Re: [time-nuts] hm H Maser
Do we know what the PHM development for Galileo cost?
Sent from Samsung tabletBob Camp kb8tq@n1k.org wrote:Hi
On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby@kirkbymicrowave.co.uk wrote:
Once 9 Jan 2017 12:59, "Bob Camp" kb8tq@n1k.org wrote:
Hi
Ok here are some rough numbers:
On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
It would be interesting to see your breakdown of the costs and man hours
for an H2 maser. I suspect that others would find cheaper/faster
solutions.
$100M for the H2
$25M for the Rb
With all due respect, and I apprectiate you have a good knowledge of this
field, but that's not a breakdown of costs or man hours I wanted to see,
but a cost which appears to be plucked from the air.
Hardly plucked from the air. The last Rb design that I was involved with was
roughly 5X that expensive.
There's a BIG difference between a volunteer effort where
- Salaries are not paid
- Items of test equipment are likely to be borrowed or people provide
access to them for no charge etc, - Academics are likely to provide consultancy for free, in return for being
on papers published. - Software licenses could probably be obtained free, or enough people get
trials.
That’s where the 5:1 cost reduction comes from.
compared to a commercial company building a maser where
- Salaries are paid
- All equipment is purchased new
- Bench power supplies with 3.5 digit displays are sent out for calibration
each year.
* No outside body will do anything except at a commercial rate. - Flights are booked for meetings which could be done over the Internet.
- High end software licenses are huge.
$500M for the fountain.
But on what basis do you arrive at that figure?
The numbers that the people who have done it come up with when you talk to them.
To get sponsorship for anything remotely close to those numbers, you
need to have some massively good credentials.
Bob
Yes agreed at $500M. But someone like Tom, who does have massively good
credentials, could perhaps get $500,000, and perhaps that wisely spent
could get a fountain built. Without knowing how you arrive at $500M, it is
not possible for anyone to look at ways of shaving that cost.
This is not a cheap field to be doing things in ….
Bob
The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring
budget. It was at the time the world's largest steerable radio telephone.
Half a century later only 2 larger ones have been built.
Maybe I am too nieve.
Dave.
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Not sure how relevant that particular example is. PHM on Galileo was new
science (at least the sapphire loaded cavity), and very different
reliability engineering.
AHM's are nothing new, the science hace been done, the construction is
known, down to exact drawings and circuit diagrams. There are numbers from
1982 that can possibly be used as a startingpoint for estimating an amateur
project in https://library.nrao.edu/public/memos/vlba/main/VLBA_65.pdf
As a side note, I am also not convinced that sourcing the fused quartz
teflon coated bulbs would be a show stopper for a limited number (<5) of
masers, I for one have one on my shelf. It is quite possible that old bulbs
for previous designs exists with the current manufacturers that they might
be willing to part with.
They are also still manufactured, Vremya or one of the others might be
willing to sell them - although I have no idea about the cost.
As another side note, on a trip to Switzerland I was allowed a glimpse of a
couple of the PHM's for Galileo in person. Impressive.
Ole
On Tue, Jan 10, 2017 at 2:18 PM, ewkehren via time-nuts time-nuts@febo.com
wrote:
Do we know what the PHM development for Galileo cost?
Sent from Samsung tabletBob Camp kb8tq@n1k.org wrote:Hi
On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
Once 9 Jan 2017 12:59, "Bob Camp" kb8tq@n1k.org wrote:
Hi
Ok here are some rough numbers:
On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
It would be interesting to see your breakdown of the costs and man
hours
for an H2 maser. I suspect that others would find cheaper/faster
solutions.
$100M for the H2
$25M for the Rb
With all due respect, and I apprectiate you have a good knowledge of
this
field, but that's not a breakdown of costs or man hours I wanted to see,
but a cost which appears to be plucked from the air.
Hardly plucked from the air. The last Rb design that I was involved with
was
roughly 5X that expensive.
