Re: [time-nuts] HP5071A with bad tube.... can I get one used?

[William H. Fite]

Brooklyn Dodgers here.

It has been caesium since I was an undergrad, at which time there were
dinosaurs grazing in the quad.




On Friday, October 25, 2019, Richard Solomon  wrote:

> When did the spelling of Cesium
> change ? As far back as I can
> remember (High School chemistry,
> easier then, we only had 52
> elements), it was spelled Cesium.
>
> But then, they are still the San
> Diego Chargers to me.
>
> 73, Dick, W1KSZ
>
> On Thu, Oct 24, 2019 at 11:00 PM Tom Knox  wrote:
>
> > The Latin form “caesium” is the internationally recognized legal
> spelling.
> > The common form “cesium” may still be found in older Symmetricom user’s
> > manuals and publications. The caesium inside any of the devices is
> > contained in a UN certified stainless steel cylinder. This cylinder meets
> > all of the
> > requirements for dangerous goods “containers” or “packages” for both
> > international and U.S. domestic shipments. The instructions in this
> document
> > refer to the labeling required on the outside of the carton or box that
> is
> > used to enclose the caesium device.
> > 1. All U.S. domestic (only) shipments must use and comply with all the
> > requirements of the DOT-SP11401 exemption. The document may be
> > downloaded from the DOT web site at
> > http://hazmat.dot.gov/sp_app/special_permits/docs/11000/E11401.pdf. All
> > Symmetricom customers who are
> > reshipping the Symmetricom device do not need to be listed as a grantee
> > and may use Symmetricom’s exemption (see Par. 8a of DOT-SP11401).
> > The prohibited “modifications or changes” to the “package” referenced in
> > Par. 8a refers to the stainless steel caesium beam tube cylinder, and not
> > any
> > other external packaging (see Par. 7a). Follow normal shipping and
> > handling practice and the following instructions.
> > 2. Attach a copy of DOT-SP11401 to the outer box or container. The
> > document may be legibly reduced, folded, placed in a clear plastic pouch
> and
> > attached outside the package (see Par. 10). The title page should be
> > readable through the pouch. Staple a copy of DOT-SP11401 to the shipping
> > invoice so that the copy attached to the package will not be disturbed.
> Do
> > not include this instruction sheet that you are now reading. Do not use
> > the preprinted, bar-coded dangerous goods label offered by the shipper,
> > which, if scanned, would incorrectly route the package to non-passenger
> > aircraft.
> > 3. Mark the outside of the package "DOT-SP11401 CAESIUM UN 1407". A
> > downloadable template is available from
> > http://www.symmttm.com/5071A/Shipping.
> > 4. Limit to five units the maximum number of caesium devices in each
> > shipment (par. 7b).
> > 5. Comply with the training requirement (Par. 11) for “Hazmat employee”
> > under 49CFR 172.704(a)(2) function-specific training (i). Explanation:
> > This requirement is fully met if the person handling the transportation
> of
> > the caesium device has read, understood and followed these
> > instructions and DOT-SP11401.
> > 6. Additional explanation: The following requirements of the IATA-DG
> > regulations are waived by DOT-SP11401., i.e. not required for U.S.
> > domestic only shipments. Paragraph numbers (Par. #) refer to the
> > paragraphs in DOT-SP11401:
> > LABELING “Dangerous When Wet” and “Danger – Do not load in passenger
> > aircraft” are waived (Par. 4).
> > PLACARDING “Dangerous When Wet” on the carrier’s vehicle is waived (Par.
> > 4).
> > AUTHORIZED PACKAGING or UN (United Nations) certified packaging is waived
> > (Par. 4). The stainless steel caesium beam tube cylinder
> > comprises the authorized or prescribed packaging. No other packaging over
> > the apparatus is required for compliance (Par. 4 and 7a).
> > PASSENGER AIRCRAFT is added as an authorized mode of shipment (Par. 9).
> > Note: FedEx recognizes DOT exemptions. Some carriers,
> > such as UPS and DHL may not recognize DOT exemptions. Check first with
> the
> > carrier when using the exemption.
> > International Shipping
> > 1. All overseas and international shipments must comply with the
> > requirements of the UN/IATA dangerous goods regulations. Visit
> > http://www.iata.org/cargo/dg/index.htm.
> > 2. Mark the outside of the package: “Inner packages comply with
> prescribed
> > specifications CAESIUM UN1407 0.009kg”, the UN package
> > certification number, the “Dangerous when wet” and “Do not load in
> > passenger aircraft” stickers. A downloadable template is available from
> the
> > Symmetricom web sites noted above. Any suitable container that is
> > reasonably strong for normal shipping and handling may be used. No other
> UN
> > certified container is required by the regulation. Visit the Symmetricom
> > web sites for more information.
> > 3. Attach a Dangerous Goods Declaration (authorized, red-stripe bordered
> > document) and fill identification as follows: Proper name CAESIUM;
> > Class 4.3; UN No. UN1407; Packing group I; Quantity and type of packing:
> 1
> > 

[time-nuts] FA-2 Data Logger details

[Perry Sandeen via time-nuts]

Yo Bubba Dudes!
Thanks to E W Kehren, he sent me the data logger details from Jureg.
They are attached below.  If it gets screwed up by yahoo mail, I'll make a PDF.

