[time-nuts] In praise of service: PTF

[Mark Kahrs]

Let me praise the support provided by PTF (www.ptf-llc.com): I obtained a
faulty GPS time clock off ebay to replace the one that was burned by a
lightning strike on the house.

First, the manual is online.  Second, the support emails provided by PTF
(probably by the owner) allowed me to diagnose the problem.  That's what I
call useful and supportive!

Now, for the disparage list...  I obtained a Zyfer GPS box that turned out
to be de-mil'd.   In spite of the manual being online, the Zyfer support
basically refused to help me out in spite of my offer to sign any and all
NDAs if needed.

Meanwhile, since the Zyfer box used a Trimble GPS subsystem, I thought
maybe I could obtain the details from Trimble.  You can guess the rest:
unresponsive.

So, I'd like to salute a company that stands behind their products enough
to answer queries about support.  Even to a guy who is obviously not going
to order 1000 boxes.
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[time-nuts] Buying a pig in a poke - Zyfer NTP box receiver problems

[Mark Kahrs]

So.  There was this nice Zyfer NTP box on the usual auction site.  I
powered it up whereupon it reported a fault on the ethernet board.

I decided to contact the source and after a while, the Zyfer support staff
responded and told me that the box was de-mil'ed by the buyer and I was
missing the Trimble Force 22 SAASM receiver.  Sure enough, that's why it
didn't lock!

Now, said box used a protocol known as TIPY (Trimble ...).  The question
is: is there a non-SAASM TIPY compatible receiver?  Or, is this just an
exercise in futility?
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Re: [time-nuts] Time nut soon to be in Shenzhen

[Mark Kahrs]

I think you need "The Essential Guide to Electronics in Shenzhen" by Bunnie
Huang.



On Sun, Nov 6, 2016 at 8:37 PM, Li Ang <379...@qq.com> wrote:

> Hi
>Welcome to Shenzhen. As far as I know there is no market that you can
> see pile of OCXO. They were taken off from equipments, and the process is
> done in the Qingyuan or Shanwei city Guangdong province. The seller might
> be in Shenzhen, but the source is in Qingyuan/Shanwei. These city have a
> lot of people doing the disassembly , recycle and alchemy work.
>
> However, there are a lot of eletronics markets near Huaqiangbei. I think
> you should pay a visit there. There are some 2nd-hand test equipment
> sellers in Duhui,  Xinyazhou market. Since the rental price is quite high
> in Huaqiangbei, most 2nd-hand test equipment selles and warehouses are not
> there.
> If you are interested in some other things, maybe I can give you more
> detailed info.(place to buy, reference price, etc.).
>
>
>
> ---Original---
> From: "Christopher Hoover"
> Date: 2016/11/6 23:13:55
> To: "Discussion of precise time and frequency measurement" com>;
> Subject: [time-nuts] Time nut soon to be in Shenzhen
>
>
> I'm in Shanghai now but will be leaving for Shenzhen in a few days.  Any
> one know of any special time nutty stuff to check out in Shenzhen?  I
> expect if I can find the right place I might see piles of OCXO's.
>
> Thanks, Christopher and 73 de AI6KG
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Re: [time-nuts] Get together at IMS?

[Mark Kahrs]

I think this makes it real easy, let's meet at Bernd's booth at 5 p.m. on
Wednesday.  Bring friends.



On Sat, May 21, 2016 at 3:46 AM, Bernd Neubig <bneu...@t-online.de> wrote:

> I will attend the IMS from Tuesday through Thursday noon time. Most time I
> will be at booth 714 (Dynamic Engineers).
> Good proposal to meet at the Industry reception on Wednesday. Please come
> up with a proposal for the meeting point, as the hall is big.
> Best regards
>
> Bernd DK1AG
>
> -Ursprüngliche Nachricht-
> Von: time-nuts [mailto:time-nuts-boun...@febo.com] Im Auftrag von Mark
> Kahrs
> Gesendet: Freitag, 20. Mai 2016 15:13
> An: Discussion of precise time and frequency measurement <
> time-nuts@febo.com>
> Betreff: [time-nuts] Get together at IMS?
>
> Anyone else going to IMS in SFO this coming week?
>
>
> I would propose meeting during the "industry Reception" Wednesday
> afternoon...
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[time-nuts] Get together at IMS?

[Mark Kahrs]

Anyone else going to IMS in SFO this coming week?


I would propose meeting during the "industry Reception" Wednesday
afternoon...
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Re: [time-nuts] Lightning 1, tbolt 0.

[Mark Kahrs]

I had a lightning strike on our roof last year - blew slate tiles at
least 15 meters away.  Burnt out several ports on my ethernet
switches.  And also took out my Symmetricom TS2100 GPS clock in
strange ways.  If anyone wants a peculiar TS2100L then let me know!



On Thu, Mar 31, 2016 at 9:13 AM, paul swed  wrote:
> Scott
> Sorry to hear that.
> I do not know whats used on the output.
> But your guess is pretty good. I had a nearby strike on a tree 50 ft away
> and it damaged a ton of equipment. Yes it was all grounded and not to start
> a debate here about grounding and such.
> Its just that a strike that close creates one heck of a pulse. Further
> todays homes may have a lot more wire in them phone cable power and
> ethernet. So lots of ways to carry the pulse.
> So if you do find the chips great.
> BUT I have experienced this numbers of times. Something about high clear
> and flat for the house. What you may see in the next 90 days is a slow but
> sure degradation of things. Just sort of watch out for it. Hard to notice,
> but one day maybe your computer has a hard time booting.Maybe the TV volume
> control starts to act odd.
>
> Good luck
> Paul
> WB8TSL
>
> On Wed, Mar 30, 2016 at 10:06 PM, Scott Newell 
> wrote:
>
>> 10 MHz output active, no PPS, no comm with LH.
>>
>> My tbolt was disconnected from the outdoor GPS antenna today, and so I
>> wasn't too concerned when we had a strike in the backyard this morning. The
>> PC attached to the serial port and PPS output died, and that cable was
>> fairly long, so I guess that's what did it in.
>>
>> Anyone know off hand what part it uses for the serial driver and the PPS
>> output buffer? Or is it likely a total loss?
>>
>> --
>> newell N5TNL
>>
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[time-nuts] Spreadsheet from Ulrich Rohde's paper

[Mark Kahrs]

If you don't have MathCAD but would like a parameter fed version in
Python... Drop me a line and I'll send you my version.
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Re: [time-nuts] MIT 2 inch cesium fountain, optically pumped

[Mark Kahrs]

For those who are interested, a relevant dissertation can be found here:

http://dspace.mit.edu/bitstream/handle/1721.1/71453/795174737.pdf

Unfortunately, you can't print it, but you can read it.  A rather complete
discussion of the construction of the experimental apparatus is included.


On Thu, Nov 20, 2014 at 5:57 PM, Bob Camp kb...@n1k.org wrote:

 HI

 I saw that when it came out. It’s a CSAC based gizmo and thus a gas cell
 rather than a beam tube / state selection device.

 Bob

  On Nov 20, 2014, at 8:37 AM, Peter Torry peter.to...@talktalk.net
 wrote:
 
  Hi Bob,
 
  Some time ago Hoptroff  produced a Cs pocket watch using the Symmetricom
 SA45s - now how long for a wrist watch !!
 
  http://www.engadget.com/2013/05/01/hoptroff-no-10/
 
  Peter
  (still pendulum controlled)
 
 
 
  On 20/11/2014 12:38, Bob Camp wrote:
  Hi
 
  So the wrist watch sized fountain that was promised 15 years ago isn’t
 gong to be here for Christmas this year?
 
