Efratom SLCR-101 Rubidium Frequency Reference disassembly

Background

Quite a few years ago now I joined the “time-nutsmailing list – a “Time Nut” as the gentle reader may be aware is an individual who tinkers with precision time keeping and/or precision frequency references, measurements and the like for hobby interest.  It’s a great list, always an interesting discussion and very high SNR indeed – fun place to virtually hang out.

Through this I became interested in playing around with some precision references at home and this in turn lead to me picking up a couple of Rubidium frequency standards off eBay from a local seller – one known working, the other known faulty.  These devices are usually ex-mobile phone base station installations where they’re commonly used to provide a precision 10MHz reference signal to drive the timing circuitry of the base station itself.  They’re usually a secondary source, the primary being a GPS Disciplined Oscillator (GPSDO) – the Rb standard is a hot spare in case the GPSDO goes out of lock for too long.

The Efratom SLCR-101

The SLCR-101 is made by US firm Efratom (now part of Symmetricom by way of Datum best I can tell) and is designed for OEM applications – so it’s basically a bare module that you feed power into and it gives you a nice clean stable 10MHz sinewave output as well as some status signals.  I’ve been unable to find any specific data on the SLCR-101 but it seems very similar indeed to the LPRO or LPRO-101 units – just lower profile – about 25mm/1″ high versus the LPROs 38mm/1.5″ height.

A bit of searching turns up a PDF of the LPRO-101 “User’s Guide and Integration Guidelines”.  Another document to seek out is Fred de Vries “Efratom LPRO-101 Repair Reference Guide”  The most recent revision of this excellent reference seems to be Revision 7, January 2011 – Fred kindly sent me an email with the latest version of his guide which, with his permission, I’ve placed here.  I am trying to find a definitive upstream source for the offical LPRO document, for now a little googleFu will get you there.

One immediate take home from these documents is that these units must not be operated for extended periods (say more than a half hour) without a proper heatsink (less than 2C/W thermal resistance to ambient) – the Rubidium lamp inside runs at around 100C so good heatsinking is required to ensure the rest of the electronics is kept within its safe operating temperature.

Disassembly

Removing the cover wasn’t difficult – I’ve a bunch of photos shared here but in particular this one shows a unit mounted on a heatsink and this one how once the connector assembly is removed (undo screws, break the slight sealing and pull straight out) With the connector removed, the cover can simply be eased up with a flat blade working around the perimeter of the casing.  Note that the unit will not operate properly without the Rubidium lamp assembly being shielded from AC lighting.  Perhaps also worth noting that you don’t need to disassemble the unit unless it’s faulty or you’re curious :)

Internals

The internals are well covered in Fred de Vries document, but by way of a quick “cooks tour”, referring to this photo; The rubidium lamp assembly is the machined section top left – lamp in the brass coloured section, photodiode etc. in the right hand side.  Slots in the PCB are to accommodate a shielded section that fits over the lamp as visible in this picture.  The cylindrical port in the top left of the shield photo is used to gain access to the frequency trimpot on the control PCB (blue, bottom right in this shot).

Close

Will have more to write on my tinkering with these units in subsequent posts – for now hopefully the little note about how to remove the connector will save someone some time :)

Edited 20170423 to include link to the repair guide kindly provided by Fred de Vries.

Comments

Lwood-20170312

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 6 to 12 March for openstack-dev:

~447 Messages (down nearly 22% relative to the long term average)

~135 Unique threads (down just shy of 25% relative to the long term average)

Traffic about the same as last week, if anything up slightly.  A busy few days conspired against me so Lwood is a bit short and a bit late this week, apologies to those who I know set their clocks by it’s arrival… ;)

Notable Discussions – openstack-dev

OpenStack Summit Boston Schedule Available

Erin Disney writes that the schedule is now up for the Boston Summit later this year.

Call for Mentors at upcoming Summit

Emily Hugenbruch notes that the upcoming Boston summit will again provide an opportunity for Mentors to assist newcomers to OpenStack in getting up to speed.  If you’re interested, please follow the info in Emily’s email and sign up.

