Re: [time-nuts] Vibration isolation of quartz oscillators
Hello Tom, (and thanks everyone for your advice) I want to do the same as you: rack mount the oscillators. Elaborate vibration isolation solutions are not possible in the available space viz 3 to 4 RU. I have the manufacturer’s test data for the oscillators, plus my own test data, so I think I will just make a trial test with the existing isolation system and then see if there any problems when in the rack. Cheers Michael On Tue, 30 Jun 2020 at 2:52 am, Tom Knox wrote: > I am enjoy this Nth degree Vibration Isolation discussion. Countless > amazing tables where I work. > I have been focused on more practical solutions for Vibration isolation of > my rack mount oscillators in my home lab, and I think at that level in some > ways are focused on eliminating resonances as well as trading one frequency > for another taking higher intensity "square waves" and dissipating them > over time. > Any thoughts? > Cheers; > > Tom Knox > > SR Test and Measurement Engineer > > Ascent Concepts and Technology > Much > 4475 Whitney Place > > Boulder Colorado 80305 > > 303-554-0307 > > act...@hotmail.com > > "Peace is not the absence of violence, but the presence of Justice" Both > MLK and Albert Einstein > > > From: time-nuts on behalf of > Poul-Henning Kamp > Sent: Monday, June 29, 2020 12:16 AM > To: Discussion of precise time and frequency measurement < > time-nuts@lists.febo.com>; ed breya > Subject: Re: [time-nuts] Vibration isolation of quartz oscillators > > > ed breya writes: > > > The nicest optical bench I've ever seen in person, was in one of our > > labs many years ago. It was a huge, precisely flat polished granite slab > > about 6-8" thick, about 4x8' or maybe 5x10', mounted on active-leveling > > pneumatic bladders. It was loaded with thousands of threaded inserts, > > uniformly spaced on a grid, for mounting optical devices and equipment. > > It is worth foot-noting here, that at that level of quality they > are usually not made from natural granite, but rather from > "epoxy-granite", which can be designed to have very low temp-co. > > > There are lower-grade type platforms available, commonly called "optical > > breadboards," that are made from thick sheets of aluminum or stainless > > steel, [...] > > and these obviously have a sizeable temp-co, so the money you saved on > your bench you get to spend on your air-con. > > They are a lot easier to move around though. > > > -- > 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, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Vibration isolation of quartz oscillators
Folks, A long time ago I worked for a division of Litton Industries. One day we visited the Litton Guidance and Control Systems Division, which manufactured Optical Gyros. Part of the test facility was a granite slab mounted using isolators on a column in a hole. I was told that the column went down to bedrock to minimize vibration. Francis Grosz ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
I am enjoy this Nth degree Vibration Isolation discussion. Countless amazing tables where I work. I have been focused on more practical solutions for Vibration isolation of my rack mount oscillators in my home lab, and I think at that level in some ways are focused on eliminating resonances as well as trading one frequency for another taking higher intensity "square waves" and dissipating them over time. Any thoughts? Cheers; Tom Knox SR Test and Measurement Engineer Ascent Concepts and Technology 4475 Whitney Place Boulder Colorado 80305 303-554-0307 act...@hotmail.com "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein From: time-nuts on behalf of Poul-Henning Kamp Sent: Monday, June 29, 2020 12:16 AM To: Discussion of precise time and frequency measurement ; ed breya Subject: Re: [time-nuts] Vibration isolation of quartz oscillators ed breya writes: > The nicest optical bench I've ever seen in person, was in one of our > labs many years ago. It was a huge, precisely flat polished granite slab > about 6-8" thick, about 4x8' or maybe 5x10', mounted on active-leveling > pneumatic bladders. It was loaded with thousands of threaded inserts, > uniformly spaced on a grid, for mounting optical devices and equipment. It is worth foot-noting here, that at that level of quality they are usually not made from natural granite, but rather from "epoxy-granite", which can be designed to have very low temp-co. > There are lower-grade type platforms available, commonly called "optical > breadboards," that are made from thick sheets of aluminum or stainless > steel, [...] and these obviously have a sizeable temp-co, so the money you saved on your bench you get to spend on your air-con. They are a lot easier to move around though. -- 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, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
If passive vibration isolation is not good enough active dampening is an option with a rig like https://www.herzan.com/products/active-vibration-control/TS-series.html I was not directly involved, but a team that I shared a lab with bought a gizmo like that one and it really helped some very sensitive optical measurements. It does not take up much room, so it might address the "Space is tight" constraint. It won't meet a "budget is tight" constraint though. -Joe Fitzgerald From: time-nuts on behalf of Poul-Henning Kamp Sent: Monday, June 29, 2020 2:16 AM To: Discussion of precise time and frequency measurement; ed breya Subject: Re: [time-nuts] Vibration isolation of quartz oscillators ed breya writes: > The nicest optical bench I've ever seen in person, was in one of our > labs many years ago. It was a huge, precisely flat polished granite slab > about 6-8" thick, about 4x8' or maybe 5x10', mounted on active-leveling > pneumatic bladders. It was loaded with thousands of threaded inserts, > uniformly spaced on a grid, for mounting optical devices and equipment. It is worth foot-noting here, that at that level of quality they are usually not made from natural granite, but rather from "epoxy-granite", which can be designed to have very low temp-co. > There are lower-grade type platforms available, commonly called "optical > breadboards," that are made from thick sheets of aluminum or stainless > steel, [...] and these obviously have a sizeable temp-co, so the money you saved on your bench you get to spend on your air-con. They are a lot easier to move around though. -- 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, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
