Re: [time-nuts] Connector options for HP10811A?

[biwa]

Sorry guys.  I thought I was writing directly to Frank.  My eyes aren't always 
pointy enough for my phone thingy.

Burt, K6OQK 

On April 8, 2020 7:54:05 PM PDT, b...@att.net wrote:
>Also... rather than clip leads, solder wires onto the board, not the
>connector pins.  Use those to hook up the power supply.
>
>Me
>
>On April 8, 2020 6:39:39 PM PDT, Frank O'Donnell 
>wrote:
>>I recently bought an HP10811A oscillator on eBay, only belatedly 
>>realizing that it's designed to interface to a 15-contact connector
>>that 
>>the manual identifies as a CINCH 250-15-30-210 or equivalent.
>>
>>A search turns up a vendor in Massachusetts called BMI Surplus Inc., 
>>that appears to have these in stock in new condition at a minimal
>>price. 
>>The only hitch is that BMI's website says they're closed down due to 
>>COVID-19 and will not process any orders until their state government 
>>authorizes businesses to return. (And at this point, it's anyone's
>>guess 
>>when that will be.)
>>
>>To get going with the oscillator, it occurs to me that I could rig up
>a
>>
>>few small alligator clips and use them on the required contacts for
>the
>>
>>time being. Any other thoughts or suggestions on how to work this? By 
>>any chance are there other known sources for the right size of
>>connector 
>>that might be operating right now?
>>
>>Thanks much,
>>
>>Frank O'Donnell
>>South Pasadena, California
>>
>>
>>
>>
>>
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Re: [time-nuts] Connector options for HP10811A?

[biwa]

Also... rather than clip leads, solder wires onto the board, not the connector 
pins.  Use those to hook up the power supply.

Me

On April 8, 2020 6:39:39 PM PDT, Frank O'Donnell  wrote:
>I recently bought an HP10811A oscillator on eBay, only belatedly 
>realizing that it's designed to interface to a 15-contact connector
>that 
>the manual identifies as a CINCH 250-15-30-210 or equivalent.
>
>A search turns up a vendor in Massachusetts called BMI Surplus Inc., 
>that appears to have these in stock in new condition at a minimal
>price. 
>The only hitch is that BMI's website says they're closed down due to 
>COVID-19 and will not process any orders until their state government 
>authorizes businesses to return. (And at this point, it's anyone's
>guess 
>when that will be.)
>
>To get going with the oscillator, it occurs to me that I could rig up a
>
>few small alligator clips and use them on the required contacts for the
>
>time being. Any other thoughts or suggestions on how to work this? By 
>any chance are there other known sources for the right size of
>connector 
>that might be operating right now?
>
>Thanks much,
>
>Frank O'Donnell
>South Pasadena, California
>
>
>
>
>
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Re: [time-nuts] The 10811 double oven mystery

[Mark Spencer]

 But cooling / heating systems designed to work over a Wide temperature range 
(ie. Parts of Northern Canada where outside temperatures of  perhaps -40C in 
the winter and +35C in the summer are within the relm of possibility) can be 
somewhat more expensive / complicated than systems designed for mild climates.

I can sort of see why someone might want electronic equipment that could work 
at -40C especially if the equipment was going to reside in an unattended 
shelter that was hard to get to.  I realize that in practice this is likely to 
be difficult (:

Mark Spencer

m...@alignedsolutions.com
604 762 4099

> On Apr 8, 2020, at 7:09 PM, Bob kb8tq  wrote:
> 
> Hi
> 
> Running a hard disk at -40 C is pretty much a no-go sort of thing. Even 
> finding CPU 
> or FPGA chips rated for operation down there is difficult / expensive. DRAM 
> chips with
> the “right” timing … not so much.  Bottom line - the heater / HVAC costs 
> *way* less than 
> designing all that stuff to work over a wide temperature range. 
> 
> Bob
> 
>> On Apr 8, 2020, at 9:58 PM, Hal Murray  wrote:
>> 
>> 
>> kb...@n1k.org said:
>>> Well, based on conversations with the people who designed the part,  the
>>> outer oven’s only function was to take care of a potential cold end  
>>> problem.
>>> At the time, the telecom guys were thinking of putting GPSDO’s in systems
>>> with no heating on the enclosures. That idea died when they ran into a
>>> variety of issues with the digital side of things at cold temperatures.
>> 
>> What's the problem with digital gear at cold temperatures?  The only one I 
>> can 
>> think of is that electrolytic capacitors stop working when the electrolyte 
>> freezes.
>> 
>> Do signal integrity problems appear when the rise time from CMOS drivers 
>> gets 
>> faster?
>> 
>> What sort of warmth did the telecom guys decide they needed?  I live in 
>> California, at sea level rather than up in the mountains.  We get occasional 
>> freezing from radiation cooling on clear nights.  They wouldn't have to work 
>> very hard to keep a box above freezing.  I'll have to look closer the next 
>> time I see some cell phone antennas.
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
>> 
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> 
> 
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Re: [time-nuts] Connector options for HP10811A?...

[Burt I. Weiner]

Frank,

Can you send me a picture of the connector?

Are you familiar with APEX (Surplus) Electronics in Sun Valley.  The 
sometimes have unusual connectors.  The problem is, you may have to 
look through the place for it.  The good news is that they can tell 
you where to start looking.


me



At 06:39 PM 4/8/2020, you wrote:
I recently bought an HP10811A oscillator on eBay, only belatedly 
realizing that it's designed to interface to a 15-contact connector 
that the manual identifies as a CINCH 250-15-30-210 or equivalent.


A search turns up a vendor in Massachusetts called BMI Surplus Inc., 
that appears to have these in stock in new condition at a minimal 
price. The only hitch is that BMI's website says they're closed down 
due to COVID-19 and will not process any orders until their state 
government authorizes businesses to return. (And at this point, it's 
anyone's guess when that will be.)


To get going with the oscillator, it occurs to me that I could rig 
up a few small alligator clips and use them on the required contacts 
for the time being. Any other thoughts or suggestions on how to work 
this? By any chance are there other known sources for the right size 
of connector that might be operating right now?