  Bob
 
  On Nov 20, 2014, at 12:17 AM, Magnus Danielson 
 mag...@rubidium.dyndns.org wrote:
 
  Hi Rick,
 
  They did not mention the complexity of the laser system they needed,
 especially considering that the optical bench of a fountain isn't all that
 small, and also because they want to de-tune lasers. While they seems to
 have an idea, they didn't touch on that subject.
 
  Nice to see that people think in a different way thought.
 
  Looking forward to see the progress on this one.
 
  Cheers,
  Magnus
 
  On 11/20/2014 05:24 AM, Richard (Rick) Karlquist wrote:
  See:
 
  http://newsoffice.mit.edu/2014/portable-atomic-clocks-1112
 
  Any comments?
 
  Rick Karlquist N6RK
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Re: [time-nuts] MIT 2 inch cesium fountain, optically pumped

[Mark Kahrs]

Hey, that's what the 'tute website said, I'm just reporting.

The aforementioned dissertation features the same octagonal cell as
described in the paper.

For those of you with access to knowledge of ultracold quartz chambers, go
right on ahead.


On Mon, Nov 24, 2014 at 12:13 PM, Chuck Harris cfhar...@erols.com wrote:

 The Linux program Okular has no trouble printing this file.

 -Chuck Harris


 Robert LaJeunesse wrote:

 I use an older XP based drag and drop freeware PDF unlocker that strips
 many PDF
 restrictions. It made the file below quite printable.

 Bob L.

  Sent: Monday, November 24, 2014 at 9:05 AM From: Mark Kahrs
 mark.ka...@gmail.com To: Discussion of precise time and frequency
 measurement time-nuts@febo.com Subject: Re: [time-nuts] MIT 2 inch
 cesium
 fountain, optically pumped

 For those who are interested, a relevant dissertation can be found here:

 http://dspace.mit.edu/bitstream/handle/1721.1/71453/795174737.pdf

 Unfortunately, you can't print it, but you can read it.  A rather
 complete
 discussion of the construction of the experimental apparatus is included.

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Re: [time-nuts] Hydrogen Maser KIT! Update #1

[Mark Kahrs]

There's been a  fair number of papers from Hahvahd about bulb coating for
masers.  Interestingly enough, here's a patent:

http://www.google.com/patents/US3859119

from 1972.

I had to figure this out, but Yuri is referring to flourophosgene a.k.a.
carbonyl flouride.

If you'd like to read a really nice detailed paper on bulb coating for Rb
cells, try this one out:

http://walsworth.physics.harvard.edu/publications/1999_Phillips_otherdoc.pdf


On Mon, Nov 3, 2014 at 3:46 PM, Chuck Harris cfhar...@erols.com wrote:

 Hi Yuri,

 It would be a very good idea to keep the temperature of
 the nichrome wire low, and that might be the biggest problem
 with the vacuum deposition technique... the wire could get
 too hot in some places, and stay too cool in others.

 A really uncontrolled experiment, aka: a thermal wire stripper,
 gets covered with white snow from the teflon vapor released
 while stripping teflon wire.

 -Chuck Harris

 Yuri Ostry wrote:

 Hello,

 Monday, November 3, 2014, 5:40:30, Chuck Harris wrote:

 C I would think that making the teflon coating would be pretty easy.

 C What I would try is to put a nichrome boat, and some teflon into the
 C vessel, and pull it down to a good vacuum.  Then heat up the boat,
 C and the teflon should sublime, and condense on the walls of the
 C vessel.

 C The nichrome boat could be something as simple as wrapping the nichrome
 C into a solenoid form around some teflon rod.

 C -Chuck Harris

 Teflon decomposes at high temperatures, releasing some sublimate and a
 lot of really nasty chemicals, like fluorfosgen. There is a chance
 that really thin even coating can be produced this way, but a lot of
 experimentation would be needed.

 I would try to take samples of PTFE-insulated hookup wire (from different
 manufacturers, say white Alfa or Belden wire and russian MGTF wire that
 use
 slightly different PTFE formula) and try to make coating inside glass
 tube samples, using copper wire as heater by itself.

 I doubt that there will be good results, though. Classic way with
 thin slurry application and heating to teflon melt point to make solid
 film may be more realistic.

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[time-nuts] Unusual 10544A

[Mark Kahrs]

Jerry Johnson has the following question:

Some of the documents that I have found show pins and feed throughs
with SMB right angle connectors for RF and probably control voltage.
This one doesn't have the SMB connecgtor, just pins. The case says
10544A part number (which I've not yet searched on) 1528A06401 but
finding a used on probably won't find the internal information that
I would like to have.

Anyone seen this before?
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Re: [time-nuts] A small piece on HP's hydrogen maser in 1968

[Mark Kahrs]

So what's all this about a Thallium Beam Tube???

(Isn't Thallium incredibly toxic?)

n.b. One of the pictures references a Th beam tube...



On Tue, Feb 25, 2014 at 2:46 AM, Poul-Henning Kamp p...@phk.freebsd.dkwrote:


  [Jim Lux]
  Wasn't that Gravity Probe B.. which finally launched in 2004, and had
  equivocal results.

 No, GPB was the gyro-experiment, it tested another part of GR than
 red shift was supposed to.

  [Tony Greene]
  In the back of my head, I beleive that project red shift did fly,
  but they dumped the hydrogen masers to use brand new lighter weight
  and much smaller rubidiums.

 I've found no trace of it.

 Are you sure you are not confusing it with the pathfinders for NavStar ?

 --
 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.
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Re: [time-nuts] A small piece on HP's hydrogen maser in 1968

[Mark Kahrs]

Thanks, also consider the HP patent:

http://www.google.com/patents/US3407295




On Tue, Feb 25, 2014 at 4:40 PM, Tom Van Baak t...@leapsecond.com wrote:

  So what's all this about a Thallium Beam Tube???

 For info about the pro/con of Thallium beam frequency standards, see:

 http://tf.boulder.nist.gov/general/pdf/9.pdf
 http://tf.boulder.nist.gov/general/pdf/211.pdf
 http://leapsecond.com/history/1965-Metrologia-v1-n3-Cesium.pdf

 Imagine 21310.833946 MHz instead of 9192.631770 MHz...

 /tvb

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Re: [time-nuts] fast edge, rise time.

[Mark Kahrs]

You might be interested to know this was discussed in a paper by Jim
Andrews (founder of Picosecond Pulse Laboratories):

http://www.nist.gov/calibrations/upload/im-25-4.pdf

From the age of the paper, I'd say this generator is probably more than 40
years young.



On Mon, Jan 13, 2014 at 2:22 PM, Bill Reed br...@otelco.net wrote:

 Hi,

 Since there is no interest in my pulse generator maybe one of you knows
 someone at NBS who can provide a schematic of the generator.
 It has  NBS Impulse Generator   SN 3-75-2  engraved on the front panel
 and is ~ 10 x 16 x 17.

 Thanks,
 Bill Reed

 -Original Message- From: Bill Reed
 Sent: Tuesday, January 07, 2014 7:53 PM

 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] fast edge, rise time.

 Hi,

 Since you guys are interested in fast pule generators, I have one you may
 be
 interested in.
 I got it in govt. auction about 25 years ago for ~ $ 50.00. I will sell it
 to anyone for  $ 50.00 plus shipping.
 I prefer to sell to someone who will restore and use it rather than parting
 it. It has more than $ 50.00 parts in it.
 There are a 30 turn 6.5 inch diameter hard line, wide band hybrid coupler,
 diode assembly and several adapters and attenuators.
 I believe the hard line discharges into a step diode. The power supply
 includes 200 V plus other voltages.
 If I remember correctly ( I have no high speed scope now ) the pulse is 2
 nanoseconds wide with a 280 picosecond rise time and and 2.5 Vpp.
 I checked with a 200 MHz digital scope and can see a pulse that verifies my
 scopes bandwidth. The rate generator works but has problems.
 See facebook (ree...@otelco.net) for pictures under Impulse.