ed breya writes: > The nicest optical bench I've ever seen in person, was in one of our > labs many years ago. It was a huge, precisely flat polished granite slab > about 6-8" thick, about 4x8' or maybe 5x10', mounted on active-leveling > pneumatic bladders. It was loaded with thousands of threaded inserts, > uniformly spaced on a grid, for mounting optical devices and equipment. It is worth foot-noting here, that at that level of quality they are usually not made from natural granite, but rather from "epoxy-granite", which can be designed to have very low temp-co. > There are lower-grade type platforms available, commonly called "optical > breadboards," that are made from thick sheets of aluminum or stainless > steel, [...] and these obviously have a sizeable temp-co, so the money you saved on your bench you get to spend on your air-con. They are a lot easier to move around though. -- 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, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
The nicest optical bench I've ever seen in person, was in one of our labs many years ago. It was a huge, precisely flat polished granite slab about 6-8" thick, about 4x8' or maybe 5x10', mounted on active-leveling pneumatic bladders. It was loaded with thousands of threaded inserts, uniformly spaced on a grid, for mounting optical devices and equipment. There are lower-grade type platforms available, commonly called "optical breadboards," that are made from thick sheets of aluminum or stainless steel, that are formed into a fairly rigid 3-D structure with a honeycomb interior bonded between the outer sheets. They likewise have a grid of threaded holes or inserts. I have a few small ones of these, salvaged from old equipment. They are about 16" square and 3" thick, with a grid of 1/4-20 threads on 1" centers. Ed ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
In my youth I worked for a time in my dad's automotive machine shop. We did a lot of work on medium-sized industrial engines, Cummins V-12s, GMC V16-71s, International TD-24s, etc. To handle these we bought a Van Norman crankshaft grinder, a sizable machine, which I operated. The shop was in downtown Tucson, right across the street from the (then) Southern Pacific Railroad tracks. The grinder was originally installed right on the 6" thick concrete slab floor. It wasn't long before I noticed that if I was grinding a journal when a trail rumbled by I got runout and had to pause grinding until the train passed We wound up moving the machine and digging a hole about 2-3 meters deep and about 2 by 3 meters "square", lining it with fiberboard and filling it up with concrete and reinstalling the machine on top. About two years ago that building was demolished as part of a "modernization" of downtown (it's still a vacant lot) and I wondered how surprised they were when they went to remove the slab. Wes N7WS On 6/28/2020 8:05 AM, Dr. David Kirkby wrote: Dr David Kirkby Ph.D C.Eng MIET Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. On Sun, 28 Jun 2020 at 12:44, Tom Van Baak wrote: About slabs and stability... Around the world there must be a hundred precision time labs, including official NMI (National Metrology Institute) labs that contribute to the calculation of UTC itself. You run into photos of these labs and their T gear on the web all the time when you search for time nutty stuff. Those of us with home labs -- even if just a few vintage frequency standards -- can relate. Anyone, one of my favorite lab photos is from VSL, the Dutch Metrology Institute. Photo attached. [1] Spend time time pan/zooming around the gear in the photo. The usual suspects: hp 105 quartz; TimeTech (I think); lots of SDI (Spectradynamics); also Truetime or Symmetricom stuff; maybe that's an old Tracor/Fluke VLF receiver on the far right (?); and of course lots of Stanford Research SR620 counters, the TIC still used by almost every time lab. But what really caught my eye was not just the four hp 5071A in the foreground but *how they are mounted* -- on top of massive granite blocks! There's a picture of a granite block here, at a former place I used to work as a student - EQD Aquila, the MODs calibration labs. https://www.derelictplaces.co.uk/main/military-sites/14101-aquila-mod-testing-facility-bromley-march-2004-a.html#.XvirQuco9PY about 60% of the way down the page. (Some of the pictures are quite amusing, as well as some of scientific interest). There's a couple of guys at my radio club used to work somewhere where a milling machine was turning high precision device. I just phoned one to ask what they used for anti-vibration, as I knew they took some precautions. He said they had dug a hole about 2 m into the ground, above that was 600 mm of "rubber", then 1.4 m of reinforced concrete. That used to stop lorries messing up the work. That's a different sort of application. I assume the OPs objects are quite large - not wrist watches. Otherwise, I was wondering if an active damping system might be practical. They certainly exist for laser tables https://www.newport.com/n/active-vibration-damping but I would imagine that for heavy 19" rack equipment, there would need to be quite a bit of power consumed in such a system. I've never done any calculations - just intuitively, I can't imagine that one could achieve anything useful without some pretty big power amplifiers. When I worked at UCL we had a laser table. Our department was near a main road. The laser table had gas-filled "dampers", but apparently these made the vibration problems worse rather than better, so the gas was removed. We never had any active system. Dave ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Dr David Kirkby Ph.D C.Eng MIET Email: drkir...