from:"Oz\-in\-DFW"

On 6/24/2016 8:23 AM, Attila Kinali wrote:
> On Thu, 23 Jun 2016 19:28:15 + (UTC)
> Bob Stewart  wrote:
Lotsa stuff deleted
>> One more related question before this topic dies, if you don't mind.
>> What about the other side of building: stuffing the boards.  My GPSDOs
>> have about 120 parts per board, plus some custom work on the SMA connectors.
>> Is there a service out there that will populate boards with SMT components
>> for small orders at a reasonable price?  Small is 10 boards.
>  The advantage of "professional"
> companies like Alktech over "hobbyist" companies like macrofab is,
> that you get full professional support while the price does not differ much.
> E.g. while macrofab only does 4 layer boards if you specially ask for it,
> for Alktech getting any number of layers is standard procedure.
>
>   Attila Kinali
>
Just to correct a misunderstanding. Macrofab, Small Batch Assembly, and
PCB:NG are all professionals, not hobbyist companies. they focus on
small runs at low cost, but they are manufacturing professionals with
commensurate results.


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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

On 6/24/2016 9:32 AM, Attila Kinali wrote:
> On Thu, 23 Jun 2016 20:16:34 -0500
> Oz-in-DFW <li...@ozindfw.net> wrote:
>> Solder stencils make **all** the difference.
> Oh, yes! Please, do not try syringe dispensers! These fail more often than
> they work. Also pay the additional couple of bucks to get a steel stencil
> instead of a kapton one. Especially if you make more than one or two boards
> or those with fine pitch.
>
>   Attila Kinali
>
Laser cut Kapton are fine for a few boards - up to 5 or so.  You start
seeing the effects of use after six or eight and steel is clearly a
value. . I use them for most protos. 

If I'm doing anything really fine that would drive me to steel on
resolution alone, I pay someone else to do it.

Oshstencils are cheap, and they will do 4 mill Stainless Steel for 2X
Kapton cost.  Deal if I'm doing more than 5 boards.

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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

On 6/23/2016 9:36 PM, Bob Camp wrote:
> Hi
>
> The gotcha with “really slow” is that once you print the solder paste on the 
> board, it has a very 
> limited “open air” life. If you don’t get the board done fairly quickly, your 
> soldering quality can
> suffer quite a bit.
>
> Bob
>
For most of the paste formulations I've had no trouble with several
hours of working time. So you need to get at it, but really don't end up
hurting yourself, but can't leave it overnight. .

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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping

On 6/23/2016 10:53 PM, Chris Albertson wrote:
>> Am I missing some obvious cheapie oven without these types of problems?
>
> A lot of people are building them from Black and Decker (and the like)
> toaster ovens.  Use Arduino for controller or just eyeballs. oven
> thermometer and wrist watch.It is not rocket science the Arduino
> controller software reads a thermocouple and controls an on/off relay.
> Lots of instructions around if you google for reflow toaster oven.
I'm using a
PicoReflow.https://apollo.open-resource.org/mission:resources:picoreflow 
It's Raspberry Pi based, so the board cost is about the same as an
Arduino, but I use my tablet as the user interface AND tweaking profile
is trivial unlike most of the Arduino based stuff. The system uses an
internal web server and can be connected to a local monitor, or a web
interface. All the control logic is in Python. I used the tablet browser
and I don't need to stand next to it to monitor operation. This is
particularly handy when I'm baking out parts.  I hand wired the
interface board (trivial I/O) and used a purchase MAX31855 based board
for another $20 from
http://www.playingwithfusion.com/productview.php?pdid=19=1001
(love the site name)

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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

Disclaimer:  I've not used any of these yet.  New style assembly houses
are MUCH cheaper than traditional proto shops.  The ones I'm planning on
trying are:

Macrofab (Houston)  https://macrofab.com/

pcb:ng http://pcb.ng/index.html (currently in beta with **deep**
discounts.   $1/sq in + BoM cost

Small Batch Assembly  http://www.smallbatchassembly.com/

All of these guys have their advocates. All will do under 10 pcs.I
plan on running a similar job through each of them and seeing what I find.

On 6/23/2016 2:28 PM, Bob Stewart wrote:
> One more related question before this topic dies, if you don't mind.  What 
> about the other side of building: stuffing the boards.  My GPSDOs have about 
> 120 parts per board, plus some custom work on the SMA connectors.  Is there a 
> service out there that will populate boards with SMT components for small 
> orders at a reasonable price?  Small is 10 boards.
>
> Bob - AE6RV
>
>

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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

2016-06-23 Thread Oz-in-DFW

I'll second this, and suggest you consider:

 1. Pick and place machines use a lot of floor space (even for the
"small" ones are more than 1/2 a bench.)
 2. Even the best ones require pretty continuous tuning. If you aren't
using them continuously each new run is a new and different
experience.  Often unpleasant for the first few scrapped boards.
 3. You can only place a limited list of parts for a run.  If you have
one more part than the machine will accomodate, its a second (or
third, or fourth pass.)
 4. They are all high maintenance in addition to requiring tuning. A lot
of the maintenance is based on calendar, not operation time.  Even
and idle machine requires time if you actually want to use it
eventually.
 5. Most are closed software loops. You work around their poor (or un)
documented formats and bugs.
 6. There are really cheap small batch assembly houses coming online
that will do under 10 units. See Macrofab, PC:NG, Small Batch
Assembly are fairly quick turns.

If all you are doing is protos, hand placement, mylar solder stencils
(see Oshstencils and others) and a hacked toaster oven are a good
solution. The $500 Chinese reflow ovens seem to require more (re)work
that a $50 toaster oven.  If you use stencils to place the solder, part
placement is as fast (or faster) than through hole parts. I have to use
a microscope.  I'm shaky enough that  may need to built some Waldoes
soon.  ;-)

I just did six moderately complex boards (no fine pitch parts) and that
was 2-3 too many for me.

Solder stencils make **all** the difference.

Oz, in DFW

On 6/23/2016 6:21 PM, Bob Camp wrote:
> Hi
>
> You can indeed get a pick and place for under a thousand dollars. I wold not 
> use one of them, but they do exist. It all depends on how much of an 
> “advantage” you want over a hand place approach. A half way decent screen 
> printer will run $500. Some sort of reflow setup will be a couple hundred. 
> You can go cheap on the printer and get it down to $100 or so. A rebuilt 
> toaster oven will run $20 or less. It all is a matter of how much hassle / 
> how tight pitch you want to deal with.
>
> Bob
>
>> On Jun 23, 2016, at 6:38 PM, Bob Stewart <b...@evoria.net> wrote:
>>
>> Thanks Bob et al,
>>
>> This is about what I expected, but I had to ask.  I wonder how long it'll 
>> take for that several thousand bucks for a pick-n-place machine to become a 
>> couple hundred?  That would be the final hurdle for the tiny electronics 
>> business.
>>
>> Anyway, I've had my say and we can let this die.  Thanks for the responses!
>>
>> Bob

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Re: [time-nuts] HP 106a oscillator connectors question

2016-06-04 Thread Oz-in-DFW

Several have suggested that these are 10-32 connectors.  If this is
true, a 10-32 nut will thread on them with no trouble.  I believe these
**may** be the 1/4" diameter variant that was 93 ohm characteristic
impedance.  I **think* they are called an S-93.  Still 32 tpi, but 1/4"
in diameter. You can test the thread pitch with a 6,8, or 10-32 bolt.
There was another even more obscure connector that used a coarser pitch. 