SDData Logger for FA-2

 

https://www.sparkfun.com/products/13712

 SDLogger - Open Hardware Data Logger - Seeed Wiki

Ebay:   Search OpenLog


 Connection:

Gnd    free plug behind the LCD  → OpenLog Blk

+5V free plug behind the LCD   →Switch → OpenLog VCC

Data    FA-2   U13 R59  → OpenLog RX  (thin wirewrap wire through 
unusedhole

    from bottom of boardupwards)  

 

Montage:

Rectangularcut-out at the FA-2 back side  4mm x16mm, 3.2 mm hole over cut-out 
(the exact position depends on the hexagon bolt)

6mm hole for the switch

Thereare no mounting holes on the OpenLog board. I glued a hexagonal bolt (M3 
10mmlong) with Araldit  (2 componentadhesive) onto the processor.

 MicroSD Card

Config.txt

Write   9600,26,3,0    into a txt file with an editor.

Savethis as  Config.txt   on the SD card.  

Inthis log mode a new log file is created on every startup (LOGX.txt).
Forother operating modes see the descriptions at Sparkfun or Seeedstudio.
Regards,
Perrier

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] GPSDO+PC as a NTP server

[Bob kb8tq]

Hi

There are a number of GPS errors that turn into “long period” disturbances. A 
normal 
OCXO (even a good one) runs with a fast enough loop that they do appear in the 
output
of the GPSDO. One (of many) sources of this sort of error is the 12/24 hour 
cyclical nature
of GPS orbits. Another is the 24 hour cycle the ionosphere goes through ….. 

Bob

> On Oct 25, 2019, at 2:09 AM, Adam Kumiszcza  wrote:
> 
> Hi!
> 
> Thanks for all the responses. As I wrote, the chip can use only 1
> constellation, and I'm not sure it can use Galileo at all, so I'm sticking
> to GPS only. As I understand it, GPS errors here smooth out anyway while
> disciplining internal OCXO, so it's not so important to have the best chip
> available. I guess u-blox zed-f9t with a bad ocxo would be worse than
> normal u-blox 7 with a better ocxo? I intend to run it 24h/day BTW.
> 
> As for FreeBSD, I like this system a lot, too. Especially for proper native
> ZFS support. I use it mainly for NAS now, but experimented with different
> versions before, so I guess I'll go this route. Does Lady Heather compile
> on FreeBSD? And is it possible to run it together with NTP for the same
> rs232 port? I found this:
> https://www.febo.com/pipermail/time-nuts/2010-February/044476.html  – but
> it's for thunderbolt and at "very early, rough stage". I would like to
> attach a small monitor and have LH run there constantly.
> 
> BTW, Fiorenzo Cattaneo, I did not get the picture of your set with
> pcengines box. Probably got cut by mailing list.
> 
> Best regards,
> Adam Kumiszcza
> 
> On Fri, Oct 25, 2019 at 2:01 AM Charles Steinmetz 
> wrote:
> 
>> Bob wrote:
>> 
>>> The “ideal” solution (at least to me) would be a setup that let you
>> estimate the time based
>>> on each system independently. Even things like survey locations vary a
>> bit system to system.
>>> Give each one the “fix” that it thinks is best and go from there. Then
>> report the output PPS time
>>> offset for each of them. Let “higher authority” decide what to make of
>> the results.
>> 
>> Well, heck, if you can count on divine guidance, what do you need the
>> GPSDOs for?   ;-)
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
>> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

[Richard Solomon]

When did the spelling of Cesium
change ? As far back as I can
remember (High School chemistry,
easier then, we only had 52
elements), it was spelled Cesium.

But then, they are still the San
Diego Chargers to me.