Thanks much,

Frank O'Donnell
South Pasadena, California





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Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
b...@att.net
K6OQK


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Re: [time-nuts] The 10811 double oven mystery

[Bob kb8tq]

Hi

Running a hard disk at -40 C is pretty much a no-go sort of thing. Even finding 
CPU 
or FPGA chips rated for operation down there is difficult / expensive. DRAM 
chips with
the “right” timing … not so much.  Bottom line - the heater / HVAC costs *way* 
less than 
designing all that stuff to work over a wide temperature range. 

Bob

> On Apr 8, 2020, at 9:58 PM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> Well, based on conversations with the people who designed the part,  the
>> outer oven’s only function was to take care of a potential cold end  problem.
>> At the time, the telecom guys were thinking of putting GPSDO’s in systems
>> with no heating on the enclosures. That idea died when they ran into a
>> variety of issues with the digital side of things at cold temperatures. 
> 
> What's the problem with digital gear at cold temperatures?  The only one I 
> can 
> think of is that electrolytic capacitors stop working when the electrolyte 
> freezes.
> 
> Do signal integrity problems appear when the rise time from CMOS drivers gets 
> faster?
> 
> What sort of warmth did the telecom guys decide they needed?  I live in 
> California, at sea level rather than up in the mountains.  We get occasional 
> freezing from radiation cooling on clear nights.  They wouldn't have to work 
> very hard to keep a box above freezing.  I'll have to look closer the next 
> time I see some cell phone antennas.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
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> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.


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[time-nuts] "Optical clocks on Tokyo Skytree help prove time passes faster at higher altitude"

[dikshie]

Apologize  for double post.

another attempt to prove general relativity:

"Optical clocks on Tokyo Skytree help prove time passes faster at
higher altitude"
article in online news paper:
url:  https://mainichi.jp/english/articles/20200407/p2a/00m/0na/012000c

article in Nature photonics (paywalled):
url: https://www.nature.com/articles/s41566-020-0619-8

Best Regards,

-- 
-dikshie-

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Re: [time-nuts] Connector options for HP10811A?

[Bob kb8tq]

Hi

The connector is a very normal 2 x 15 position 0.156” spaced edge connector. 
You can buy them on Amazon:

https://www.amazon.com/gp/product/B0721L5VSD/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 


From Mouser:

https://www.mouser.com/ProductDetail/587-307-030-520-201 


From various people on eBay:

https://www.ebay.com/itm/Card-edge-connector-row-30-Pin-3-96mm-pitch-805-slot-solder-PCB-2x15-socket-NMGG/293411808673?ssPageName=STRK%3AMEBIDX%3AIT&var=592241315857&_trksid=p2057872.m2749.l2649
 


https://www.ebay.com/itm/TRW-Cinch-Connector-252-18-30-301-Lot-of-6/122819145572?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
 


( ummm …. errr …. no, not that last one, it’s 18 pin … I only counted the pins 
*after* they got here :) )

or from a variety of other sources. 

If you dig a bit there is even a guy selling the full adapter for the 10811, 
(for a crazy price) but not identifying it
as working with the 10811


Bob




> On Apr 8, 2020, at 9:39 PM, Frank O'Donnell  wrote:
> 
> I recently bought an HP10811A oscillator on eBay, only belatedly realizing 
> that it's designed to interface to a 15-contact connector that the manual 
> identifies as a CINCH 250-15-30-210 or equivalent.
> 
> A search turns up a vendor in Massachusetts called BMI Surplus Inc., that 
> appears to have these in stock in new condition at a minimal price. The only 
> hitch is that BMI's website says they're closed down due to COVID-19 and will 
> not process any orders until their state government authorizes businesses to 
> return. (And at this point, it's anyone's guess when that will be.)
> 
> To get going with the oscillator, it occurs to me that I could rig up a few 
> small alligator clips and use them on the required contacts for the time 
> being. Any other thoughts or suggestions on how to work this? By any chance 
> are there other known sources for the right size of connector that might be 
> operating right now?
> 
> Thanks much,
> 
> Frank O'Donnell
> South Pasadena, California
> 
> 
> 
> 
> 
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Re: [time-nuts] The 10811 double oven mystery

[Hal Murray]

kb...@n1k.org said:
> Well, based on conversations with the people who designed the part,  the
> outer oven’s only function was to take care of a potential cold end  
> problem.
> At the time, the telecom guys were thinking of putting GPSDO’s in systems
> with no heating on the enclosures. That idea died when they ran into a
> variety of issues with the digital side of things at cold temperatures. 

What's the problem with digital gear at cold temperatures?  The only one I can 
think of is that electrolytic capacitors stop working when the electrolyte 
freezes.

Do signal integrity problems appear when the rise time from CMOS drivers gets 
faster?

What sort of warmth did the telecom guys decide they needed?  I live in 
California, at sea level rather than up in the mountains.  We get occasional 
freezing from radiation cooling on clear nights.  They wouldn't have to work 
very hard to keep a box above freezing.  I'll have to look closer the next 
time I see some cell phone antennas.


-- 
These are my opinions.  I hate spam.




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[time-nuts] Connector options for HP10811A?

[Frank O'Donnell]

I recently bought an HP10811A oscillator on eBay, only belatedly 
realizing that it's designed to interface to a 15-contact connector that 
the manual identifies as a CINCH 250-15-30-210 or equivalent.


A search turns up a vendor in Massachusetts called BMI Surplus Inc., 
that appears to have these in stock in new condition at a minimal price. 
The only hitch is that BMI's website says they're closed down due to 
COVID-19 and will not process any orders until their state government 
authorizes businesses to return. (And at this point, it's anyone's guess 
when that will be.)


To get going with the oscillator, it occurs to me that I could rig up a 
few small alligator clips and use them on the required contacts for the 
time being. Any other thoughts or suggestions on how to work this? By 
any chance are there other known sources for the right size of connector 
that might be operating right now?


Thanks much,

Frank O'Donnell
South Pasadena, California





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Re: [time-nuts] Ultra Stable Rb

[Richard (Rick) Karlquist]

On 4/8/2020 3:33 PM, Dana Whitlow wrote:

Bob, what I' was getting at was: what do you do differently to make a
stable Rb versus one
that drifts a lot?  Never mind price issues.


My understanding from working on the HP10816 Rb standard
is that aging (as opposed to temperature drift) is due
to the vagaries of Rb atoms moving around and blocking
the light causing light shift.  The lamp also has
wearout mechanisms having to do with the Rb dissolving
into the glass and possibly making it opaque etc.  If
the cell is not "flooded", then how unflooded it is changes
as Rb gets absorbed by the glass.  The glass used is the
next best thing to Fused Quartz, in order to make it
as impervious as possible to Rb.