There's a BIG difference between a volunteer effort where
- Salaries are not paid
- Items of test equipment are likely to be borrowed or people provide
access to them for no charge etc, - Academics are likely to provide consultancy for free, in return for
being
on papers published.
- Software licenses could probably be obtained free, or enough people
get
trials.
That’s where the 5:1 cost reduction comes from.
compared to a commercial company building a maser where
- Salaries are paid
- All equipment is purchased new
- Bench power supplies with 3.5 digit displays are sent out for
calibration
each year.
- No outside body will do anything except at a commercial rate.
- Flights are booked for meetings which could be done over the Internet.
- High end software licenses are huge.
$500M for the fountain.
But on what basis do you arrive at that figure?
The numbers that the people who have done it come up with when you talk to
them.
To get sponsorship for anything remotely close to those numbers, you
need to have some massively good credentials.
Bob
Yes agreed at $500M. But someone like Tom, who does have massively good
credentials, could perhaps get $500,000, and perhaps that wisely spent
could get a fountain built. Without knowing how you arrive at $500M, it
is
not possible for anyone to look at ways of shaving that cost.
This is not a cheap field to be doing things in ….
Bob
The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring
budget. It was at the time the world's largest steerable radio
telephone.
Half a century later only 2 larger ones have been built.
Maybe I am too nieve.
Dave.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
and follow the instructions there.
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To unsubscribe, go to https://www.febo.com/cgi-bin/
mailman/listinfo/time-nuts
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... having said that, I for one think I'm with Bob on this one. The thing about masers are that they are big. At least active masers. And they require a substantial volume be kept at ultra high vacuum - which is not trivial, especially not in a homeshop. The cavity needs to be kept at a temperature stable to 0.001 degree C. With 4-5 magnetic shields. Add to this costly pumps to keep the vacuum this low even if you succeed at reaching that vacuum.. There's easily 1-2KUSD running cost per year just to keep the maser running.
Granted, I've never built a maser, but personally I think the problems that would need to solving (and lead to learning) would be much more on the vacuum-systems, shielding and temperature long before electronics becomes a major factor. And the chance of actually get a result comparable to a commercial maser (or even just better than what you could realistically pick up from ebay for a few K) are pretty slim. And LOT of time and cash would be burned before you are even close to getting some sort of oscillation.
A rubidium does look like a more realistic project..
Dont get me wrong - it would be beyond cool if someone built a homemade maser. The first ones were built by regular people in regular labs, so sure it can be done.
Well, my $0.02 has been spent..
Ole
Den 10. jan. 2017 kl. 15.15 skrev Ole Petter Ronningen opronningen@gmail.com:
Not sure how relevant that particular example is. PHM on Galileo was new science (at least the sapphire loaded cavity), and very different reliability engineering.
AHM's are nothing new, the science hace been done, the construction is known, down to exact drawings and circuit diagrams. There are numbers from 1982 that can possibly be used as a startingpoint for estimating an amateur project in https://library.nrao.edu/public/memos/vlba/main/VLBA_65.pdf
As a side note, I am also not convinced that sourcing the fused quartz teflon coated bulbs would be a show stopper for a limited number (<5) of masers, I for one have one on my shelf. It is quite possible that old bulbs for previous designs exists with the current manufacturers that they might be willing to part with.
They are also still manufactured, Vremya or one of the others might be willing to sell them - although I have no idea about the cost.
As another side note, on a trip to Switzerland I was allowed a glimpse of a couple of the PHM's for Galileo in person. Impressive.
Ole
On Tue, Jan 10, 2017 at 2:18 PM, ewkehren via time-nuts time-nuts@febo.com wrote:
Do we know what the PHM development for Galileo cost?
Sent from Samsung tabletBob Camp kb8tq@n1k.org wrote:Hi
On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby@kirkbymicrowave.co.uk wrote:
Once 9 Jan 2017 12:59, "Bob Camp" kb8tq@n1k.org wrote:
Hi
Ok here are some rough numbers:
On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
It would be interesting to see your breakdown of the costs and man hours
for an H2 maser. I suspect that others would find cheaper/faster
solutions.
