Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Richard (Rick) Karlquist]

On 10/30/2020 5:05 PM, Bob kb8tq wrote:

Hi

Gradients are a really big deal in an OCXO. Thermal mass works against
you if you are after quick warmup ….

Bob



I'll take this opportunity to plug my 1997 FCS paper:
"The Theory of Zero Gradient Ovens" explaining how
we got thermal gain over 1 million.  You better
believe gradients are a really big deal.

Rick N6RK

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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Bruce Griffiths]

Not true 
The Wiedemann-Franz gives the ratio of the thermal conductivity to electrical 
conductivity of a metal:
( pi^2 / 3 ) * ( (k/e)^2 ) * T

Bruce
> On 31 October 2020 at 12:49 "Dr. David Kirkby" 
>  wrote:
> 
> 
> On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba  wrote:
> 
> > My bad... copper is the second, losing only to silver, as a thermal
> > conductor.
> >
> 
> I think you are mistaken.  Copper is second to silver for *electrical*
> conductivity, but I doubt that is so for thermal conductivity. I think
> diamond, which is a form of carbon, is the best thermal conductor, and
> around 5x better than copper.
> 
> Dave
> 
> -- 
> Dr. David Kirkby,
> Kirkby Microwave Ltd,
> drkir...@kirkbymicrowave.co.uk
> https://www.kirkbymicrowave.co.uk/
> Telephone 01621-680100./ +44 1621 680100
> 
> Registered in England & Wales, company number 08914892.
> Registered office:
> Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
> Kingdom
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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Bob kb8tq]

Hi

Gradients are a really big deal in an OCXO. Thermal mass works against
you if you are after quick warmup ….

Bob

> On Oct 30, 2020, at 6:23 PM, Attila Kinali  wrote:
> 
> On Fri, 30 Oct 2020 17:58:24 -0400
> Bob kb8tq  wrote:
> 
>> Simple answer: conductivity. You don’t get much heat capacity either way.
> 
> Ah.. so it is more important to have less temperature gradients
> than having high capacity?
> 
>   Attila Kinali
> 
> -- 
>   The bad part of Zurich is where the degenerates
>throw DARK chocolate at you.
> 
> ___
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[time-nuts] OCXO housings - Why copper and not iron/steel?

[Mark Sims]

And (if I remember the numbers properly) Isotopically pure diamond has twice 
the thermal conductivity of natural diamond.  There are places that make 
diamond-like carbon thermal pads.  Also places that make actual diamond ones 
(which are not as expensive as you would think),

-

> Actually, diamond has five times better thermal conductivity than silver,
so is the most conductive element, although graphene is suspected to be
better still.
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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Richard (Rick) Karlquist]

Diamond, graphite and graphene are all forms of the
element carbon.  They all can have more conductivity
than silver.

Rick N6RK

On 10/30/2020 3:25 PM, Andy Talbot wrote:

Actually, diamond has five times better thermal conductivity than silver,
so is the most conductive element, although graphene is suspected to be
better still.


Andy
www.g4jnt.com




Virus-free.
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba  wrote:


My bad... copper is the second, losing only to silver, as a thermal
conductor.

Enviado do meu iPhone


Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba <

l...@intercat.com.br> escreveu:


If my memory serves me, copper has the better conductivity of all the

periodic table...


Enviado do meu iPhone


Em 30 de out. de 2020, à(s) 18:56, Attila Kinali 

escreveu:


Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?


   Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
The bad part of Zurich is where the degenerates
   throw DARK chocolate at you.

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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Dr. David Kirkby]

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba  wrote:

> My bad... copper is the second, losing only to silver, as a thermal
> conductor.
>

I think you are mistaken.  Copper is second to silver for *electrical*
conductivity, but I doubt that is so for thermal conductivity. I think
diamond, which is a form of carbon, is the best thermal conductor, and
around 5x better than copper.

Dave

-- 
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkir...@kirkbymicrowave.co.uk
https://www.kirkbymicrowave.co.uk/
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom
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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Dave Daniel]

Heat capacity is essentially a measure of how much heat a material can hold (to 
a first approximation). Thermal conductivity is a measure of how well a 
material moves heat between two different temperatures mechanically connected 
to the material. When using a material as a heat sink, one wants to transfer 
the heat from the device being cooled to the (presumably cooler) ambient 
environment as quickly as possible, so thermal conductivity is more important 
than heat capacity for that application.