Could one buy, say, a PRS-10, extract the physics package from it, then
engineer a stable
Rb with that as a core?


No, the aging is a function of the physics package, especially
the glassware.  The electronics would have to be fairly poorly
designed to contribute to aging.

Note:  thermal drift (as opposed to aging) is a different
discussion altogether.  There are a gazillion temperature
effects, both in the physics and the electronics that need
to be addressed.  I think some designs simply use a TCXO
type of technique to address all of these at once.

Rick





Dana


On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq  wrote:


Hi

The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up
and running,
the order volume drops off. The idea was to branch out into the broader
military market.
The design of the FRK did not change in any way as the price “morphed”.
They simply
had been making a pretty healthy margin on the product.  What happened to
the RFS
in the years after I left … no idea.

Bob


On Apr 8, 2020, at 4:32 PM, djl  wrote:

So it's Chinese engineering? Find something good that works, start

removing parts until it doesn't, put in the part last removed, and sell it?


My granddad worked for a guy in LA called Madman Muntz who made tv's

that way in the late 1940's. They worked. Sorta. For a while. If the signal
was strong enough.

Voila! $X-$400

On 2020-04-08 13:51, Bob kb8tq wrote:

Hi
At the time EG&G had done the GPS Rb’s but not done any other
military parts. Some research showed that indeed the FRK went into
a variety of systems and the price was $X. (It varied a bit with

quantity)

Push the numbers around and look at this and that. The decision was made
that indeed if you could sell a few hundred to maybe a thousand a year

at

$X, it was a good thing. A design was done and (as noted earlier) it was
a good little device.
The fun part came with that $X pricing. Out comes a request for some few
hundred pieces to this or that organization. Bid $X, order goes down to

the

competition for X-$300. Next request for a few hundred, bid X-$400,

order

goes down to the other guy for X-$500. This step by step process goes on
for a year …. same result again and again.
At the end of that time period it was far less clear just *why* one

does up

an FRK like part ….
Bob

On Apr 8, 2020, at 2:32 PM, djl  wrote:
What a tease! OK, very well WHY???
Don
On 2020-04-08 08:04, Bob kb8tq wrote:

Hi
A few of the long running FRK’s ( in a very similar package …
hmmm ….. wonder why …. yes, I was there way back then
and know very well why :) ) have crazy good long term aging.
That said, I don’t think that I’ve seen a FRK quite this good.
Thanks for sharing !!!
Bob

On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
Hi Guys,
Just though you'd be interested in my prototype rubidium frequency

standard

I made in the 1990's.
http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
I have measured its frequency at random intervals for the past 18

years.

Its never been adjusted and is just free running.
It was turned off in 2005 and sent to a customer in Japan for a few

weeks,

then returned and turned back on.
For the past 18 years its stayed within plus/minus 3 x 10E-11.
The overall linear drift is something like 1.85 x 10E-13 per month.
This is not an advert.  There's no way any of our production units

are as

good as this one, well I assume so as I've never measured any for 18

years

continuous!
Its now over 25 years old, have hardly ever been turned off.  Any

day I

expect it to fail, but it keeps on running!!
Regards
Martyn
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VOX: 406-626-4304
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Re: [time-nuts] Ultra Stable Rb

[Bob kb8tq]

Hi

The “conventional wisdom” is that the “big cell” Rb’s ( like the GPS Rb and the 
5065 )  *do* have a fundamental advantage. The 5065 design dates to the 60’s.
There are a lot of things that can be addressed there. PHK has a great set of 
observations on his web site looking into that. 

The “ultimate” Rb would likely be a large cell version. Various groups are 
working 
on tune up’s for things like the FRK. Things like compensation that simply
where not considered back in the day, may be rational today. How close this gets
you …. only time will tell. 

Best guess is that Rb’s and OCXO’s share some basic gotchas. Your design only
gets you just so far. Some percentage of the parts will be utterly rotten. Some 
percentage will be pretty amazing. There will be a significant group in the 
middle. 

Screening has *always* been a way to deal with this. If you are willing to run
through a few hundred samples to get less than 5 “good ones”, you can do pretty
crazy things. This is done on OCXO’s, I don’t know of any examples of it being
done on Rb’s. 

Bob

> On Apr 8, 2020, at 6:33 PM, Dana Whitlow  wrote:
> 
> Bob, what I' was getting at was: what do you do differently to make a
> stable Rb versus one
> that drifts a lot?  Never mind price issues.
> 
> Could one buy, say, a PRS-10, extract the physics package from it, then
> engineer a stable
> Rb with that as a core?
> 
> Dana
> 
> 
> On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq  wrote:
> 
>> Hi
>> 
>> The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up
>> and running,
>> the order volume drops off. The idea was to branch out into the broader
>> military market.
>> The design of the FRK did not change in any way as the price “morphed”.
>> They simply
>> had been making a pretty healthy margin on the product.  What happened to
>> the RFS
>> in the years after I left … no idea.
>> 
>> Bob
>> 
>>> On Apr 8, 2020, at 4:32 PM, djl  wrote:
>>> 
>>> So it's Chinese engineering? Find something good that works, start
>> removing parts until it doesn't, put in the part last removed, and sell it?
>>> 
>>> My granddad worked for a guy in LA called Madman Muntz who made tv's
>> that way in the late 1940's. They worked. Sorta. For a while. If the signal
>> was strong enough.
>>> Voila! $X-$400
>>> 
>>> On 2020-04-08 13:51, Bob kb8tq wrote:
 Hi
 At the time EG&G had done the GPS Rb’s but not done any other
 military parts. Some research showed that indeed the FRK went into
 a variety of systems and the price was $X. (It varied a bit with
>> quantity)
 Push the numbers around and look at this and that. The decision was made
 that indeed if you could sell a few hundred to maybe a thousand a year
>> at
 $X, it was a good thing. A design was done and (as noted earlier) it was
 a good little device.
 The fun part came with that $X pricing. Out comes a request for some few
 hundred pieces to this or that organization. Bid $X, order goes down to
>> the
 competition for X-$300. Next request for a few hundred, bid X-$400,
>> order
 goes down to the other guy for X-$500. This step by step process goes on
 for a year …. same result again and again.
 At the end of that time period it was far less clear just *why* one
>> does up
 an FRK like part ….
 Bob
> On Apr 8, 2020, at 2:32 PM, djl  wrote:
> What a tease! OK, very well WHY???
> Don
> On 2020-04-08 08:04, Bob kb8tq wrote:
>> Hi
>> A few of the long running FRK’s ( in a very similar package …
>> hmmm ….. wonder why …. yes, I was there way back then
>> and know very well why :) ) have crazy good long term aging.
>> That said, I don’t think that I’ve seen a FRK quite this good.
>> Thanks for sharing !!!
>> Bob
>>> On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
>>> Hi Guys,
>>> Just though you'd be interested in my prototype rubidium frequency
>> standard
>>> I made in the 1990's.
>>> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
>>> I have measured its frequency at random intervals for the past 18
>> years.
>>> Its never been adjusted and is just free running.
>>> It was turned off in 2005 and sent to a customer in Japan for a few
>> weeks,
>>> then returned and turned back on.
>>> For the past 18 years its stayed within plus/minus 3 x 10E-11.
>>> The overall linear drift is something like 1.85 x 10E-13 per month.
>>> This is not an advert.  There's no way any of our production units
>> are as
>>> good as this one, well I assume so as I've never measured any for 18
>> years
>>> continuous!
>>> Its now over 25 years old, have hardly ever been turned off.  Any
>> day I
>>> expect it to fail, but it keeps on running!!
>>> Regards
>>> Martyn
>>> ___
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>> http://lists.febo.com/mailman/listinfo/time-nuts