$100M for the H2
$25M for the Rb
With all due respect, and I apprectiate you have a good knowledge of this
field, but that's not a breakdown of costs or man hours I wanted to see,
but a cost which appears to be plucked from the air.
Hardly plucked from the air. The last Rb design that I was involved with was
roughly 5X that expensive.
There's a BIG difference between a volunteer effort where
- Salaries are not paid
- Items of test equipment are likely to be borrowed or people provide
access to them for no charge etc, - Academics are likely to provide consultancy for free, in return for being
on papers published. - Software licenses could probably be obtained free, or enough people get
trials.
That’s where the 5:1 cost reduction comes from.
compared to a commercial company building a maser where
- Salaries are paid
- All equipment is purchased new
- Bench power supplies with 3.5 digit displays are sent out for calibration
each year. - No outside body will do anything except at a commercial rate.
- Flights are booked for meetings which could be done over the Internet.
- High end software licenses are huge.
$500M for the fountain.
But on what basis do you arrive at that figure?
The numbers that the people who have done it come up with when you talk to them.
To get sponsorship for anything remotely close to those numbers, you
need to have some massively good credentials.
Bob
Yes agreed at $500M. But someone like Tom, who does have massively good
credentials, could perhaps get $500,000, and perhaps that wisely spent
could get a fountain built. Without knowing how you arrive at $500M, it is
not possible for anyone to look at ways of shaving that cost.
This is not a cheap field to be doing things in ….
Bob
The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring
budget. It was at the time the world's largest steerable radio telephone.
Half a century later only 2 larger ones have been built.
Maybe I am too nieve.
Dave.
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"The European Commission and the European Space Agency have approved the Galileo GNSS programme. Two experimental satellites will be launched in late 2005 or early 2006. Atomic clocks are critical for satellite navigation. After more than ten years of development and an overall budget of € 30M, two onboard clock technologies have been qualified. The author considers their current status and performance."
https://www.gim-international.com/content/article/onboard-galileo-atomic-clocks
Ole
Den 10. jan. 2017 kl. 14.18 skrev ewkehren via time-nuts time-nuts@febo.com:
Do we know what the PHM development for Galileo cost?
Sent from Samsung tabletBob Camp kb8tq@n1k.org wrote:Hi
On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby@kirkbymicrowave.co.uk wrote:
Once 9 Jan 2017 12:59, "Bob Camp" kb8tq@n1k.org wrote:
Hi
Ok here are some rough numbers:
On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
It would be interesting to see your breakdown of the costs and man hours
for an H2 maser. I suspect that others would find cheaper/faster
solutions.
$100M for the H2
$25M for the Rb
With all due respect, and I apprectiate you have a good knowledge of this
field, but that's not a breakdown of costs or man hours I wanted to see,
but a cost which appears to be plucked from the air.
Hardly plucked from the air. The last Rb design that I was involved with was
roughly 5X that expensive.
There's a BIG difference between a volunteer effort where
- Salaries are not paid
- Items of test equipment are likely to be borrowed or people provide
access to them for no charge etc, - Academics are likely to provide consultancy for free, in return for being
on papers published. - Software licenses could probably be obtained free, or enough people get
trials.
That’s where the 5:1 cost reduction comes from.
compared to a commercial company building a maser where
- Salaries are paid
- All equipment is purchased new
- Bench power supplies with 3.5 digit displays are sent out for calibration
each year. - No outside body will do anything except at a commercial rate.
- Flights are booked for meetings which could be done over the Internet.
- High end software licenses are huge.
$500M for the fountain.
But on what basis do you arrive at that figure?
The numbers that the people who have done it come up with when you talk to them.
To get sponsorship for anything remotely close to those numbers, you
need to have some massively good credentials.