 Bill Reed256 586-3446

 -Original Message- From: ct1dmk
 Sent: Sunday, December 29, 2013 7:36 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] fast edge, rise time.

 Thank you all for your comments on this subject.
 Happy new year.

 Luis Cupido.
 ct1dmk.
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[time-nuts] DARPA SBIR - Portable Microwave Cold Atomic Clock

[Mark Kahrs]

SB141-004   TITLE: *Portable Microwave Cold Atomic
Clock*



TECHNOLOGY AREAS: Materials/Processes, Sensors, Electronics



This topic is eligible for the DARPA Direct to Phase II Pilot Program.
Please see section 4.0 of the DARPA instructions for additional
information.  To be eligible, offerors are required to provide information
demonstrating the scientific and technical merit and feasibility of a Phase
I project. DARPA will not evaluate the offeror's related Phase II proposal
where it determines that the offeror has failed to demonstrate the
scientific and technical merit and feasibility of the Phase I project.
Offerors must choose between submitting a Phase I proposal OR a Direct to
Phase II proposal, and may not submit both for the same topic.



OBJECTIVE: Develop a laser-cooled microwave atomic clock with small volume
( 1 L) and weight ( 1 kg), low power consumption ( 5 W), and the
stability (10^-12 at 1 s) of a primary atomic frequency standard.



DESCRIPTION: Frequency and timing devices are essential components in
modern military systems. The stability and accuracy of these devices impact
the performance of communication, navigation, surveillance, and missile
guidance systems. Atomic clocks are at the cores of many of these systems,
either directly or via time-transfer from a master clock.



By employing techniques used in current laboratory atomic clocks, military
clocks can be improved by orders-of-magnitude. Such clocks will enable
secure data routing, communication systems that are insensitive to jamming,
higher resolution coherent radar, and more reliable and robust global
positioning.



Laser-cooled optical lattice atomic clocks are currently the world's most
stable clocks, with stability below 10^-18 at 6 hours of averaging [1].
DARPA's QuASAR program aims to miniaturize and ruggedize such
high-performance optical atomic clocks for deployment in the field [2].
While this work could enable widespread adoption of optical clock
technology, many applications cannot tolerate the size, weight, and power
(SWaP) of these first generation portable optical clocks (S  50 L, W  50
kg, P  150 W). DARPA's Chip Scale Atomic Clock (CSAC) program has
developed miniature microwave atomic clocks with extremely low SWaP values
(S ~ 16 cm^3, W ~ 35 g, P ~ 125 mW) and good short-term stability (10^-10
at 1 sec) [3]. However these clocks drift over long timescales making them
unsuitable for many applications.


The goal of this SBIR is to bridge the gap between these extremes by
developing an atomic frequency standard with long term stability (
5x10^-15 at 1 day), approaching that of laboratory frequency standards such
as the NIST F1 microwave Cs fountain clock [4] but with reasonable SWaP
values (S  1 L, W  1 kg, P  5 W).



To achieve these goals, this SBIR will combine aspects of the two extreme
clock architectures mentioned above: laser cooling (as used in QuASAR
optical clocks) and microwave hyperfine transitions (as used in CSAC).
Alternative strategies will also be considered if sufficiently justified.
Special attention will need to be focused on reducing the power
requirements of the requisite lasers, microwave sources, and local
oscillators. Furthermore, the final device should be robust to
environmental fluctuations (e.g. temperature, magnetic field, vibration) in
a relevant operating environment.



PHASE I: Develop an initial design and model key elements of the proposed
clock. The chosen work must be compatible with a fractional frequency
stability of  10^-12 at 1 second averaging and  5x10^-15 for 1 day of
averaging. It should have a size  1 L, weight  1 kg, and power
consumption  5 W. Develop a detailed analysis of the predicted performance
in a relevant environment accounting for expected environmental
fluctuations such as temperature, magnetic field, and vibration
fluctuations. Exhibit the feasibility of the approach through a laboratory
demonstration of critical components. Phase I deliverables will include a
design review including expected device performance and a report presenting
the plans for Phase II.



DIRECT TO PHASE II - Offerors interested in submitting a Direct to Phase II
proposal in response to this topic must provide documentation to
substantiate that the scientific and technical merit and feasibility
described in the Phase I section of this topic has been met and describes
the potential commercial applications. Documentation should include all
relevant information including, but not limited to: technical reports, test
data, prototype designs/models, and performance goals/results. Read and
follow Section 4.0 of the DARPA Instructions



PHASE II: Construct and demonstrate a prototype device validating the
device performance outlined in Phase I. The Transition Readiness Level to
be reached is 5: Component and/or bread-board validation in relevant
environment.



PHASE III: The low SWaP of the clock developed in this program should
enable widespread 

Re: [time-nuts] HP 4193A 4815A probe compatibility?

[Mark Kahrs]

Except that if you blow the 54701A front-end, the IC is made of
unobtanium.  Likewise, buying an untested probe...

As for the 4193A, if you know of an instrument without probe for $1, please
let me know ASAP!!!

The connector of the 4193A is the same awful connector as the 8411A so if
you wanted to build your own, you could start from there.





On Wed, Oct 16, 2013 at 4:42 PM, Tom Knox act...@hotmail.com wrote:

 I agree the 54701A is really a great product. Great point on attenuation,
 I always forget the 10x attn value changes when not being used on a O-Scope
 as a voltage probe.
 Thanks;
 Thomas Knox



  From: saidj...@aol.com
  Date: Wed, 16 Oct 2013 15:22:13 -0400
  To: time-nuts@febo.com
  Subject: Re: [time-nuts] HP 4193A 4815A probe compatibility?
 
  Hi Rick, Tom,
 
  one little bit of knowledge I learned: I like the HP 54701A FET probes
 for
  frequency-domain stuff.
 
  Available for $300 on Ebay sometimes. I built a small power supply for
  one
  of mine, and use it as a probe for my Spectrum analyzer and scopes.
 Almost
  indestructable.
 
  It works really well up to about 3GHz and beyond, especially for relative
  measurements.
 
  The only disadvantage is that it has 100K resistance to ground which may
  affect sensitive capacitive circuits, and that it has 20dB attenuation.
 
  Otherwise it works really well for Spectrum analyzer and Network analyzer
  applications.
 
  bye,
  Said
 
 
  In a message dated 10/16/2013 11:33:11 Pacific Daylight Time,
  rich...@karlquist.com writes:
 
  The  4815A used P channel FETs which were available 50 years ago
  and are now  unobtainium.
 
  The 4193A used N channel FETs which were available 10 to  30 years
  ago and may even be currently available.
 
  They are  DEFINITELY NOT INTERCHANGEABLE.
 
  This is according to ex-HP'er George  Standford, who used to
  support vector impedance meters with HP's  blessing.  He held
  the worlds remaining supply of P channel FETs for  fixing probes.
  He was in New Jersey, but my contact info for him is no  longer
  valid.
 
  I don't know how to identify them, but in principle an  ohmmeter might
  be able to identify the polarity of the FETs.
 