Re: [time-nuts] The 10811 double oven mystery

[Richard (Rick) Karlquist]

On 4/8/2020 2:02 PM, Tom Holmes wrote:

Then what was the purpose of the inner oven?

Tom Holmes, N8ZM

-Original Message-


The inner oven has a thermal gain around
1,000.  When my colleagues at HP proposed
to wrap a 2nd oven around it, I predicted
that the additional thermal gain due to
this oven would not be much, and they
proved me right by building it. and measuring
it.  It's raison d'etre is dealing with low
ambient temperatures.  Any thermal gain
improvement is just a bonus.  The
designers downplayed this bonus since it
wasn't anything to brag about.

Rick N6RK

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Re: [time-nuts] Ultra Stable Rb

[Dana Whitlow]

Bob, what I' was getting at was: what do you do differently to make a
stable Rb versus one
that drifts a lot?  Never mind price issues.

Could one buy, say, a PRS-10, extract the physics package from it, then
engineer a stable
Rb with that as a core?

Dana


On Wed, Apr 8, 2020 at 4:19 PM Bob kb8tq  wrote:

> Hi
>
> The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up
> and running,
> the order volume drops off. The idea was to branch out into the broader
> military market.
> The design of the FRK did not change in any way as the price “morphed”.
> They simply
> had been making a pretty healthy margin on the product.  What happened to
> the RFS
> in the years after I left … no idea.
>
> Bob
>
> > On Apr 8, 2020, at 4:32 PM, djl  wrote:
> >
> > So it's Chinese engineering? Find something good that works, start
> removing parts until it doesn't, put in the part last removed, and sell it?
> >
> > My granddad worked for a guy in LA called Madman Muntz who made tv's
> that way in the late 1940's. They worked. Sorta. For a while. If the signal
> was strong enough.
> > Voila! $X-$400
> >
> > On 2020-04-08 13:51, Bob kb8tq wrote:
> >> Hi
> >> At the time EG&G had done the GPS Rb’s but not done any other
> >> military parts. Some research showed that indeed the FRK went into
> >> a variety of systems and the price was $X. (It varied a bit with
> quantity)
> >> Push the numbers around and look at this and that. The decision was made
> >> that indeed if you could sell a few hundred to maybe a thousand a year
> at
> >> $X, it was a good thing. A design was done and (as noted earlier) it was
> >> a good little device.
> >> The fun part came with that $X pricing. Out comes a request for some few
> >> hundred pieces to this or that organization. Bid $X, order goes down to
> the
> >> competition for X-$300. Next request for a few hundred, bid X-$400,
> order
> >> goes down to the other guy for X-$500. This step by step process goes on
> >> for a year …. same result again and again.
> >> At the end of that time period it was far less clear just *why* one
> does up
> >> an FRK like part ….
> >> Bob
> >>> On Apr 8, 2020, at 2:32 PM, djl  wrote:
> >>> What a tease! OK, very well WHY???
> >>> Don
> >>> On 2020-04-08 08:04, Bob kb8tq wrote:
>  Hi
>  A few of the long running FRK’s ( in a very similar package …
>  hmmm ….. wonder why …. yes, I was there way back then
>  and know very well why :) ) have crazy good long term aging.
>  That said, I don’t think that I’ve seen a FRK quite this good.
>  Thanks for sharing !!!
>  Bob
> > On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
> > Hi Guys,
> > Just though you'd be interested in my prototype rubidium frequency
> standard
> > I made in the 1990's.
> > http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
> > I have measured its frequency at random intervals for the past 18
> years.
> > Its never been adjusted and is just free running.
> > It was turned off in 2005 and sent to a customer in Japan for a few
> weeks,
> > then returned and turned back on.
> > For the past 18 years its stayed within plus/minus 3 x 10E-11.
> > The overall linear drift is something like 1.85 x 10E-13 per month.
> > This is not an advert.  There's no way any of our production units
> are as
> > good as this one, well I assume so as I've never measured any for 18
> years
> > continuous!
> > Its now over 25 years old, have hardly ever been turned off.  Any
> day I
> > expect it to fail, but it keeps on running!!
> > Regards
> > Martyn
> > ___
> > 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.
> >>> --
> >>> Dr. Don Latham  AJ7LL
> >>> PO Box 404, Frenchtown, MT, 59834
> >>> VOX: 406-626-4304
> >>> ___
> >>> time-nuts mailing list -- time-nuts@lists.febo.com
> >>> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >>> and follow the instructions there.
> >> ___
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> >> To unsubscribe, go to
> >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> >
> > --
> > Dr. Don Latham  AJ7LL
> > PO Box 404, Frenchtown, MT, 59834
> > VOX: 406-626-4304
> >
> >
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Re: [time-nuts] Ultra Stable Rb

[Bob kb8tq]

Hi

The GPS Rb’s are “couple million dollar” sort of devices. Once GPS is up and 
running, 
the order volume drops off. The idea was to branch out into the broader 
military market. 
The design of the FRK did not change in any way as the price “morphed”. They 
simply
had been making a pretty healthy margin on the product.  What happened to the 
RFS
in the years after I left … no idea. 