And before the 'not 50 ohm' firestorm starts - it doesn't matter.  This
is only 6" or so of cable, the mismatch impact is miniscule at this
frequency.  They were far more concerned with mechanical ruggedness.

On 6/3/2016 4:04 PM, cdel...@juno.com wrote:.

> Need help identifying the RF connectors on the unit.
>
> They are not SMA but look to be the same diameter. would need two
> adaptors or a couple old cables with the matching connector I could
> splice into. I had to poke in a wire and use clip leads!
>
> Cheers,
>
> Corby
>

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Re: [time-nuts] Spectrum Analyzer Specifications [Phase noise tester Bare Boards and Layout]

2016-03-28 Thread Oz-in-DFW

On 3/24/2016 1:08 PM, Bob Bownes wrote:
> Don't really need anyone who can order up bare boards in bulk anymore. 
Oshpark; www.oshpark.org does 2 layer for $5/sq in and 4 layer for
$10/sq.  That price gets you three boards. Designs can be made public so
anyone can buy them. I buy from them all the time. About 2 weeks turn.

There are several Chinese suppliers that will do 2 X 2 inch boards for
about $20 for 10 copies, about $30 by the time you have them in your
hands. Also about 2 Weeks turn, though may end up as much as 4 weeks.
> Many
> of the board houses will make them on demand for single customers. They fit
> them into empty spaces in larger board orders.
>
> I'd love one if someone is willing to draw it up. I'll even put together a
> Mouser BOM that can be shared if N8UR will layout the board. :)
If we can hash out a schematic, I can do a layout as a spare time
project - but I don't have a huge amount of spare time in the plan
before June or July.  I'd use KiCAD

We can do a public BoM on Digikey or Mouser so folks in the EU most of
the rest of the world have easy access.

There are few questions I have - surface mount or through-hole.  Through
hole parts are getting harder to get.  If you are afraid of SM we have
have a low cost service like Macrofab build small batches (they'll do as
few as one) and if we use parts from their standard parts list we only
pay the part cost, not the insertion cost. They'll also buy boards from
Oshpark. If you are not afraid of SM, buy a stencil from Oshstencils
https://oshstencils.com and get your hotplate out.

Connectors: SMA are cheap and reliable. More delicate than TNC, but not
by much, and a whole lot cheaper and more available as surplus.

> Bob
> KI2L
Oz, N1OZ

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Re: [time-nuts] LPRO-101 BITE (~lock) Signal Always Low...

2016-03-23 Thread Oz-in-DFW

On 3/23/2016 11:45 AM, Burt I. Weiner wrote:
> Would someone please tell me what "BITE" signal is.
>
> Thanks,
>
> Burt, K6OQK
>
> >Hi
> >
> >Which strongly suggests that the BITE line is telling the truth. The
> unit is
> not in lock
BITE = Built In Test Equipment

It's used to describe internal features designed to indicate the
operation of the unit in which they are incorporated.  Milspeak for
self-test, but implying more (usually far more) than a cursory test.

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Re: [time-nuts] Fw: 5065

2016-03-20 Thread Oz-in-DFW

On 3/19/2016 1:43 AM, tim...@timeok.it wrote:
>
>
>
> Tom,
> it is not, see the Farnell code below followed by Amphenol part number:
>
>
> Farnell code: 1914117 pn 97-3106A18-22S connector
> Farnell code: 1654733 pn 9779-513-8 plastic ring
> Farnell code: 151628 pn 97-3057-1010-1 cable clamp and bush
>
> see also: 
> http://canada.newark.com/amphenol-industrial/97-3106a-18-22s/circular-connector-plug-3-position/dp/74C6856
>
> Luciano
> www.timeok.it
>
> Message sent via Atmail Open - http://atmail.org/
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If you are in the US, Mouser's price and delivery for these is MUCH
better. They show 7 in stock. Mouser also has a presence in the EU and
some places in Asia, but I can't see the pricing or availability

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Re: [time-nuts] Why would Keysight UK uncertainty measuring 1 MHz be as high as 7.6 Hz?

2015-08-28 Thread Oz-in-DFW

The uncertainly listed seems to be 7.6 mHz (milliHertz, or .0076 Hz. A
bit better that you mention..

On 8/28/2015 3:48 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
My LCR meter came back from Keysight UK last week, where it was
calibrated. This instrument works at various frequencies from 20 Hz to 1
MHz, so obviously has some sort of oscillator in it. But I don't think the
absolute accuracy on frequency is important on this, as it does not even
have the ability to set to an arbitrary frequency. There are only 8000 or
so steps, and at the high end, some of those steps are more than 100 kHz
apart!!! So clearly frequency accuracy on this instrument is not that
important.

Anyway, the cal certificate, a copy of which I put here

http://www.kirkbymicrowave.co.uk/cal_certificates/Keysight-standard-calibration-with-uncertainties-for-4284A-precison-LCR-meter-18-08-2015.pdf

shows on page 5 that it was checked at 1, 8, 20, 80, 400 kHz, and 1 MHz.
But the uncertainty reported (7.6 Hz) seems extremely high, given they used
a 53132A counter as a working standard, and a 5071A primary frequency
standard. Why should the uncertainty be so high? Am I missing something?

When they done my VNA last year

http://www.kirkbymicrowave.co.uk/cal_certificates/Keysight-standard-calibration-with-uncertainties-for-8720D-vector-network-analyzer-16-09-2014.pdf

the uncertainty on frequency was about 5 orders of magnitude better than
that. The 10 MHz timebase was measured with an uncertainty of 0.0010 Hz.

I checked the Keysight UK accreditation (by UKAS) for frequency

http://www.keysight.com/upload/cmc_upload/All/UKAS_S_2015-08-14_Eng.pdf

and see over the range 0.1 Hz to 500 MHz, which covers the LCR meter, their
accreditation is 6.0 in 10^11 + 0.020 nHz.

I can't believe they are unable to measure better than 7.6 ppm on
frequency, so are wondering why the uncertainty is so high, even though I
am sure such an uncertainly is very acceptable for this application.

It is either an error on the cal certificate, or I am missing something. I
expect it is the latter, and hoping someone here can fill me in.