  While  we are on the topic, it turns out that the market is such
  that a 4193A with  probe might sell for $5000, but if you break
  up the set, the probe is worth  $4999 and the instrument is worth
  $1.  Well, maybe I exaggerated that  a little, but not much :-)
  I actually know someone who paid $5000 for just  a 4193 probe.
  He made the mistake of purchasing an instrument without a  probe,
  and paid way too much.
 
  It is also worth noting that now you  can buy a very nice vector
  impedance meter from Tomco in Austrailia for  only $3000 new.
  I A/B'ed one of these with an HP one, and I will have to  admit
  that the Tomco is the real deal, not a cheap knockoff.
 
  Rick  Karlquist N6RK
 
 
  On 2013-10-16 09:15, Tom Knox wrote:
   I hope  this is not to far off topic. Does any one know if the 4193A
   and 4815A  probe are physically interchangeable and electronically
   compatible? If  not does anyone know the differences and how to
   identify which is  which? If you feel this is to far off topic please
   contact me  directly. Thanks very much.
  
   Thomas Knox
  
  
  
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Re: [time-nuts] pin-wheel antenna

[Mark Kahrs]

I'm surprised no one has mentioned the patent of interest:

http://www.freepatentsonline.com/7250916.html

An antenna is provided for acquiring RF signals from various satellite
ranging systems including GPS, GLONASS, GALILEO and OmniSTAR®. The antenna
configuration includes a radiating structure of multi-arm spiral slots
terminated with fractal loops. A leaky wave microstrip spiral feed network
is used to excite the radiating structure of the antenna. The fixed beam
phased array of aperture coupled slots is optimized to receive a right hand
polarized signal. The proposed antenna is made out of a single PCB board.
The antenna has a very uniform phase and amplitude pattern in the azimuth
plane from 1.15 to 1.65 GHz, therefore providing consistent performance at
GPS, GLONASS, GALILEO and OmniSTAR® frequencies. The antenna also has a
common phase center at the various frequencies from 1175 MHz to 1610 MHz
and substantially the same radiation pattern and axial ratio
characteristics.



On Mon, Apr 22, 2013 at 10:57 AM, b...@lysator.liu.se wrote:

  Hi Dave,
 
  On 04/21/2013 10:32 AM, David Kirkby wrote:
  On 20 April 2013 20:52, Tom Van Baakt...@leapsecond.com  wrote:
 
  For the rest of you:
 
  http://www.leapsecond.com/images/gps-pinwheel-1.jpg
  http://www.leapsecond.com/images/gps-pinwheel-2.jpg
 
  It's a thing of mysterious beauty. And the GPS World photo saves me
  from the temptation to break open my own pinwheel antenna just to see
  what's hidden inside.
 
  /tvb
 
  Does the antenna work better than other types?
 
  You should get close to choke-ring antenna performance at a much smaller
  size. For many purposes its good enough.

 Note that the traditional JPL type choke-ring is beeing replaced by more
 advanced designs in the money-is-no-problem market.

 http://www.topconpositioning.com/sites/default/files/PN-A5_white_paper.pdf

 http://www.novatel.com/assets/Documents/Papers/3D_choke_ring.pdf

 --

 Björn

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Re: [time-nuts] PTTI 2012, part 2

[Mark Kahrs]

I couldn't resist and did a little reading.

So, the MIT Flea has MOT cells?  That would seem to be the deal breaker to
me.  The rest is just plumbing.  And smoke and mirrors.

On Tue, Dec 4, 2012 at 8:23 PM, ewkeh...@aol.com wrote:




 In a message dated 12/4/2012 6:10:36 P.M. Eastern Standard Time,
 docdai...@gmail.com writes:

 I will  build one right away.. but I didnt see your request.  My problem
  is
 surface mount components (the multipin or no leads)... I am not  confident
 in that.  but I would certainly try.   I am not a  programmer and also
 figure somebody with more soldering skills than those I  have picked up
 ruining things would be desired.  I am always willing  to try not to ruin
 something.

 Doc
 KX0O


 On Tue, Dec 4,  2012 at 4:25 PM, ewkeh...@aol.com wrote:

  Paul
   Frankly I do not think I will live long enough to see a time nut build
  a
  fountain Rb. Over the four years I have watched many smoke and  mirror
  projects  with nothing coming out of is. In German we have  a saying:
 paper
  is
  patient. We  should walk before we  run.
  Many members did buy a FE 5680, how many do you think are in  operation,
 if,
   there would be discussions about its temperature  performance. take a
 close
  look  on page 7 figure 5 of the  brochure, I also see it. Personally I
 use a
  Shera  loop. But that  is an overkill and for some to complex since it
  requires direct   analog C field control. My real focus is on controlling
  FRK-H,
   M100 and HP  5065.
  What is needed is a coordinated effort to  start with temperature
 control, a
   simple GPSDO only taking care  of aging using RS232 interface an analog
  loop for  controlling  something like a Morion. Stability and accuracy
  could be
  in  the 1  E-12 range, low cost able to be assembled by 90% of list
 members,
  but then I  proposed it once before looking for some one  to develop the
  filter. No response,  it is clear that very few  are willing or able to
  actually
  build something.
  When  Corby wrote about his experience with the dual mixer / counter,
 large
   response and we will have a complete documentation set, but when I
  asked
  for a  few that would be willing to build one right away, I  would make
  complete kits, I  got one response. Sad, but that is  the reality.
  How many FE 5680A door stops do you think are out there?  How many
  PICTICII's do you think are in use?
  Bert  Kehren   Miami.
 
 
  In a message dated 12/4/2012  9:49:29 A.M. Eastern Standard Time,
  paulsw...@gmail.com  writes:
 
  Basements the key. So for me bigger is better. Heck if  its a rack  thats
  ok.
  It gets interesting in what types  of components you can use if  you are
  willing to go  larger.
  Great point on the laser and optics. Funny  thing is for  small change
 you
  can actually get used optics bench components   at least at the last MIT
  flea
  I ran across the items. They  were snapped up  by the way.
  From what I have seen of  time-nuttery and Hydrogen masers I am  actually
  not
  all  that sure its beyond this  group.
  Regards
   Paul
 
  On Tue, Dec 4, 2012 at 9:34 AM, Bob Camp   li...@rtty.us wrote:
 
   Hi
  
Indeed, you likely  won't get USNO grade with a shoe box sized part.
 You
  can
   get one to  work and do quite good ADEV. No,  I haven't done it, I'm
 just
   going on  what I've been told.  The main point being that for a
 basement
   project  - smaller  is probably lower cost.
  
   Bob
  
 -Original Message-
   From:  time-nuts-boun...@febo.com  [mailto:time-nuts-boun...@febo.com]
 On
   Behalf Of Poul-Henning  Kamp
   Sent: Tuesday,  December 04, 2012 9:19 AM
   To: Discussion  of precise time  and frequency measurement; Bill Dailey
   Subject: Re:   [time-nuts] PTTI 2012, part 2
  
   
In  message
 CAMPhiorJihW9z6-q0+Qfd+GPLjs6e8_ovWrDxQoxV=92hgj...@mail.gmail.com
 , Bill Dailey writes:
  
   If you look at  the papers on  portable rubidium fountains
   they are  significantly bigger than a  shoebox (65 cm).
  
Diameter is controlled by dispersion of the  launched atoms
  (=recovery
  rate)
   and the layers of   shielding.
  
   65cm looked like close to a minimum for  USNO grade,  amateurs could
  probably
   make do with  less shielding.
  
--
   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.
  