Bob

> On Apr 8, 2020, at 4:32 PM, djl  wrote:
> 
> So it's Chinese engineering? Find something good that works, start removing 
> parts until it doesn't, put in the part last removed, and sell it?
> 
> My granddad worked for a guy in LA called Madman Muntz who made tv's that way 
> in the late 1940's. They worked. Sorta. For a while. If the signal was strong 
> enough.
> Voila! $X-$400
> 
> On 2020-04-08 13:51, Bob kb8tq wrote:
>> Hi
>> At the time EG&G had done the GPS Rb’s but not done any other
>> military parts. Some research showed that indeed the FRK went into
>> a variety of systems and the price was $X. (It varied a bit with quantity)
>> Push the numbers around and look at this and that. The decision was made
>> that indeed if you could sell a few hundred to maybe a thousand a year at
>> $X, it was a good thing. A design was done and (as noted earlier) it was
>> a good little device.
>> The fun part came with that $X pricing. Out comes a request for some few
>> hundred pieces to this or that organization. Bid $X, order goes down to the
>> competition for X-$300. Next request for a few hundred, bid X-$400, order
>> goes down to the other guy for X-$500. This step by step process goes on
>> for a year …. same result again and again.
>> At the end of that time period it was far less clear just *why* one does up
>> an FRK like part ….
>> Bob
>>> On Apr 8, 2020, at 2:32 PM, djl  wrote:
>>> What a tease! OK, very well WHY???
>>> Don
>>> On 2020-04-08 08:04, Bob kb8tq wrote:
 Hi
 A few of the long running FRK’s ( in a very similar package …
 hmmm ….. wonder why …. yes, I was there way back then
 and know very well why :) ) have crazy good long term aging.
 That said, I don’t think that I’ve seen a FRK quite this good.
 Thanks for sharing !!!
 Bob
> On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
> Hi Guys,
> Just though you'd be interested in my prototype rubidium frequency 
> standard
> I made in the 1990's.
> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
> I have measured its frequency at random intervals for the past 18 years.
> Its never been adjusted and is just free running.
> It was turned off in 2005 and sent to a customer in Japan for a few weeks,
> then returned and turned back on.
> For the past 18 years its stayed within plus/minus 3 x 10E-11.
> The overall linear drift is something like 1.85 x 10E-13 per month.
> This is not an advert.  There's no way any of our production units are as
> good as this one, well I assume so as I've never measured any for 18 years
> continuous!
> Its now over 25 years old, have hardly ever been turned off.  Any day I
> expect it to fail, but it keeps on running!!
> Regards
> Martyn
> ___
> 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.
>>> --
>>> Dr. Don Latham  AJ7LL
>>> PO Box 404, Frenchtown, MT, 59834
>>> VOX: 406-626-4304
>>> ___
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, 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.
> 
> -- 
> Dr. Don Latham  AJ7LL
> PO Box 404, Frenchtown, MT, 59834
> VOX: 406-626-4304
> 
> 
> ___
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Re: [time-nuts] The 10811 double oven mystery

[Richard (Rick) Karlquist]

On 4/8/2020 12:53 PM, Jarl Risum wrote:

I have been puzzled by a mistake which has been published recently on this
list and elsewhere as well. It concerns the operation of the HP 10811
double oven TCXO used in the HP Z3801 GPSDO.

It is claimed that the outer oven is only in use during start up or during
extremely low ambient temperatures and is not operating during normal
conditions. This is not correct.

Jarl
___


How did you determine that the statement is not correct?
There will be some ambient temperature at which the
outer oven heater power reaches zero and therefore
it becomes inactive above that.  All you are arguing
about is whether the shutdown temperature is correctly
described in terms of "extremely low" and "normal",
whatever those adjectives mean.

Rick

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Re: [time-nuts] The 10811 double oven mystery

[Tom Holmes]

Then what was the purpose of the inner oven?

Tom Holmes, N8ZM

-Original Message-
From: time-nuts  On Behalf Of Jarl Risum
Sent: Wednesday, April 08, 2020 3:53 PM
To: time-nuts@lists.febo.com
Subject: [time-nuts] The 10811 double oven mystery

I have been puzzled by a mistake which has been published recently on this
list and elsewhere as well. It concerns the operation of the HP 10811
double oven TCXO used in the HP Z3801 GPSDO.

It is claimed that the outer oven is only in use during start up or during
extremely low ambient temperatures and is not operating during normal
conditions. This is not correct.

The 10811 outer oven circuit in the HP Z3801 is designed to maintainin a
stable temperature around the 10811-60158 OCXO somewhere in the interval
between 60 and 65 deg. C in order to reduce the 10811-60158 OCXO's
sensitivity to temperature changes which – without the outer oven - is
specified as 4,5 x 10 e-9 from 0 to 71 deg. C.

The HP Z3801 was made as a GPS disciplined timebase for synchronization of
CDMA Cellular Wireless Land Network base stations and was required to
maintain system syncronization for up to 24 hours in situations with
failure of GPS reception. In order to satisfy this requirement, the HP
Z3801's internal processor keep track of the gradual ageing of the 10811
during normal GPS-disciplined operation and applies a calculated, predicted
correction voltage to keep the OCXO on frequency during periods with no GPS
signal (HP's Smart Clock technology).

A diagram and detailed description of the 10811 outer oven circuit can be
found at KO4BB's manual collection under
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing/Z3801.
Pictures of the outer oven can be found at
www.realhamradio.com/GPS_Frequency_Standard.htm.

In 2013 Warren Sarkison published an improved 10811 Outer Oven Controller
with improved temperature regulation. Description and numerous references
to his design can be found by Googling ”Warren S. Design 10811 Outer Oven
Controller”. This circuit - or something similar - is much to be
recommended if optimum operation of the dual oven 10811 outside of the HP
Z3801 is considered.

Jarl
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Re: [time-nuts] Ultra Stable Rb

[djl]

So it's Chinese engineering? Find something good that works, start 
removing parts until it doesn't, put in the part last removed, and sell 
it?