73, Dick, W1KSZ

On Thu, Oct 24, 2019 at 11:00 PM Tom Knox  wrote:

> The Latin form “caesium” is the internationally recognized legal spelling.
> The common form “cesium” may still be found in older Symmetricom user’s
> manuals and publications. The caesium inside any of the devices is
> contained in a UN certified stainless steel cylinder. This cylinder meets
> all of the
> requirements for dangerous goods “containers” or “packages” for both
> international and U.S. domestic shipments. The instructions in this document
> refer to the labeling required on the outside of the carton or box that is
> used to enclose the caesium device.
> 1. All U.S. domestic (only) shipments must use and comply with all the
> requirements of the DOT-SP11401 exemption. The document may be
> downloaded from the DOT web site at
> http://hazmat.dot.gov/sp_app/special_permits/docs/11000/E11401.pdf. All
> Symmetricom customers who are
> reshipping the Symmetricom device do not need to be listed as a grantee
> and may use Symmetricom’s exemption (see Par. 8a of DOT-SP11401).
> The prohibited “modifications or changes” to the “package” referenced in
> Par. 8a refers to the stainless steel caesium beam tube cylinder, and not
> any
> other external packaging (see Par. 7a). Follow normal shipping and
> handling practice and the following instructions.
> 2. Attach a copy of DOT-SP11401 to the outer box or container. The
> document may be legibly reduced, folded, placed in a clear plastic pouch and
> attached outside the package (see Par. 10). The title page should be
> readable through the pouch. Staple a copy of DOT-SP11401 to the shipping
> invoice so that the copy attached to the package will not be disturbed. Do
> not include this instruction sheet that you are now reading. Do not use
> the preprinted, bar-coded dangerous goods label offered by the shipper,
> which, if scanned, would incorrectly route the package to non-passenger
> aircraft.
> 3. Mark the outside of the package "DOT-SP11401 CAESIUM UN 1407". A
> downloadable template is available from
> http://www.symmttm.com/5071A/Shipping.
> 4. Limit to five units the maximum number of caesium devices in each
> shipment (par. 7b).
> 5. Comply with the training requirement (Par. 11) for “Hazmat employee”
> under 49CFR 172.704(a)(2) function-specific training (i). Explanation:
> This requirement is fully met if the person handling the transportation of
> the caesium device has read, understood and followed these
> instructions and DOT-SP11401.
> 6. Additional explanation: The following requirements of the IATA-DG
> regulations are waived by DOT-SP11401., i.e. not required for U.S.
> domestic only shipments. Paragraph numbers (Par. #) refer to the
> paragraphs in DOT-SP11401:
> LABELING “Dangerous When Wet” and “Danger – Do not load in passenger
> aircraft” are waived (Par. 4).
> PLACARDING “Dangerous When Wet” on the carrier’s vehicle is waived (Par.
> 4).
> AUTHORIZED PACKAGING or UN (United Nations) certified packaging is waived
> (Par. 4). The stainless steel caesium beam tube cylinder
> comprises the authorized or prescribed packaging. No other packaging over
> the apparatus is required for compliance (Par. 4 and 7a).
> PASSENGER AIRCRAFT is added as an authorized mode of shipment (Par. 9).
> Note: FedEx recognizes DOT exemptions. Some carriers,
> such as UPS and DHL may not recognize DOT exemptions. Check first with the
> carrier when using the exemption.
> International Shipping
> 1. All overseas and international shipments must comply with the
> requirements of the UN/IATA dangerous goods regulations. Visit
> http://www.iata.org/cargo/dg/index.htm.
> 2. Mark the outside of the package: “Inner packages comply with prescribed
> specifications CAESIUM UN1407 0.009kg”, the UN package
> certification number, the “Dangerous when wet” and “Do not load in
> passenger aircraft” stickers. A downloadable template is available from the
> Symmetricom web sites noted above. Any suitable container that is
> reasonably strong for normal shipping and handling may be used. No other UN
> certified container is required by the regulation. Visit the Symmetricom
> web sites for more information.
> 3. Attach a Dangerous Goods Declaration (authorized, red-stripe bordered
> document) and fill identification as follows: Proper name CAESIUM;
> Class 4.3; UN No. UN1407; Packing group I; Quantity and type of packing: 1
> Steel Container, 1A1 0.009 kg Overpack Used; Packing inst. 412.
> Cross out the words: “Passenger Aircraft” and “Radioactive”. Fill all
> relevant fields such as Shipper and Consignee appropriately.
>
>
> Tom Knox
>
> 303-554-0307
>
> act...@hotmail.com
>
> "Peace is not the absence of violence, but the presence of Justice" Both
> MLK and Albert Einstein
>
> 

Re: [time-nuts] The TAI zero epoch of 1958

[Scott Stuart]

Thanks for the help everyone!

Steve's explanation makes sense that until 1972 LORAN was attempting to
match UT2.  So when LORAN switched to SI seconds in 1972 the offset between
LORAN and TAI matched (approximately) the offset between UTC and TAI.