Dave
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Re: [time-nuts] Small time server for mobile use.

2015-05-24 Thread Oz-in-DFW

On 5/24/2015 5:46 AM, Attila Kinali wrote:
 On Wed, 13 May 2015 09:07:44 -0500
 bownes bow...@gmail.com wrote:

 For the advocates of RPi solutions, I put about half a dozen in to support 
 some non mission critical infrastructure about a year ago. We are using them 
 for for logging, reading QR codes, running a vending machine, kiosk web 
 browsers, and similar tasks. In short, nothing requiring heavily lifting. 

 I've been incredibly dissappointed in the results. Well over half of them 
 have needed replacement and not a one runs reliably. They need rebooting at 
 intervals from hours to a few tens of days to recover from total lock up. 
 The problem is not environmental, power or SD cards. 
 Do you know what the problem is?

 I know that the RPI has pretty cheap design (like most of these super-cheap
 SoC boards) and does suffer from a few problems. The most common one
 is under-designed power supply. Together with the ultra-cheap wall-wart
 supplies mostly used results in a quite decreased MTBF due to spikes/drops
 on the power rails (BTW: soekris suffers from that too, just that a better
 wall-wart supply doesn't help). Depending on the environment, in which
 those boards are run, overheating might also be a problem.

 Other than that, i am not aware of any software or hardware issues that
 would cause the RPI, or any other board, to run unreliably.

   Attila Kinali
Many of the chips in the original PI run rather hot and need heatsinking
if used in other than free-air ambient temperatures.  I've given up on
them for anything that I can't easily reset.

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Re: [time-nuts] Time in a cave

2015-05-14 Thread Oz-in-DFW

On 5/13/2015 4:44 PM, Tucek, Joseph wrote:
 In response to Oz-in-DFW

 Given your description here, I'm guessing a millisecond or ten 
 will do that as long as local cluster relative accuracy is maintained.
 Spot on; I hope I'd made it clear earlier, but perhaps I've been 
 communicating poorly. 
Sort of.  All I remember without combing through the notes were
subjective relative statements and no quantitative values.
  My goals w.r.t. to sync to UTC and w.r.t. holdover are very loose.

 I do need time sync intra-cluster to be tight (sub millisecond, 100 nano as a 
 stretch goal).  
There are four orders of magnitude between 1 millisecond and 100
nanoseconds - that's a heck of a stretch.  Is this what you really
mean?  What is the cluster doing that needs such good absolute time? 
did you mean 100 microseconds as a stretch (one order of magnitude.)
 UTC sync can comparatively be terrible; 10-1 ms is fine,
10 e -1 milliseconds as in 100 microseconds?  This is achievable but
will require some care.  Even 10 ms is 'pretty darn good' for all but a
very few industrial applications. Most datacenter applications I've done
only guarantee 100 ms absolute.  Internal distribution is much better of
course.
  and I can live with bad NTP, 100 ms if I must.  From specs, */really/* 
 good quartz is my limit and /good/ quartz is acceptable, so long as it 
 doesn't mess with the intra-node PTP tightness.  
It doesn't until it gets really bad.  Like shattered bad. 
 I'm mostly looking at TCXO options. OCXO isn't out of the question, but 
 rubidium doesn't seem to give $/value.
This begins to sound like you really don't know what you need and are
specing the best you can afford to be sure. In my experience this is a
good way to get bitten, because you really are not sure.  Many
industrial applications require excellent relative accuracy within a
cluster. Time synchronizing chains of rotating machinery is surprisingly
demanding, but you almost don't care about absolute accuracy outside the
local clock domain. It's a rare application that /needs/ better than a
second absolute. Most of these are 'big science' projects or
infrastructure that covers a large geographical areas.  Time errors can
be catastrophic.  If you are working with one of the rare ones, you
really need to understand the real requirement and then design for that
with margin. If not, you should still be able to estimate the absolute
need and /then/ add margin to that. 
 Yes, the master will have a fairly low phase noise local oscillator as
 it's internal reference. Everything will synch to that.  If all you are
 doing is syncing the local cluster you don't even care about time
 outside. This is true for most industrial applications that are just
 syncing machinery.
 Thanks for the info.  PTP isn't as well understood/documented as NTP, so I've 
 not been as certain about my decisions. Of course, that is fair for a 
 relatively new standard. 
PTP is both well understood and documented, but it sounds like it's not
for your industry and application. This tends to imply that it's not
time critical.
  

 Currently, I think my two best options are: 1) CDMA enabled PTP appliance 
 (set and forget), or 
No, for a few reasons:

First, it's going away sooner than you think. Verizon says 2021, but
they are doing everything they can to accelerate that.  I'll be
surprised if it's still viable in 2018. Analog cellular was shut off
in February of 2008, but was barely useable in metro areas several
years before that. The operators shut off all but the absolute
minimum capacity to save costs and provide incentive to move to
newer technologies. Expect your cave to lose coverage much sooner
than 2021.

Second, while in-spec cellular is a good frequency reference, there
is no requirement for absolute time that you have access to.  The
time available over the air interface can be off by /minutes./ 
Typically it's within seconds of UTC and many operators now do far
better than that.  You are better off with WWVB or open Internet NTP
in terms of predictable accuracy.

 2) PTP appliance running as stratum 2 from good NTP.
Yes, or something you operate that is network close and has a GPS
reference.

 Thanks to everybody for the feedback.

 -joe

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Re: [time-nuts] Time in a cave

2015-05-13 Thread Oz-in-DFW

On 5/12/2015 6:00 PM, Tucek, Joseph wrote:
 I'm looking for information on non-GPS time sources.

 For background, I need to provide PTP to a cluster where we don't have line 
 of sight to the sky, and are unlikely to get roof-rights without a fight.  
 There are CDMA solutions that would work (e.g. Endrun Technologies), but I 
 was wondering if there were any other options.  I either need an indoor 
 capable PTP, or an indoor capable PPS.  Microsemi claims to have an indoor 
 capable GNSS system, but I've yet to find a sales rep to talk about it; if 
 anyone has a link to one who can, I'd love to find out the problems^W^W^W^W 
 talk to them about it.

 For an example of something that almost but doesn't quite work, Beagle 
 Software has a CDMA NTP server, but they do neither PTP nor PPS in the CDMA 
 version.  Similarly, Meinberg will sell a PTP unit that freeruns (if you 
 override the config), but they have no solution to discipline via CDMA.

 I'm also curious if anyone has any idea about non-GPS time sync after CDMA 
 gets turned off (can I get time from 4G?).

 My endgame worst case is to just do PPS from a stratum 2 NTP (or even a 
 freerunning oscillator) and lie to my PTP server; hard sync to UTC is a 
 secondary concern so long as the cluster agrees with itself.  Endrun is 
 looking pretty good, but I'd really like to have a second option to compare 
 against.