Bob
Yes agreed at $500M. But someone like Tom, who does have massively good
credentials, could perhaps get $500,000, and perhaps that wisely spent
could get a fountain built. Without knowing how you arrive at $500M, it is
not possible for anyone to look at ways of shaving that cost.
This is not a cheap field to be doing things in ….
Bob
The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring
budget. It was at the time the world's largest steerable radio telephone.
Half a century later only 2 larger ones have been built.
Maybe I am too nieve.
Dave.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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On 1/10/17 7:35 AM, Ole Petter Rønningen wrote:
... having said that, I for one think I'm with Bob on this one. The
thing about masers are that they are big. At least active masers. And
they require a substantial volume be kept at ultra high vacuum -
which is not trivial, especially not in a homeshop. The cavity needs
to be kept at a temperature stable to 0.001 degree C. With 4-5
magnetic shields. Add to this costly pumps to keep the vacuum this
low even if you succeed at reaching that vacuum.. There's easily
1-2KUSD running cost per year just to keep the maser running.
Lots of people spend $4/day on coffee.. that's $1200/yr..
I'd give up a cup of coffee to run a AHM <grin>
Granted, I've never built a maser, but personally I think the
problems that would need to solving (and lead to learning) would be
much more on the vacuum-systems, shielding and temperature long
before electronics becomes a major factor.
This fits in the bucket of a cross-disciplinary project, like building a
fusor, or a pulsed TEA laser, a Bose-Einstein Condensate generator, or
any of a variety of similar projects.
You can almost always find a commercial solution that can do it
better/cheaper/more reliably - but the learning experience is valuable.
I have almost zero desire to fool with high vacuum systems again, but
the time I did it, I learned a lot.
And the chance of
actually get a result comparable to a commercial maser (or even just
better than what you could realistically pick up from ebay for a few
K) are pretty slim. And LOT of time and cash would be burned before
you are even close to getting some sort of oscillation.
A rubidium does look like a more realistic project..
Dont get me wrong - it would be beyond cool if someone built a
homemade maser. The first ones were built by regular people in
regular labs, so sure it can be done.
On Tuesday, January 10, 2017, jimlux jimlux@earthlink.net wrote:
<snip>This fits in the bucket of a cross-disciplinary project, like building a
fusor, or a pulsed TEA laser, a Bose-Einstein Condensate generator, or any
of a variety of similar projects.
Or a Lazar gravity warp generator.....
You can almost always find a commercial solution that can do it
better/cheaper/more reliably - but the learning experience is valuable. I
have almost zero desire to fool with high vacuum systems again, but the
time I did it, I learned a lot.
And t
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ailman/listinfo/time-nuts
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--
If you gaze long into an abyss, your coffee will get cold.
Hello,
Two kind of clocks were developed and qualified, a Rb and the PHM, and
it seems that this is the cost for the development of both (since it
mentions two on-board clock technologies). And this includes the
development of breadboards (EBBs, really full-fledged prototypes with no
qualified parts) and of qualification models (
http://www.spectratime.com/uploads/documents/ispace/PTTI_FCS_RAFS_PHM_2005.pdf
), designed and manufactured with flight-quality components since the
EQMs are submitted to all testing (thermal vacuum, vibration, life,
EMC...) to levels a lot more estringent than those applicable for a
commercial-use maser.
Taking into account that GIOVE-B (used as the in-flight test bed for the
PHM) cost was 72M€, surely excluding launch and deployment costs, I
suppose that excluding the PHM itself, it seem that 100M€ is the order
of magnitude for the development including in-flight testing platform.
Regards,
Javier
On 10/01/2017 17:22, Ole Petter Rønningen wrote:
"The European Commission and the European Space Agency have approved the Galileo GNSS programme. Two experimental satellites will be launched in late 2005 or early 2006. Atomic clocks are critical for satellite navigation. After more than ten years of development and an overall budget of € 30M, two onboard clock technologies have been qualified. The author considers their current status and performance."
https://www.gim-international.com/content/article/onboard-galileo-atomic-clocks
Ole
Den 10. jan. 2017 kl. 14.18 skrev ewkehren via time-nuts time-nuts@febo.com:
Do we know what the PHM development for Galileo cost?