OpenStack PTG Atlanta summary of summaries

As mentioned in the previous couple of Lwoods, with the Atlanta event concluded summaries of the event, mostly from a projects standpoint are rolling in. There were a few more this week past, listed below, and the original blog post has been updated too.

End of Week Wrap-ups, Summaries and Updates

Two this week; Ironic (Ruby Loo) and Nova (Balazs Gibizer)

People and Projects

Core nominations & changes

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

No tunes this week, was again working remotely and needed all the concentration I could muster despite the relative simplicity of the task at hand! :)

Comments

OpenStack PTG Atlanta 2017 Summary of Summaries

Background

The last couple of editions of Lwood included a list of links to mailing list posts from the preceding week where the writers have provided a summary of particular PTG sessions and/or commentary about the overall event.

Like the previous ones for Austin and Barcelona, the list below is aggregate of these weekly posts into one readily searchable list.

Summaries posted to the OpenStack-Dev mailing list

This list will be updated each week with any new summaries that are posted to the list.  Additions/corrections welcome.

Updates: 20170314 – Added Acceleration, Heat, Ironic, Mistral, Neutron and Octavia links; 20170313 – Corrected TripleO link;

Comments

Lwood-20170305

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 27 February to 5 March for openstack-dev:

~424 Messages (down nearly 26% relative to the long term average)

~154 Unique threads (down a bit over 14% relative to the long term average)

Traffic picked up a bit relative to last week though once again a fairly brief Lwood – the main thing of note to many will I suspect be the summary of summaries from the PTG

Notable Discussions – openstack-dev

OpenStack Summit returns to Vancouver in 2018

Allison Price announced that the Summit is returning to the fair city of Vancouver in May 2018.

OpenStack PTG Atlanta summary of summaries

With Atlanta PTG concluded the summaries are starting to come in – as I’ve done previously I’ll link them over the next few Lwoods then put together an aggregated list

OpenStack Community Leadership Training open to all

The opportunity to take the well regarded leadership training program that had previously been made available to the TC, Board and Foundation staff is now being extended to all Community members writes Colette Alexander.

End of Week Wrap-ups, Summaries and Updates

Three this week; Horizon (Rob Cresswell), Ironic (Ruby Loo) and Zuul (Robyn Bergernon)

People and Projects

Core nominations & changes

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

No tunes this week, was working remotely and wasn’t an appropriate setting for tunes (aka I forgot headphones :)

Comments

Lwood-20170226

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 20 to 26 February for openstack-dev:

~346 Messages (down nearly 40% relative to the long term average)

~146 Unique threads (down a bit over 18% relative to the long term average)

Historically traffic drops around the time of a Summit, not unexpectedly it seems it’s same around the PTGs.  A correspondingly brief Lwood too :)

Notable Discussions – openstack-dev

OpenStack PTG Atlanta summary of summaries

With Atlanta PTG wrapping up last week the summaries are starting to come in – as I’ve done previously I’ll link them over the next few Lwoods then put together a combined list early next month. Just five our this week, next week I suspect there’ll be rather more… :)

End of Week Wrap-ups, Summaries and Updates

Pretty much supplanted by the PTG wraps this week, listed above.

People and Projects

Core nominations & changes

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

This weeks edition of Lwood brought to you by a large music collection on random track play, so had Eric Clapton, Queensrÿche, David Francey, Elvis Costello, Weather Report, Coldplay, Miles Davis, Bruce Hornsby, Rush and Sásta amongst others.

Comments

Lwood-20170219

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 13 to 19 February for openstack-dev:

~575 Messages (three messages more than the long term average)

~212 Unique threads (up about 18% relative to the long term average)

Traffic picked up a fair bit this week – almost exactly on the long term average for messages.  Threads up a bit more – lots of short threads, a mixture of those about project logos and PTG logistics contributing there I think.