 -Joe
LTE and WCDMA both provide time, but it's a function of how carefully
the operators actually maintain it.  That's less of a problem today, but
there are no absolute /guarantees/, even with IS-95 CDMA.  The only
guarantee is that the basestations in the system will track within a few
microseconds of each other.

What you don't say is how much accuracy you need.  Is a hundred
milliseconds enough, or do you need sub-microsecond absolute accuracy?
How much holdover accuracy do you need? These are considerably different
probelms.  You indicate that you need to provide PTP to a 'cluster.'  Is
relative accuracy within the cluster all that's important, or do you
need to coordinate with the outside?  If so, there are a host of other
considerations.

Too many applications grossly over specify some requirements in the name
of safety and miss critical performance needs.  More information might
let the group a more complete answer. 

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Re: [time-nuts] Time in a cave

2015-05-13 Thread Oz-in-DFW

On 5/13/2015 1:01 PM, Tucek, Joseph wrote:
 In reply to everyone (but mostly Mark Spencer):

 Does your cave have any connectivity to the outside world ?
 The cave has network connectivity, and is network close (but not physically 
 close) to a high-quality surveyed GPS disciplined stratum 1 NTP server which 
 we have permission to run off of.  The cave is actually partially 
 underground, and the bit that isn't has building on top of it.  CDMA comes in 
 enough to make your phone ring or receive a text, but phone calls are all 
 I'm amazed it didn't drop ye[call dropped].  Antenna runs for GPS are not 
 an option (I asked); it's too expensive/hard to get permission/too long, 
 depending on which route to sky you want to take.

 Are there any places your cave has connectivity to that might 
 have enough of a sky view to provide periodic gps coverage ?
 See above, but yes.

 Do you need a COTS (commercial off the shelf) solution or 
 can you accept something that has been kludged together ?
 I can accept semi-kludge.  Custom firmware on a model xyz phone sourced 
 from ebay with a mere 5 wires soldered is great for fun time (and for fun I'd 
 love to try it), but not so much for this.  Single COTS would be great (yeah, 
 and I want a side of fries with my flying unicorn), but here's two (or 3, or 
 n) COTS things you usually won't plug together, but... is fine.  Maybe 1 
 soldered wire

 Do you need a Peng or other professional to sign off on 
 the solution ?
 Thank goodness no.  We also don't need traceability to NIST either.

  A bit more information that people requested.  We only need to be 1ms to UTC 
 (100us would make some people happier, but then so would a GPS antenna run).  
 The PTP sync inside the cluster, however, needs to be tight (sub 1 us if 
 possible).  
PTP will do this if proper implemented, so it sounds like you're good
there.
 Holdover isn't critical (24 hour OK, weekend better, month is overkill) so 
 long as sync within the cluster remains tight. 
This is where a lot of smart people get into trouble. Don't thing of
holdover as meeting all worst case specs.  Figure out what you /really/
need.  What will allow everything to work without catching fire?  Given
your description here, I'm guessing a millisecond or ten will do that as
long as local cluster relative accuracy is maintained.

It's really easy to over-specify this and get into exotic clock (for an
industrial application) territory. 100 usec in 72 hours is 3.86 e-10
which is still in the range of a */really/***good quartz oscillator.

There's a nice chart on slide 13 here:
http://freqelec.com/oscillators/understnding_osc_specs.pdf

I had a telecom customer that needed 5 us relative accuracy between all
nodes synced over GigE.  The specified 72 hour holdover at 1 us
(3.86E-12) and were surprised (and offended) when when we said it would
require a Rhubidium standard. After saner heads prevailed we were able
to ship standard product.
  The cluster itself has proper hardware PTP support (NICs and switches) 
 throughout, and is low radius -- 2 switch traversals from the grandmaster 
 to each node tops.

 As for everyone's comments so far, it seems that there is an assumption that 
 any PTP master worth its salt will keep its slaves tightly synced to 
 one-another even if it has lousy sync to UTC.  Am I reading between the lines 
 correctly?
Yes, the master will have a fairly low phase noise local oscillator as
it's internal reference. Everything will synch to that.  If all you are
doing is syncing the local cluster you don't even care about time
outside. This is true for most industrial applications that are just
syncing machinery.

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Re: [time-nuts] Acquired a Symmetricom 5817A-05Q / Power connector Question

2015-05-09 Thread Oz-in-DFW

On 5/8/2015 9:11 PM, M. George wrote:
 I took delivery of a Symmetricom 5817A with the 05Q DC power option.  The 8
 port seems to be going a little less than the 4 ports... not sure on the
 reasoning there... however I picked it up on the usual auction site for
 ~125.00 shipped.  I thought that was reasonable assuming it works.

 Anyway, I'm not too proud to admit that I'm not familiar with the power
 connector that apparently comes with the 05Q option.  I have a link below
 to a couple of pictures.   Maybe I missed something obvious when poking
 around on the internet for documentation, but I can't find anything that
 describes this connector.  I assume it is stock?  The +DC input pin/wire
 can be seen just inside the white tube... again, maybe this is obvious to
 real time-nuts!  I'm working on that time-nut thing!

 You can browse to the pictures here:

 http://www.nc7j.com/downloads/NG7M/Time-Nuts/5817A-05Q/

 Max NG7M
According to the datasheet it should be a female SMC but that's hard
to call in this case.  SMC connectors have jacks and plugs, not Jacks
and Jills because the contact and housing genders lead to confusion. 
See the top of the right column of page 3 here:

http://www.marubun.co.jp/product/network/base/qgc18e03bzbd-att/GPS_Active_Splitters.pdf

I believe they mean a jack, which should look like this: 

http://www.amphenolrf.com/media/wysiwyg/SMC_4.jpg

Yours appears to have been broken off.  I don't think I have any repair
parts, though I do have some mating connectors.

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Re: [time-nuts] Striking change in iPhone time accuracy with 8.2

2015-04-02 Thread Oz-in-DFW


On 4/1/2015 2:31 PM, Paul wrote:

On Wed, Apr 1, 2015 at 12:33 PM, Reid Oda reid@gmail.com wrote:


This seems to imply that the iPhone does get sub-second timing info from
GPS. Can anyone confirm/deny this?


As of iOS N where I believe N == 5 it does the equivalent of calling
ntpdate every few hours if the network is available.  I assume it uses the
mobile system if the network is unavailable and you have a cellular radio
because the devices (can) have a lot of drift.
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The phone has to keep synch within a few microseconds of the network.  
There was a time when operators were very sloppy about clock time and 
really only worried about network frequency, but most operators are now 
maintaining 50 ns or so at the base stations and have to maintain within 
5 microseconds to meet the LTE specs.  How much of this is preserved 
through to the user interface is anyone's guess.


