryer, and the occational good "rocking-through" on the Rauna-Njord speakers. I've tried playing the recordings back through head-phones, but none of those signals were audible. The vibration compactor on the other hand... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Hello Tom, go to ebay and get a cheap geophone. Attach a resistor in parallel acc. datasheet, and use a data logger (simple: HX711 weigh scale ADC plus two resistors to fake a bridge circuit, arduino for interrogation and logging to PC) and you will have knowledge about the short-term events at your location. You might gain enough knowledge to be able to compensate for the movements by postprocessing. Or, nut-conorm, you might put your clocks and the geophone on a table which rests on, say, elastomer in parallel to a voice coil actuator, applying some control theory magic, have the arduino (or something analog or a mix) use the geophone feedback for the voice coil to keep the table aligned. BR Hendrik ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
I've seen discussion of making a seismic vault (though not sure if they used that name, making it harder to find in the haystack of posts) on this mailing list, maybt 15 or 20 years ago, so nut sure if this is helpful: https://www.seismicnet.com/maillist.html For possible immunity from earthquakes, LIGO uses some quite complex control and feedback systems to hang its mirrors so that mild earthquakes and local noise won't affect them. From what I've seen over the years a lot of this info has been published, but I imagine it would be quite expensive to reproduce. Maybe some sort of Ligo Lite system would be feasible. On Thu, Sep 9, 2021 at 10:13 AM Brent wrote: > > Seismic vaults are built similar to your requirements. I suggest looking > up the Earthscope program - there should be info out on the web as to how > their vaults were designed, but in a nutshell, dig a hole, put some gravel > in the bottom, place a large culvert on end in the hole, pour a few inches > of concrete in the culvert, put instrumentation in a pedestal inside, run > power and comms, put a bilge pump and outflow pipe in it on the floor > (below pedastal), and put a cap on the whole thing. Those were then > re-buried, but that prevents easy access (although it probably improves > temperature stability). A septic tank would be larger, but more effort, and > may expose more surface area to the sun (temp variation). > > I've been in various seismic vaults and they can vary from very extravagant > to downright crude. > > > > On Thu, Sep 9, 2021 at 9:04 AM Bob kb8tq wrote: > > > Hi > > > > You could do some research on the climate in various parts of the world. > > Pick the ideal location and move there :) :) You also could optimize the > > location for various tidal forces …. > > > > How deep can you go on your property before you run into something > > massive? Around here, I can go down between a foot and maybe two > > feet. At that point it’s time for dynamite. You do not ask “how much to > > put in a swimming pool?” in this neighborhood. Part of this is the > > geology, > > part is how the builder graded things to put in the subdivision. > > > > While that *sounds* ideal, the shale is tilted due to some thing running > > into > > something else a while ago. The net result is ground water running here > > and there to some fairly significant depths. As the seasons change that > > ground water and its somewhat random route changes isn’t ideal for > > temperature stability. > > > > Yes, it’s all about some *very* local aspects of your geology. With some > > care, I could move a few miles in one direction or another and be in a > > *very* > > different situation. (again thanks to just how this ran into that ….). > > > > Since temperature stability is only part of the design and mechanical > > stability is the other. This location might work ok for half of the design > > goals …. Granite likely would do better than fractured shale though ... > > > > Bob > > > > > On Sep 9, 2021, at 1:20 AM, Poul-Henning Kamp > > wrote: > > > > > > > > > Tom Van Baak writes: > > > > > >> 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. > > > > > > I researched this extensively before we built a house 5 years ago. > > > > > > Look at the plot on page 37 in this paper: > > > > > > > > https://www.researchgate.net/publication/279526204_Temperatur_og_temperaturgradienter_ved_og_under_jordoverfladen_i_relation_til_lithologi > > > > > > It shows that in Denmark the yearly temperature variations in > > > penetrates to a depth of 15 meters, and that even at 10 meters > > > depth, you can expect the swing to be several Kelvin in any year. > > > > > > I did find handwaving which said tree-cover reduced the swing by > > > "a lot" but no measurements to substantiate it. > > > > > > In the end I concluded that I could do better in the comfort of my lab. > > > > > > You should try to find similar data for your local climate and > > > geology, before you pour too much money into a hole in the ground. > > > > > > -- > > > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > > > p...@freebsd.org | TCP/IP since RFC 956 > > > FreeBSD committer | BSD since 4.3-tahoe > > > Never attribute to malice what can adequately be explained by > > incompetence. > > > ___ > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > > send an email to time-nuts-le...@lists.febo.com > > > To unsubscribe, go to and follow the instructions there. > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > > an email to