Scott

On Thu, Oct 24, 2019 at 11:00 PM Steve Allen  wrote:

> On Thu 2019-10-24T15:37:38-0400 Scott Stuart hath writ:
> > The context is that someone is going to be communicating timestamps to me
> > in TAI formatted as the number of elapsed seconds since 1958 Jan 1
> > 00:00:00.  To make sure that I understand how this is being calculated, I
> > reviewed the history of the establishment of TAI and UTC in the late 60s
> > and early 70s.  I understand why 1972 Jan 1 00:00:00 UTC == 1972 Jan 1
> > 00:00:10 TAI and why TAI is now 37 seconds ahead of UTC.  I can also see
> > that propagating backwards from the 1961 time conversion formulas to 1958
> > Jan 1 gives TAI - UTC very close to 0 (within about 2 milliseconds).  So,
> > it makes sense to use 1958 Jan 1 00:00:00 UTC == 1958 Jan 1 00:00:00 TAI
> as
> > the 0 epoch for TAI in seconds.
>
> On 1958-01-01 the USNO time scale systematically differed from the
> international average by 0.035 seconds because USNO had adopted a
> value of its longitude which turned out not to be globally consistent.
> Other sources of time had similarly large offsets plus random errors.
> https://www.ucolick.org/~sla/leapsecs/BHsHn05p142.html
> Try not to demand exactness for time scale before 1972-01-01.
>
> Nothing that might be called UTC existed before 1959-08 when H.M.
> Smith hosted folks involved with the USNO and UK time broadcasts for
> tea in his living room.  That was when the US and UK informally agreed
> to use cesium chronometers to coordinate their time broadcasts by
> choosing a frequency offset from cesium such that the broadcast
> seconds would attempt to match UT2 seconds.  The formal agreement to
> do that coordination, and the actual coordination, did not occur until
> 1960.  So there was no UTC before 1960, and that name was not used in
> print until 1965.
>
> In 1960-09 the URSI General Assembly recommended that everyone should
> use this scheme and that BIH should choose the frequency offset.  BIH
> provided a value for frequency offset starting with 1961, and in
> 1961-08 at the IAU General Assembly BIH was officially tasked with
> providing the frequency offsets for radio broadcast time signals.
>
> TAI did not exist in 1958.  In 1958 several labs were using cesium to
> construct unpublished time scales.  During 1961 BIH took on the task
> of combining all the available atomic time scales.  By 1964 the BIH
> realized that some atomic chronometers were better than others, and
> using the three best they created A3.  The epoch at which A3
> was set 1961-01-01T20:00:00 UT2.
> https://www.ucolick.org/~sla/leapsecs/taiepoch.html
> The calculation of A3 evolved and on 1971-10-04 the 14th CGPM
> authorized the CIPM to define TAI and work with the BIH to realize the
> definition.
>
> For practical purposes the LORAN broadcasts in the 1960s used the time
> scale as the broadcast time signals, so LORAN was using frequency
> offsets to match UT2 with seconds longer than what became the SI
> second.  Therefore by 1972-01-01 the LORAN time scale was 10 seconds
> behind what had then become TAI.
>
> These gory details are not neatly summarized because of the
> contentious climate during those decades.  The 4th meeting of the CCDS
> first happened during 1966, but the results of that meeting were
> voided.  The second 4th meeting of CCDS happened in 1967-07, and its
> proceedings do not include detailed minutes of the discussions.  The
> proceedings of the 6th meeting of CCDS best reveal why the summaries
> are not complete.  In annex S15 of CCDS6
> https://www.bipm.org/utils/common/pdf/CC/CCTF/CCDS6.pdf
> G.  Winkler of USNO wrote "we should limit discussion of this question
> to people aware of the implied problems".  Only by scouring
> contemporary publications for quotes from many folks who were present
> does it begin to become clear how much that attitude prevented clear
> description of the history.
>
> --
> Steve Allen  WGS-84 (GPS)
> UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat
> +36.99855
> 1156 High Street   Voice: +1 831 459 3046 Lng
> -122.06015
> Santa Cruz, CA 95064   https://www.ucolick.org/~sla/  Hgt +250 m
>
> ___
> 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.
>


-- 
"Of what avail are forty freedoms without a blank spot on the map? "
— Aldo Leopold
___
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 

Re: [time-nuts] The TAI zero epoch of 1958

[Steve Allen]