My granddad worked for a guy in LA called Madman Muntz who made tv's 
that way in the late 1940's. They worked. Sorta. For a while. If the 
signal was strong enough.

Voila! $X-$400

On 2020-04-08 13:51, Bob kb8tq wrote:

Hi

At the time EG&G had done the GPS Rb’s but not done any other
military parts. Some research showed that indeed the FRK went into
a variety of systems and the price was $X. (It varied a bit with 
quantity)


Push the numbers around and look at this and that. The decision was 
made
that indeed if you could sell a few hundred to maybe a thousand a year 
at
$X, it was a good thing. A design was done and (as noted earlier) it 
was

a good little device.

The fun part came with that $X pricing. Out comes a request for some 
few
hundred pieces to this or that organization. Bid $X, order goes down to 
the
competition for X-$300. Next request for a few hundred, bid X-$400, 
order
goes down to the other guy for X-$500. This step by step process goes 
on

for a year …. same result again and again.

At the end of that time period it was far less clear just *why* one 
does up

an FRK like part ….

Bob


On Apr 8, 2020, at 2:32 PM, djl  wrote:

What a tease! OK, very well WHY???
Don

On 2020-04-08 08:04, Bob kb8tq wrote:

Hi
A few of the long running FRK’s ( in a very similar package …
hmmm ….. wonder why …. yes, I was there way back then
and know very well why :) ) have crazy good long term aging.
That said, I don’t think that I’ve seen a FRK quite this good.
Thanks for sharing !!!
Bob

On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
Hi Guys,
Just though you'd be interested in my prototype rubidium frequency 
standard

I made in the 1990's.
http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
I have measured its frequency at random intervals for the past 18 
years.

Its never been adjusted and is just free running.
It was turned off in 2005 and sent to a customer in Japan for a few 
weeks,

then returned and turned back on.
For the past 18 years its stayed within plus/minus 3 x 10E-11.
The overall linear drift is something like 1.85 x 10E-13 per month.
This is not an advert.  There's no way any of our production units 
are as
good as this one, well I assume so as I've never measured any for 18 
years

continuous!
Its now over 25 years old, have hardly ever been turned off.  Any 
day I

expect it to fail, but it keeps on running!!
Regards
Martyn
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--
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304


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--
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304


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Re: [time-nuts] The 10811 double oven mystery

[Bob kb8tq]

Hi

Well, based on conversations with the people who designed the part, 
the outer oven’s only function was to take care of a potential cold end 
problem. At the time, the telecom guys were thinking of putting GPSDO’s
in systems with no heating on the enclosures. That idea died when they
ran into a variety of issues with the digital side of things at cold 
temperatures.

The issue isn’t the *sensitivity* as much as the simple fact that the 
10811 will not warm up at all from a really cold temperature. There just 
isn’t enough heater power. If you want to dig into just why a “jacket” like 
this is not going to give you super oven performance, the various papers
Rick published on his single oven are a good start.

Bob




> On Apr 8, 2020, at 3:53 PM, Jarl Risum  wrote:
> 
> I have been puzzled by a mistake which has been published recently on this
> list and elsewhere as well. It concerns the operation of the HP 10811
> double oven TCXO used in the HP Z3801 GPSDO.
> 
> It is claimed that the outer oven is only in use during start up or during
> extremely low ambient temperatures and is not operating during normal
> conditions. This is not correct.
> 
> The 10811 outer oven circuit in the HP Z3801 is designed to maintainin a
> stable temperature around the 10811-60158 OCXO somewhere in the interval
> between 60 and 65 deg. C in order to reduce the 10811-60158 OCXO's
> sensitivity to temperature changes which – without the outer oven - is
> specified as 4,5 x 10 e-9 from 0 to 71 deg. C.
> 
> The HP Z3801 was made as a GPS disciplined timebase for synchronization of
> CDMA Cellular Wireless Land Network base stations and was required to
> maintain system syncronization for up to 24 hours in situations with
> failure of GPS reception. In order to satisfy this requirement, the HP
> Z3801's internal processor keep track of the gradual ageing of the 10811
> during normal GPS-disciplined operation and applies a calculated, predicted
> correction voltage to keep the OCXO on frequency during periods with no GPS
> signal (HP's Smart Clock technology).
> 
> A diagram and detailed description of the 10811 outer oven circuit can be
> found at KO4BB's manual collection under
> http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing/Z3801.
> Pictures of the outer oven can be found at
> www.realhamradio.com/GPS_Frequency_Standard.htm.
> 
> In 2013 Warren Sarkison published an improved 10811 Outer Oven Controller
> with improved temperature regulation. Description and numerous references
> to his design can be found by Googling ”Warren S. Design 10811 Outer Oven
> Controller”. This circuit - or something similar - is much to be
> recommended if optimum operation of the dual oven 10811 outside of the HP
> Z3801 is considered.
> 
> Jarl
> ___
> 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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[time-nuts] The 10811 double oven mystery

[Jarl Risum]

I have been puzzled by a mistake which has been published recently on this
list and elsewhere as well. It concerns the operation of the HP 10811
double oven TCXO used in the HP Z3801 GPSDO.

It is claimed that the outer oven is only in use during start up or during
extremely low ambient temperatures and is not operating during normal
conditions. This is not correct.

The 10811 outer oven circuit in the HP Z3801 is designed to maintainin a
stable temperature around the 10811-60158 OCXO somewhere in the interval
between 60 and 65 deg. C in order to reduce the 10811-60158 OCXO's
sensitivity to temperature changes which – without the outer oven - is
specified as 4,5 x 10 e-9 from 0 to 71 deg. C.

The HP Z3801 was made as a GPS disciplined timebase for synchronization of
CDMA Cellular Wireless Land Network base stations and was required to
maintain system syncronization for up to 24 hours in situations with
failure of GPS reception. In order to satisfy this requirement, the HP
Z3801's internal processor keep track of the gradual ageing of the 10811
during normal GPS-disciplined operation and applies a calculated, predicted
correction voltage to keep the OCXO on frequency during periods with no GPS
signal (HP's Smart Clock technology).

A diagram and detailed description of the 10811 outer oven circuit can be
found at KO4BB's manual collection under
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing/Z3801.
Pictures of the outer oven can be found at
www.realhamradio.com/GPS_Frequency_Standard.htm.