[time-nuts] Re: in-ground clock room
Sounds like we need a volunteer time-nut with motion picture camera capability to document this event. --- Graham On Thu, Sep 9, 2021 at 5:17 PM Lux, Jim wrote: > On 9/8/21 6:54 PM, Tom Van Baak 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. > > > A few years back, we were looking at building a "test rubble pile" for > search and rescue applications (actually for testing equipment that > would be used for this). > > For the depths you're talking about (few meters) the easiest approach is > to get someone with a backhoe to dig a pit, then use the backhoe to > carry the precast vault, drop it in, and you're done. If you were going > more than "backhoe depth" you're looking at something like an auger, and > they can drill any diameter (up to about 4 feet) and any depth, as long > as they can get the truck into position (same as the backhoe). > > I went around looking at the precast concrete vendors - they're > available in any size you want. You can also just sink a drain pipe of > any size vertically, and fill the bottom with concrete. The vaults often > come with "knockouts" - places where you can bring conduit in by > knocking out the plug of concrete (it's cast with a thin ring, so you > hit it with a sledge) - the conduit (or duct, or sewer pipe) to vault > seal is done with a variety of goops. Some of the ones I've seen look > like tar (the same stuff used to fix roads, roofs, shower pans), others > use some sort of foam. > > The prices for this stuff are fairly standardized - your local utility > or roads department probably has a "standard bid list" for most of the > more common items that they use for doing estimates. Caltrans certainly > does (a 48" precast concrete manhole is about $1500). So that gives you > a ballpark when you start calling vendors. The big driver for most > people in a "residential" environment would be access. It's one thing > to have a double flatbed show up with a bunch of concrete pipe on it at > a business, totally another on a winding residential street. We had > stuff delivered on a flatbed truck with a small crane - but they could > just pull up to the site, sling the vault, and lower it to the ground, > and then the backhoe guy moved it. Going up a driveway, around the > corner, avoiding the fence, etc. would be different. Or, A *really big* > crane - I've seen that done - 80 or 100 foot boom in the street - they > pick the load up, lift it up and over the house and place it in the back > yard. > > https://precastconcretesales.com/manholes/ > > https://www.columbiaprecastproducts.com/products/precast-manholes/ > > https://www.gardenstateprecast.com/pdf/2019-price-list.pdf > > Google "precast concrete manhole" and select accordingly. > > > > You're looking at the "more than $1000 probably less than $10k" range, > all done in a day, plus a day of prep and a day of cleanup. > > Backhoes (in SoCal) are going for $300-500/day plus the operator > ($50-60/hr).. Or you can learn - it's hard to do precise work as > a rookie, but digging a hole is pretty easy to learn on your own. And I > just looked it up, the smaller skid-steer bobcat type could probably dig > a 2 meter deep hole, and you're less likely to do major damage like you > can with a full sized unit. > > Home Depot actually rents them.. 2-3 ton miniexcavator is $359/day , > $1005/week > > > https://www.compactpowerrents.com/rental-equipment/mini-excavator/25-3-ton-mini-excavator/ > You might find someone who's usually doing stuff like pools and spas, > and will dig your hole for you. In any case, probably not more than $1000 > > > One other source for design is "storm shelters" - FEMA has published > pre-engineered designs for a variety of inground shelters (often, > installed below a garage) > > > One final thing - even if it's waterproofed, it *will collect water* > either by condensation or seepage. You might need to make your clock > vault have some sort of dehumidifier and/or sump pump. > > > The other alternative is to "build a basement" - dig the hole by hand, > pour a slab, and either pour walls or stack blocks and pour into the > cavities. 1x1x2 meters is sort of doable.. figure standard 8x16" > blocks, so the "hole" is going to be
[time-nuts] Re: in-ground clock room
