Re: [time-nuts] time-nuts Digest, Vol 65, Issue 103
Should I assume from these posts that there are no portable low power
commercial products better than a thermocompensated quartz watch
working at ~10^-7?
Ronald
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Today's Topics:
1. Re: chip scale atomic clock (Robert Lutwak)
2. Re: Cheap Rubidium (Bob Camp)
3. Re: chip scale atomic clock (paul swed)
4. Re: chip scale atomic clock (Bob Camp)
Message: 1
Date: Sat, 26 Dec 2009 12:30:08 -0500
From: Robert Lutwak Lutwak@alum.mit.edu
Subject: Re: [time-nuts] chip scale atomic clock
To: Discussion of precise time and frequency measurement
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Notwithstanding the performance of one physics package, I think it's
safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
That figure (5B) shows the Allan deviation of 10 physics packages
(measured with optimal laboratory electronics) and you are correct
that the best of the bunch is down around 2-3e-11 at 1-second. At
that time, with low-power CSAC electronics, the performance of that
same physics package was up around 1e-10 and most were in the 2-3e-10
range (see Figure 6), which would have led to a spec somewhere north
of there, perhaps 3-4e-10.
For your amusement, I just added a more recent paper (from the 2009
FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more
recent results with (newer, better, and lower power) electronics but
similar physics package architecture. These days, typical CSAC
instability is in the range of 8-10e-11 @ 1second, which might lead
to a spec in the 1-3e-10 range.
-RL
At 11:41 AM 12/26/2009, you wrote:
Hi
I knew I'd seen a chart somewhere that was getting close to
1x10-11 at 1 second for the best of the group.
It's figure B on page 7 of your FSM 2008 paper.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
I pay pretty close attention to what people in this field are
saying, and I've never heard anyone say "we'll get to 1e-11 short
term stability at 1 second real soon now."
1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or
PRS10). There are good (physics) reasons why those units all draw
100X more power than a CSAC.
CSAC is intended for portable battery-powered operation. Surely
your basement has the space and wallplug power to support an LPRO.
(p.s. don't cool the damn thing, heat it).
The cats were much happier during the CsIII development (see
http://home.comcast.net/~rlutwak). It was bigger and warmer. Any
Cat-Nuts out there who can help me find one with significantly lower SWAP?
-RL
At 10:08 AM 12/26/2009, you wrote:
Hi
1x10-11 at 1 second, going down by tau^0.5.
That makes them candidates for the basement system ....
Bob
On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
How "good" do you want?
At 09:13 AM 12/26/2009, you wrote:
Hi
They still seem to be at the stage of "we'll get to good
short term stability at 1 second real soon now".
Bob
On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
I read about this a while ago. Has anyone seen anything recent about
it, notably desktop or even portable units?
Ronald
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-RL
Robert Lutwak
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Robert Lutwak
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Message: 2
Date: Sat, 26 Dec 2009 12:37:06 -0500
From: Bob Camp lists@cq.nu
Subject: Re: [time-nuts] Cheap Rubidium
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
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Hi
Unfortunately, I can see the main water tower from my front yard. We don't spend much money heating shower water in the summer.....
Bob
On Dec 26, 2009, at 12:03 PM, J. Forster wrote:
In most single family houses, the water supply is pretty constant
temperature because the pipes typically run well underground for miles and
miles. Seasonal temperature variations don't usually go down more than a
few feet. The pipes are often deeper.
-John
=============
Hi,
In most rural or semi-rural areas over here in Canterbury, New
Zealand, water is provided by a well on the domicile section. Wells
are drilled into the natural aquifer formed by volcanic ash which we
live on so it is relatively easy to create a bore hole and take
advantage of the naturally filtered water from quite a distance below
the surface. I wouldn't mind betting that this water comes out of the
ground at a very constant temperature season by season and the amount
needed to flow over the rb heatsink to hold it steady would not be so
great as to be able to be wasted back into the drains.
Ths would save all the messing about pumping water down into a bore
and pumping it back up again. Although I appreciate that not everone
is in the position to do this but some may already have a water supply
like this, even for garden irrigation. When I lived out in the sticks
I had reticulated water on the drip for the house uses but my own bore
for garden irrigation.
73
Steve
2009/12/25 Bob Camp lists@cq.nu:
Hi
Actually burying a recirculating loop might work pretty well. The gotcha
is that going much deeper than 18" would require significant amounts of
blasting powder. I suspect the neighbors might object ....
Bob
On Dec 24, 2009, at 3:32 PM, Don Latham wrote:
Actually, couldn't you just squeeze your fish before you eat it? Should
have a lot of mercury in notime, according to the scaremongers.