Note that a “heat sink” may also be used to warm up a cold material (e.g., 
reverse heat flow). A trivial example of this is that if you want to quickly 
defrost a piece of food, lay it on a good thermally conductive  surface such as 
a large aluminum or copper pan or tray. The food will defrost quickly because 
one is moving heat from the ambient environment into the food more quickly than 
if the food is just sitting on one’s countertop.

DaveD

> On Oct 30, 2020, at 18:23, Attila Kinali  wrote:
> 
> On Fri, 30 Oct 2020 17:58:24 -0400
> Bob kb8tq  wrote:
> 
>> Simple answer: conductivity. You don’t get much heat capacity either way.
> 
> Ah.. so it is more important to have less temperature gradients
> than having high capacity?
> 
>Attila Kinali
> 
> -- 
> The bad part of Zurich is where the degenerates
>throw DARK chocolate at you.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Richard (Rick) Karlquist]

Yes, we want conductivity, and not heat capacity.

On 10/30/2020 3:06 PM, Luiz Alberto Saba wrote:

If my memory serves me, copper has the better conductivity of all the periodic 
table...



Actually, carbon is at the top of the list.
Then silver, then copper.

Rick N6RK



Enviado do meu iPhone


Em 30 de out. de 2020, à(s) 18:56, Attila Kinali  escreveu:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?


Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Andy Talbot]

Actually, diamond has five times better thermal conductivity than silver,
so is the most conductive element, although graphene is suspected to be
better still.


Andy
www.g4jnt.com




Virus-free.
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba  wrote:

> My bad... copper is the second, losing only to silver, as a thermal
> conductor.
>
> Enviado do meu iPhone
>
> > Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba <
> l...@intercat.com.br> escreveu:
> >
> > If my memory serves me, copper has the better conductivity of all the
> periodic table...
> >
> > Enviado do meu iPhone
> >
> >> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali 
> escreveu:
> >>
> >> Moin,
> >>
> >> I have been looking at heat capacities of different materials
> >> lately. One thing that struk me odd is, that the volumetric
> >> heat capacity of copper, which is the thing that most people
> >> use when building something that needs to have high heat capacity
> >> to get stable temperature, has only a volumetric heat capacity
> >> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
> >> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
> >> even 3.75 J/(cm^3·K).
> >>
> >> In an OCXO, which is generally size limited, getting the most
> >> heat capacity in the limited volume would be the main goal,
> >> wouldn't it? Also optimizing for price would be a major thing.
> >> I can understand that iron is probably not the right choice
> >> due to its tendency to oxidize. But using a soft (annealed) steel
> >> would be easy to machine, cheaper per piece and give almost 10%
> >> higher heat capacity in the same volume.
> >>
> >> So why do people choose copper instead of steel?
> >>
> >>
> >>   Attila Kinali
> >>
> >> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
> >> at 25°C. We should fill OCXOs with water! :-D
> >>
> >> --
> >> The bad part of Zurich is where the degenerates
> >>   throw DARK chocolate at you.
> >>
> >> ___
> >> 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.
>
>
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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Attila Kinali]

On Fri, 30 Oct 2020 17:58:24 -0400
Bob kb8tq  wrote:

> Simple answer: conductivity. You don’t get much heat capacity either way.

Ah.. so it is more important to have less temperature gradients
than having high capacity?

Attila Kinali

-- 
The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Luiz Alberto Saba]

My bad... copper is the second, losing only to silver, as a thermal conductor.

Enviado do meu iPhone

> Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba  
> escreveu:
> 
> If my memory serves me, copper has the better conductivity of all the 
> periodic table...
> 
> Enviado do meu iPhone
> 
>> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali  escreveu:
>> 
>> Moin,
>> 
>> I have been looking at heat capacities of different materials
>> lately. One thing that struk me odd is, that the volumetric
>> heat capacity of copper, which is the thing that most people
>> use when building something that needs to have high heat capacity
>> to get stable temperature, has only a volumetric heat capacity
>> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
>> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel 
>> even 3.75 J/(cm^3·K).
>> 
>> In an OCXO, which is generally size limited, getting the most
>> heat capacity in the limited volume would be the main goal,
>> wouldn't it? Also optimizing for price would be a major thing.
>> I can understand that iron is probably not the right choice
>> due to its tendency to oxidize. But using a soft (annealed) steel
>> would be easy to machine, cheaper per piece and give almost 10%
>> higher heat capacity in the same volume. 
>> 
>> So why do people choose copper instead of steel?
>> 
>> 
>>   Attila Kinali
>> 
>> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
>> at 25°C. We should fill OCXOs with water! :-D
>> 
>> -- 
>> The bad part of Zurich is where the degenerates
>>   throw DARK chocolate at you.
>> 
>> ___
>> 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.