@kirkbymicrowave.co.uk Web: https://www.kirkbymicrowave.co.uk/ Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT. On Sun, 28 Jun 2020 at 12:44, Tom Van Baak wrote: > About slabs and stability... Around the world there must be a hundred > precision time labs, including official NMI (National Metrology > Institute) labs that contribute to the calculation of UTC itself. You > run into photos of these labs and their T gear on the web all the time > when you search for time nutty stuff. Those of us with home labs -- even > if just a few vintage frequency standards -- can relate. > > Anyone, one of my favorite lab photos is from VSL, the Dutch Metrology > Institute. Photo attached. [1] > > Spend time time pan/zooming around the gear in the photo. The usual > suspects: hp 105 quartz; TimeTech (I think); lots of SDI > (Spectradynamics); also Truetime or Symmetricom stuff; maybe that's an > old Tracor/Fluke VLF receiver on the far right (?); and of course lots > of Stanford Research SR620 counters, the TIC still used by almost every > time lab. > > But what really caught my eye was not just the four hp 5071A in the > foreground but *how they are mounted* -- on top of massive granite blocks! > There's a picture of a granite block here, at a former place I used to work as a student - EQD Aquila, the MODs calibration labs. https://www.derelictplaces.co.uk/main/military-sites/14101-aquila-mod-testing-facility-bromley-march-2004-a.html#.XvirQuco9PY about 60% of the way down the page. (Some of the pictures are quite amusing, as well as some of scientific interest). There's a couple of guys at my radio club used to work somewhere where a milling machine was turning high precision device. I just phoned one to ask what they used for anti-vibration, as I knew they took some precautions. He said they had dug a hole about 2 m into the ground, above that was 600 mm of "rubber", then 1.4 m of reinforced concrete. That used to stop lorries messing up the work. That's a different sort of application. I assume the OPs objects are quite large - not wrist watches. Otherwise, I was wondering if an active damping system might be practical. They certainly exist for laser tables https://www.newport.com/n/active-vibration-damping but I would imagine that for heavy 19" rack equipment, there would need to be quite a bit of power consumed in such a system. I've never done any calculations - just intuitively, I can't imagine that one could achieve anything useful without some pretty big power amplifiers. When I worked at UCL we had a laser table. Our department was near a main road. The laser table had gas-filled "dampers", but apparently these made the vibration problems worse rather than better, so the gas was removed. We never had any active system. Dave ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Tom Van Baak writes: > Note the unknown mystery support technique underneath. No mystery at all. Such supports are standard equipment for a lot of "nano" kit, such as optical tables, SEM microscopes and similar. Google "optical table vibration isolation" and you will find lots of heavy duty stuff. -- 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, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Once I get my OSA 8607 back I plan on mounting it along with a FRK/M100 RB in a HP chassis. Attached a picture of a vibration mount for the OSA. Very soft. Can not be used for the Rb because of weight but also vibration mounted. The Rb is fan cooled with a Sunon MagLev 80X80x15 30db(A) mounted with rubber mounts that where sold at one time for hard disk drives. I can not feel or hear any thing on the housing. I turned in to a frequency nut while living in Miami so when I moved to Palm City that included massive downsizing the lab down to 9 by 20 feet, my work bench with all instruments except frequency take up 240X31 inches. The frequency instruments are in a short 19 inch rack on the opposite side. Home is on a concrete slab and walls are concrete block Miami code. In the corner a half size Sears bench with a half height 19 inch rack. The unit will be placed on top which will be eye level. Right now there is soft foam with a metal plate will be replaced with 1 inch 18X18 marble. Will experiment with soft foam versus bubble pack. My biggest problem is the HP54132A, I have one on each side. To much vibration. That is why I bought a FA2. My HP5065A which has super AV rests on a shelf mounted on the outside wall since it is not part of my long term plan but is needed during testing of the Rb/OSA. The limited space forces me to make decisions. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Through the mysteries of business consolidation and the resulting asset transfers, I have in my Virginia basement a rather nice Zeiss metallurgical microscope (which I have absolutely no use for but I couldn't stand to see consigned to a dumpster), which is perched on its original mount, a 30"x48"x4" granite slab. The slab sits on a square-tube-steel table that is actually a low-pressure vessel that has four round rubber bladders mounted in the top corners, holding up the slab. Each bladder has its own valve which has a short arm that contacts the bottom of the slab and servos that corner of the slab. This marvellous air-suspension microscope has tags indicating it came from AT Bell Labs in NJ. Since it shares the basement with three milling machines and one lathe, my kids will already have their hands full when my time comes, so what the hell... ;-) 73, geo - n4ua On Sun, Jun 28, 2020 at 7:44 AM Tom