Also, consider a heatsink buried about 10-15 feet deep. The temperature
at
that depth in the ground does not vary very much at all. The trick to
all
of this is to have a heatsink/source at a constant temp somewhere...
Merry Christams to all the nuts!
Don
Bruce Griffiths
Magnus Danielson wrote:
Bruce,
Bruce Griffiths wrote:
At your location, at present, it wouldnt be a significant problem as
long as the basement was unheated.
Depends. But having 3 dm snow on the ground helps to keep the ground
around the house warmer, as it will insulate against the cold of the
open sky. -12.8 C is the lowest so far. Since winter is reoccuring,
we
build the houses accordingly.
Also good ventilation would help, together with a thin layer of oil
on top of the mercury.
Mmm. Yes, didn't think about covering the baths with fluids.
The biggest obstacle would be the cost of the Mercury.
Actually, it could be an obstcle just obtaining in those amounts it
here within EC, so it would involve some form of approval of some
form
of excempt since it is mercury is a ROS element.
Cheers,
Magnus
Guidline price is around $US600/flask (1 flask = 34.5kg).
Thus cost for 145 ton would be around $US2.5million.
The Canadians have a liquid mercury mirror telescope about 6m in
diameter.
Whilst this doesn't use 145 tons of mercury the surface area would be
of
the same order.
Bruce
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Dr. Don Latham AJ7LL
Six Mile Systems LLP
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VOX 406-626-4304
www.lightningforensics.com
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Message: 3
Date: Sat, 26 Dec 2009 13:01:08 -0500
From: paul swed paulswedb@gmail.com
Subject: Re: [time-nuts] chip scale atomic clock
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
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So when do we see them on ebay?? ;-) Like the low power aspect. instead of
20-40 watts or more
On Sat, Dec 26, 2009 at 11:14 AM, Bob Camp lists@cq.nu wrote:
Hi
Not ment as a knock, just a comment that a lot of work is still being done
on getting short term stability closer to a 100~1000X bigger device.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
I pay pretty close attention to what people in this field are saying, and
I've never heard anyone say "we'll get to 1e-11 short term stability at 1
second real soon now."
1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or PRS10).
There are good (physics) reasons why those units all draw 100X more power
than a CSAC.
CSAC is intended for portable battery-powered operation. Surely your
basement has the space and wallplug power to support an LPRO. (p.s. don't
cool the damn thing, heat it).
The cats were much happier during the CsIII development (see
http://home.comcast.net/~rlutwak http://home.comcast.net/%7Erlutwak). It
was bigger and warmer. Any Cat-Nuts out there who can help me find one with
significantly lower SWAP?
-RL
At 10:08 AM 12/26/2009, you wrote:
Hi
1x10-11 at 1 second, going down by tau^0.5.
That makes them candidates for the basement system ....
Bob
On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
How "good" do you want?
At 09:13 AM 12/26/2009, you wrote:
Hi
They still seem to be at the stage of "we'll get to good short term
stability at 1 second real soon now".
Bob
On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
I read about this a while ago. Has anyone seen anything recent
about
it, notably desktop or even portable units?
Ronald
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-RL
Robert Lutwak
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-RL
Robert Lutwak
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Robert Lutwak
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Message: 4
Date: Sat, 26 Dec 2009 13:09:06 -0500
From: Bob Camp lists@cq.nu
Subject: Re: [time-nuts] chip scale atomic clock
To: Discussion of precise time and frequency measurement
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Hi
Thanks, that's one I hadn't seen yet. I did not get Besancon this year.
I guess my main point is that if the physics package is capable of ~2x10^-11 with good electronics, then what ever you get past that is simply mission related. A different system requirement could take the performance closer to that "ideal".
Good to see that the RbXO is coming back to life (again). It would have been nice to get it into production back at EG&G.
Bob
On Dec 26, 2009, at 12:30 PM, Robert Lutwak wrote:
Notwithstanding the performance of one physics package, I think it's safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
That figure (5B) shows the Allan deviation of 10 physics packages (measured with optimal laboratory electronics) and you are correct that the best of the bunch is down around 2-3e-11 at 1-second. At that time, with low-power CSAC electronics, the performance of that same physics package was up around 1e-10 and most were in the 2-3e-10 range (see Figure 6), which would have led to a spec somewhere north of there, perhaps 3-4e-10.
For your amusement, I just added a more recent paper (from the 2009 FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more recent results with (newer, better, and lower power) electronics but similar physics package architecture. These days, typical CSAC instability is in the range of 8-10e-11 @ 1second, which might lead to a spec in the 1-3e-10 range.