On Fri 2019-10-25T05:12:54-0700 jimlux hath writ:
> So why was 1958-01-01 chosen as an epoch time for TAI (or is it, really,
> maybe TAI defines the time scale, and you use -mm-dd hh:mm:ss.s.
> and it's only some other standard that defines what "zero" means when you
> want to represent it as a single "number"
>
> for example CCSDS 301.0-B-4 "Time Codes"  says:
> "The CCSDS-Recommended epoch is that of 1958 January 1 (TAI) and the
> recommended time unit is the second, using TAI as reference time scale, for
> use as a level 1 time code. This time code is not UTC-based and leap-second
> corrections do not apply. "
>
> https://public.ccsds.org/Pubs/301x0b4e1.pdf

In the full context the exact wording of the 1971 CGPM approval to
create TAI, and other recorded decisions, is important.
https://www.bipm.org/en/CGPM/db/14/1/
and also resolution 2 gloss over recorded discussions that BIH was the
place that could best implement TAI, but that BIH by itself did not
have appropriate international standing to administer TAI, in part
because despite its name 80% to 90% of BIH funding was slush money
from the director of Observatoire de Paris, thus really France.

Among various contributions to the meetings in the late 1960s are some
that express serious concerns that the time scale which became TAI did
not have a rigorous definition.  I have found no recorded response to
these suggestions, just silence.  Everyone in the time services knew
that BIH had re-set all their atomic time scales in 1964 using the
epoch 1961.  They knew the basis of UT2 was shifted as of 1962
https://www.ucolick.org/~sla/leapsecs/seasonal.html
because of the new defintion of UT2 and the change from FK3 to FK4.
They knew that the origin of A3, and thus TAI, was offset from the
current notion of what the value of time should have been.

My impression is that the lack of recorded responses is partly due to
not having any way to fund BIH in an "appropriate" fashion, not having
any way to create a replacement for BIH which had appropriate
foundations, and not wanting to create yet another atomic time scale
effectively the same as TAI but, by basis of a new, rigorous
definition, offset from what everyone had been using in their
communications and publications to that point.

I think also that nobody wanted to clearly document the changes that
happened at 1961 and 1962 because doing that would have emphasized
that the value of atomic time scales is entirely arbitrary, not
connected with any event that is observable, and not connected with
calendar days of earth rotation which were and are the legal and
commonly understood basis of civil time.  So my impression was that
they allowed the origin of TAI to be said to be about 1958 as part of
trying to avoid talking about how exactly that came about.

The switch from old-1960s-rubber-second UTC to new-1972-leap-second
UTC was in part motivated by interpretations of a new law in Germany
that old UTC was no longer legal to brodcast.  So I think the lack of
clear documentation was trying to avoid letting any more national
bureaucrats who controlled the funding of other national time labs
raise questions about whether this new no-longer-related-to-days time
scale could be the basis of legal time in their country.

Looking carefully at what the practitioners of time did shows that the
USNO decided not to use new-UTC in its navigational broadcasts.  In
the USNO time service publications Winkler announced that the USNO
navigational broadcasts would become an offset from TAI (and that is
eventually what GPS, Galileo, and all the other satnav systems also
chose).  Therein lies the basis of the LORAN offset question that
prompted this thread.

Similarly the astronomers did not use UTC in tabulations of any
almanac.  They continued to use just plain UT for things on earth, and
ET (now relativisticly TT, or TCB, or TDB) for things not on earth.

The principal printed appearance of new-UTC was in decrees from
bureaucrats who were protected from seeing that the pracitioners of
time did not agree that new-UTC was the best thing to use for
technical purposes.

--
Steve Allen  WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street   Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064   https://www.ucolick.org/~sla/  Hgt +250 m

___
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] Rubidium cell or lamp rejuvenation. WAS-HP 5065A owners, a question!

[cdelect]

There are two separate Rubidium migration problems.

The first is Lamp flooding which occurs when too much Rubidium enters the
main bulb and plates onto the bulb envelope. (usually after long storage
or storage at high temperatures) This mainly in the small telecomm
Rubidiums due to design flaws. The 5065A is immune to this problem and I
believe the PRS10 is also.

The second is cell flooding where too much Rubidium enters the resonance
cell and blocks the light.
This is mainly a 5065A problem although older Varian V4700 and R20 units
also can be effected.
The procedure in the manual cools the tip of the stem and collects the
Rubidium back where it belongs!
This takes about a week and then after reconfiguring the TED back to
normal cooling levels another week to stabilize the Rubidium level in the
cell. Telecomm units have "starved" cells and don't exhibit this effect.