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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Bob kb8tq]

Hi

Simple answer: conductivity. You don’t get much heat capacity either way.

Bob

> On Oct 30, 2020, at 5:49 PM, Attila Kinali  wrote:
> 
> Moin,
> 
> I have been looking at heat capacities of different materials
> lately. One thing that struk me odd is, that the volumetric
> heat capacity of copper, which is the thing that most people
> use when building something that needs to have high heat capacity
> to get stable temperature, has only a volumetric heat capacity
> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel 
> even 3.75 J/(cm^3·K).
> 
> In an OCXO, which is generally size limited, getting the most
> heat capacity in the limited volume would be the main goal,
> wouldn't it? Also optimizing for price would be a major thing.
> I can understand that iron is probably not the right choice
> due to its tendency to oxidize. But using a soft (annealed) steel
> would be easy to machine, cheaper per piece and give almost 10%
> higher heat capacity in the same volume. 
> 
> So why do people choose copper instead of steel?
> 
> 
>   Attila Kinali
> 
> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
> at 25°C. We should fill OCXOs with water! :-D
> 
> -- 
>   The bad part of Zurich is where the degenerates
>throw DARK chocolate at you.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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Re: [time-nuts] OCXO housings - Why copper and not iron/steel?

[Luiz Alberto Saba]

If my memory serves me, copper has the better conductivity of all the periodic 
table...

Enviado do meu iPhone

> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali  escreveu:
> 
> Moin,
> 
> I have been looking at heat capacities of different materials
> lately. One thing that struk me odd is, that the volumetric
> heat capacity of copper, which is the thing that most people
> use when building something that needs to have high heat capacity
> to get stable temperature, has only a volumetric heat capacity
> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel 
> even 3.75 J/(cm^3·K).
> 
> In an OCXO, which is generally size limited, getting the most
> heat capacity in the limited volume would be the main goal,
> wouldn't it? Also optimizing for price would be a major thing.
> I can understand that iron is probably not the right choice
> due to its tendency to oxidize. But using a soft (annealed) steel
> would be easy to machine, cheaper per piece and give almost 10%
> higher heat capacity in the same volume. 
> 
> So why do people choose copper instead of steel?
> 
> 
>Attila Kinali
> 
> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
> at 25°C. We should fill OCXOs with water! :-D
> 
> -- 
> The bad part of Zurich is where the degenerates
>throw DARK chocolate at you.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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[time-nuts] OCXO housings - Why copper and not iron/steel?

[Attila Kinali]

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel 
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume. 

So why do people choose copper instead of steel?


Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

-- 
The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

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Re: [time-nuts] "When you google word ..."

[Hal Murray]

t...@leapsecond.com said:
> Right, OCXO are not stable enough at the desired tau to do a blueshift
> experiment. So that's why atomic (and now, optical) clocks are used. But
> note that many experimental confirmations of general relativity, from
> planets to black holes, do not involve clocks, per se.

A friend who worked at the VLA told me (roughly) the following story.

NASA had a probe way out near Saturn or Jupiter.  They wanted a refinment on 
the location.  So the VLA pointed their antennas at the probe, got some data, 
crunched the numbers, and gave the answer to NASA.  NASA didn't like that 
answer.  After the typical head scratching that goes with debugging a 
complicated pile of software, the VLA figured out that they had never done the 
blue-shift calculations for something that was already half way down the solar 
gravity well.  The things they normally look at are much farther away, at the 
top of the well.  NASA was much happier with a revised answer.
 
-

For time-nuts, GPS has got to be the most obvious confirmation of relativity.

If I look inside a high-end GPS receiver, are there any relativity corrections 
due to elevation?





-- 
These are my opinions.  I hate spam.