-RL
At 11:41 AM 12/26/2009, you wrote:
Hi
I knew I'd seen a chart somewhere that was getting close to 1x10-11 at 1 second for the best of the group.
It's figure B on page 7 of your FSM 2008 paper.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
I pay pretty close attention to what people in this field are saying, and I've never heard anyone say "we'll get to 1e-11 short term stability at 1 second real soon now."
1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or PRS10). There are good (physics) reasons why those units all draw 100X more power than a CSAC.
CSAC is intended for portable battery-powered operation. Surely your basement has the space and wallplug power to support an LPRO. (p.s. don't cool the damn thing, heat it).
The cats were much happier during the CsIII development (see http://home.comcast.net/~rlutwak). It was bigger and warmer. Any Cat-Nuts out there who can help me find one with significantly lower SWAP?
-RL
At 10:08 AM 12/26/2009, you wrote:
Hi
1x10-11 at 1 second, going down by tau^0.5.
That makes them candidates for the basement system ....
Bob
On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
How "good" do you want?
At 09:13 AM 12/26/2009, you wrote:
Hi
They still seem to be at the stage of "we'll get to good short term stability at 1 second real soon now".
Bob
On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
I read about this a while ago. Has anyone seen anything recent about
it, notably desktop or even portable units?
Ronald
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End of time-nuts Digest, Vol 65, Issue 103
Hi
A lot depends on your definition of low power.
To some an EMXO is low power, to other's it's grossly high power. People have indeed rigged up portable rubidiums with battery packs. I would not call them low power, but they are portable.
If the microamp current drain of a quartz watch at a bit over a volt is the standard of low power, then the answer is no. There's nothing lower power than that with better accuracy.
As always the answer is indeed that depends ...
- How big / heavy / rugged?
- How long does it operate on it's own?
- What's the temperature range and the rest of the environment?
- How accurate do you need?
- Does it need to be autonomous?
Tough to beat a self winding quartz wrist watch, unless it's not accurate enough to do what you need to do.
Bob
On Dec 26, 2009, at 5:25 PM, Ronald Held wrote:
Should I assume from these posts that there are no portable low power
commercial products better than a thermocompensated quartz watch
working at ~10^-7?
Ronald
On Sat, Dec 26, 2009 at 1:09 PM, time-nuts-request@febo.com wrote:
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Today's Topics:
- Re: chip scale atomic clock (Robert Lutwak)
- Re: Cheap Rubidium (Bob Camp)
- Re: chip scale atomic clock (paul swed)
- Re: chip scale atomic clock (Bob Camp)
Message: 1
Date: Sat, 26 Dec 2009 12:30:08 -0500
From: Robert Lutwak Lutwak@alum.mit.edu
Subject: Re: [time-nuts] chip scale atomic clock
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
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Notwithstanding the performance of one physics package, I think it's
safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
That figure (5B) shows the Allan deviation of 10 physics packages
(measured with optimal laboratory electronics) and you are correct
that the best of the bunch is down around 2-3e-11 at 1-second. At
that time, with low-power CSAC electronics, the performance of that
same physics package was up around 1e-10 and most were in the 2-3e-10
range (see Figure 6), which would have led to a spec somewhere north
of there, perhaps 3-4e-10.
For your amusement, I just added a more recent paper (from the 2009
FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more
recent results with (newer, better, and lower power) electronics but
similar physics package architecture. These days, typical CSAC
instability is in the range of 8-10e-11 @ 1second, which might lead
to a spec in the 1-3e-10 range.
-RL
At 11:41 AM 12/26/2009, you wrote:
Hi
I knew I'd seen a chart somewhere that was getting close to
1x10-11 at 1 second for the best of the group.
It's figure B on page 7 of your FSM 2008 paper.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
I pay pretty close attention to what people in this field are
saying, and I've never heard anyone say "we'll get to 1e-11 short
term stability at 1 second real soon now."
1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or
PRS10). There are good (physics) reasons why those units all draw
100X more power than a CSAC.
CSAC is intended for portable battery-powered operation. Surely
your basement has the space and wallplug power to support an LPRO.
(p.s. don't cool the damn thing, heat it).
The cats were much happier during the CsIII development (see
http://home.comcast.net/~rlutwak). It was bigger and warmer. Any
Cat-Nuts out there who can help me find one with significantly lower SWAP?
-RL
At 10:08 AM 12/26/2009, you wrote:
Hi
1x10-11 at 1 second, going down by tau^0.5.
That makes them candidates for the basement system ....
Bob
On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
How "good" do you want?