On 9/8/21 6:54 PM, Tom Van Baak 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. A few years back, we were looking at building a "test rubble pile" for search and rescue applications (actually for testing equipment that would be used for this). For the depths you're talking about (few meters) the easiest approach is to get someone with a backhoe to dig a pit, then use the backhoe to carry the precast vault, drop it in, and you're done. If you were going more than "backhoe depth" you're looking at something like an auger, and they can drill any diameter (up to about 4 feet) and any depth, as long as they can get the truck into position (same as the backhoe). I went around looking at the precast concrete vendors - they're available in any size you want. You can also just sink a drain pipe of any size vertically, and fill the bottom with concrete. The vaults often come with "knockouts" - places where you can bring conduit in by knocking out the plug of concrete (it's cast with a thin ring, so you hit it with a sledge) - the conduit (or duct, or sewer pipe) to vault seal is done with a variety of goops. Some of the ones I've seen look like tar (the same stuff used to fix roads, roofs, shower pans), others use some sort of foam. The prices for this stuff are fairly standardized - your local utility or roads department probably has a "standard bid list" for most of the more common items that they use for doing estimates. Caltrans certainly does (a 48" precast concrete manhole is about $1500). So that gives you a ballpark when you start calling vendors. The big driver for most people in a "residential" environment would be access. It's one thing to have a double flatbed show up with a bunch of concrete pipe on it at a business, totally another on a winding residential street. We had stuff delivered on a flatbed truck with a small crane - but they could just pull up to the site, sling the vault, and lower it to the ground, and then the backhoe guy moved it. Going up a driveway, around the corner, avoiding the fence, etc. would be different. Or, A *really big* crane - I've seen that done - 80 or 100 foot boom in the street - they pick the load up, lift it up and over the house and place it in the back yard. https://precastconcretesales.com/manholes/ https://www.columbiaprecastproducts.com/products/precast-manholes/ https://www.gardenstateprecast.com/pdf/2019-price-list.pdf Google "precast concrete manhole" and select accordingly. You're looking at the "more than $1000 probably less than $10k" range, all done in a day, plus a day of prep and a day of cleanup. Backhoes (in SoCal) are going for $300-500/day plus the operator ($50-60/hr).. Or you can learn - it's hard to do precise work as a rookie, but digging a hole is pretty easy to learn on your own. And I just looked it up, the smaller skid-steer bobcat type could probably dig a 2 meter deep hole, and you're less likely to do major damage like you can with a full sized unit. Home Depot actually rents them.. 2-3 ton miniexcavator is $359/day , $1005/week https://www.compactpowerrents.com/rental-equipment/mini-excavator/25-3-ton-mini-excavator/ You might find someone who's usually doing stuff like pools and spas, and will dig your hole for you. In any case, probably not more than $1000 One other source for design is "storm shelters" - FEMA has published pre-engineered designs for a variety of inground shelters (often, installed below a garage) One final thing - even if it's waterproofed, it *will collect water* either by condensation or seepage. You might need to make your clock vault have some sort of dehumidifier and/or sump pump. The other alternative is to "build a basement" - dig the hole by hand, pour a slab, and either pour walls or stack blocks and pour into the cavities. 1x1x2 meters is sort of doable.. figure standard 8x16" blocks, so the "hole" is going to be 16+39=55" square - figure 5 ft. That's big enough to stand in, but there is a significant cave-in hazard, If you're down 2 meters, and the side collapses on you, you'll probably die before they can dig you out. Or, your soil is sturdy enough, you manage the risk. I don't think you could dig 2
[time-nuts] Re: [time nuts] Re: in-ground clock room
--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 ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Hmm, this list isn't called time-science, time-research, time-hardware, or time-trivia. It's called time-nuts. This is probably one of the most on topic (and fun) posts I've seen on this list. :) Regards, John On 9/8/2021 7:54 PM, Tom Van Baak wrote: In case this gets too off-topic for time-nuts, off-list email to me is fine (t...@leapsecond.com). Thanks, /tvb ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