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[time-nuts] Changes in commercial GPS clocks over the decades

[The Fiber Guru]

During my telco career I was responsible for Network Synchronization and
witnessed several generations of clock designs.  Post-telco I now
manufacture and sell Network synchronization systems.  Here are a few
observations from legacy and modern topologies:

 

1. BITS clocks used to consume an entire 8 ft rack in a large central office

2. Legacy clocks easily cost $35k to $50k

3. The most critical part of clock installation is the antenna..this has
never changed.  If you get this wrong the clock will flop around like a fish
out of water

4. Most critical part of antenna installation is to have unobstructed view
of the sky, but not be the highest electrical element (for lightning
protectioncome of protection).  Of equal importance is selecting the
proper size antenna cable for the required distance (RG58 up to 100 ft,
RG213 up to 300 ft, LMR400 up to 600 ft)

5. Always, always, always install a lightning arrester.  Get away from me
with, "But we don't get lightning strikes."  Arresters are WAY less
expensive than GPS receiver modules in commercial clocks

6. The latest "smart ocxo's meet the performance of legacy Rb oscillators at
a fraction of the cost, and last much longer with very low heat dissipation

7. Since they don't use Composite Clock signals in Europe (64kbps with an
8kHz error rate), almost none of the Network Synchronization systems outside
the USA provide these TDM outputs, but thousands of small carriers and
government sites still require it

8. IEEE 1588 has been really slow to catch on.  Our first PTP product was
available for a decade with extremely low sales

9. We started with grandmasters, but now also have boundary and transparent
clocks to cut down on segments

10.  I've sold clocks for $50k, then we got them down to $30k, then $15k, to
$7k and we now sell $millions of clocks sub-$5k.  That's all in a 15-year
span.

When I present material on Network Synchronization, I always point out the
irony that multi-gigabit transmissions systems are synchronized by clocks
that rely entirely on a 

1 PPS signal (derived from GPS to discipline an oscillator).  So our fastest
networks are dependent on our slowest (but highly accurate) signal!

 

I enjoy reading your comments and learning about your projects.

 

Daniel B. Burch (The Fiber Guru)

  www.fiber.guru

 

 

 

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Re: [time-nuts] "When you google word ..."

[Tom Van Baak]

Azelio,

Right, OCXO are not stable enough at the desired tau to do a blueshift 
experiment. So that's why atomic (and now, optical) clocks are used. But 
note that many experimental confirmations of general relativity, from 
planets to black holes, do not involve clocks, per se. See, for example:


https://en.wikipedia.org/wiki/Pound%E2%80%93Rebka_experiment

Here's a historical summary of GR experiments from a Physics textbook:

https://www.relativity.li/uploads/pdf/English/I_en.pdf

Another good list:

https://en.wikipedia.org/wiki/Tests_of_general_relativity

And Clifford Will's classic:

https://link.springer.com/article/10.12942/lrr-2014-4

https://arxiv.org/abs/1403.7377

/tvb


On 10/30/2020 7:44 AM, Azelio Boriani wrote:

Was the blueshift only ever tested by using atomic clocks? OK, OCXOs
alone are not stable enough to try and we can't go that far from our
planet with the necessary equipment.

On Fri, Oct 30, 2020 at 2:27 PM Bob kb8tq  wrote:

Hi

So there might be a reason (other than NIST) to believe that frequency and
gravity are related to each other ? :)

Bob


On Oct 30, 2020, at 7:28 AM, Tom Van Baak  wrote:


Time Too Good to Be True, Daniel Kleppner
Physics Today, March 2006, page 10
https://physicstoday.scitation.org/doi/10.1063/1.2195297

An adventure in relative time-keeping, Tom Van Baak
Physics Today, March 2007, page 16
https://physicstoday.scitation.org/doi/10.1063/1.2718741

/tvb






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Re: [time-nuts] HP 5345A Noise Floor

[Bob kb8tq]

Hi

Ummm ….. er …… not so much :)

The time base of the counter is only just so good. 

I would guess that there is a glitch somewhere in the data transfer / data file 
formatting. 