Cheers,

Corby


___
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] Cold Rubidium?

[AC0XU (Jim)]

Does anyone have any experience/first hand knowledge of this Cold Rubidium 
standard?

https://spectradynamics.com/products/crb-clock/

The specs look very good. The mfr claims that, unlike traditional rubidium 
oscillators, it has no long-term drift.
Thanks!
Jim
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

[Poul-Henning Kamp]

> Well, I started shipping them back to the factory in the 1990’s and
> did so a number of times since then. If there was an exemption, the
> factory was not aware of it. They were the driver for being sure
> it was shipped as hazmat. Each time (knowing what the issues would
> be), I offered to drive the unit up there and drop it off. That
> never seemed to be an acceptable process.

In general HazMat exemptions happen where "circumstances" are such
that they reduce the risk of harm.

In this particular case, those "circumstances" would likely be
"tested, certified & packed at the factory in specific emballage
approved as part of the exemption."

Ie: HP had an exemption to ship to customers, but not the other way.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] GPSDO+PC as a NTP server

[Adam Kumiszcza]

Hi!

Thanks for all the responses. As I wrote, the chip can use only 1
constellation, and I'm not sure it can use Galileo at all, so I'm sticking
to GPS only. As I understand it, GPS errors here smooth out anyway while
disciplining internal OCXO, so it's not so important to have the best chip
available. I guess u-blox zed-f9t with a bad ocxo would be worse than
normal u-blox 7 with a better ocxo? I intend to run it 24h/day BTW.

As for FreeBSD, I like this system a lot, too. Especially for proper native
ZFS support. I use it mainly for NAS now, but experimented with different
versions before, so I guess I'll go this route. Does Lady Heather compile
on FreeBSD? And is it possible to run it together with NTP for the same
rs232 port? I found this:
https://www.febo.com/pipermail/time-nuts/2010-February/044476.html  – but
it's for thunderbolt and at "very early, rough stage". I would like to
attach a small monitor and have LH run there constantly.

BTW, Fiorenzo Cattaneo, I did not get the picture of your set with
pcengines box. Probably got cut by mailing list.

Best regards,
Adam Kumiszcza

On Fri, Oct 25, 2019 at 2:01 AM Charles Steinmetz 
wrote:

> Bob wrote:
>
> > The “ideal” solution (at least to me) would be a setup that let you
> estimate the time based
> > on each system independently. Even things like survey locations vary a
> bit system to system.
> > Give each one the “fix” that it thinks is best and go from there. Then
> report the output PPS time
> > offset for each of them. Let “higher authority” decide what to make of
> the results.
>
> Well, heck, if you can count on divine guidance, what do you need the
> GPSDOs for?   ;-)
>
> Best regards,
>
> Charles
>
>
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] The TAI zero epoch of 1958

[jimlux]

On 10/24/19 3:32 PM, Steve Allen wrote:

On Thu 2019-10-24T15:37:38-0400 Scott Stuart hath writ:

The context is that someone is going to be communicating timestamps to me
in TAI formatted as the number of elapsed seconds since 1958 Jan 1
00:00:00.  To make sure that I understand how this is being calculated, I
reviewed the history of the establishment of TAI and UTC in the late 60s
and early 70s.  I understand why 1972 Jan 1 00:00:00 UTC == 1972 Jan 1
00:00:10 TAI and why TAI is now 37 seconds ahead of UTC.  I can also see
that propagating backwards from the 1961 time conversion formulas to 1958
Jan 1 gives TAI - UTC very close to 0 (within about 2 milliseconds).  So,
it makes sense to use 1958 Jan 1 00:00:00 UTC == 1958 Jan 1 00:00:00 TAI as
the 0 epoch for TAI in seconds.



This stuff is fascinating..




On 1958-01-01 the USNO time scale systematically differed from the
international average by 0.035 seconds because USNO had adopted a
value of its longitude which turned out not to be globally consistent.
Other sources of time had similarly large offsets plus random errors.
https://www.ucolick.org/~sla/leapsecs/BHsHn05p142.html
Try not to demand exactness for time scale before 1972-01-01.

Nothing that might be called UTC existed before 1959-08 when H.M.
Smith hosted folks involved with the USNO and UK time broadcasts for
tea in his living room.  That was when the US and UK informally agreed
to use cesium chronometers to coordinate their time broadcasts by
choosing a frequency offset from cesium such that the broadcast
seconds would attempt to match UT2 seconds.  The formal agreement to
do that coordination, and the actual coordination, did not occur until
1960.  So there was no UTC before 1960, and that name was not used in
print until 1965.

In 1960-09 the URSI General Assembly recommended that everyone should
use this scheme and that BIH should choose the frequency offset.  BIH
provided a value for frequency offset starting with 1961, and in
1961-08 at the IAU General Assembly BIH was officially tasked with
providing the frequency offsets for radio broadcast time signals.