With a slight cantilevered cavity at the base, instrumental as a *nut cracker… o:)) * = time? > Le 9 sept. 2021 à 18:35, Dana Whitlow a écrit : > > One might also consider mounting smaller items inside the cylinders of the > engine block, > to get the most out of its thermal mass. > > Dana > > > On Thu, Sep 9, 2021 at 11:03 AM Joseph Gwinn wrote: > >> On Thu, 09 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com >> wrote: >> Re: time-nuts Digest, Vol 209, Issue 6 >> >> >>> -- Date: Wed, 8 Sep 2021 18:54:03 -0700 >>> From: Tom Van Baak >>> Subject: [time-nuts] in-ground clock room >>> To: Discussion of precise time and frequency measurement >>> >>> Message-ID: <4037f6cb-ade3-8c01-8c36-7edf19327...@leapsecond.com> >>> 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 (t...@leapsecond.com). >> >> 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 -- time-nuts@lists.febo.com -- To unsubscribe send >> an email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
One might also consider mounting smaller items inside the cylinders of the engine block, to get the most out of its thermal mass. Dana On Thu, Sep 9, 2021 at 11:03 AM Joseph Gwinn wrote: > On Thu, 09 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com > wrote: > Re: time-nuts Digest, Vol 209, Issue 6 > > > > -- > > > Date: Wed, 8 Sep 2021 18:54:03 -0700 > > From: Tom Van Baak > > Subject: [time-nuts] in-ground clock room > > To: Discussion of precise time and frequency measurement > > > > Message-ID: <4037f6cb-ade3-8c01-8c36-7edf19327...@leapsecond.com> > > 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 (t...@leapsecond.com). > > 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 -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Rather than custom casting a structure you might want to consider use of a precast concrete septic tank or transformer vault as cost will be much lower. You will also need to consider waterproofing the tank it already has a layer of waterproofing but a couple of additional layers will probably be necessary as well as ensuring proper drainage around it as it will need to be both above local water table and be able to drain off percolating rainwater. You will also need to control temperature and humidity On Sep 9, 2021, at 12:03 PM, Joseph Gwinn wrote: On Thu, 09 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com wrote: Re: time-nuts Digest, Vol 209, Issue 6 > -- >> Date: Wed, 8 Sep 2021 18:54:03 -0700 > From: Tom Van Baak > Subject: [time-nuts] in-ground clock room > To: Discussion of precise time and frequency measurement > > Message-ID: <4037f6cb-ade3-8c01-8c36-7edf19327...@leapsecond.com> > 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 (t...@leapsecond.com). 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 -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Wed 2021-09-08T18:54:03-0700 Tom Van Baak hath writ: > 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. How deep? Bulletin Horaire v3n46p262 (1929-02-10) reports the equipment, facilities, and operations of Bureau International de l'Heure at Observatoire de Paris. The highest precision pendulum clocks, the ones which had mechanisms to correct for temperature and pressure (the "garde-temps") were kept 27 m below ground in caves and galleries which were part of the Paris catacombs. Various issues of Bulletin Horaire report discontinuities in the operation of those clocks due to distant earthquakes. -- Steve Allen WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Thu, 09 Sep 2021 03:30:35 -0400, time-nuts-requ...@lists.febo.com wrote: Re: time-nuts Digest, Vol 209, Issue 6 > -- > > Date: Wed, 8 Sep 2021 18:54:03 -0700 > From: Tom Van Baak > Subject: [time-nuts] in-ground clock room > To: Discussion of precise time and frequency measurement > > Message-ID: <4037f6cb-ade3-8c01-8c36-7edf19327...@leapsecond.com> > 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 (t...@leapsecond.com). 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 -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Seismic vaults are built similar to your requirements. I suggest looking up the Earthscope program - there should be info out on the web as to how their vaults were designed, but in a nutshell, dig a hole, put some gravel in the bottom, place a large culvert on end in the hole, pour a few inches of concrete in the culvert, put instrumentation in a pedestal inside, run power and comms, put a bilge pump and outflow pipe in it on the floor (below pedastal), and put a cap on the whole thing. Those were then re-buried, but that prevents easy access (although it probably improves temperature stability). A septic tank would be larger, but more effort, and may expose more surface area to the sun (temp variation). I've been in various seismic vaults and they can vary from very extravagant to downright crude. On Thu, Sep 9, 2021 at 9:04 AM Bob kb8tq wrote: > Hi > > You could do some research on the climate in various parts of the world. > Pick the ideal location and move there :) :) You also could optimize the > location for