At 09:13 AM 12/26/2009, you wrote:
Hi
They still seem to be at the stage of "we'll get to good
short term stability at 1 second real soon now".
Bob
On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
I read about this a while ago. Has anyone seen anything recent about
it, notably desktop or even portable units?
Ronald
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Message: 2
Date: Sat, 26 Dec 2009 12:37:06 -0500
From: Bob Camp lists@cq.nu
Subject: Re: [time-nuts] Cheap Rubidium
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 0CF40F1B-AE56-4F94-8D72-4BFA9BE1E347@cq.nu
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Hi
Unfortunately, I can see the main water tower from my front yard. We don't spend much money heating shower water in the summer.....
Bob
On Dec 26, 2009, at 12:03 PM, J. Forster wrote:
In most single family houses, the water supply is pretty constant
temperature because the pipes typically run well underground for miles and
miles. Seasonal temperature variations don't usually go down more than a
few feet. The pipes are often deeper.
-John
=============
Hi,
In most rural or semi-rural areas over here in Canterbury, New
Zealand, water is provided by a well on the domicile section. Wells
are drilled into the natural aquifer formed by volcanic ash which we
live on so it is relatively easy to create a bore hole and take
advantage of the naturally filtered water from quite a distance below
the surface. I wouldn't mind betting that this water comes out of the
ground at a very constant temperature season by season and the amount
needed to flow over the rb heatsink to hold it steady would not be so
great as to be able to be wasted back into the drains.
Ths would save all the messing about pumping water down into a bore
and pumping it back up again. Although I appreciate that not everone
is in the position to do this but some may already have a water supply
like this, even for garden irrigation. When I lived out in the sticks
I had reticulated water on the drip for the house uses but my own bore
for garden irrigation.
73
Steve
2009/12/25 Bob Camp lists@cq.nu:
Hi
Actually burying a recirculating loop might work pretty well. The gotcha
is that going much deeper than 18" would require significant amounts of
blasting powder. I suspect the neighbors might object ....
Bob
On Dec 24, 2009, at 3:32 PM, Don Latham wrote:
Actually, couldn't you just squeeze your fish before you eat it? Should
have a lot of mercury in notime, according to the scaremongers.
Also, consider a heatsink buried about 10-15 feet deep. The temperature
at
that depth in the ground does not vary very much at all. The trick to
all
of this is to have a heatsink/source at a constant temp somewhere...
Merry Christams to all the nuts!
Don
Bruce Griffiths
Magnus Danielson wrote:
Bruce,
Bruce Griffiths wrote:
At your location, at present, it wouldnt be a significant problem as
long as the basement was unheated.
Depends. But having 3 dm snow on the ground helps to keep the ground
around the house warmer, as it will insulate against the cold of the
open sky. -12.8 C is the lowest so far. Since winter is reoccuring,
we
build the houses accordingly.
Also good ventilation would help, together with a thin layer of oil
on top of the mercury.
Mmm. Yes, didn't think about covering the baths with fluids.
The biggest obstacle would be the cost of the Mercury.
Actually, it could be an obstcle just obtaining in those amounts it
here within EC, so it would involve some form of approval of some
form
of excempt since it is mercury is a ROS element.
Cheers,
Magnus
Guidline price is around $US600/flask (1 flask = 34.5kg).
Thus cost for 145 ton would be around $US2.5million.
The Canadians have a liquid mercury mirror telescope about 6m in
diameter.
Whilst this doesn't use 145 tons of mercury the surface area would be
of
the same order.
Bruce
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Message: 3
Date: Sat, 26 Dec 2009 13:01:08 -0500
From: paul swed paulswedb@gmail.com
Subject: Re: [time-nuts] chip scale atomic clock
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID:
ac803ca80912261001m510f4120s2f3dea9063cfa7e2@mail.gmail.com
Content-Type: text/plain; charset=ISO-8859-1
So when do we see them on ebay?? ;-) Like the low power aspect. instead of
20-40 watts or more
On Sat, Dec 26, 2009 at 11:14 AM, Bob Camp lists@cq.nu wrote:
Hi
Not ment as a knock, just a comment that a lot of work is still being done
on getting short term stability closer to a 100~1000X bigger device.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
I pay pretty close attention to what people in this field are saying, and
I've never heard anyone say "we'll get to 1e-11 short term stability at 1
second real soon now."
1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or PRS10).
There are good (physics) reasons why those units all draw 100X more power
than a CSAC.
CSAC is intended for portable battery-powered operation. Surely your
basement has the space and wallplug power to support an LPRO. (p.s. don't
cool the damn thing, heat it).