Bob

> On Oct 30, 2020, at 1:14 PM, Giorgio Barinetti  wrote:
> 
> Hi Bob,
> 
> 
> 
> The current setup is:
> 
> 
> 
> Counter locked ( 10 mhz in ) to the Cesium.
> 
> 
> 
> Same 10 mhz signal from the Cesium feeds both the inputs and counter is 
> running in “phase difference” so time A-B.
> 
> 
> 
> That means the resolution will be hiher, I guess, since the counter is 
> counting the “difference” between the two
> 
> Signals, not the whole 10 mhz.
> 
> 
> 
> I’m a complete dumdum in maths but I’m sure that somebody here can explain in 
> a simple way.
> 
> 
> 
> 
> 
> Regards,
> 
> Giorgio.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Hi
> 
> 
> 
> According to page 1-3 in 
> https://bama.edebris.com/download/hp/5345a/5345a_6.pdf 
> 
> 
> 
> 
> The 5345 is a 2 ns counter. Roughly speaking, that normally gets you around  
> 2x10^-9
> 
> at 1 second.
> 
> 
> 
> That would suggest there is something a bit off in your setup.
> 
> 
> 
> Bob
> 
> 
> 
>> On Oct 29, 2020, at 9:26 AM, Giorgio Barinetti > barinetti.it>
>>  wrote:
> 
>> 
> 
>> Hi All.
> 
>> 
> 
>> While I’m waiting for a 5370B to come ( find it cheap and beautiful from 
>> France ) I’ve put my old 5345A on a trial, connecting both the
> 
>> Inputs to the 10 mhz out from an Oscilloquartz 3200 Cesium Oscillator.
> 
>> 
> 
>> Those are the results. Please advise 😊
> 
>> 
> 
>> Regards,
> 
>> Giorgio.
> 
>> [cid:image001.gif at 
>> 01D6ADF5.5EDF8CF0]
> 
>> ___
> 
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>> lists.febo.com
> 
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[time-nuts] HP 5345A Noise Floor

[Giorgio Barinetti]

Hi Bob,



The current setup is:



Counter locked ( 10 mhz in ) to the Cesium.



Same 10 mhz signal from the Cesium feeds both the inputs and counter is running 
in “phase difference” so time A-B.



That means the resolution will be hiher, I guess, since the counter is counting 
the “difference” between the two

Signals, not the whole 10 mhz.



I’m a complete dumdum in maths but I’m sure that somebody here can explain in a 
simple way.





Regards,

Giorgio.









Hi



According to page 1-3 in https://bama.edebris.com/download/hp/5345a/5345a_6.pdf 




The 5345 is a 2 ns counter. Roughly speaking, that normally gets you around  
2x10^-9

at 1 second.



That would suggest there is something a bit off in your setup.



Bob



> On Oct 29, 2020, at 9:26 AM, Giorgio Barinetti  barinetti.it>
>  wrote:

>

> Hi All.

>

> While I’m waiting for a 5370B to come ( find it cheap and beautiful from 
> France ) I’ve put my old 5345A on a trial, connecting both the

> Inputs to the 10 mhz out from an Oscilloquartz 3200 Cesium Oscillator.

>

> Those are the results. Please advise 😊

>

> Regards,

> Giorgio.

> [cid:image001.gif at 
> 01D6ADF5.5EDF8CF0]

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Re: [time-nuts] "When you google word ..."

[The Fiber Guru]

The NIST seminars are interesting, but if you attend multiple years the
material is nearly always the same.

db

-Original Message-
From: time-nuts  On Behalf Of Bob kb8tq
Sent: Friday, October 30, 2020 7:56 AM
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] "When you google word ..."

Hi

So there might be a reason (other than NIST) to believe that frequency and
gravity are related to each other ? :)

Bob

> On Oct 30, 2020, at 7:28 AM, Tom Van Baak  wrote:
> 
> > Time Too Good to Be True, Daniel Kleppner Physics Today, March 2006, 
> > page 10
> > https://physicstoday.scitation.org/doi/10.1063/1.2195297
> 
> An adventure in relative time-keeping, Tom Van Baak Physics Today, 
> March 2007, page 16
> https://physicstoday.scitation.org/doi/10.1063/1.2718741
> 
> /tvb
> 
> 
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Re: [time-nuts] "When you google word ..."

[Azelio Boriani]

Was the blueshift only ever tested by using atomic clocks? OK, OCXOs
alone are not stable enough to try and we can't go that far from our
planet with the necessary equipment.