Van Baak wrote: > About slabs and stability... Around the world there must be a hundred > precision time labs, including official NMI (National Metrology > Institute) labs that contribute to the calculation of UTC itself. You > run into photos of these labs and their T gear on the web all the time > when you search for time nutty stuff. Those of us with home labs -- even > if just a few vintage frequency standards -- can relate. > > Anyone, one of my favorite lab photos is from VSL, the Dutch Metrology > Institute. Photo attached. [1] > > Spend time time pan/zooming around the gear in the photo. The usual > suspects: hp 105 quartz; TimeTech (I think); lots of SDI > (Spectradynamics); also Truetime or Symmetricom stuff; maybe that's an > old Tracor/Fluke VLF receiver on the far right (?); and of course lots > of Stanford Research SR620 counters, the TIC still used by almost every > time lab. > > But what really caught my eye was not just the four hp 5071A in the > foreground but *how they are mounted* -- on top of massive granite blocks! > > The answer is [42]. In this case the question is how many cm wide is a > 5071A cesium clock? That means the scale of the 1600x1200 JPG is about > 1.5 mm per pixel, which implies the blocks are exactly 50x50x40 cm. > That's nearly half a ton of mass. Note the unknown mystery support > technique underneath. Either they had spare black granite blocks lying > around their office that looked really cool or they put some thought > into vibration isolation of their clocks. Still, tell me more about > inner tubes. > > I personally don't know the background of this setup. If you have VSL or > .NL connections please let us know. I remember when I first talked with > them about their lab many years ago, the UTC(VSL) BIPM stability numbers > seemed unusually good to me for "a national lab with only 4 cesium > clocks" so the granite blocks left a heavy impression on me. > > Anyway, for those of you looking for maximum quartz oscillator / > frequency standard stability and vibration isolation, maybe the granite > block isolation idea is worth looking into. I know Michael mentioned > space constraints for his BVA so this rock solid slab solution might not > help him. > > /tvb > > [1] I can't find the original vsl.nl web photo that I remember. But a > recent one like it is: > > https://elpromatime.com/wp-content/uploads/2018/10/VSL.jpg , via: > > https://elpromatime.com/portfolio_page/time-server-nts9000 , via: > > many google image searches for words including: VSL dutch metrology .nl > caesium 5071a clocks UTC BIPM > > [42] > > https://en.wikipedia.org/wiki/42_(number)#The_Hitchhiker's_Guide_to_the_Galaxy > > > On 6/27/2020 5:09 PM, Neville Michie wrote: > > An old trick I learned from an Australian standards lab was to make a > vibration free > > table with a 2 foot by 2 foot by 2 inch paving slab supported by a > partly inflated > > wheel barrow inner tube. > > I tried it recently for measurements of force in an electric clock > movement > > and it cut out the background vibration in a spectacular way. > > cheers, Neville Michie > > > >> On 27 Jun 2020, at 22:02, Michael Wouters > wrote: > >> > >> I have three Oscilloquartz 8607-Bs that I'm rehousing. > >> > >> In their former life they were part of the frequency synthesis chains > >> for H-masers and they hung vertically from a rubber suspension that was > >> presumably intended to provide vibration isolation. Unfortunately, the > >> person responsible for this has long since retired so is no longer > >> around to ask questions of. > >> > >> In the experiment I will be averaging over 100 s, which suggests to > >> me that very low frequencies are what I need to filter out (if at > >> all), and I am skeptical that the rubber will do this. Space is tight > >> so I am wondering > >> whether I should simply ditch the isolation. > >> > >> What do other people do with their quartzes ? I thought I should ask > >> for some advice before attempting measurements. > >> > >> Cheers > >> Michael > >> > >>
Re: [time-nuts] Vibration isolation of quartz oscillators
Neville Michie writes: > An old trick I learned from an Australian standards lab was to make a > vibration free > table with a 2 foot by 2 foot by 2 inch paving slab supported by a partly > inflated > wheel barrow inner tube. Yes, that works surprisingly well, because the toroid shape of the inner tube. -- 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, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Hi There are tables made for low vibration test setups. They are (essentially) a big heavy cast iron table sitting on air cushions under each of the legs. Not a great approach for a low G OCXO …. Bob > On Jun 27, 2020, at 8:09 PM, Neville Michie wrote: > > An old trick I learned from an Australian standards lab was to make a > vibration free > table with a 2 foot by 2 foot by 2 inch paving slab supported by a partly > inflated > wheel barrow inner tube. > I tried it recently for measurements of force in an electric clock movement > and it cut out the background vibration in a spectacular way. > cheers, Neville Michie > >> On 27 Jun 2020, at 22:02, Michael Wouters wrote: >> >> I have three Oscilloquartz 8607-Bs that I'm rehousing. >> >> In their former life they were part of the frequency synthesis chains >> for H-masers and they hung vertically from a rubber suspension that was >> presumably intended to provide vibration isolation. Unfortunately, the >> person responsible for this has long since retired so is no longer >> around to ask questions of. >> >> In the experiment I will be averaging over 100 s, which suggests to >> me that very low frequencies are what I need to filter out (if at >> all), and I am skeptical that the rubber will do this. Space is tight >> so I am wondering >> whether I should simply ditch the isolation. >> >> What do other people do with their quartzes ? I thought I should ask >> for some advice before attempting measurements. >> >> Cheers >> Michael >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