 

Notable Discussions – openstack-dev

Proposed Pike release schedule

Thierry Carrez posted to the list with some information on the proposed Pike release schedule.  The human friendly version is here.  Week zero – release week – is the week of August 28

Assistance sought for the Outreachy program

From Mahati Chamarthy an update about the Outreachy program – an initiative that helps folk from underrepresented groups get involved in FOSS. It’s a worthy initiative if there were ever one, a lot of support was shown from it at linux.conf.au recently as it happens too.

Please consider getting involved and/or supporting the programs work financially.

Session voting open for OpenStack Summit Boston

Erin Disney writes to advise that voting is open for sessions in Boston until 7:59am Wednesday 22nd February (UTC)  She notes that unique URLs for submissions have been returned based on community feedback.

Final Team Mascots

A slew of messages this week announcing the final versions of the team mascots that the OpenStack Foundation has been coordinating.  I briefly contemplated listing them all here but that seemed a sub-optimal way to spend the next hour – so if you want to find one for your favourite project, follow this link and use your browser search for “mascot” or “logo” – mostly the former. The Foundation will, I gather, be publishing a canonical list of them all shortly in any case.

In a thread about licensing for the images kicked off by Graham Hayes was the clarification that they’ll be CC-BY-ND

End of Week Wrap-ups, Summaries and Updates

People and Projects

Project Team Lead Election Conclusion and Results

Kendall Nelson summarises the results of the recent PTL elections in a post to the list.  Most Projects had the one PTL nominee, those that went to election were Ironic, Keystone, Neutron, QA and Stable Branch Maintenance.  Full details in Kendall’s message.

Core nominations & changes

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

This weeks edition of Lwood brought to you by Daft Punk (Random Access Memories) and DeeExpus (King of Number 33)

 

Comments

Lwood-20170212

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 6 to 12 February for openstack-dev:

~348 Messages (down about 39% relative to the long term average)

~124 Unique threads (down about 31% relative to the long term average)

One of those weeks where I wonder if should ever speculate what is going to happen with traffic on the list!  Much quieter this week relative to average – there does seem to be a trend where traffic falls away a bit around a PTG or Summit so perhaps just a side effect of the proximity to next weeks PTG in Boston.  Bit of a shorter Lwood as a result

Notable Discussions – openstack-dev

New OpenStack Security Notices

Users of Glance may be able to replace active image data [OSSN-0065]

From the summary: “When Glance has been configured with the “show_multiple_locations” option enabled with default policy for set and delete locations, it is possible for a non-admin user having write access to the image metadata to replace active image data.”

What is your favourite/most embarrassing IRC gaffe ?

So asks Kendall Nelson in his email – he’s gathering stories from the community as part of an article he’s writing. In fairness I won’t risk inadvertently stealing his thunder by repeating or summarising the stories here but if you want something to brighten your morning/afternoon, have a quick peek at the thread :)

End of Week Wrap-ups, Summaries and Updates

People and Projects

Project Team Lead Election Conclusion and Results

Kendall Nelson summarises the results of the recent PTL elections in a post to the list.  Most Projects had the one PTL nominee, those that went to election were Ironic, Keyston, Neutron, QA and Stable Branch Maintenance.  Full details in Kendall’s message.

Core nominations & changes

A quiet week this week other than the PTL elections winding up

  • [Dragonflow] Nominating Xiao Hong Hui for core of Dragonflow – Omer Anson

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

This weeks edition of Lwood brought to you by Bruce Hornsby (Scenes from the Southside) and Bruce Springsteen (Greatest Hits).

In this my first Lwood post Rackspace I place on record my thanks to the Rack for a great few years and, of course, for supporting producing Lwood as part of my role there. I intend continuing to write Lwood for the foreseeable future modulo what my new (yet to be determined) gig might entail :)

 

Comments

Lwood-20170205

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 30 January to 5 February for openstack-dev:

  • ~474 Messages (down about 17% relative to the long term average)
  • ~163 Unique threads (down about 9% relative to the long term average)

A little little quieter than last week but overall back into “normal” territory for list traffic volume.  That said, not a lot of traffic that met the Lwood criteria this week – one of (from memory) only two or three weeks where this has occurred.  Was it something I said ? :)

Notable Discussions – openstack-dev

Survey on Open Source Collaboration practices

A reminder that Allison Randal is running a brief survey on collaboration practices in Open Source development, particularly within corporations and OpenStack as part of academic research she’s undertaking.  This was flagged last week, but if you haven’t already and you can spare a few minutes to answer the brief (ten question) survey it would be much appreciated. THe Survey is here.