On Fri, Oct 30, 2020 at 2:27 PM Bob kb8tq  wrote:
>
> Hi
>
> So there might be a reason (other than NIST) to believe that frequency and
> gravity are related to each other ? :)
>
> Bob
>
> > On Oct 30, 2020, at 7:28 AM, Tom Van Baak  wrote:
> >
> > > Time Too Good to Be True, Daniel Kleppner
> > > Physics Today, March 2006, page 10
> > > https://physicstoday.scitation.org/doi/10.1063/1.2195297
> >
> > An adventure in relative time-keeping, Tom Van Baak
> > Physics Today, March 2007, page 16
> > https://physicstoday.scitation.org/doi/10.1063/1.2718741
> >
> > /tvb
> >
> >
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Re: [time-nuts] Frequency Counter Choice

[Didier Juges]

Just for reference, I have an HP5334 that is missing the entire display
assembly and it works just fine over GPIB. Try it, it would most likely
work.

Didier KO4BB

On Thu, Oct 22, 2020, 9:46 AM Mark Spencer 
wrote:

> I am just curious how viable would it be to use a 531xx series counter
> with Timelab if the counter display has failed ?
>
> Thanks in advance
>
> Mark Spencer
> m...@alignedsolutions.com
> 604 762 4099
>
> > On Oct 22, 2020, at 6:36 AM, Bob kb8tq  wrote:
> >
> > Hi
> >
> >> On Oct 22, 2020, at 7:50 AM, Giorgio Barinetti 
> wrote:
> >>
> >> Hi,
> >>
> >> As a newbie in the field, I've collected, by chance, some frequency
> standards.
> >>
> >> Now is the time to measure them, and see how they perform.
> >>
> >> I've inherited a 5371, but something tells me that is not the right
> instrument - and maybe is even faulty.
> >>
> >> So, I'm in the need to buy a counter to use togheter with TimeLab.
> >>
> >> Choices are many, but I'll try to avoid the "older" machines lile 5370
> or 5335. The 531xx series seems nice ( money apart )
> >> But again : which one between the 3 ? 53131, 53132 or 53181 ?
> >
> > 53181 = single channel 400 ps counter
> > 53131 = dual channel 400 ps counter
> > 53132 = dual channel 100 ps counter
> >
> > 5370 (when working) = dual channel 20 ps counter
> >
> > The gotcha is that none of them are good enough to properly measure 1
> > second ADEV on a good ( but still could be cheap ) OCXO. A mixer based
> > setup is a cheap way to get things done, even with a 5335.
> >
> > The 531xx counters all share a couple of issues:
> >
> > 1) The power supply was made by who knows who and their quality is not
> > the best. Good news is that the power supply out of a (cheap) 53181 will
> > swap over to revive an expensive 53132.
> >
> > 2) They have a fan, it plugs with dust. When that happens it gets hot
> inside
> > the cabinet. Things (like the power supply) die as a result.
> >
> > 3) They have a VFD display. It’s a nice one, but they do wear out.
> Replacing
> > them is problematic.
> >
> > 4) They have a fancy setup to add digits to a frequency measurement. It
> > can lead you astray. It also tends to go deaf right at 10 MHz. There are
> app
> > notes out there that explain the details.
> >
> > 5) With *any* counter, a good external reference is the way to go for
> “Time Nut”
> > grade measurements.
> >
> > None of that is to say they are a bad counter, far from it. I have a
> number
> > of them and have been using them here and at work for decades. The 532xx
> > counters are the latest and greatest. They are on eBay, but not cheap.
> >
> > Bob
> >
> >
> >
> >>
> >> Can somebody shed some light, and maybe help even to found a baseline
> for us beginners ?
> >>
> >> Regards,
> >> IZ2JGB
> >> Giorgio
> >>
> >> My NTP servers: (ntpd on FreeBSD - PPS in via Serial)
> >>
> >> HP/Symmetricom 55300A  https://www.ntppool.org/scores/93.41.196.243
> >>
> >> Efratom Rb/Xc GPSDO https://www.ntppool.org/scores/95.255.136.126
> >>
> >>
> >>
> >> ___
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Re: [time-nuts] "When you google word ..."

[Bob kb8tq]

Hi

So there might be a reason (other than NIST) to believe that frequency and
gravity are related to each other ? :)

Bob

> On Oct 30, 2020, at 7:28 AM, Tom Van Baak  wrote:
> 
> > Time Too Good to Be True, Daniel Kleppner
> > Physics Today, March 2006, page 10
> > https://physicstoday.scitation.org/doi/10.1063/1.2195297
> 
> An adventure in relative time-keeping, Tom Van Baak
> Physics Today, March 2007, page 16
> https://physicstoday.scitation.org/doi/10.1063/1.2718741
> 
> /tvb
> 
> 
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Re: [time-nuts] SiTime Stratum 3E DCOCXO

[Bob kb8tq]

Hi

Indeed, they are pretty amazing for a tiny little part. Ultimately physics does
catch up with them. The resonator in the heart of the device has it’s 
limitations
compared to a big chunk of quartz.