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Re: [time-nuts] Minicircuits specs

2014-11-29 Thread Oz-in-DFW


On 11/29/2014 12:08 PM, Thomas S. Knutsen wrote:

2014-11-29 16:24 GMT+01:00 Dave M dgmin...@mediacombb.net:



Yeah, that's a good way to completely avoid the issue.  Since I'm the only
target audience for my efforts, then I don't mind the extra components.
I'm beginning to realize, as I get deeper into building my own stuff, that
a VNA is quite a desireable piece of equipment.  Unfortunately, I'll have
to make use of my spectrum analyzer and RLC meters instead.



Going a bit off topic, but there are decent VNA's avaible for an fair
price. There is the N2PK VNA thats avaible as an board + digikey partlist
and gives a 120dB dynamic range VNA from 10KHz to 50MHz, or there are the
VNWA avaible ready buildt from the UK with 70-80dB dynamic range to 1.3GHz.
Those are the ones I know that have true phase reading and can solve for
the sign of the phase.

Of course there are older HP or RS boxes, and probably others as well, and
by shopping around one can get decent gear at a fair price, but with some
added complexity of doing the measurments.
Having an VNA helps doing measurments, but a lot of cool things can be done
with a spectrum analyzer, adding a simple return loss bridge makes that
into an quite decent scalar VNA.

Brr. (its probably cold up here in the north :)
Thomas LA3PNA.


Or the DG8SAQ 1.3 GHz VNA for about £350 GBP or ~$550 I suspect this is 
what you are calling the VNWA available ready built from the UK with 
70-80dB dynamic range to 1.3GHz.


http://sdr-kits.net/VNWA3_Description.html

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Re: [time-nuts] Quad Driven Mixer 5 to 10 MHz Doubler Atricle

2014-11-12 Thread Oz-in-DFW

Only a small subset of QEX articles on available in digital format. This 
isn't one of them. We'll either need to get a copy from the author, or 
from a QEX subscriber.


On 11/12/2014 2:34 PM, Dave M wrote:
I am able to download the files associated with the article, but not 
the article itself.  Guess I need to be a paying member to get the 
article.  The only files in the download are the XLS file for 
calculating the filter values, and the parts list.


It's at http://www.arrl.org/qexfiles in the year 2011 listings, 
filename 3x11_Roos.zip
titled Converting a Vintage 5 MHz Frequency Standard to 10 MHz with a 
Low Spurious Frequency Doubler


Dave M

John C. Roos via time-nuts wrote:

Several list members contacted me expressing interest in the
article. None of them were able to download much or anything
from the ARRL QEX web site. That includes me and other ARRL members.
I am working the issue with one call to ARRL so far today. I will
contact Larry Wolfgang at ARRL and see what Ican bust loose. So
hang in there. It is a cute technique, not originated by me, but
useful. Right now I have to get the ARRL FMT done first.
-73 john c roos k6iql



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Re: [time-nuts] quartz oscillator injection locking

2014-07-20 Thread Oz-in-DFW

On 7/19/2014 3:45 PM, paul swed wrote:
 Attilla I did look at some of the documents. But none showed practical HF
 class injection locking. Say as an example a 6 MHz xtal to a 1 or 2 MHz
 reference.
 It maybe as easy as a single transistor in the oscillators ground lead.
Paul, everything I seen done in this frequency range has been a small
coupling cap in the base/gate of the crystal oscillator - small enough
that the reactance was large relative to the base/gate impedance.  The
resulting injected signal amplitude was ~5-10% of the normal operating
amplitude at the base. Lock detection was done with a mixer looking for
DC output.
 Always on till a brief pulse from the 1 or 2 MHz ref cuts it off. I think I
 just talked myself into an attempt.
 Regards
 Paul
 WB8TSL



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[time-nuts] Symmetricom Z3827A Info? [seems similar to 58534A]

2014-07-19 Thread Oz-in-DFW

This looks like the same mechanical package and interface connector as
the venerable Symmetricom/HP 58534A timing receiver.  All the
descriptions I can find describe identical function seemingly targeted
at the cellular base station market.

Does anyone have a pointer to documentation on these? Google has not
been my friend in this case.

I'm, looking for a few more 58534A for spares in an application and I'm
wondering if these might be close enough to do the deed.

Oz, In DFW

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Re: [time-nuts] question for expert time guys

2013-02-01 Thread Oz-in-DFW

On 2/1/2013 3:45 AM, Hal Murray wrote:
 rickhar...@gmail.com said:
 I would like to triangulate a position of a device which moves using 3 fixed
 positions devices of known location. The idea is to have these operate on
 915mhz or 434mhz or 2.4ghz or appropriate frequency. 
 I'd like a range of 150 feet or better and accuracy of 3 feet or better. 
Doing this on radio will be tough.  You are likely to need on the order
of 10 or 20  MHz of ranging bandwidth to get the accuracy you want. 
This is also overkill in the extreme. 

For this range an line of sight I'd do it acoustically. Get some
piezoceramic transducers and do it at 40 KHz or so.  Transducers are ~$6
in single quantities.
http://www.mouser.com/ds/2/209/KT-400482-193462.pdf  Time of flight is
about 13.5 inches per *milli* second, so your microprocessor will have
time to do it's nails after processing ranging data.  You should also
get good accuracy and resolution. In general you shouldn't need to if
you are using active transmitters at both ends, but if you are worried
about multipath reflection use a PN code and use the first correlation
peak. 

Rich

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Re: [time-nuts] OT - USB to LPT Adapter - Does it exist?

2013-01-11 Thread Oz-in-DFW

On 1/11/2013 7:09 AM, J. L. Trantham wrote:
 Not sure where to ask this question but thought I would start here.  

 Is there a way to connect a parallel port to a computer via USB?  Not a
 device that shows up as 'USB Print Support' but, instead, shows up in Device
 Manager as an LPT port?  I have been able to do it via PCMCIA to Parallel
 Port adapters but I have never found a USB device that would do this.

 My goal is to connect a parallel port chip programmer via USB but the
 software only looks for LPT ports.  It works with PCMCIA to parallel port
 adapters but I haven't solved the puzzle yet with a USB connected device.
Yes, there are standard devices that do this.


$10 from Newegg if you are in the US (and it looks like you are.)

http://www.newegg.com/Product/Product.aspx?Item=N82E16812186125nm_mc=KNC-GoogleAdwordscm_mmc=KNC-GoogleAdwords-_-pla-_-NA-_-NAgclid=CPGX2bqK4bQCFemiPAodDXcAzQ

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Re: [time-nuts] GPS antenna in attic?

2012-11-27 Thread Oz-in-DFW

While NPT (US) and BSPT (UK) are different, 1/2 and 3/4 variants are
both 14 threads per inch and are similar enough to intermate, but are
unlikely to seal.  Since sealing is not a requirement here it ought to
be good enough. 