In 2013 Warren Sarkison published an improved 10811 Outer Oven Controller
with improved temperature regulation. Description and numerous references
to his design can be found by Googling ”Warren S. Design 10811 Outer Oven
Controller”. This circuit - or something similar - is much to be
recommended if optimum operation of the dual oven 10811 outside of the HP
Z3801 is considered.

Jarl
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Re: [time-nuts] Ultra Stable Rb

[Bob kb8tq]

Hi

At the time EG&G had done the GPS Rb’s but not done any other 
military parts. Some research showed that indeed the FRK went into 
a variety of systems and the price was $X. (It varied a bit with quantity)

Push the numbers around and look at this and that. The decision was made
that indeed if you could sell a few hundred to maybe a thousand a year at
$X, it was a good thing. A design was done and (as noted earlier) it was
a good little device. 

The fun part came with that $X pricing. Out comes a request for some few 
hundred pieces to this or that organization. Bid $X, order goes down to the 
competition for X-$300. Next request for a few hundred, bid X-$400, order 
goes down to the other guy for X-$500. This step by step process goes on 
for a year …. same result again and again. 

At the end of that time period it was far less clear just *why* one does up
an FRK like part ….

Bob

> On Apr 8, 2020, at 2:32 PM, djl  wrote:
> 
> What a tease! OK, very well WHY???
> Don
> 
> On 2020-04-08 08:04, Bob kb8tq wrote:
>> Hi
>> A few of the long running FRK’s ( in a very similar package …
>> hmmm ….. wonder why …. yes, I was there way back then
>> and know very well why :) ) have crazy good long term aging.
>> That said, I don’t think that I’ve seen a FRK quite this good.
>> Thanks for sharing !!!
>> Bob
>>> On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
>>> Hi Guys,
>>> Just though you'd be interested in my prototype rubidium frequency standard
>>> I made in the 1990's.
>>> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
>>> I have measured its frequency at random intervals for the past 18 years.
>>> Its never been adjusted and is just free running.
>>> It was turned off in 2005 and sent to a customer in Japan for a few weeks,
>>> then returned and turned back on.
>>> For the past 18 years its stayed within plus/minus 3 x 10E-11.
>>> The overall linear drift is something like 1.85 x 10E-13 per month.
>>> This is not an advert.  There's no way any of our production units are as
>>> good as this one, well I assume so as I've never measured any for 18 years
>>> continuous!
>>> Its now over 25 years old, have hardly ever been turned off.  Any day I
>>> expect it to fail, but it keeps on running!!
>>> Regards
>>> Martyn
>>> ___
>>> 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.
> 
> -- 
> Dr. Don Latham  AJ7LL
> PO Box 404, Frenchtown, MT, 59834
> VOX: 406-626-4304
> 
> 
> ___
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Re: [time-nuts] Ultra Stable Rb

[djl]

What a tease! OK, very well WHY???
Don

On 2020-04-08 08:04, Bob kb8tq wrote:

Hi

A few of the long running FRK’s ( in a very similar package …
hmmm ….. wonder why …. yes, I was there way back then
and know very well why :) ) have crazy good long term aging.
That said, I don’t think that I’ve seen a FRK quite this good.

Thanks for sharing !!!

Bob


On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:

Hi Guys,

Just though you'd be interested in my prototype rubidium frequency 
standard

I made in the 1990's.

http://www.ptsyst.com/RFS10-FrequencyDrift.pdf

I have measured its frequency at random intervals for the past 18 
years.


Its never been adjusted and is just free running.

It was turned off in 2005 and sent to a customer in Japan for a few 
weeks,

then returned and turned back on.

For the past 18 years its stayed within plus/minus 3 x 10E-11.

The overall linear drift is something like 1.85 x 10E-13 per month.

This is not an advert.  There's no way any of our production units are 
as
good as this one, well I assume so as I've never measured any for 18 
years

continuous!

Its now over 25 years old, have hardly ever been turned off.  Any day 
I

expect it to fail, but it keeps on running!!

Regards

Martyn


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PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304


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Re: [time-nuts] Ultra Stable Rb

[Dana Whitlow]

Martyn, is there anything special about the design to which you
might attribute the low drift?  Even if your unit's siblings are not
"quite as good", they might still be quite a bit better than the usual
run-of-the-mill Rbs.

Thanks,

Dana


On Wed, Apr 8, 2020 at 8:46 AM  wrote:

> Hi Guys,
>
> Just though you'd be interested in my prototype rubidium frequency standard
> I made in the 1990's.
>
> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
>
> I have measured its frequency at random intervals for the past 18 years.
>
> Its never been adjusted and is just free running.
>
> It was turned off in 2005 and sent to a customer in Japan for a few weeks,
> then returned and turned back on.
>
> For the past 18 years its stayed within plus/minus 3 x 10E-11.
>
> The overall linear drift is something like 1.85 x 10E-13 per month.
>
> This is not an advert.  There's no way any of our production units are as
> good as this one, well I assume so as I've never measured any for 18 years
> continuous!
>
> Its now over 25 years old, have hardly ever been turned off.  Any day I
> expect it to fail, but it keeps on running!!
>
> Regards
>
> Martyn
>
>
> ___
> 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] Ultra Stable Rb

[Bob kb8tq]

Hi

A few of the long running FRK’s ( in a very similar package …
hmmm ….. wonder why …. yes, I was there way back then 
and know very well why :) ) have crazy good long term aging. 
That said, I don’t think that I’ve seen a FRK quite this good.

Thanks for sharing !!!

Bob

> On Apr 8, 2020, at 9:45 AM, mar...@ptsyst.com wrote:
> 
> Hi Guys,
> 
> Just though you'd be interested in my prototype rubidium frequency standard
> I made in the 1990's.
> 
> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
> 
> I have measured its frequency at random intervals for the past 18 years.
> 
> Its never been adjusted and is just free running.
> 
> It was turned off in 2005 and sent to a customer in Japan for a few weeks,
> then returned and turned back on.
> 
> For the past 18 years its stayed within plus/minus 3 x 10E-11.
> 
> The overall linear drift is something like 1.85 x 10E-13 per month.
> 
> This is not an advert.  There's no way any of our production units are as
> good as this one, well I assume so as I've never measured any for 18 years
> continuous!
> 
> Its now over 25 years old, have hardly ever been turned off.  Any day I
> expect it to fail, but it keeps on running!!
> 
> Regards
> 
> Martyn
> 
> 
> ___
> 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] Ultra Stable Rb

[Mike Ingle]

respect.