Things like ADEV or phase noise aren’t their strong suit when compared to a 
good OCXO. Note that the OCXO would be much larger and would probably 
pull a lot more power. It’s a good bet that the silicon gizmo will withstand a 
much
harsher environment ( shock / vibe / acceleration …..) without there being much
impact. 

How useful are they? It very much depends on what you are trying to do ….

Bob

> On Oct 30, 2020, at 7:27 AM, John Moran, Scawby Design 
>  wrote:
> 
> Does anyone have any knowledge of the suitability of these silicon vs quartz 
> frequency sources for TimeNuts applications?
> 
> https://www.sitime.com/products/stratum-3e-dcocxos/sit5721
> 
> The published specs seem quite remarkable for a device that is 5 x 7 x 9mm
> 
> You have to request a data sheet, which is then for your eyes only, but they 
> are quite forthcoming with that.
> 
> I have requested a price for a one-off sample and will report back if and 
> when they respond.
> 
> John
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Re: [time-nuts] "When you google word ..."

[Tom Van Baak]

> Time Too Good to Be True, Daniel Kleppner
> Physics Today, March 2006, page 10
> https://physicstoday.scitation.org/doi/10.1063/1.2195297

An adventure in relative time-keeping, Tom Van Baak
Physics Today, March 2007, page 16
https://physicstoday.scitation.org/doi/10.1063/1.2718741

/tvb


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[time-nuts] SiTime Stratum 3E DCOCXO

[John Moran, Scawby Design]

Does anyone have any knowledge of the suitability of these silicon vs quartz 
frequency sources for TimeNuts applications?

https://www.sitime.com/products/stratum-3e-dcocxos/sit5721

The published specs seem quite remarkable for a device that is 5 x 7 x 9mm

You have to request a data sheet, which is then for your eyes only, but they 
are quite forthcoming with that.

I have requested a price for a one-off sample and will report back if and when 
they respond.

John
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Re: [time-nuts] "When you google word ..."

[David G. McGaw]

I am not sure why they would be discouraged.  We have known of the 
gravitational red-shift for a while and it is of course part of GPS 
calculations.  The Mossbauer effect, which involves a very narrow 
nuclear resonance, was used to demonstrate it in 1959 over a height of 
22.5 meters (the Pound–Rebka experiment).  It is cool that we now have 
clocks accurate enough to detect changes of the order of meters and 
getting better.


David N1HAC

On 10/29/20 10:32 PM, The Fiber Guru wrote:

I actually had the privilege of hearing David Allan present his theories in the 
yearly NIST conference in Boulder.  Interesting fellow.

One thing that was pretty cool is that NIST developed a fountain clock that is 
so accurate it is influenced by altitude.  They had to raise the clock once to 
install a new floor beneath and when they raised the clock it impacted the 
frequency.  Originally discouraged by this it suddenly occurred to someone that 
they had developed an extremely accurate way to measure height!  Now they just 
have to miniaturize it and make it affordable (of course this is the bane of 
laboratory experiments).

I was once Dir of R&D at a fortune 50 electronics firm and love hanging out in 
labs like NIST.

db


On Oct 29, 2020, at 7:00 PM, cdel...@juno.com wrote:

Also when you google  "alien deviation" you get:

About 11,800,000 results (0.50 seconds)

Cheers! :>)

Corby
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Re: [time-nuts] "When you google word ..."

[Hal Murray]

fiber.g...@fiber.guru said:
> One thing that was pretty cool is that NIST developed a fountain clock that
> is so accurate it is influenced by altitude.  They had to raise the clock
> once to install a new floor beneath and when they raised the clock it
> impacted the frequency.  Originally discouraged by this it suddenly occurred
> to someone that they had developed an extremely accurate way to measure
> height!  Now they just have to miniaturize it and make it affordable (of
> course this is the bane of laboratory experiments). 

Time Too Good to Be True, Daniel Kleppner
Physics Today, March 2006, page 10
https://physicstoday.scitation.org/doi/10.1063/1.2195297



-- 
These are my opinions.  I hate spam.




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