TAI did not exist in 1958.  In 1958 several labs were using cesium to
construct unpublished time scales.  During 1961 BIH took on the task
of combining all the available atomic time scales.  By 1964 the BIH
realized that some atomic chronometers were better than others, and
using the three best they created A3.  The epoch at which A3
was set 1961-01-01T20:00:00 UT2.
https://www.ucolick.org/~sla/leapsecs/taiepoch.html
The calculation of A3 evolved and on 1971-10-04 the 14th CGPM
authorized the CIPM to define TAI and work with the BIH to realize the
definition.


So why was 1958-01-01 chosen as an epoch time for TAI (or is it, really, 
maybe TAI defines the time scale, and you use -mm-dd 
hh:mm:ss.s.   and it's only some other standard that defines 
what "zero" means when you want to represent it as a single "number"


for example CCSDS 301.0-B-4 "Time Codes"  says:
"The CCSDS-Recommended epoch is that of 1958 January 1 (TAI) and the 
recommended time unit is the second, using TAI as reference time scale, 
for use as a level 1 time code. This time code is not UTC-based and 
leap-second corrections do not apply. "


https://public.ccsds.org/Pubs/301x0b4e1.pdf






For practical purposes the LORAN broadcasts in the 1960s used the time
scale as the broadcast time signals, so LORAN was using frequency
offsets to match UT2 with seconds longer than what became the SI
second.  Therefore by 1972-01-01 the LORAN time scale was 10 seconds
behind what had then become TAI.

These gory details are not neatly summarized because of the
contentious climate during those decades.  


It hasn't changed - well maybe for time, but for other standards

 Only by scouring

contemporary publications for quotes from many folks who were present
does it begin to become clear how much that attitude prevented clear
description of the history.



Well, I've always maintained that standards start as someone talking to 
someone else in the hall, or over drinks, tea, and then someone starts 
drawing on a tablecloth, napkin, or board.  And there's a lot of body 
language (if not spoken words) that go into some of the design 
discussions.  This is my contention as to why video conferencing (or 
worse, telecons and ppt) can not replace in person conferences.




___
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] WWVB converter

[D. Resor]

Here is what seems to be a circuit design to allow WWVB clock receivers work
with the current signal format.

2012 WWVB Receiver Modification
Modification makes homebrew receiver insensitive to WWVB's new
biphase-shifted time code.

http://www.maxmcarter.com/rubidium/2012_mod/ 

Donald Resor
N6KAW






___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] HP5071A with bad tube.... can I get one used?

[Tom Knox]

The Latin form “caesium” is the internationally recognized legal spelling. The 
common form “cesium” may still be found in older Symmetricom user’s
manuals and publications. The caesium inside any of the devices is contained in 
a UN certified stainless steel cylinder. This cylinder meets all of the
requirements for dangerous goods “containers” or “packages” for both 
international and U.S. domestic shipments. The instructions in this document
refer to the labeling required on the outside of the carton or box that is used 
to enclose the caesium device.
1. All U.S. domestic (only) shipments must use and comply with all the 
requirements of the DOT-SP11401 exemption. The document may be
downloaded from the DOT web site at 
http://hazmat.dot.gov/sp_app/special_permits/docs/11000/E11401.pdf. All 
Symmetricom customers who are
reshipping the Symmetricom device do not need to be listed as a grantee and may 
use Symmetricom’s exemption (see Par. 8a of DOT-SP11401).
The prohibited “modifications or changes” to the “package” referenced in Par. 
8a refers to the stainless steel caesium beam tube cylinder, and not any
other external packaging (see Par. 7a). Follow normal shipping and handling 
practice and the following instructions.
2. Attach a copy of DOT-SP11401 to the outer box or container. The document may 
be legibly reduced, folded, placed in a clear plastic pouch and
attached outside the package (see Par. 10). The title page should be readable 
through the pouch. Staple a copy of DOT-SP11401 to the shipping
invoice so that the copy attached to the package will not be disturbed. Do not 
include this instruction sheet that you are now reading. Do not use
the preprinted, bar-coded dangerous goods label offered by the shipper, which, 
if scanned, would incorrectly route the package to non-passenger
aircraft.
3. Mark the outside of the package "DOT-SP11401 CAESIUM UN 1407". A 
downloadable template is available from
http://www.symmttm.com/5071A/Shipping.
4. Limit to five units the maximum number of caesium devices in each shipment 
(par. 7b).
5. Comply with the training requirement (Par. 11) for “Hazmat employee” under 
49CFR 172.704(a)(2) function-specific training (i). Explanation:
This requirement is fully met if the person handling the transportation of the 
caesium device has read, understood and followed these
instructions and DOT-SP11401.
6. Additional explanation: The following requirements of the IATA-DG 
regulations are waived by DOT-SP11401., i.e. not required for U.S.
domestic only shipments. Paragraph numbers (Par. #) refer to the paragraphs in 
DOT-SP11401:
LABELING “Dangerous When Wet” and “Danger – Do not load in passenger aircraft” 
are waived (Par. 4).
PLACARDING “Dangerous When Wet” on the carrier’s vehicle is waived (Par. 4).
AUTHORIZED PACKAGING or UN (United Nations) certified packaging is waived (Par. 
4). The stainless steel caesium beam tube cylinder
comprises the authorized or prescribed packaging. No other packaging over the 
apparatus is required for compliance (Par. 4 and 7a).
PASSENGER AIRCRAFT is added as an authorized mode of shipment (Par. 9). Note: 
FedEx recognizes DOT exemptions. Some carriers,
such as UPS and DHL may not recognize DOT exemptions. Check first with the 
carrier when using the exemption.
International Shipping
1. All overseas and international shipments must comply with the requirements 
of the UN/IATA dangerous goods regulations. Visit
http://www.iata.org/cargo/dg/index.htm.
2. Mark the outside of the package: “Inner packages comply with prescribed 
specifications CAESIUM UN1407 0.009kg”, the UN package
certification number, the “Dangerous when wet” and “Do not load in passenger 
aircraft” stickers. A downloadable template is available from the
Symmetricom web sites noted above. Any suitable container that is reasonably 
strong for normal shipping and handling may be used. No other UN
certified container is required by the regulation. Visit the Symmetricom web 
sites for more information.
3. Attach a Dangerous Goods Declaration (authorized, red-stripe bordered 
document) and fill identification as follows: Proper name CAESIUM;
Class 4.3; UN No. UN1407; Packing group I; Quantity and type of packing: 1 
Steel Container, 1A1 0.009 kg Overpack Used; Packing inst. 412.
Cross out the words: “Passenger Aircraft” and “Radioactive”. Fill all relevant 
fields such as Shipper and Consignee appropriately.