The cats were much happier during the CsIII development (see
http://home.comcast.net/~rlutwak http://home.comcast.net/%7Erlutwak). It
was bigger and warmer. Any Cat-Nuts out there who can help me find one with
significantly lower SWAP?
-RL
At 10:08 AM 12/26/2009, you wrote:
Hi
1x10-11 at 1 second, going down by tau^0.5.
That makes them candidates for the basement system ....
Bob
On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
How "good" do you want?
At 09:13 AM 12/26/2009, you wrote:
Hi
They still seem to be at the stage of "we'll get to good short term
stability at 1 second real soon now".
Bob
On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
I read about this a while ago. Has anyone seen anything recent
about
it, notably desktop or even portable units?
Ronald
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Robert Lutwak
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Message: 4
Date: Sat, 26 Dec 2009 13:09:06 -0500
From: Bob Camp lists@cq.nu
Subject: Re: [time-nuts] chip scale atomic clock
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: CE6AC93C-5478-4F4A-8494-4BFB106C67BC@cq.nu
Content-Type: text/plain; charset=us-ascii
Hi
Thanks, that's one I hadn't seen yet. I did not get Besancon this year.
I guess my main point is that if the physics package is capable of ~2x10^-11 with good electronics, then what ever you get past that is simply mission related. A different system requirement could take the performance closer to that "ideal".
Good to see that the RbXO is coming back to life (again). It would have been nice to get it into production back at EG&G.
Bob
On Dec 26, 2009, at 12:30 PM, Robert Lutwak wrote:
Notwithstanding the performance of one physics package, I think it's safe to say that no-one is holding their breath waiting for a 1e-11 CSAC.
That figure (5B) shows the Allan deviation of 10 physics packages (measured with optimal laboratory electronics) and you are correct that the best of the bunch is down around 2-3e-11 at 1-second. At that time, with low-power CSAC electronics, the performance of that same physics package was up around 1e-10 and most were in the 2-3e-10 range (see Figure 6), which would have led to a spec somewhere north of there, perhaps 3-4e-10.
For your amusement, I just added a more recent paper (from the 2009 FCS/EFTF) to my WWW site. Figure 3 in that paper shows some more recent results with (newer, better, and lower power) electronics but similar physics package architecture. These days, typical CSAC instability is in the range of 8-10e-11 @ 1second, which might lead to a spec in the 1-3e-10 range.
-RL
At 11:41 AM 12/26/2009, you wrote:
Hi
I knew I'd seen a chart somewhere that was getting close to 1x10-11 at 1 second for the best of the group.
It's figure B on page 7 of your FSM 2008 paper.
Bob
On Dec 26, 2009, at 10:36 AM, Robert Lutwak wrote:
I pay pretty close attention to what people in this field are saying, and I've never heard anyone say "we'll get to 1e-11 short term stability at 1 second real soon now."
1e-11 at 1 second is the XPRO spec (and 2X better than LPRO or PRS10). There are good (physics) reasons why those units all draw 100X more power than a CSAC.
CSAC is intended for portable battery-powered operation. Surely your basement has the space and wallplug power to support an LPRO. (p.s. don't cool the damn thing, heat it).
The cats were much happier during the CsIII development (see http://home.comcast.net/~rlutwak). It was bigger and warmer. Any Cat-Nuts out there who can help me find one with significantly lower SWAP?
-RL
At 10:08 AM 12/26/2009, you wrote:
Hi
1x10-11 at 1 second, going down by tau^0.5.
That makes them candidates for the basement system ....
Bob
On Dec 26, 2009, at 9:33 AM, Robert Lutwak wrote:
How "good" do you want?
At 09:13 AM 12/26/2009, you wrote:
Hi
They still seem to be at the stage of "we'll get to good short term stability at 1 second real soon now".
Bob
On Dec 26, 2009, at 8:23 AM, Ronald Held wrote:
I read about this a while ago. Has anyone seen anything recent about
it, notably desktop or even portable units?
Ronald
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Hi,
2009/12/27 Bob Camp lists@cq.nu:
Tough to beat a self winding quartz wrist watch, unless it's not accurate enough to do what you need to do.
And perhaps that's the point we sometimes miss.
73
Steve
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
Hi
But being rational about all this takes out most of the fun ....
Bob
On Dec 28, 2009, at 5:30 AM, Steve Rooke wrote:
Hi,
2009/12/27 Bob Camp lists@cq.nu:
Tough to beat a self winding quartz wrist watch, unless it's not accurate enough to do what you need to do.
And perhaps that's the point we sometimes miss.
73
Steve
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A man with one clock knows what time it is;
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