Failing that, maybe one of our members on the continent would send you a
short piece for a nominal fee.  As I understand it, all continental
European plumbing that is not hard metric is BSPT, and most is not hard
metric so it's a hardware store item.

Rich


On 11/26/2012 8:28 PM, Peter Gottlieb wrote:
 Unfortunately not, it's part of the molded bottom piece of the antenna
 casing.

 On 11/26/2012 9:24 PM, Chris Albertson wrote:



 On Mon, Nov 26, 2012 at 5:51 PM, Peter Gottlieb n...@verizon.net
 mailto:n...@verizon.net wrote:

 The antenna I got fron Nichegeek on ebay uses British Pipe
 Threads! Just
 can't get anything here that matches it.  Perhaps I should just
 get a unit
 with regular NPT size threads?  Can anyone recommend a specific
 model
 which works well with the Thunderbolt and has such a threaded
 bottom?


 The typical antenna has a flat bottom that is bolted to some kind of
 mounting adaptor.   Perhaps the thing with the British treads will
 un-bolt.   THen you can buy a pipe flange at any hardware store.
 -- 

 Chris Albertson
 Redondo Beach, California
 


 No virus found in this message.
 Checked by AVG - www.avg.com http://www.avg.com
 Version: 10.0.1427 / Virus Database: 2629/5420 - Release Date: 11/26/12



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Re: [time-nuts] Warning if buying from directly from Agilent via eBay with Paypal.

2012-11-17 Thread Oz-in-DFW

On 11/17/2012 4:37 PM, J. Forster wrote:
 Perhaps. That opens the possibility of linking a PayPal account to a bank
 account, then zeroing the balance. Somehow, I doubt that actually works.

 -John


Then you pay the overdraft charge...

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[time-nuts] FS: Datum 18636-04 Timing RX

2012-10-24 Thread Oz-in-DFW

Operating condition unknown; $10 + shipping. 

If someone can offer the pinout I'll power it up and test it. 

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[time-nuts] Sold: Tek DC510 TM500 Counter (parts or repair)

2012-01-22 Thread Oz-in-DFW

On 1/22/2012 1:14 PM, Oz-in-DFW wrote:
 Unknown, untested, looks to be complete but clearly needs attention.

 Known issues:

 INST ID button is sticky
 Missing a side cover
 CHANNEL B BNC out of round, but looks reshapeable.
 ARM SMB is damaged and will need to be replaced.

 High Res pics at http://www.ozindfw.net/sell/DC510/

 $50 or best offer +$15 shipping in US.  International shipping is
 available, but you'll cover all costs, fees, and tariffs.
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Re: [time-nuts] No more 60Hz! TEC Elimination

2011-06-27 Thread Oz-in-DFW



On 6/24/2011 9:20 PM, Will Matney wrote:
 However, I should have
 said, one should never run a 60 Hz transformer, or motor, on the same line
 voltage it was rated for at a lower 50 Hz.
Most modern commodity transformers for electronic power supplies are
specified for rated performance from 47 to 63 Hz.

Most power distribution system products for use in the US I've seen are
rated at 60 ± 3 Hz though some stuff from European manufacturers is
rated at ± 2.5 Hz.  I guess it's a holdover from 50 Hz specs. 

The power companies seem to spec normal variation at a max of 0.1 Hz
though I understand the max offset they use by agreement for phase
adjustment is about 0.02 Hz.

A lot of large machinery has a a great deal of independence from the AC
line frequency.  Even a 60 year old paper mill I did some work for had a
mechanical phase adjustment driven by large DC motors on the machines in
their line.  IIRC the controls guy said they could compensate for 1 Hz
line frequency variations over 10 seconds. This was a lot faster than I
expected.  Paper mills have lots of spinning mass that takes a long time
to influence.

Oz (in DFW)

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Re: [time-nuts] What are these towers?

2011-05-26 Thread Oz-in-DFW

Looks like it's an AM broadcast directional array;

http://wireless2.fcc.gov/UlsApp/AsrSearch/asrRegistration.jsp?regKey=603263

On 5/20/2011 4:54 PM, Jason Rabel wrote:
 I was just browsing around on Google Earth and came across this cluster of 
 transmission towers... Anyone care to take a guess what they are for? 

 Television, radio, navigation... or something else? Looks like 11 towers...

 29° 59' 34N,  95° 28' 24W
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Re: [time-nuts] Extron distribution Amp on EBay

2011-04-19 Thread Oz-in-DFW

Where are you? 

There are lots of impressive asking prices, but the one mentioned below
on on eBay closed for $17.50.  I checked completed listings on all NTSC
stuff and they've closed from $0.01 to $20

$15?

On 4/18/2011 10:36 PM, saidj...@aol.com wrote:
 Hi guys,  

 I have an Extron ADA 6 300MX HV distribution amp if anyone wants it.  
 Haven't had the time to place it on Ebay.
  
 It's the big brother of the ADA 3 that David mentions below, see also the  
 attached photo.

 Will take offers..
  
 bye,
 Said

  
  
 In a message dated 4/18/2011 16:26:01 Pacific Daylight Time,  
 dgmin...@mediacombb.net writes:

 There's  an excellent buy available right now on Ebay, item# 380320968033. 
 There  has been some discussion on using this DA for poor man's standard 
 freq  
 distribution with good results.  I have one in service... it serves  me 
 quite 
 well.
 See http://www.ko4bb.com/Timing/Distribution_Amp/ and  
 http://www.ko4bb.com/ham_radio/Extron_3_80/.
 These amps usually sell  for many times the Buy it now price.

 David
 dgminala at mediacombb  dot net



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Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

2011-04-16 Thread Oz-in-DFW



On 4/9/2011 11:29 AM, Greg Broburg wrote:
 deletia

 I expect that I am missing something obvious here
 a little nudge may help.

 Regards;

 Greg

What you are missing is that the concept only applies to small integer
(2 or 3) division ratios and won't work as speculated here.  It's sort
of (long stretch here) like injection locking in reverse.  If you want
I'll try and post some links to papers later.