An old trick I learned from an Australian standards lab was to make a vibration free table with a 2 foot by 2 foot by 2 inch paving slab supported by a partly inflated wheel barrow inner tube. I tried it recently for measurements of force in an electric clock movement and it cut out the background vibration in a spectacular way. cheers, Neville Michie > On 27 Jun 2020, at 22:02, Michael Wouters wrote: > > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. Unfortunately, the > person responsible for this has long since retired so is no longer > around to ask questions of. > > In the experiment I will be averaging over 100 s, which suggests to > me that very low frequencies are what I need to filter out (if at > all), and I am skeptical that the rubber will do this. Space is tight > so I am wondering > whether I should simply ditch the isolation. > > What do other people do with their quartzes ? I thought I should ask > for some advice before attempting measurements. > > Cheers > Michael > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Hi Michael; I know Craig Nelson, Archita Hati, and Dave Howe were doing some related research at NIST. I did a quick search and think this may be the paper, but there may be others. As I remember cable vibration can be a greater uncertainty then the oscillator. https://www.intechopen.com/books/aerial_vehicles/vibration-induced_pm_noise_in_oscillators_and_its_suppression [https://cdn.intechopen.com/books/images_new/3696.jpg]<https://www.intechopen.com/books/aerial_vehicles/vibration-induced_pm_noise_in_oscillators_and_its_suppression> Vibration-Induced PM Noise in Oscillators and Its Suppression | IntechOpen<https://www.intechopen.com/books/aerial_vehicles/vibration-induced_pm_noise_in_oscillators_and_its_suppression> Archita Hati, Craig Nelson and David Howe (January 1st 2009). Vibration-Induced PM Noise in Oscillators and Its Suppression, Aerial Vehicles, Thanh Mung Lam, IntechOpen, DOI: 10.5772/6476. Available from: www.intechopen.com Cheers; Tom Knox SR Test and Measurement Engineer Ascent Concepts and Technology 4475 Whitney Place Boulder Colorado 80305 303-554-0307 act...@hotmail.com "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein From: time-nuts on behalf of Tom Van Baak Sent: Saturday, June 27, 2020 12:56 PM To: time-nuts@lists.febo.com Subject: Re: [time-nuts] Vibration isolation of quartz oscillators Michael, These are really good oscillators so in addition to guessing what sounds like a good solution verify with actual vibration / acceleration experiments. Last year I tested some Oscilloquartz BVA's for axis sensitivity to acceleration. It's quite easy. Some plots here: http://leapsecond.com/pages/bva-rotate/ At the end of that page are two videos showing the Arduino-driven stepper motor rotating platform that I used. If anyone can't view the videos let me know off-list (my email is t...@leapsecond.com). If you end up doing something similar I would very much like to see how your results compare. Thanks, /tvb On 6/27/2020 5:02 AM, Michael Wouters wrote: > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. Unfortunately, the > person responsible for this has long since retired so is no longer > around to ask questions of. > > In the experiment I will be averaging over 100 s, which suggests to > me that very low frequencies are what I need to filter out (if at > all), and I am skeptical that the rubber will do this. Space is tight > so I am wondering > whether I should simply ditch the isolation. > > What do other people do with their quartzes ? I thought I should ask > for some advice before attempting measurements. > > Cheers > Michael > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Would a mechanical image-stabilisation system work ? https://en.wikipedia.org/wiki/Image_stabilization#Stabilizing_the_camera_body On Sat, Jun 27, 2020 at 7:58 PM Tom Van Baak wrote: > Michael, > > These are really good oscillators so in addition to guessing what sounds > like a good solution verify with actual vibration / acceleration > experiments. > > Last year I tested some Oscilloquartz BVA's for axis sensitivity to > acceleration. It's quite easy. Some plots here: > > http://leapsecond.com/pages/bva-rotate/ > > At the end of that page are two videos showing the Arduino-driven > stepper motor rotating platform that I used. If anyone can't view the > videos let me know off-list (my email is t...@leapsecond.com). > > If you end up doing something similar I would very much like to see how > your results compare. > > Thanks, > /tvb > > > On 6/27/2020 5:02 AM, Michael Wouters wrote: > > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > > > In their former life they were part of the frequency synthesis chains > > for H-masers and they hung vertically from a rubber suspension that was > > presumably intended to provide vibration isolation. Unfortunately, the > > person responsible for this has long since retired so is no longer > > around to ask questions of. > > > > In the experiment I will be averaging over 100 s, which suggests to > > me that very low frequencies are what I need to filter out (if at > > all), and I am skeptical that the rubber will do this. Space is tight > > so I am wondering > > whether I should simply ditch the isolation. > > > > What do other people do with their quartzes ? I thought I should ask > > for some advice before attempting measurements. > > > > Cheers > > Michael > > > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