Sent from Samsung tabletBob Camp kb8tq@n1k.org wrote:Hi
On Jan 10, 2017, at 2:45 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkirkby@kirkbymicrowave.co.uk wrote:
Once 9 Jan 2017 12:59, "Bob Camp" kb8tq@n1k.org wrote:
Hi
Ok here are some rough numbers:
On Jan 9, 2017, at 4:35 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <
drkirkby@kirkbymicrowave.co.uk> wrote:
It would be interesting to see your breakdown of the costs and man hours
for an H2 maser. I suspect that others would find cheaper/faster
solutions.
$100M for the H2
$25M for the Rb
With all due respect, and I apprectiate you have a good knowledge of this
field, but that's not a breakdown of costs or man hours I wanted to see,
but a cost which appears to be plucked from the air.
Hardly plucked from the air. The last Rb design that I was involved with was
roughly 5X that expensive.
There's a BIG difference between a volunteer effort where
- Salaries are not paid
- Items of test equipment are likely to be borrowed or people provide
access to them for no charge etc, - Academics are likely to provide consultancy for free, in return for being
on papers published. - Software licenses could probably be obtained free, or enough people get
trials.
That’s where the 5:1 cost reduction comes from.
compared to a commercial company building a maser where
- Salaries are paid
- All equipment is purchased new
- Bench power supplies with 3.5 digit displays are sent out for calibration
each year. - No outside body will do anything except at a commercial rate.
- Flights are booked for meetings which could be done over the Internet.
- High end software licenses are huge.
$500M for the fountain.
But on what basis do you arrive at that figure?
The numbers that the people who have done it come up with when you talk to them.
To get sponsorship for anything remotely close to those numbers, you
need to have some massively good credentials.
Bob
Yes agreed at $500M. But someone like Tom, who does have massively good
credentials, could perhaps get $500,000, and perhaps that wisely spent
could get a fountain built. Without knowing how you arrive at $500M, it is
not possible for anyone to look at ways of shaving that cost.
This is not a cheap field to be doing things in ….
Bob
The Lovell Telescope at Jodrell Bank in the UK was built on a shoestring
budget. It was at the time the world's largest steerable radio telephone.
Half a century later only 2 larger ones have been built.
Maybe I am too nieve.
Dave.
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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--
Javier Herrero
Chief Technology Officer EMAIL: jherrero@hvsistemas.com
HV Sistemas S.L. PHONE: +34 949 336 806
Teide 4, Núcleo 1 Of. 0.1 FAX: +34 949 336 792
28703 San Sebastián de los Reyes - Madrid - Spain WEB: http://www.hvsistemas.com
On 10 January 2017 at 15:35, Ole Petter Rønningen opronningen@gmail.com
wrote:
... having said that, I for one think I'm with Bob on this one. The thing
about masers are that they are big. At least active masers. And they
require a substantial volume be kept at ultra high vacuum - which is not
trivial, especially not in a homeshop. The cavity needs to be kept at a
temperature stable to 0.001 degree C. With 4-5 magnetic shields. Add to
this costly pumps to keep the vacuum this low even if you succeed at
reaching that vacuum.. There's easily 1-2KUSD running cost per year just to
keep the maser running.
Looking at the Microsemi MHM 2010 Active Hydogen Maser data sheet, the
maser has a peak power of 150 W and an operating power of 75 W. Based on a
power consumption of 75 W, that is 657 kW hr / year of energy. I pay around
£0.20 (GBP) per kW hr for electricity, so that's £131 (GBP) annually. I
believe electricity is cheaper in the USA than here in the UK, but
converting £131 (GBP) to USD, that's around $161/year in electricity. So
running costs don't seem to be an issue.