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Re: [time-nuts] BNC Question

2011-04-16 Thread Oz-in-DFW



On 4/16/2011 2:59 PM, shali...@gmail.com wrote:
 As pointed out earlier (by Bruce and others), there is a vast quantity of 75 
 ohm BNC connectors which mate perfectly with 50 ohm BNC sockets (save for 
 impedance mismatch). I have a set of 10 cables bought off the *bay with such 
 connectors. These cables are 75 ohm, so there will be a mismatch in a 50 ohm 
 system no matter what the connector is.
No doubt, but I think you'll also find these are the Amphenol
proprietary parts - which will damage the MIL-STD 75 ohm parts that HP
and a lot of other vendors used for a long time, just damaged less
frequently. 
 I am not sure what would make those less *true* that anything else.
Strictly speaking, BNC, TNC, and N are rooted in MIL-STDs from the
fourties, the other stuff intermates and has improvements of varying
nature.  This gets into detailed semantics.  Are the cheapie import
connectors that can't sweep past 100 Mhz Ns or something else? They
intermate, but they don't work so well.
  I am sure the mismatch of the connectors themselves, within the frequency 
 range they are intended for will be well below the level where most would 
 care.
Right, but the issue was intermating and damaging one type with another
and poor mating reliability.   The fact is that there ARE BNC (and N and
TNC) variants that will have this problem.  There are a number of folks
here who have flatly stated that this is not the case, but it really is. 
 If you try to use BNC for precision RF measurements, be prepared to be 
 surprised.
BNCs can be as good as TNCs when properly applied, but the bayonet
mechanism allows too much mechanical alignment play for reasonable
reliability past a GHz or so.  If they are properly installed and the
cable is not allowed to put a radial or significant tensile load they
perform as well as a TNC and close to an N.  For all that, I won't use
them in designs above 100 Mhz without a compelling reason.  F's are
cheaper, and SMAs are more reliable.  If it's hard coded at 75 ohms and
related to measuremnts - I use Ns.
 Unless the argument is about what they should be, what the standard says is 
 irrelevant when you have a box of parts and wonder if you can used them.
I think we're in 'violent agreement' here.  My point is that you need to
be aware of the many variations of connectors that have appeared in the
last 50+ years and use care lest you end up with an undesired repair. 
 Don't assume anything, just check before you plug.
And this is the point.  There *are* connectors that will not reliably
intermate and will be damaged.  This is true in BNC as well as N and TNC. 
 Didier KO4BB
  

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Re: [time-nuts] Datronn Wavetek 4910

2011-04-16 Thread Oz-in-DFW

I suspect this was an inadvertent mis-post to time-nuts intended for
volt-nuts


On 4/16/2011 4:01 PM, WB6BNQ wrote:
 JF,

 Not meaning to be unfriendly, BUT this list * *  IS NOT  * * a general test 
 equipment repair faculty.

 The unit in question is a series of regulated voltage sources that are 
 adjustable.  Being adjustable means it is not absolute.  Equally so, your 
 3458A is, likewise, adjustable and is totally dependent upon the references 
 it was adjusted against.  Besides the type of wires and corresponding 
 thermals in your connection arrangement, you have the ambient
 temperature in the mix.

 As you state you just bought it used, how do you expect it to be perfect ?  
 It has most likely been kicked around for a while and with no known 
 calibration history, those values do not surprise me at all.  Do you really 
 think your 3458A is perfect ?  Is your cal lab really up to the job ?  If 
 so, then send your new BOX to them and compare after you
 get it back.

 Your question What is the reference of the replacement batteries ? is 
 ambiguous.  If you meant the part number, then open it up and do the 
 research.  As for the batteries, except for mounting issues, they are just a 
 power source for all the different regulated supplies that feed those front 
 panel connectors.

 BillWB6BNQ


 JF PICARD wrote:

 I am looking for the service manual of the Datron Wavetek 4910. I have just 
 got  this reference standard from Ebay : is it normal to see 3 cells at 2 or 
 3 µv under 10V  and one at + 13µv (23°C with 3458A just calibrated 
 yesterday) or it is an obvious problem with the cell (the third one) ? What 
 is the reference of the replacement batteries ? Thanks.
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Re: [time-nuts] cheap 5V OCXO in 14DIP has about 1E-9 drift per day

2011-04-07 Thread Oz-in-DFW



On 4/7/2011 4:05 PM, Greg Broburg wrote:
 Size and power look good so far.

 Starting point for me is to run the little oscillators for a week and
 see how they muster up.
Take a look at Beale's earlier post (be...@bealecorner.com) He's done
most of that for you. 

http://www.bealecorner.org/best/measure/time/26MHz-osc-notes.txt

http://www.bealecorner.org/best/measure/time/Pletronics-26MHz-OCXO-tuning.pdf


 If that looks good then maybe a few parts from DigiKey to build the
 filters

 Greg

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[time-nuts] Bunsen on Google

2011-03-31 Thread Oz-in-DFW

Why is this a Time-Nuts item?  Because Bunsen was the chemist who
discovered the elements Caesium and Rubidium.  He's honored on Google's
search page with today's special logo.

He invented the Bunsen cell battery, and merely improved the burner that
bears his name and every high school student seems to know, the Bunsen
burner.

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Re: [time-nuts] RS XSRM Rubidium

2011-02-16 Thread Oz-in-DFW

And cold fluorescent tubes.  I can often get my attic fluorescents to
start with a bright flashlight applied close to an end. 

On 1/22/2011 5:05 PM, Bob Camp wrote:
 Hi

 Neon bulbs do the same thing. The ignition voltage is light sensitive. If you 
 see a place they are being used as a voltage reference, they get painted 
 black.

 Bob


 On Jan 22, 2011, at 6:02 PM, WB6BNQ wrote:

 Paul,

 The LED thing is interesting.  Are you sure you were not just seeing a 
 reflection
 of some sort ?

 BillWB6BNQ

 paul swed wrote:

 Other thing, measuring ignition time. On the first run just for the heck of
 it I flashed a led light into the ampule and it ignited instantly. So
 perhaps for old hard starting end of life RB lamps this might be a trick to
 at least get it going for a bit longer.

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Re: [time-nuts] SRS PRS10 problem

2011-02-16 Thread Oz-in-DFW

MRF134s are pretty available.  Usually under $25.

http://www.rfparts.com/transistors_MRF-TP.html


 In the PRS10 the lamp is exited by a strong RF field @ 150Mhz
 this is generated by an MRF134 within the lamp package

 The failure mode was caused by the growth of a substantial tin whisker
 within the lamp assembly which appears to have killed the MRF134.

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[time-nuts] Fwd: RFM Looking for a Frequency Control Engineer

2011-02-03 Thread Oz-in-DFW

Not *precisely* on topic, but likely of general interest..

Subject: RFM Looking for a Frequency Control Engineer

Date: Tuesday, February 1, 2011, 8:03 AM

RFM's manufacturing partner in Taiwan recently bought a high
end frequency control company and RFM is partnering
with them to market these products in the US and Europe.

RFM is looking for a senior RF engineer that is very comfortable with
the nuances of high performance
oscillators - drift, aging, phase noise, Allen variance, jitter, etc.

Drop me a private note if you want contact info. 

Oz

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FC-Req.doc
Description: MS-Word document
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Re: [time-nuts] Fwd: RFM Looking for a Frequency Control Engineer

2011-02-03 Thread Oz-in-DFW

Dallas Metro area.  **I** like it ;-)

Sounds like it might be location negotiable though.

On 2/3/2011 2:25 PM, John Allen wrote:
 Where is the position located?  Tks, John

 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf
 Of Oz-in-DFW
 Sent: Thursday, February 03, 2011 3:16 PM
 To: Discussion of precise time and frequency measurement
 Subject: [time-nuts] Fwd: RFM Looking for a Frequency Control Engineer

 Not *precisely* on topic, but likely of general interest..