various tidal forces …. > > How deep can you go on your property before you run into something > massive? Around here, I can go down between a foot and maybe two > feet. At that point it’s time for dynamite. You do not ask “how much to > put in a swimming pool?” in this neighborhood. Part of this is the > geology, > part is how the builder graded things to put in the subdivision. > > While that *sounds* ideal, the shale is tilted due to some thing running > into > something else a while ago. The net result is ground water running here > and there to some fairly significant depths. As the seasons change that > ground water and its somewhat random route changes isn’t ideal for > temperature stability. > > Yes, it’s all about some *very* local aspects of your geology. With some > care, I could move a few miles in one direction or another and be in a > *very* > different situation. (again thanks to just how this ran into that ….). > > Since temperature stability is only part of the design and mechanical > stability is the other. This location might work ok for half of the design > goals …. Granite likely would do better than fractured shale though ... > > Bob > > > On Sep 9, 2021, at 1:20 AM, Poul-Henning Kamp > wrote: > > > > > > Tom Van Baak writes: > > > >> 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. > > > > I researched this extensively before we built a house 5 years ago. > > > > Look at the plot on page 37 in this paper: > > > > > https://www.researchgate.net/publication/279526204_Temperatur_og_temperaturgradienter_ved_og_under_jordoverfladen_i_relation_til_lithologi > > > > It shows that in Denmark the yearly temperature variations in > > penetrates to a depth of 15 meters, and that even at 10 meters > > depth, you can expect the swing to be several Kelvin in any year. > > > > I did find handwaving which said tree-cover reduced the swing by > > "a lot" but no measurements to substantiate it. > > > > In the end I concluded that I could do better in the comfort of my lab. > > > > You should try to find similar data for your local climate and > > geology, before you pour too much money into a hole in the ground. > > > > -- > > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > > p...@freebsd.org | TCP/IP since RFC 956 > > FreeBSD committer | BSD since 4.3-tahoe > > Never attribute to malice what can adequately be explained by > incompetence. > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe > send an email to time-nuts-le...@lists.febo.com > > To unsubscribe, go to and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Hi You could do some research on the climate in various parts of the world. Pick the ideal location and move there :) :) You also could optimize the location for various tidal forces …. How deep can you go on your property before you run into something massive? Around here, I can go down between a foot and maybe two feet. At that point it’s time for dynamite. You do not ask “how much to put in a swimming pool?” in this neighborhood. Part of this is the geology, part is how the builder graded things to put in the subdivision. While that *sounds* ideal, the shale is tilted due to some thing running into something else a while ago. The net result is ground water running here and there to some fairly significant depths. As the seasons change that ground water and its somewhat random route changes isn’t ideal for temperature stability. Yes, it’s all about some *very* local aspects of your geology. With some care, I could move a few miles in one direction or another and be in a *very* different situation. (again thanks to just how this ran into that ….). Since temperature stability is only part of the design and mechanical stability is the other. This location might work ok for half of the design goals …. Granite likely would do better than fractured shale though ... Bob > On Sep 9, 2021, at 1:20 AM, Poul-Henning Kamp wrote: > > > Tom Van Baak writes: > >> 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. > > I researched this extensively before we built a house 5 years ago. > > Look at the plot on page 37 in this paper: > > > https://www.researchgate.net/publication/279526204_Temperatur_og_temperaturgradienter_ved_og_under_jordoverfladen_i_relation_til_lithologi > > It shows that in Denmark the yearly temperature variations in > penetrates to a depth of 15 meters, and that even at 10 meters > depth, you can expect the swing to be several Kelvin in any year. > > I did find handwaving which said tree-cover reduced the swing by > "a lot" but no measurements to substantiate it. > > In the end I concluded that I could do better in the comfort of my lab. > > You should try to find similar data for your local climate and > geology, before you pour too much money into a hole in the ground. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Tom,
Andy brings up good points, especially about water leaks.