But I must admit, the thought of spending a lot of time/money to build
something I could have bought for a lot less with higher performance is not
that attractive, although of course there would be a satisfaction from
building it yourself.
Dave
This may be a dumb question, but how much of an H Maser's advantage over a Cs Standard, for us mere mortal time-nuts, is down to the output oscillator it uses, rather than the reference source (H MASER or Cs beam)?
Bob
From: Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby@kirkbymicrowave.co.uk>
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Tuesday, January 10, 2017 4:12 PM
Subject: Re: [time-nuts] hm H Maser
On 10 January 2017 at 15:35, Ole Petter Rønningen opronningen@gmail.com
wrote:
... having said that, I for one think I'm with Bob on this one. The thing
about masers are that they are big. At least active masers. And they
require a substantial volume be kept at ultra high vacuum - which is not
trivial, especially not in a homeshop. The cavity needs to be kept at a
temperature stable to 0.001 degree C. With 4-5 magnetic shields. Add to
this costly pumps to keep the vacuum this low even if you succeed at
reaching that vacuum.. There's easily 1-2KUSD running cost per year just to
keep the maser running.
Looking at the Microsemi MHM 2010 Active Hydogen Maser data sheet, the
maser has a peak power of 150 W and an operating power of 75 W. Based on a
power consumption of 75 W, that is 657 kW hr / year of energy. I pay around
£0.20 (GBP) per kW hr for electricity, so that's £131 (GBP) annually. I
believe electricity is cheaper in the USA than here in the UK, but
converting £131 (GBP) to USD, that's around $161/year in electricity. So
running costs don't seem to be an issue.
But I must admit, the thought of spending a lot of time/money to build
something I could have bought for a lot less with higher performance is not
that attractive, although of course there would be a satisfaction from
building it yourself.
Dave
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and follow the instructions there.
Hi
On Jan 10, 2017, at 5:26 PM, Bob Stewart bob@evoria.net wrote:
This may be a dumb question, but how much of an H Maser's advantage over a Cs Standard, for us mere mortal time-nuts, is down to the output oscillator it uses, rather than the reference source (H MASER or Cs beam)?
Pretty much none. You can design one with a crummy OCXO, but the question becomes - why would you do that? Putting a $10,000 OCXO into a $150K device is not that big a deal. If you put the same OCXO into a Cs standard, it would run a bit better out to the cross over point (a few 100 seconds or so). Indeed some Cs standards have such OCXO’s in them and that’s what they do.
Bob
Bob
From: Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby@kirkbymicrowave.co.uk>
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Tuesday, January 10, 2017 4:12 PM
Subject: Re: [time-nuts] hm H Maser
On 10 January 2017 at 15:35, Ole Petter Rønningen opronningen@gmail.com
wrote:
... having said that, I for one think I'm with Bob on this one. The thing
about masers are that they are big. At least active masers. And they
require a substantial volume be kept at ultra high vacuum - which is not
trivial, especially not in a homeshop. The cavity needs to be kept at a
temperature stable to 0.001 degree C. With 4-5 magnetic shields. Add to
this costly pumps to keep the vacuum this low even if you succeed at
reaching that vacuum.. There's easily 1-2KUSD running cost per year just to
keep the maser running.
Looking at the Microsemi MHM 2010 Active Hydogen Maser data sheet, the
maser has a peak power of 150 W and an operating power of 75 W. Based on a
power consumption of 75 W, that is 657 kW hr / year of energy. I pay around
£0.20 (GBP) per kW hr for electricity, so that's £131 (GBP) annually. I
believe electricity is cheaper in the USA than here in the UK, but
converting £131 (GBP) to USD, that's around $161/year in electricity. So
running costs don't seem to be an issue.
But I must admit, the thought of spending a lot of time/money to build
something I could have bought for a lot less with higher performance is not
that attractive, although of course there would be a satisfaction from
building it yourself.
Dave
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