You might try a sandwich of rubbery or foamy stuff alternating with heavy, stiff stuff, like silicon pads/steel plate. And keep air drafts away. At least that method I am about to try to decouple my geophones during experiments. BR Hendrik ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Michael, These are really good oscillators so in addition to guessing what sounds like a good solution verify with actual vibration / acceleration experiments. Last year I tested some Oscilloquartz BVA's for axis sensitivity to acceleration. It's quite easy. Some plots here: http://leapsecond.com/pages/bva-rotate/ At the end of that page are two videos showing the Arduino-driven stepper motor rotating platform that I used. If anyone can't view the videos let me know off-list (my email is t...@leapsecond.com). If you end up doing something similar I would very much like to see how your results compare. Thanks, /tvb On 6/27/2020 5:02 AM, Michael Wouters wrote: I have three Oscilloquartz 8607-Bs that I'm rehousing. In their former life they were part of the frequency synthesis chains for H-masers and they hung vertically from a rubber suspension that was presumably intended to provide vibration isolation. Unfortunately, the person responsible for this has long since retired so is no longer around to ask questions of. In the experiment I will be averaging over 100 s, which suggests to me that very low frequencies are what I need to filter out (if at all), and I am skeptical that the rubber will do this. Space is tight so I am wondering whether I should simply ditch the isolation. What do other people do with their quartzes ? I thought I should ask for some advice before attempting measurements. Cheers Michael ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Hi Accelerometer compensation of OCXO’s is indeed possible. There are parts out there that will do the job. Phase shift is your enemy in this case. You are trying to get two AC signals to sum to zero. Fairly small phase shifts will limit the “floor” of a process like this. Mounting the accelerometer *very* close to the blank is the key. In a large package part like the 8700 series / working from the outside …. yikes ….. Your “max frequency” is going to be mighty low. Forget about taking care of fan blade noise …. Bob > On Jun 27, 2020, at 10:29 AM, Dana Whitlow wrote: > > If compactness is needed and you're operating in anything like a 1 g field, > I think that > it will be impossible to do a spring suspension that is both compact and > effective > down to the milli-Hz level (or less). > > It might be worthwhile doing a compensation scheme based on a 3-axis > accelerometer > (one should suffice for multiple oscillators) whose outputs are scaled and > combined > to form a single signal (per oscillator) to be summed into the EFC input. > > But some strong caveats immediately come to mind: > 1. Noise in the accelerometers' outputs. > 2. Dealing with the inevitable tuning nonlinearity of the oscillators. > 3. Calibrating the compensation system well enough to satisfy. > > Good luck. > > Dana > > > On Sat, Jun 27, 2020 at 7:38 AM Michael Wouters > wrote: > >> I have three Oscilloquartz 8607-Bs that I'm rehousing. >> >> In their former life they were part of the frequency synthesis chains >> for H-masers and they hung vertically from a rubber suspension that was >> presumably intended to provide vibration isolation. Unfortunately, the >> person responsible for this has long since retired so is no longer >> around to ask questions of. >> >> In the experiment I will be averaging over 100 s, which suggests to >> me that very low frequencies are what I need to filter out (if at >> all), and I am skeptical that the rubber will do this. Space is tight >> so I am wondering >> whether I should simply ditch the isolation. >> >> What do other people do with their quartzes ? I thought I should ask >> for some advice before attempting measurements. >> >> Cheers >> Michael >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
On 6/27/2020 5:48 AM, Gerhard Hoffmann wrote: Am 27.06.20 um 14:02 schrieb Michael Wouters: What do other people do with their quartzes ? I thought I should ask for some advice before attempting measurements. A sand box? Literally? Some bags filled with sand really helped with my turntable. Make sure that it stays in the bags. Gerhard There was a turntable stand with the creative name "lead balloon" that worked like your sand box (I actually don't know what substance the "lead" balloon used for ballast). You might also consider locating the oscillator in your garage/basement on the concrete. The ideal setup is to pour concrete for a "floor safe" sort of container and then mount the oscillator inside the container below ground level. For the advanced user, dig a 5 foot deep hole with a post hole digger than put in a pipe with the oscillator at the bottom. As a free bonus, you will get temperature stabilization. Rick N6RK ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Hi Michael; So what I did with one of my 8607's was placed it in a cast aluminum box with 1/2 of soft silicon foam (it will never break down over time and heat) on all sides to provide not only mechanical isolation but thermal isolation as well. I actually did a bit more then that and would be glad to send you photos directly if interested. With an oscillator like the 8607 I think it is worth the effort. Stay Safe; Tom Knox SR Test and Measurement Engineer Ascent Concepts and Technology 4475 Whitney Place Boulder Colorado 80305 303-554-0307 act...@hotmail.com "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein From: time-nuts on behalf of Michael Wouters Sent: Saturday, June 27, 2020 6:02 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Vibration isolation of quartz oscillators I have three Oscilloquartz 8607-Bs that I'm rehousing. In their former life they were part of the frequency synthesis chains for H-masers and they hung vertically from a rubber suspension that was presumably intended to provide vibration isolation. Unfortunately, the person responsible for this has long since retired so is no longer around to ask questions of. In the experiment I will be averaging over 100 s, which suggests to me that very low frequencies are what I need to filter out (if at all), and I am skeptical that the rubber will do this. Space is tight so I am wondering whether I should simply ditch the isolation. What do other people do with their quartzes ? I thought I should ask for some advice before attempting measurements. Cheers Michael ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