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Re: [time-nuts] Loran

[Mark Kahrs]

Very interesting topic.  So, it appears that UrsaNav bought a pair of
companies that have interesting IP.  In particular, CrossRate has a few
interesting patents -- this may be the most relevant:

United States Patent Application 20080144744:

 A system for demodulation of the Loran Data Channel transmitted over the
Enhanced Loran (eLoran) system including a quadrature filter. The
quadrature filter calculates the real and quadrature phase components of a
received ninth pulse. The resultant components are used to obtain the angle
of the ninth pulse. This angle is then compared with a set of pre-tabulated
angles/symbols that are calculated using the same quadrature filter on
thirty-two different simulated ninth pulses. The closest angle match gives
the corresponding symbol. Such twenty-four symbols make up a single Reed
Solomon encoded message. This message is then passed through a Reed Solomon
decoder and the transmitted message is obtained.

Also, UrsaNav teamed with Nautel, noted LF amplifier designer for this
system.  Interesting.



On Sat, Dec 1, 2012 at 10:42 AM, Chuck Harris cfhar...@erols.com wrote:

 Remove the that from pdfthat ?


 paul swed wrote:

 Not sure why the link does not work but the docs under the whitepapers.

 On Fri, Nov 30, 2012 at 9:17 PM, Alan Hochhalter alanh...@gmail.com
 wrote:

  There is some info here http://www.ursanav.com/ - click on the Latest LF
 News on the right side.

 There is a paper here

 http://www.nautelnav.com/wp-**content/uploads/2011/09/**
 Nautel-UrsaNav-NAV10-Research-**Paper.pdfthathttp://www.nautelnav.com/wp-content/uploads/2011/09/Nautel-UrsaNav-NAV10-Research-Paper.pdfthat
 I think is relevant.  It will take me some time to wade through it
 with no guarantee I'll understand it enough to be sure it is talking
 about
 the same thing so I thought I'd pass it along.

 Alan

 On Fri, Nov 30, 2012 at 6:46 PM, paul swed paulsw...@gmail.com wrote:

  Well as predicted they went home at 5pm. Signals off the air.

 On Fri, Nov 30, 2012 at 7:26 PM, Bill Riches bill.ric...@verizon.net

 wrote:


  Nothing going on in Cape May for a while - I don't know if they are

 done

 testing.

 Bill WA2DVU
 Cape May, NJ

 -Original Message-
 From: time-nuts-boun...@febo.com 
 [mailto:time-nuts-bounces@**febo.comtime-nuts-boun...@febo.com
 ]

 On

 Behalf Of Mike Garvey
 Sent: Friday, November 30, 2012 3:25 PM
 To: 'Discussion of precise time and frequency measurement'
 Subject: Re: [time-nuts] Loran


 Might be these guys; this abstract is from the Precision Time and Time
 Interval (PTTI) Meeting which took place in Reston, VA during this past
 week.

 There will be a follow-up manuscript.

 Mike

 -Original Message-
 From: time-nuts-boun...@febo.com 
 [mailto:time-nuts-bounces@**febo.comtime-nuts-boun...@febo.com
 ]

 On

 Behalf Of paul swed
 Sent: Thursday, November 29, 2012 6:35 PM
 To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] Loran

 Rich
 Did not see anyone respond. Are you still hearing the signal?
 Paul
 WB8TSL

 On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz rp...@bnin.net

 wrote:


  Hi all;

 I 'm hearing Loran C signals here in northern Indiana this evening, I
 guessing from New Jersey. Anyone else hearing these?

 Rich

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Re: [time-nuts] Schematic capture, anyone?

[Mark Kahrs]

I'll add my $0.01 (depreciated).

I am working on a project with Eagle.  I started with the Gnu cad
stuff but like many free software projects, it has multiple user
interfaces and clunks.  I tired of it and switched to Eagle.

Eagle also has quirks but has the ability to switch back and forth
between schematic and layout.  I have added parts with the XML format
and while painful, it's not impossible.  Also, the user library of
scripts is very useful: there is one that converts the schematic to a
SPICE netlist (suitable for LTSpice with a little massaging).

If/when I need a larger board than the free version then I'll have to
decide what to do.  But for the time being, it's OK.

(And, as I like to say, when it comes to advice, you get what you pay for).

On Fri, Feb 24, 2012 at 2:49 AM, Chris Albertson
albertson.ch...@gmail.com wrote:
 On Thu, Feb 23, 2012 at 10:52 PM, Charles P. Steinmetz
 charles_steinm...@lavabit.com wrote:
 I've been using LTspice for schematic capture and simulation at home.  Will
 the PCB CAD tools being discussed (Eagle, DesignSpark, FreePCB, etc.) import
 netlists from LTspice?  Or do folks prefer to do the schematic capture in a
 CAD tool and export that netlist to LTspice for simulation?


 LT Spice is basically just the normal Spice simulator with a schematic
 capture program acting as a front end.    LTspice can export standard
 Spice net lists and can save to it's own file format too.  The spice
 net lists don't have any graphical information and don't have
 footprints.

 I find I don't  need to move data from a simulation to a design
 program because to rarely simulate exactly the target circuit.  You
 usually have to Spice specific stuff components like signal generators
 or maybe some parasitic capacitance for realism.  These parts only
 exist in a simulation not on the PCB.
 Chris Albertson
 Redondo Beach, California

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[time-nuts] Norman Ramsey obit

[Mark Kahrs]

http://www.nytimes.com/2011/11/07/us/norman-ramsey-dies-at-96-work-led-to-the-atomic-clock.html
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Re: [time-nuts] alkali metals and water

[Mark Kahrs]

I have to say that youtoob has completely revitalized the teaching of
chemistry (if only the teachers realize it).   Videos just like that
one have fascinated my offspring to the point I had to dig out my copy
of the Rare earth handbook.   Chemistry has a whole new allure...
Mention alkalai metals and the eyes brighten!

On Wed, Mar 2, 2011 at 8:43 AM, jimlux jim...@earthlink.net wrote:
 You know, elements we love, Rb, Cs...

 http://www.youtube.com/watch?v=eCk0lYB_8c0

 Totally safe for work.. (my daughters turned me on to this video, they saw
 it in their 8th grade science class)

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Re: [time-nuts] Calculate spectral content from a series of zero crossing time stamps?

[Mark Kahrs]

The Goertzel algorithm is only useful when you want a few frequences
(i.e., it evaluates specific frequencies on the unit circle).  For
general all purpose slicing and dicing, the FFT is what you want.  See
the ancient book by Rabiner for the details.

On Tue, Feb 8, 2011 at 3:14 AM, Tijd Dingen tijddin...@yahoo.com wrote:


  From what I could find so far, one method to go about this is use a
  Lomb/Scargle Periodogram. And specifically the method by Press  Rybicki
  that extirpolates the unevenly timed samples to an regular timed mesh,
  after which a regular DFT is done.

 Just knowing the time of the zero-crossings is very little information
 to go by, but you have to make some kind of assumption about the
 perfection of curve shape between those points, in order to say
 anything meaningful.

 Correct. And for now the working assumption is that the input signal is
 sinusoidal, with just a smattering of noise.

 The dirty but not necessarily quick way to analyze the data, is to
 turn it into a +/- 1 squarewave at 1GHz (1/1ns), low-pass filter
 it with a 15-18 kHz cut-off and do the usual FFT.

 Yeah, I thought of that one. But it becomes prohibitive in terms of resources
 real fast. ;)

 The other option is to normalize your zero-crossings, so you get
 signed numbers telling how early/late they happen, and do a FFT
 on that.  Its too early in the morning for me to be able to see
 how you transform the resulting phase-deviation spectrum to a
 normal frequency offset plot, but a few tests with synthetic data
 should tell you that.