Are you familiar with "Whitlow's 5th law" (which can be summarized
as "everything leaks")?
Dana Whitlow
On Thu, Sep 9, 2021 at 7:29 AM Andy Gardner, ZL3AG via time-nuts <
time-nuts@lists.febo.com> wrote:
>
>
> So the 2 things you're after are thermal insulation and vibration
> insulation?
>
> Digging can be expensive, and you have to worry about water table in many
> locations.
>
> How about the thickest concrete water tank you can find, plonk it in a
> nice location, spray layers of polyurethane foam over the top and sides for
> thermal insulation, then build a wind shield ("shed") around it. The shed
> could be an old coolstore, adding more insulation.
>
> Concrete water tanks are out of fashion these days due to plastics, so if
> you shop around you can find a cheap used one, and then it's just the
> trucking/crane charges.
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send
> an email to time-nuts-le...@lists.febo.com
> To unsubscribe, go to and follow the instructions there.
>
___
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email to time-nuts-le...@lists.febo.com
To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
So the 2 things you're after are thermal insulation and vibration insulation?
Digging can be expensive, and you have to worry about water table in many
locations.
How about the thickest concrete water tank you can find, plonk it in a nice location,
spray layers of polyurethane foam over the top and sides for thermal insulation, then
build a wind shield ("shed") around it. The shed could be an old coolstore,
adding more insulation.
Concrete water tanks are out of fashion these days due to plastics, so if you
shop around you can find a cheap used one, and then it's just the
trucking/crane charges.
___
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an
email to time-nuts-le...@lists.febo.com
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[time-nuts] Re: in-ground clock room
It seems to me that in order to derive much thermal stabilization, the *top* of the space would need to be several feet underground (depending on geographic location). And I think that the means for human access would likely "spoil the broth" unless fairly extreme measures were taken. Wouldn't it be sufficient to use a space whose thermal coupling were weak enough to make the time constant a few days (instead of months)? Then, ordinary inexpensive means like GPS-locked Rb standards with suitable (longish) time constants should clean up "GPS noise", yet enable the loop to take care of low rate temperature variations in the protected space due to outside temperature changes. Remember, perfection in clocks is expensive- according to recent things I've read about entropy of timekeeping, a perfect clock would require infinite power, and that alone would blow away all one's efforts at temperature control. Dana On Thu, Sep 9, 2021 at 6:19 AM B Riches via time-nuts < time-nuts@lists.febo.com> wrote: > How about using a round septic tank. Mine is about 5 feet wide and 6 > feet deep Large hole in the top - put ladder for entry. > 73, > Bill, WA2DVUCape May, NJ > On Thursday, September 9, 2021, 02:29:40 AM EDT, Bill Beam < > wb...@gci.net> wrote: > > On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: > > >On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). > > >>Thanks, > >>/tvb > > >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. > > I spent a few years as a geotechnic/soils engineer and learned as others > have pointed out > that a thermal wave of period one year and wave length of several meters > propagates > downward thru the soil. Peak amplitude of a few degrees can be expected > near the surface. > > Consider building an "oven" with the clock vault freely floating in a > water-ice mixture. This will > provide constant temperature (0C) and limited mechanical isolation from > earth quakes. > > But of course this will be expensive to operate. > > As you know 'good' clocks require a lot of energy and generate a lot of > entropy. > > Protecting the quartz oscillators is much easier than protecting the > pendulum clocks. > > > > > Bill Beam > NL7F > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
How about using a round septic tank. Mine is about 5 feet wide and 6 feet deep Large hole in the top - put ladder for entry. 73, Bill, WA2DVUCape May, NJ On Thursday, September 9, 2021, 02:29:40 AM EDT, Bill Beam wrote: On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: >On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). >>Thanks, >>/tvb >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. I spent a few years as a geotechnic/soils engineer and learned as others have pointed out that a thermal wave of period one year and wave length of several meters propagates downward thru the soil. Peak amplitude of a few degrees can be expected near the surface. Consider building an "oven" with the clock vault freely floating in a water-ice mixture. This will provide constant temperature (0C) and limited mechanical isolation from earth quakes. But of course this will be expensive to operate. As you know 'good' clocks require a lot of energy and generate a lot of entropy. Protecting the quartz oscillators is much easier than protecting the pendulum clocks. