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

Fri Oct 25 05:24:29 UTC 2019

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

actast at hotmail.com

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

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bob kb8tq <kb8tq at n1k.org>
Sent: Thursday, October 24, 2019 7:06 PM
To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
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 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.

Bob

> On Oct 24, 2019, at 5:14 PM, Tom Knox <actast at hotmail.com> wrote:
>
> Actually, unless it has changed in recent years the 5071A has a DOT shipping exemption.
> Sadly last I checked several years ago the standard tube was over $28K. Years ago there was a gentlemen in Colo Spring actually repairing tube but I believe he passed away a few years ago.
> My guess is the main hurdle repairing these is the precision machining and welding required to cut these in half and weld them back together.
> Cheers;
>
> Tom Knox
>
> 303-554-0307
>
> actast at hotmail.com
>
> "Peace is not the absence of violence, but the presence of Justice" Both MLK and Albert Einstein
>
> ________________________________
> From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Bob kb8tq <kb8tq at n1k.org>
> Sent: Thursday, October 24, 2019 12:23 PM
> To: Taka Kamiya <tkamiya9 at yahoo.com>; Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
> Subject: Re: [time-nuts] HP5071A with bad tube.... can I get one used?
>
> Hi
>
> Based on running a high performance tube version of the 5071A for a number of years, the
> tubes last about 5 to 7 years when run 24/7/365. Once they die, the practical ($$$$$$$)
> alternative is to send the beast back to the factory for a new tube. Indeed given the price
> and the complexity of shipping (it’s a hazmat item), this is only practical if you are a company
> that needs to use the device.
>
> At least on the high performance 5071, the “end of life” process is not an immediate death sort of
> thing. The stability (ADEV) of the device degrades as the tube wears out. If you have a stability
> requirement (not just function) the wear out point will be a bit earlier than the numbers above.
> Just how much earlier depends a bit on how picky you are. ( = if you high performance tube is
> worse than a standard tube, how happy are you?) You also would need the gear to test the ADEV.
>
> Some of what’s in the 5071A is running based on firmware and settings shot in here and there
> on the device. Updating / adjusting / tweaking those settings has not been documented out
> here “in the wild” AFIK. The factory (obviously) does understand how to tweak this or that.
> The degree to which tweaks might be needed with this or that unusual tube is very much
> open to debate.
>
> The whole “can’t get a tube” issue is hardly unique to the 5071A. I have a pair of Cs standards
> in the basement. Both have tube issues. One may be repairable if I ever get around to playing
> with the fix. Once “fixed” will it run for another few months or a few more years? There is no way
> to know without trying it.
>
> Will this or that tube last a month, a year or two or a decade or thee? I know of no external test that will
> guarantee a decade of capacity. There are indeed tests that will suggest that you are limping along.
> Most (but not all) basement Cs standards are in the “limping along” category. As with the 5071,
> just what constitutes limping along, depends a bit on how close to (or how much better than) the
> factory spec you need to be.
>
> Bob
>
>> On Oct 23, 2019, at 11:42 PM, Taka Kamiya via time-nuts <time-nuts at lists.febo.com> wrote:
>>
>> I have an HP5071A with a high performance option that does not work.  All of my tests indicate the faulty component is a tube itself.  Buying a new tube is way out of my budget.  I am now torn between parting it out and see what I can use and keeping it intact with hope something might pop up.
>>
>> Question for the group....  Obtaining a used tube for this, I don't care if its high performance or not, as long as it works with the chassis, is really not a possibility, correct?  I have never seen one on eBay.
>>
>> ---------------------------------------
>> (Mr.) Taka Kamiya
>> KB4EMF / ex JF2DKG
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>
>
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