End of Week Wrap-ups

A few more projects starting to produce “regular” weekly updates and/or meeting summaries.  This week we have ones for Horizon from Richard Jones, Ironic courtesy of Ruby Loo, TripleO CI from Attila Darazs and Triple O Containers from Flavio Percoco.

Notable Discussions – other OpenStack lists

No traffic particularly stood out on the other lists this last week.

People and Projects

PTL nominations & Changes

As Kendall Nelson points out in his email elections are underway and will end on February 7 2017 at 23:45 UTC.  Ironic, Keystone, Neutron, Quality Assurance and Stable Branch Maintenance are the five projects that have multiple candidates and so go to the vote.

If you do wish to review the Candidacy Statements, they are listed on the OpenStack Governance page.  If you’re eligible to vote you should have already received an email from the Condorcet system to allow you to do so.

Core nominations & changes

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

Finally got speakers set up (bliss) and so very much enjoyed listening to The Lachy Doley Group’s new album, Lovelight while preparing Lwood this week.

Last but by no means least, thanks, as always, to Rackspace :)

Comments

Lwood-20170129

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 23 to 29 January for openstack-dev:

  • ~516 Messages (down just shy of 10% relative to the long term average)
  • ~175 Unique threads (down about 2% relative to the long term average)

List traffic pretty much back to the long term normal!

Notable Discussions – openstack-dev

Supporting our Global Community

Jonathan Bryce, writing on on behalf of Lauren Sell, Mark Collier and himself note their disagreement with the executive order issued by the President of the USA restricting travel to the US for some nationals.

A disagreement I believe is shared by many if not all in the OpenStack Foundation, OpenStack Community and certainly by your humble correspondent…

Survey on Open Source Collaboration practices

Allison Randal is running a brief survey on collaboration practices in Open Source development, particularly within corporations and OpenStack as part of academic research she’s undertaking.  If you can spare a few minutes to answer the brief (ten question) survey it would be much appreciated.  Survey is here.

Update on OpenStack PTLs (Program Team Leads) election

Somewhere around a quarter of list traffic this week past was PTL related being as it was the final week of nominations before the election proper commenced.

Kendall Nelson confirmed the end of the nomination period and noted there was only one project without a candidate – OpenStack UX.  There were five projects (Ironic, Keystone, Neutron, Quality Assurance and Stable Branch Maintenance) that had more than one candidate and so these will go to an election.

As an aside there was some discussion on the list that the important work of the UX Project would be better done through a working group – will update on this thread as it progresses in the coming week.

For further reading, here are the official candidacy statements.  Just the one not re-standing messages in the People and Projects section below from Richard Jones (retiring Horizon PTL)

One Hundred and Eleven Thousand, One Hundred and Eleven openstack-dev messages and counting

A bit of trivia: I happened to notice while preparing Lwood that the list archive had ticked over 111,111 messages.  The lucky (!) message was from Travis Truman giving a +1 on the nomination of Amy Marrich to openstack-ansible core by Alexandra Settle the newly elected Docs PTL.

End of Week Wrap-ups

Just the one this week from Ruby Loo for Ironic.

Notable Discussions – other OpenStack lists

No traffic particularly stood out on the other lists this last week.

People and Projects

Working Group Changes

Carol Barrett notes that she is retiring from Intel and so stepping down from her roles in the Product Working Group and the Enterprise Working Group.

I have had the good fortune to work with Carol as part of my own modest contributions to the PWG and happily add my best wishes to her here in this forum to those she’s rightly received from many on the list itself.  Good luck Carol!