On Sat, June 27, 2020 7:02 am, Michael Wouters wrote: > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. That sounds to me like isolation from local equipment vibrations, such as fans in the same rack, or an air conditioning air handler that was bolted to the same room structure. Your assessment should be correct that that type of suspension could not provide isolation in the deep sub-Hz region that you say you are interested in. -- Chris Caudle ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
I have mounted OCXOs, Rbs, and PLOs on small rubber motor mounts - the kind like for fan vibration reduction and such. The problem is that it's more of a guessing/empirical task, with no idea of the actual susceptibility of the device, or the mounting attenuation specs or degree of improvement, without doing actual mechanical vibration tests. If you have access to a commercial shake table or driver, you can readily make such tests. You can make crude DIY shaker setups with motors or big loudspeakers to rattle things around, and with proper instrumentation, measure the acceleration, displacement, frequency, etc. It can get quite complicated though. In any case, with DUTs like these, you also have to isolate the effects of magnetic emissions from the mover, from the true mechanical displacement effects, by adequate shielding and distance, and making comparative measurements. It's a lot of stuff to go through. I think the simplest approach, and most effective in all axes, would be to mount the unit in a box of rubbery foam padding material. Of course, with an OCXO, you don't want it to insulate too well - the power has to be dissipated, and the foam has to handle the operating case temperature, so the thermal and material issues would need to be worked out. If the available space is too small for at least a cm or so foam all around, you can look for small vibration isolation mounts, which should be available in all sorts of characteristics. Another possibility is to suspend the unit assembly on a thin rubber sheet, or from metal expansion springs or rubber o-rings tensioned in opposing directions as needed. For metal springs, you'd want to use lightest "k" ones as possible, that will adequately support the mass, with bits of foam shoved inside them to dampen self-resonances. Anyway, there are a lot of of options, but you still won't know how well they work without actual testing. Ed ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
If compactness is needed and you're operating in anything like a 1 g field, I think that it will be impossible to do a spring suspension that is both compact and effective down to the milli-Hz level (or less). It might be worthwhile doing a compensation scheme based on a 3-axis accelerometer (one should suffice for multiple oscillators) whose outputs are scaled and combined to form a single signal (per oscillator) to be summed into the EFC input. But some strong caveats immediately come to mind: 1. Noise in the accelerometers' outputs. 2. Dealing with the inevitable tuning nonlinearity of the oscillators. 3. Calibrating the compensation system well enough to satisfy. Good luck. Dana On Sat, Jun 27, 2020 at 7:38 AM Michael Wouters wrote: > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. Unfortunately, the > person responsible for this has long since retired so is no longer > around to ask questions of. > > In the experiment I will be averaging over 100 s, which suggests to > me that very low frequencies are what I need to filter out (if at > all), and I am skeptical that the rubber will do this. Space is tight > so I am wondering > whether I should simply ditch the isolation. > > What do other people do with their quartzes ? I thought I should ask > for some advice before attempting measurements. > > Cheers > Michael > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Hi First thing to find out is what the per axis sensitivities of your oscillators are. There should be significant variation between the three directions. What you find on one may or may not be what you find on the rest. Just about any source of (single directional) vibration will work for this test. Measure the phase noise sidebands at the vibe frequency and go from there. As long as the input is < 100 Hz you should be away. from any internal resonances. Next step is to measure the vibe levels in your masers on an axis by axis basis. This may take a while to do. You want to see what all the bumps and thumps from operating this or that ( pump …) contribute. Conventional vibe isolators will help you above 100 Hz. If you have significant energy up there, you may want to do a proper sweep of your OCXO’s on a vibe table. There *will* be resonances …. The rubber tubing (and other similar approaches) damping is aimed at getting down into the 10’s or even single Hz range for significant attenuation. The trick is that you don’t want things very tight. Tight gets you more of a resonance. You want damping. Hanging on a loose tube is better (attenuation wise) than suspended between a set of tight tubes. Indeed having things hang loose inside the Maser is less than ideal if you ever need to *move* the beast … there is a bit of a tradeoff. Wires and cables get into the act. Flexing a piece of coax can impart phase modulation. This is also worth watching out for when you test your OCXO’s. Taping the coax down is normally adequate when testing. Pretty much any good OCXO should have a worst case vector sensitivity < 2 ppb / g. I would expect a good SC to be below 5x10^-10 / g. A good BVA should be even better. What tubing works best? What lasts the longest? What do you have in