Tom Knox

303-554-0307

act...@hotmail.com

"Peace is not the absence of violence, but the presence of Justice" Both MLK 
and Albert Einstein


From: time-nuts  on behalf of Bob kb8tq 

Sent: Thursday, October 24, 2019 7:06 PM
To: Discussion of precise time and frequency measurement 

Subject: Re: [time-nuts] HP5071A with bad tube can I get one used?

Hi

Well, I started shipping them back to the factory in the 1990’s and did so a 
number
of times since then. If there was an exemption, the factory was not aware of 
it. They
were the 

Re: [time-nuts] The TAI zero epoch of 1958

[Steve Allen]

On Thu 2019-10-24T16:51:53-0700 jimlux hath writ:
> I suspect that 1 Jan 1958 was chosen because it was in the middle of the
> International Geophysical Year (IGY) - perhaps the promulgators of TAI did
> it as part of IGY?

No, not really.  The original UK atomic time scale "Greenwich Atomic"
(GA) started its counting from a date mid 1955.  The original USNO
time scale A.1 put its match with UT2 at 1958-01-01T00:00 UT2(USNO)
which was 0.035 s different from the international value of UT2.
Other labs started their time scales from various different dates, and
some labs counted their scales using seconds which were of a different
duration than what became the SI second.

All of the scales were constructed by hand, hand integrations
(quadratic?  trapezoidal?  who knows, but Runge-Kutta is unlikely) of
the frequency offsets which had been measured by eye off of
oscillographs, and hand typing the tabulations.  BIH obtained all the
tabulations they could, and by hand they compensated for the time
offsets and the frequency offsets, and by hand they re-interpolated
them to points at 20h UT2 in order to combine them, and by hand they
tabulated the results, and by hand the printers transcribed them to be
published in Bulletin Horaire, and by hand they plotted them.  BIH
chose to set their original alignment with UT2 at 1958-01-01T20:00
UT2(BIH).  And in 1964 by hand BIH decided to re-align and re-set all
their atomic time scales as of 1961 and create the A3 that eventually
became TAI, and preserving only approximately a value equal to UT2 on
1958-01-01.  And in 1966 BIH re-interpolated all their atomic time
scale points from 20h UT to 0h UT.

I have transcribed many of these tabulations into digital form,
plotted them, and I can all the "by hand" because it is painfully
evident where there were typos and where some integration went awry
for several points before returning to match again.  Not possible to
see, of course, are cases where the numbers went awry and stayed
that way.

--
Steve Allen  WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street   Voice: +1 831 459 3046 Lng -122.06015
Santa Cruz, CA 95064   https://www.ucolick.org/~sla/  Hgt +250 m

___
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.