On Wed, Apr 8, 2020 at 3:46 PM  wrote:

> Hi Guys,
>
> Just though you'd be interested in my prototype rubidium frequency standard
> I made in the 1990's.
>
> http://www.ptsyst.com/RFS10-FrequencyDrift.pdf
>
> I have measured its frequency at random intervals for the past 18 years.
>
> Its never been adjusted and is just free running.
>
> It was turned off in 2005 and sent to a customer in Japan for a few weeks,
> then returned and turned back on.
>
> For the past 18 years its stayed within plus/minus 3 x 10E-11.
>
> The overall linear drift is something like 1.85 x 10E-13 per month.
>
> This is not an advert.  There's no way any of our production units are as
> good as this one, well I assume so as I've never measured any for 18 years
> continuous!
>
> Its now over 25 years old, have hardly ever been turned off.  Any day I
> expect it to fail, but it keeps on running!!
>
> Regards
>
> Martyn
>
>
> ___
> 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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[time-nuts] Ultra Stable Rb

[martyn]

Hi Guys,

Just though you'd be interested in my prototype rubidium frequency standard
I made in the 1990's.

http://www.ptsyst.com/RFS10-FrequencyDrift.pdf

I have measured its frequency at random intervals for the past 18 years.

Its never been adjusted and is just free running.

It was turned off in 2005 and sent to a customer in Japan for a few weeks,
then returned and turned back on.

For the past 18 years its stayed within plus/minus 3 x 10E-11.

The overall linear drift is something like 1.85 x 10E-13 per month.

This is not an advert.  There's no way any of our production units are as
good as this one, well I assume so as I've never measured any for 18 years
continuous!

Its now over 25 years old, have hardly ever been turned off.  Any day I
expect it to fail, but it keeps on running!!

Regards

Martyn


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Re: [time-nuts] Phase noise principle and measuring confusion

[Tobias Pluess]

Hi Perrier

I try to explain phase noise in a simple way.
Assume you have a perfect oscillator which outputs a perfectly pure sine
wave. How would that oscillator's signal look like on a perfect spectrum
analyzer? it would be zero everywhere, except at the carrier frequency,
there would be an infinitely sharp "needle" peak.
However, a real oscillator does not behave like this. If you could look at
a real oscillator with a perfect spectrum analyzer, you would see what is
called "noise skirts", i.e. the signal has a peak at the carrier and decays
more or less steeply on both sides of the oscillator frequency, i.e. the
"needle" peak is broadened.
Since we usually don't have access to perfect spectrum analyzers, the
needle peak is always also broadened a bit by the spectrum analyzer's
response itself, so most of the time, we are not able to directly see the
noise skirts of a real oscillator with a real spectrum analyzer because the
analyzer is far too noisy.
So if we can't see the signal why do we want to measure it and why care
about it? answer: if the noisy oscillator is used as local oscillator for a
mixer in a receiver, the noise on both sides of the carrier also goes into
the mixer, and mixes down other frequencies we actually don't want to
receive. So the phase noise degrades the receiver performance. This is only
one example where the phase noise is important, there are many more.

A more exact description of what phase noise is can be given as follows.
The output voltage of any oscillator is:
Vo(t) = A*cos(2*pi*f*t + phi(t))
where
A = amplitude
f = frequency (obviously)
t = time
phi(t) = noise term
So for a noiseless oscillator, phi(t) is a constant. However, for a real
oscillator, phi(t) is fluctuating a bit. There are two contributions (maybe
more, but I know only of the following two):

- short term fluctuations: if phi(t) bumps around at very short intervals,
like 1sec and lower, we call this "short term" variations and it is counted
as phase noise as the short term variations make the oscillator signal look
wider on a spectrum analyzer.
- long term fluctuations: this is when phi(t) varies over long periods of
time, e.g. 10sec or even hours or days, and is called "stability" and
"drift". This is the parameter I am currently trying to measure.

If you look at above equation, the phase term is
phase(t) = 2*pi*f*t + phi(t)
so if you would plot phase(t), a perfect oscillator would yield a perfect
straight line which rises for increasing time. A real oscillator does, in
general, the same, but the slope of the line varies a bit, sometimes it is
a bit steeper and sometimes a bit less steep. Again, the time it takes for
these fluctuations to occur depends whether we call it phase noise or
stability.


I am not sure whether I understood your last question correctly, but I
assume you want to use the 10811 as reference for a 3336 synthesizer and
then use the synthesizer as local oscillator for a mixer?
if that is what you want to do, then it works fine. There are, however, as
always, several things to be considered:
- the 3336A synthesizer will increase the phase noise of the 10811A (the
amount of increase is called residual phase noise). Therefore, the phase
noise of the local oscillator generated in this way is for sure worse than
the original 10811.
- if you want to analyze the stability of an oscillator, the above is
perhaps (hopefully others can correct me on this if I am wrong) not so
much of a problem. If you analyze stability, you need to have a reference
which is more stable than your DUT, so if your DUT is worse than an 10811A,
then this setup can be used. You could not test an 10811A in this way!
- if you want to analyze phase noise, then the residual phase noise of the
3336A may be a problem as it degrades the reference oscillator's (your
10811A) phase noise. The residual phase noise of the synthesizer is the
absolute lower limit, so no matter how good your reference to the 3336A
will be, the phase noise at its output will be at least as high as the
3336A's residual phase noise. If your DUT is, say, at least 10dB or more,
worse than this residual phase noise, you are good to go and you can use
this setup to measure phase noise.
- if your DUT has a phase noise which is lower or in the same order of
magnitude as your 3336A's phase noise, then the 3336A cannot be used, no
matter how good your reference oscillator for it is, and you need to search
for a lower phase noise alternative.

There are the HP 8662A and 8663A signal generators which were exactly
designed for these types of measurement. They have very low residual phase
noise and can be electronically tuned, so you can build a PLL with it.

Does that somewhat answer your questions?


Best
Tobias
HB9FSX



On Wed, Apr 8, 2020 at 1:43 AM Perry Sandeen via time-nuts <
time-nuts@lists.febo.com> wrote:

> Learned Gentleman,
> I've read several articles on phase noise but I'm lost.
> I need a *Ding-Dong* school explanation of what it is, why it's