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Wed, 08 Sep 2021 18:36:11 -0800, Bill Beam wrote: >On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). >>Thanks, >>/tvb >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. I spent a few years as a geotechnic/soils engineer and learned as others have pointed out that a thermal wave of period one year and wave length of several meters propagates downward thru the soil. Peak amplitude of a few degrees can be expected near the surface. Consider building an "oven" with the clock vault freely floating in a water-ice mixture. This will provide constant temperature (0C) and limited mechanical isolation from earth quakes. But of course this will be expensive to operate. As you know 'good' clocks require a lot of energy and generate a lot of entropy. Protecting the quartz oscillators is much easier than protecting the pendulum clocks. Bill Beam NL7F ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On 09/09/2021 03:36, 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, It sounds as if you live in an area where monitoring of earthquakes would be of interest! If you haven't got something already, you might like to look at the Raspberry Shake: https://raspberryshake.org/ The devices are not at the professional seismograph level. They operate a world-wide network. 73, David GM8ARV -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-tay...@blueyonder.co.uk Twitter: @gm8arv ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Tom Van Baak writes: >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. I researched this extensively before we built a house 5 years ago. Look at the plot on page 37 in this paper: https://www.researchgate.net/publication/279526204_Temperatur_og_temperaturgradienter_ved_og_under_jordoverfladen_i_relation_til_lithologi It shows that in Denmark the yearly temperature variations in penetrates to a depth of 15 meters, and that even at 10 meters depth, you can expect the swing to be several Kelvin in any year. I did find handwaving which said tree-cover reduced the swing by "a lot" but no measurements to substantiate it. In the end I concluded that I could do better in the comfort of my lab. You should try to find similar data for your local climate and geology, before you pour too much money into a hole in the ground. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
Temperature stability will vary with climate. Here in upstate NY, you’ll need to get to >50” of depth to start to get any real year round thermal stability. But a local civil engineer should know that number well. We also have to worry about water intrusion, even with concrete, depending on depth. Interesting subject. > On Sep 8, 2021, at 22:09, djl wrote: > > I think you can use precast concrete such as a septic tank or rings. My > measurements made a LONG time ago in NM indicate that a mere 18 inches depth > leads to less than one degree (God's units as revealed by the French) over > the period of a year. Bring wiring in via a trench at the surface level of > the top of the vault. Ideally, the cover should be insulation to near > surface, then soil. That's the one sticky point because as you will know, > thermal vortices will be set up in the vault air. very small slow fans may > control? The flow can be modeled, I think. > Don > >> On 2021-09-08 19:54, Tom Van Baak 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 (t...@leapsecond.com). >> Thanks, >> /tvb >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe >> send an email to time-nuts-le...@lists.febo.com >> To unsubscribe, go to and follow the instructions there. > > > The whole world is a straight man. > -- > Dr. Don Latham AJ7LL > PO Box 404, Frenchtown, MT, 59834 > VOX: 406-626-4304 > ___ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
On Wed, 8 Sep 2021 18:54:03 -0700, Tom Van Baak 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 (t...@leapsecond.com). >Thanks, >/tvb 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 ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Re: in-ground clock room
I think you can use precast concrete such as a septic tank or rings. My measurements made a LONG time ago in NM indicate that a mere 18 inches depth leads to less than one degree (God's units as revealed by the French) over the period of a year. Bring wiring in via a trench at the surface level of the top of the vault. Ideally, the cover should be insulation to near surface, then soil. That's the one sticky point because as you will know, thermal vortices will be set up in the vault air. very small slow fans may control? The flow can be modeled, I think. Don On 2021-09-08 19:54, Tom Van Baak 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 (t...@leapsecond.com). Thanks, /tvb ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there. The whole world is a straight man. -- Dr. Don Latham AJ7LL PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