 There's an idea. I will be doing a curve fit of the time stamps anyway, so I
 get the time deviations from the fit for free. Normalize the time deviations
 into
 phase deviations, and use that. Worth a try, thanks!

 Fred




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[time-nuts] Choice of MASER gas

[Mark Kahrs]

John Miles brought up an interesting question that got lost in the
discussion of high vacuum systems: what about the choice of gas?

Besides H, there is a dual Xe/He system detailed in:

http://www.cfa.harvard.edu/Walsworth/pdf/Bear%20thesis.pdf

And, as mentioned before, Harvard has built Rb masers:

http://cfa-www.harvard.edu/~dphil/work/coat.pdfhttp://cfa-www.harvard.edu/%7Edphil/work/coat.pdf
http://cfa-www.harvard.edu/%7Edphil/work/coat.pdf

And John mentioned HN3 masers (advantage: you would be able to smell the
leak!).
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Re: [time-nuts] homebrew H maser

[Mark Kahrs]

The Hahvahd physics dept. has all number of interesting papers.

For example there's Humphrey's
dissertation:www.physics.harvard.edu/Thesespdfs/humphrey.pdf

If you've ever wanted to make your own Rb cell, how about this
one?cfa-www.harvard.edu/~dphil/work/coat.pdf
http://cfa-www.harvard.edu/%7Edphil/work/coat.pdf%20


On Sun, Aug 29, 2010 at 11:07 AM, Attila Kinali att...@kinali.ch wrote:

 On Sun, 29 Aug 2010 16:13:21 +0200
 Magnus Danielson mag...@rubidium.dyndns.org wrote:

  On 08/29/2010 03:55 PM, Attila Kinali wrote:
   Does anyone know whether any of those people collected their results
   somewhere? And if, where i could find them?
 
  The physical package is definitely where most of the effort goes in.

 I know, that's why i'm asking.
 The papers i've read sofar all suggest that the difficult part is to
 compensate for cavity detuning, wall shift and second order doppler
 effect. Somehow all these papers seem to assume that getting an
 oscillation at all is so easy that everyone could do it (yes, i know that
 this is normal with scientific papers).

 I thought, that if someone build a homebrew H maser, he'd write about
 the difficulties getting there. Which would be a very interesting reading
 and teach a lot about the physics (and tool making, mechanics, etc)
 of these devices.

  A
  complicating aspect is the self-tuning stuff for which several
  strategies may be chosen.

 I'd start here at getting a cavity that is resonant at the frequency
 at all. Getting sub-milimeter precision in tooling is quite easy
 (given you have the tools and knowledge, or can pay someone to do it for
 you),
 but if the cavity has to be resonant within a couple of Hz of the
 1.4xxxGHz, then you have to get a precission in the range of 10^-9
 which basically impossible mechanically. So the cavity would need to have
 a mechanical tuning system too, but one that doesn't lower the cavity's
 Q or add any additional resonant modes.

  You need to balance the rate of the atoms, as both too few and too many
  kills the oscillation.

 Or get to the basic requirement of getting a pure H2 source to feed
 the beam source. The beam source itself, including the dissociator,
 would be a formidable project to do at home by itself.

  The size of the glass-bulb is not a fixed thing, during research and
  development different sizes glass-bulbs is used to establish the
  wall-shift aspects in order to adjust for it, which is needed in order
  to make absolute measurements on the free atom resonance or compensate
  into that regard.

 Interestingly, i think that the bulb would be the easiest part
 these days. At least around here, there are a few glas blowers
 for the chemical/pharmaceutical industry that also do single pieces.
 Getting it coated would only involve finding a company that does
 teflon coating (there do seem enough of them). From what i gather
 it's shape doesnt have to be exactly spherical down to the
 sub-milimeter range.

  As for reference, there is about one set of books and papers from a
  handful of journals and a bunch of patents which needs to the read in
  order to build up the knowledge-base for attempting something like it.

 Which papers/books would you recommend reading?

 And no, i don't think i'd attempt to build a H maser.
 I'm quite confident i could do the electronics part, but i know that
 i don't know anything when it comes to mechanics. Much less about
 handling high vacuum and atomic gas beams.

  It's a complicated field and several traps to fall into on the way. It
  is a fairly sizeable project to attempt.

 Yes, but it's fun to read about it :-)

Attila Kinali

 --
 The trouble with you, Shev, is you don't say anything until you've saved
 up a whole truckload of damned heavy brick arguments and then you dump
 them all out and never look at the bleeding body mangled beneath the heap
-- Tirin, The Dispossessed, U. Le Guin

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Re: [time-nuts] A philosophy of science view on the tight pll discussion

[Mark Kahrs]

I for one, have grown tired of the ad-hominem anti-intellectual attacks.
This is supposed to be about science and engineering, not words.  Therefore,
I'd like to see analysis.  As Lord Kelvin put it:

In physical science the first essential step in the direction of learning
any subject is to find principles of numerical reckoning and practicable
methods for measuring some quality connected with it. I often say that when
you can measure what you are speaking about, and express it in numbers, you
know something about it; but when you cannot measure it, when you cannot
express it in numbers, your knowledge is of a meagre and unsatisfactory
kind; it may be the beginning of knowledge, but you have scarcely in your
thoughts advanced to the state of Science, whatever the matter may be.

What I want to see in the future are equations.  Please use LaTex notation
so we all can see what's going on.  Until that happens, it's all just fuzzy
semantics --- neither science nor engineering.  If you make a claim, support
it with equations.  If you can't, then don't make the claim.  It's that
simple.


On Fri, Jun 4, 2010 at 11:15 AM, Steve Rooke sar10...@gmail.com wrote:

 On 4 June 2010 07:11, Didier Juges did...@cox.net wrote:
 
   WarrenS warrensjmail-...@yahoo.com wrote:
  Ulrich posted a bunch of logic stuff, some of which I did not
 understand.
 
  but  I do think he missed the main point
 
 
  I personally think Warren missed the point entirely, but it's just my
 opinion. This statement is a good summary of what has been going on. You
 cannot dismiss something that you do not understand, yet that's what you
 have been trying to do for a long time now.

 I'm not sure that that the point was made clear or if even there was a
 point to this unless you are taking a specific side.

 Examining things:-

 The physicist obviously had a a good general education which included
 biology, genealogy, logic and nursery rhymes. He deduced correctly
 that the likelihood of a black sheep occurring naturally via a second
 occurrence of natural selection and that the black coat was due to a
 genetic anomaly which indicated that it was very likely that the gene
 for a black coat was in the sheep that were close to the this place
 which meant that it was most likely that black sheep were in Germany.
 He dismissed the idea that the farmer had just shipped the black sheep
 into Germany because his daughter liked nursery rhymes as he logically
 knew that farmers never do anything that costs them anything only
 things that make them money. He remembered the age old saying, you'll
 never see a farmer on a bike. He therefore deduced that this was proof
 that there are black sheep in Germany.

 The mathematician was obviously deeply engrossed in his complex
 mathematics education which took up most of his time and didn't care
 to much for other subjects. He was a romantic and remembered his
 mother saying all the nursery rhymes to him when he was young. Being
 that he spent so much of his time in his own head, he had no real idea
 of life outside that and really had a childlike attitude to things in
 the outside World. When he saw the farm and the black sheep he
 obviously thought of a happy farming family and deduced that the
 really nice farmer had gone out of his way to find the only black
 sheep in Europe so that he could make his daughter happy. It did not
 cross his mind that a black sheep had anything to do with genetics but
 he had enough sense to know that animals had the same colours on each
 side, after all the zebra in his little farm set he had as a child had
 stripes on both sides. That was logical to him so he deduced that
 there was at least one black sheep in Germany.