PTL nominations & Changes

With PTL elections coming up as noted above, a non-candidacy messages and bunch candidacy statements this week.

Unlike previous elections I won’t list candidates individually here as it was both time consuming and prone to errors, but will list the folk not-standing for re-election as it’s nice to see their efforts recognised.  If you do wish to review the Candidacy Statements, they are listed on the OpenStack Governance page as they are approved by the election officials.

Thanks to those stepping down…

Core nominations & changes

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

No tunes, no speakers yet, still surrounded by boxes…

Last but by no means least, thanks, as always, to Rackspace :)

Comments

Lwood-20170122

Introduction

Welcome to Last week on OpenStack Dev (“Lwood”) for the week just past. For more background on Lwood, please refer here.

Basic Stats for the week 16 to 22 January for openstack-dev:

  • ~485 Messages (down about 15% relative to the long term average)
  • ~164 Unique threads (down about 8% relative to the long term average)

List traffic well and truly rebounding now – last time we had message counts in the high 400’s was mid/late October last year and we’re getting within cooee of the long term average again.  This in part I suspect because I opined to someone at linux.conf.au last week that maybe the list traffic was slowing for good ;)

Notable Discussions – openstack-dev

Refreshing and revalidating API compatibility guidelines

From Chris Dent on behalf of the API Working Group, an email noting that the API-WG are in the process of (as the subject suggests!) revalidating and refreshing the API compatibility guidelines.

As Chris rightly points out, API Compatibility is an important part of the overall API piece of OpenStack – the API in turn being what our users see and interact with daily as they develop their applications that use OpenStack.
This then an important initiative as they are not only ensuring the current documentation makes sense, is consistent etc. but also that common language is used around the definitions of APIs themselves.  Feedback from the broader user community is welcomed for both.

If you do any OpenStack development, please read this thread and engage if it piques your interest.

Nominations for OpenStack PTLs (Program Team Leads) are now open

Kendall Nelson announced that nominations for OpenStack PTLs are now open and will remain so until Jan 29, 2017 23:45 UTC.

I’ve provided links to the page that lists the official candidacy statements as well as links to the not-standing messages in the People and Projects section below :)

Identifying expected “Base Services”

Thierry Carrez draws attention to a great initiative that has been kicked off by the Architecture Working Group – he sums it up succinctly and eloquently in the first couple of paras of his email and so I quote:

“In OpenStack all components can assume that a number of external services will be present and available for them to use (think: a message queue), but we never had a clear name to describe them or a clear list.”

“Work has started[0] within the Architecture working group[1] to prepare a definition for those ‘base services’, a current list and a process for growing that list.”

This is bound to be a boon for both OpenStack developers and integrators looking to run OpenStack on their OS of choice alike.

End of Week Wrap-ups

Two this week from Ruby Loo and Richard Jones for Ironic and Horizon respectively.

Notable Discussions – other OpenStack lists

No traffic particularly stood out on the other lists this last week.

People and Projects

PTL nominations & Changes

With PTL elections coming up as noted above, a few non-candidacy messages and bunch candidacy statements this week.

Unlike previous elections I won’t list candidates individually here as it was both time consuming and prone to errors, but will list the folk not-standing for re-election as it’s nice to see their efforts recognised.  If you do wish to review the Candidacy Statements, they are listed on the OpenStack Governance page as they are approved by the election officials.

Thanks to those stepping down…

Core nominations & changes

  • [CloudKitty] Proposing Jeremy Liu as core for cloudkitty​ – Christophe Sauthier
  • [Puppet] Nominating Mykyta Karpin (mkarpin) for core – Alex Schultz
  • [Release][Stable] nominating Alan Pevec (apevec) for stable release core – Doug Hellmann

Miscellanea

Further reading

Don’t forget these excellent sources of OpenStack news – most recent ones linked in each case

Credits

No tunes as recovering from an enjoyable linux.conf.au and, err, don’t have my speakers set up yet…

Last but by no means least, thanks, as always, to Rackspace :)

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