stock? I’d start with silicone based rubber tubing. It should last the longest. It’s also fairly easy to get. Lots of fun !! Bob > On Jun 27, 2020, at 8:02 AM, Michael Wouters > wrote: > > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. Unfortunately, the > person responsible for this has long since retired so is no longer > around to ask questions of. > > In the experiment I will be averaging over 100 s, which suggests to > me that very low frequencies are what I need to filter out (if at > all), and I am skeptical that the rubber will do this. Space is tight > so I am wondering > whether I should simply ditch the isolation. > > What do other people do with their quartzes ? I thought I should ask > for some advice before attempting measurements. > > Cheers > Michael > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Michael Wouters writes: > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. Unfortunately, the > person responsible for this has long since retired so is no longer > around to ask questions of. Make sure that you orient the OCXO so it is least sensitive to acceleration along the vertical axis. You find this by flipping the OCXO upside/down in various orientations while measuring the frequency shift. Notice that in general the minimum sensitivity is not guaranteed to correspond to any of X/Y/Z. Check if Oscilloquartz have documented the optimal orientation. -- 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, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Damping at time constants of a fraction of second or longer can be done with shock absorbers which are usually some form of dashpots filled with viscous fluid or gas. In the industry I work in we often use airbag suspensions up to time constants of several seconds. I might guess that most vibrations in a lab you would want to eliminate would be fans humming in the same rack or folks opening and closing doors. These would be vibrations that are in the acoustic range. I’m thinking the original rubber mounts were intended for this class of vibration dampening. Tim N3QE > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of > Michael Wouters > Sent: Saturday, June 27, 2020 08:03 > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Vibration isolation of quartz oscillators > > I have three Oscilloquartz 8607-Bs that I'm rehousing. > > In their former life they were part of the frequency synthesis chains > for H-masers and they hung vertically from a rubber suspension that was > presumably intended to provide vibration isolation. Unfortunately, the > person responsible for this has long since retired so is no longer > around to ask questions of. > > In the experiment I will be averaging over 100 s, which suggests to > me that very low frequencies are what I need to filter out (if at > all), and I am skeptical that the rubber will do this. Space is tight > so I am wondering > whether I should simply ditch the isolation. > > What do other people do with their quartzes ? I thought I should ask > for some advice before attempting measurements. > > Cheers > Michael > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
You could make some reasonable assumptions about vibration levels and g-sensitivity and calculate the effect on ADEV. This would let you know if you're in the ballpark for your requirements. Also, Lord makes vibration isolators that address topics like damping and they are designed to do it in minimalist space. Likely not to be able to get much isolation at 100s without the rubber suspensions, I suspect. You might also look at the work at NIST on the trapped ion work where they hung (search Jim Bergquist) local oscillators from surgical tubing. Mike -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Michael Wouters Sent: Saturday, June 27, 2020 08:03 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Vibration isolation of quartz oscillators I have three Oscilloquartz 8607-Bs that I'm rehousing. In their former life they were part of the frequency synthesis chains for H-masers and they hung vertically from a rubber suspension that was presumably intended to provide vibration isolation. Unfortunately, the person responsible for this has long since retired so is no longer around to ask questions of. In the experiment I will be averaging over 100 s, which suggests to me that very low frequencies are what I need to filter out (if at all), and I am skeptical that the rubber will do this. Space is tight so I am wondering whether I should simply ditch the isolation. What do other people do with their quartzes ? I thought I should ask for some advice before attempting measurements. Cheers Michael ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Vibration isolation of quartz oscillators
Am 27.06.20 um 14:02 schrieb Michael Wouters: What do other people do with their quartzes ? I thought I should ask for some advice before attempting measurements. A sand box? Literally? Some bags filled with sand really helped with my turntable. Make sure that it stays in the bags. Gerhard ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Vibration isolation of quartz oscillators
I have three Oscilloquartz 8607-Bs that I'm rehousing. In their former life they were part of the frequency synthesis chains for H-masers and they hung vertically from a rubber suspension that was presumably intended to provide vibration isolation. Unfortunately, the person responsible for this has long since retired so is no longer around to ask questions of. In the experiment I will be averaging over 100 s, which suggests to me that very low frequencies are what I need to filter out (if at all), and I am skeptical that the rubber will do this. Space is tight so I am wondering whether I should simply ditch the isolation. What do other people do with their quartzes ? I thought I should ask for some advice before attempting measurements. Cheers Michael ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