 The logician ate, drank and slept pure logic all his life. As far as
 he was concerned, the World was all binary, true and false, black and
 white. To him everything in the World could be explained by logic and
 everything was logical. As logic explained everything he had no time
 for any other disciplines as they were superfluous, after all,
 everything could be explained by logic. Having never ventured from his
 deep dark dungeon with black and white walls he was intrigued to see
 the World outside. He made no assumptions on what he saw and always
 understood that everything could be explained by logic. It was
 therefore completely logical for him to deduce that what he was
 looking at was the black side of a sheep whereas he could not make a
 deduction on the other sheep as they were all facing the other way. So
 his deduction that there was at least one sheep with one black sheep
 was perfectly logical to him and he went back to enjoying his train
 journey.

 And the moral of the story is, you only see the World with eyes that
 are open and been trained to see what you have experience in. To step
 out of the square you are standing in can be very hard but the best
 approach to life is to adopt that of a child and enjoy all the
 wonderment around you.

  

Re: [time-nuts] Datum 2100L issues

[Mark Kahrs]

Ah, all good things come to those who wait.

patience is a virtue

An hour later, it had locked.

Meanwhile, this is what I have inside:

Boot Code - Tymserve_2100
  Rev 1.1   12/20/1996 13:07:21
Main Code - TymServe_2100LD
  Rev 2.85  11/06/2000 10:23:29

Is this the most recent firmware for the 2100LD?

On Thu, Oct 29, 2009 at 8:02 PM, Christopher Hoover c...@murgatroid.com wrote:
 Mark Kahrs wrote:

 I'm finally trying to get this epay 2100L time server to go.  First
 step was to talk to it, change the host number and then see what I
 had...

 It appears to me (or it, depending on who you ask), that two
 satellites are in view, to wit:

 26 ? sig
 09 0.000
 04 17.604
 10 0.000
 15 0.000
 01 0.000
 07 0.000
 28 0.000
 02 9.802
 27 ? sat
 Auto 2-D Sats: 4 2

 Above 6.0 is considered good.   But, the status command reveals it
 is freewheeling --- clearly, since it is neither tracking or
 locking.

 If I try and use the position command, I get this:

 28 ? pos
 GPS Engine Busy:2

 I can query the GPS software edition:

 14 ? gpsversion
 Nav 8.8 4/1/0 Sig 10.16 4/1/0


 You can give a position, but I don't believe it will lock it in -- it is a
 hint.  Here's how mine behaves:

 8 ? tim

 9 ? sig

 Invalid Command

 10 ? gps

 11 ? sig

 12 6.802

 02 -1.000

 29 1.600

 30 5.198

 15 0.000

 05 1.8

 10 4.401

 21 5.401

 12 ? sat

 Auto 3-D Sats: 12 30 10 21
 13 ? pos

 lat: 37.2678299 lon: -121.9767228 alt: 62.6665573

 14 ? gpsversion

 Nav 8.8 4/1/0 Sig 10.16 4/1/0

 15 ? vers
 Boot Code - Tymserve_2100
  Rev 1.1   12/20/1996 13:07:21
 Main Code - TymServe_2100
  Rev 4.1   12/01/2005 14:45:23
 16 ?

 What version is your software?

 -ch





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[time-nuts] Datum 2100L issues

[Mark Kahrs]

I'm finally trying to get this epay 2100L time server to go.  First
step was to talk to it, change the host number and then see what I
had...

It appears to me (or it, depending on who you ask), that two
satellites are in view, to wit:

26 ? sig
09 0.000
04 17.604
10 0.000
15 0.000
01 0.000
07 0.000
28 0.000
02 9.802
27 ? sat
Auto 2-D Sats: 4 2

Above 6.0 is considered good.   But, the status command reveals it
is freewheeling --- clearly, since it is neither tracking or
locking.

If I try and use the position command, I get this:

28 ? pos
GPS Engine Busy:2

I can query the GPS software edition:

14 ? gpsversion
Nav 8.8 4/1/0 Sig 10.16 4/1/0

So, any ideas?

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[time-nuts] HP 8660C-K10 phase modulation test set

[Mark Kahrs]

Among my mistaken acquisitions over the past is a phase modulation
test set for the 8660C (model 8660C-K10).

I've put two pictures here:

http://www.caip.rutgers.edu/~kahrs/ebay/8660C-K.1.JPG
http://www.caip.rutgers.edu/~kahrs/ebay/8660C-K.2.JPG

This looks like a type of phase noise test set: there is a LO in a
sealed box in one corner.  There are mixers and detectors and a
divider board.

I thought I would see if there was any interest from time-nuts before
I put it on the usual auction site.

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Re: [time-nuts] HP 106B part no.

[Mark Kahrs]

1854-0003:

Material: Silicon
NPN
Pw = 800 mW
Ft = 50 MHz
Vceo = 28 V
Package = TO-5
Hfe = 60/240 10 mA

No JEDEC part number.

On Sun, Aug 9, 2009 at 1:02 PM, Glenn Little
WB4UIVglennmaill...@bellsouth.net wrote:
 1854-0003 is a good part number. I have a few here that were removed from
 equipment.
 Possibly someone with the proper equipment could characterize this part and
 determine a suitable parametric substitute.

 73
 Glenn
 WB4UIV

 At 11:43 AM 8/9/2009, you wrote:

 Double check: Q11 is marked as 1854-0003.  I can't find it in any of the
 HP cross references.

 Brian - KD4FM


 Jim Palfreyman wrote:

 Hi all,

 Latest update.

 With some help and phone calls from Bill the fault seems to have been
 isolated. I have removed Q11 from inside the oven and it is cactus. Q9
 is also very suspect so I'm going to replace that for good measure.

 Q9 is a 2N1701 in a T08 package. Thanks to various people I should be
 able to track one down. Q11 is marked as 1854-0003 and that's an HP
 internal number and all I know. Might have to substitute that one.

 After all this I have some quality photos and can knock up some good
 descriptions of the repairs and the 106B internals if anyone is
 interested. Any websites hanging around that want to take what I have?

 Regards and thanks to all!

 Jim Palfreyman


 2009/8/9 Adrian rfn...@arcor.de:

 Re-read Jim's posts.

 To me it seems clear that he is talking about the 2N1701 Q3 in the upper
 right corner of fig. 5-12.
 He mentioned that +18 measures high, around 26V.
 So, the problem is NOT in the battery charger circuit.

 The purpose of that Q3 is to generate +17.4V (and +7V) from +26V, with
 the
 base being connected to +18V, thus the emitter voltage of Q3 is +18V -
 0.6
 to - 0.7V.

 The +18V regulator circuit is on the lower left of fig 5-8, A1A4 Outer
 Oven
 Controller. For a circuit description see 4-40 to 4-44.

 The +18V feed the AC amplifier (A1A2), the +15V through R14 (might be
 cooked
 if run at 26V for extended time) and CR2 on the same board, the power
 amplifier (A1A3), the outer oven temperature control circuit (decoupled
 +18V), and the inner oven control cuircuit A1A5.
 The 17.4V that are derived from +18V feed the dividers.

 Any adjustments make sense only after fixing the +18V supply.

 Actually, Q3 might as well be shorted. I would first remove it from the
 circuit to see if the +18V are then correct.
 If not, check the voltages at Q9 and Q7 of A1A4. Q9 is mounted on the
 oven
 housing cover.

 Regards,
 Adrian

 Bruce Griffiths schrieb:

 christopher hoover wrote:


  The 2N1701 is a general purpose transistor rated at 60V, 2.5A.


 I've mentioned this before, but it bears repeating.

 If you are having trouble with an old school linear power supply, in
 many cases you can replace the TO-220 PNP pass transistor *and* the
 reguatlor circuit (based on a 723 or whatever) with a modern
 integrated regulator in TO-220 such as an LT1581.  Strip the regular
 board of everything except for the the input and output caps (if they
 are still good) and wire up a pair of resistors to set the voltage.
  Add
 a couple of jumpers to complete the circuit.   And then you are
 good to go.

 -ch



 That probably wont work in this case.
 The supply is actually an NPN discrete darlington buffered 32V zener
 with a current limit transistor to set the battery charging current to
 one of 2 values.
 With the battery removed the supply output should rise to 32V - 2Vbe -
 a
 diode drop, ie about 29.8V or so.
 The series diode is required to isolate the battery from the regulator
 output when the main fails.
 It should be much quicker and easier to just find suitable transistors.

 Bruce


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[time-nuts] Stanford Telecom units

[Mark Kahrs]

Before I put these on flea bay, I thought I'd see if there was any
interest here.

These are Stanford Telecom GPS units of some variety I believe: model
5440 coder / data demod and 5430 baseband coder (featuring I/Q input).
I have no other information.

If there's no interest, they go onto da bay.

No reasonable offer refused - unreasonable offers ignored.

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Re: [time-nuts] Loran vets: http://www.loran-history.info/

[Mark Kahrs]

That umich document has to be one of the more interesting historical
tidbits...  For those who are in doubt, it appears to be D. L. Mills
bachelor's thesis (!).

On Tue, Jun 10, 2008 at 10:02 PM, Poul-Henning Kamp [EMAIL PROTECTED] wrote:

 For those of you playing with Loran-C, I found this page of Loran-C
 veterans material:
http://www.loran-history.info/

 This is also an interesting historical/technical document:
http://deepblue.lib.umich.edu/handle/2027.42/6634

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

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Re: [time-nuts] Neat toys on eBay for PN measurement

[Mark Kahrs]

); SAEximRunCond expanded to false
Errors-To: [EMAIL PROTECTED]

Hey, why not buy a 11848A (160117841068) from the same seller?  Only 2.6K$!
Put that in your PN system...

On 7/4/07, Richard (Rick) Karlquist [EMAIL PROTECTED] wrote:

 ); SAEximRunCond expanded to false
 Errors-To: time-nuts-bounces+mark.kahrs=
 [EMAIL PROTECTED]

  Basically this is a general-purpose microwave downconverter whose LO
 uses
  harmonics of the 640-MHz reference output from an 8662A/8663A to
  downconvert
  the signal to be measured to a frequency below 1280 MHz, where it is
 then
  mixed down to a baseband IF with the same 8662A's output.  An 8662A is
 not
  mandatory, but it's convenient because it can provide both LOs at once.

 Not only is an 8662A mandatory, but it must have the optional 640 MHz
 output
 AFAIK.
 How do you propose to operate an 11729 without an 8662?  It's not like you
 can
 feed any old 640 MHz reference into it.

 Rick Karlquist N6RK


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Re: [time-nuts] Government Liquidation

[Mark Kahrs]

I bought from DRMS directly before they contracted to govliquidation
and also from GL. I can say that it was smart of the govt. since they
(GL) are getting a lot more for each lot.  That being said, it's
always been a case of caveat emptor.  They have lots of interesting
stuff that doesn't normally see the light of day.  If you buy
remotely, then you'll have to pay a shipper: my experience with this
has been good but pricey.  Plan on $100 per package.


On 3/19/07, jshank [EMAIL PROTECTED] wrote:
 Hi,



 I have bought items from this site on and off over the years as well as
 directly form military DRMO.  You really need to go to the site to preview
 the item prior to purchase.  You will be surprised how good the items looks
 in the picture as opposed to what it actually looks like in person.  Be
 prepared to spend several hours getting into and out of some bases with the
 current security in place.  On a recent purchase of two 2465b which were
 advertised as powering up I found that neither would display a trace, in
 fact one was completely gutted of all the hybrid chips.  Even if I would
 have previewed these scopes I would have been unable to look inside as
 usually when viewing items you are escorted by a security personal, look but
 don't touch.



 It is incredible how high these items go when consideration all of the risks
 of buying.  As little as ten years ago you could regularly pick up bargains
 and if the unit worked it was a great deal and if it did not it was a fair
 price for a parts unit.

 Hope my experiences help.



 Jeff

 - Original Message -
 From: Jason Rabel [EMAIL PROTECTED]
 To: 'Discussion of precise time and frequency measurement'
 time-nuts@febo.com
 Sent: Monday, March 19, 2007 11:12 AM
 Subject: [time-nuts] Government Liquidation


  This is kind of on the same topic as the government surplus chit-chat...
 
  Just curious but has anyone bought stuff from the website:
 
  www.govliquidation.com
 
  
 
  I just started looking at it last night, they have a ton of stuff and
  right
  now everything has zero bids. I don't know if people all snipe at the last
  second or what.
 
  Thoughts / Opinions?
 
 
  Jason
 
 
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[time-nuts] STEL boxes

[Mark Kahrs]

I am going through my lab finally sorting things out.  I have uncovered two
STEL boxes I bought a while back.  They are models 5430 and 5440.  The 5430
is a baseband coder and the 5440 is a coder/data demodulator.  Because
of the labels (e.g. P(Y) clock, C/A clock, etc), I believe these to be GPS
widgets.  Would anyone know more?

Thanks!
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[time-nuts] Abbreviated book review

[Mark Kahrs]

I sent this last week but didn't see it, so I'll try again.

I checked out a new book from my local physics library Frequency Standards 
by Riehle (who is a PTB guy). It is published by Wiley-VCH.

Here's a table of contents:

1. Introduction
2. Basics of Freq. Stds
3. Characterization of Amplitude and Frequency Noise
4. Macroscope frequency references
5. Atomic and molecular frequency references
6. Preparation and Interrogation of Atoms and Molecules
7. Caesium Atomic Clocks
8. Microwave frequency standards
9. Laser frequency standards
10. Ion trap frequency standards
11. Synthesis and division of optical frequences
12. Time Scales and Time Dissemination
13. Technical and Scientific Applications
14. To the limits and beyond

I would say this is graduate level material, the equations come fast and 
furious, but overall it's comprehensive and interesting. The bibliography 
alone has 884 entries, which makes it possibly worth the price of admission. 
Speaking of which, it ain't cheap. But you probably guessed that, didn't 
you. How pricey? Like almost $200 pricey.
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[time-nuts] New? book

[Mark Kahrs]

I checked out a new book from my local physics library Frequency Standards 
by Riehle (who is a PTB guy). It is published by Wiley-VCH.

Here's a table of contents:

1. Introduction
2. Basics of Freq. Stds
3. Characterization of Amplitude and Frequency Noise
4. Macroscope frequency references
5. Atomic and molecular frequency references
6. Preparation and Interrogation of Atoms and Molecules
7. Caesium Atomic Clocks
8. Microwave frequency standards
9. Laser frequency standards
10. Ion trap frequency standards
11. Synthesis and division of optical frequences
12. Time Scales and Time Dissemination
13. Technical and Scientific Applications
14. To the limits and beyond

I would say this is graduate level material, the equations come fast and 
furious, but overall it's comprehensive and interesting. The bibliography 
alone has 884 entries, which makes it possibly worth the price of admission. 
Speaking of which, it ain't cheap. But you probably guessed that, didn't 
you. How pricey? Like almost $200 pricey.
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