 Subject: RFM Looking for a Frequency Control Engineer

 Date: Tuesday, February 1, 2011, 8:03 AM
  
 RFM's manufacturing partner in Taiwan recently bought a high
 end frequency control company and RFM is partnering
 with them to market these products in the US and Europe.
  
 RFM is looking for a senior RF engineer that is very comfortable with
 the nuances of high performance
 oscillators - drift, aging, phase noise, Allen variance, jitter, etc.
  
 Drop me a private note if you want contact info. 

 Oz


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Re: [time-nuts] T-Bolts object to being dropped.....

2011-01-08 Thread Oz-in-DFW

My first order guess would be something like the crystal support wires
annealing after the shock.  Second would be contaminants knocked loose
onto the crystal changing it's mass, and thus operating frequency and
boiling back off with some operating time (or maybe just standby
time.) Third would be that the crystal slid a fraction of a thou or so
in it's mounts and needed to seal the connection with a little
operation.  All gross speculation, of course.

On 1/8/2011 8:21 AM, Raj wrote:
 I wonder what could have caused this? Other than the xtals, what could be 
 shock sensitive I wonder!

 At 08-01-2011, you wrote:
   Hello, Time Nutters
   Last week I was rearranging gear
   on a shelf over my workbench. I managed
   to knock my T-bolt off the shelf and onto
   the top of the workbench, about a 20-inch
   fall.  After I finished calling myself a
   $...@$%*#@ idiot, I hooked it back up and,
   just as I feared, there was a BAD OSCILLATOR
   warning and something about an OSCILLATOR
   AGE warning.  There was no oscillator
   output.  ggg
   Taking it apart to see what I could find, I
   noted that the OCXO WAS running, but apparently
   so far off that no lock occurred.
   Thinking I had nothing to lose, I considered
   removing the access screw over the oscillator
   tweaking adjustment and seeing if I could
   resurrect it, but decided I had done enough
   damage for the day and went back into the house
   whimpering over the demise of my T-bolt.
   However, the next day, it had recovered all on its
   own, at least enough that there was normal
   output, although the steering voltage was nearly
   at its limit.  Over the following week, it
   slowly recovered and appears now to be back to
   normal with all parameters right where they
   used to be. No permanent damage seems to have
   been done
   Mike Baker



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Re: [time-nuts] Us Time Nuts and... Wrist Watches.

2011-01-05 Thread Oz-in-DFW

I'm not too far different. I have a Timex Easy Reader which has an
MSRP of $40, but I paid $19.95 at Target. Very large dial numerals with
an equally loud and satisfying tick. The Indiglo dial face is great,
too.  Loses a few seconds a month so far.

On 12/26/2010 3:25 PM, Robert Darlington wrote:
 Right now my favorite watch is a $13.99 U.S. Time military style watch
 that was made in China.  I replaced the band with one that I like better so
 I guess maybe it's worth $14.99 now.  It keeps pretty good time (better than
 Harrison's clocks but that's not really hard with a quartz oscillator),
 takes a beating with my day to day and it's cheap enough that I don't care
 about scratches although I don't seem to have any major ones.   I generally
 don't care about what time is it now? time as much as intervals, and this
 thing has a second hand for when I need to measure huge intervals with low
 precision!

 http://www.uscav.com/productinfo.aspx?productid=9981tabid=548

 -Bob


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Re: [time-nuts] how to open a Trimble mushroom ?

2011-01-03 Thread Oz-in-DFW

I've opened similar packages (Motorola PVT-6 antennas) up with
compressed air. 

  YOU NEED TO BE VERY CAREFUL IF YOU DO THIS

The plastic can shatter and fire off a million splinters.  Probably into
you.  I wrapped the object of my attention in heavy canvas rolled up to
form a rough tube (to guide and baffle the pressure wave front) and wore
a shop apron and face sheild.  I used a rubber tip blow gun to (slowly!)
pressurize the package and it popped. 120 psi across a 6 diameter
package is a couple of tons of force.  It should separate. ;-)

On 12/24/2010 4:00 PM, Pete Lancashire wrote:
 More goodies from storage

 I have a few 'special' Trimble mushroom GPS's. I'm trying to open one up
 but can't seem to get very far. I've pulled all the tabs out but still can't 
 pry
 the case open.

 They interface between the two sections doesn't look welded or glued.

 Here a couple picts

 http://petelancashire.com/gallery/main.php?g2_itemId=21208

 The data on these guys was trashed long ago when the company closed
 up. I could not locate it anywhere.

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[time-nuts] 3586A HQ PDF Manual - Alternate Repository

2010-12-10 Thread Oz-in-DFW

To distribute some of the (down)load I've dropped them at:

http://www.n1oz.net/JustNuts/3586_Serv_Man_HQ.zip (232 MB)
http://www.n1oz.net/JustNuts/3586_Oper_Man_HQ.zip (52 MB)

These are copies pulled from Roberto's Site this morning. 

This isn't a long term archive, but should help meet some of the initial
peak demand. I'll leave them up for a month or so, or until demand falls
off.

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Re: [time-nuts] WTB up to 10 pieces - Rockwell Jupiter - TU30-D140

2010-12-09 Thread Oz-in-DFW

i don't have 10, but I have a few that will want new homes. will have to
dig this WE

On 12/9/2010 3:43 PM, Dabney Crump wrote:
 Hi All,
 I'm looking for approximately 10 of the Jupiter GPS modules
 for a personal timing project; I time automotive speed events.

 I'm aware of the units available on eBay from Hong Kong but
 would like to try to source them from US markets first.

 Thanks for any assistance,
 Dabney in Denver
 303-324-1084




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Re: [time-nuts] DMTD for different input frequencies

2010-11-22 Thread Oz, in DFW

On 11/14/2010 12:08 PM, Magnus Danielson wrote:
 In the first stage, the input signals is mixed by the average
 frequency (37 MHz in this case) causing the beat frequencies to become
 roughly the same (27 MHz in this case). The second stage would then
 act as as the normal offset local oscillator and beat-frequency mix-down. 
Magnus,

I'm writing you directly because I want to avoid a nitpicking flame war
or I agree with your math, but your nomenclature seems a bit confusing. 
The arithmetic mean or average is 27 Mhz.  It seems that for  the
general case is the local oscillator is the arithmetic mean plus the
lower frequency.  You want to have high side injection for the low
frequency and low side injection for the high frequency.

I'd call the average frequency the intermediate frequency and define
it as the arithmetic mean of the two frequencies of interest, because it
literally is and because it conforms to common use for superheterodyne
receivers.  Likewise I'd call the injection the first local oscillator
or first injection and define it as the intermediate frequency plus or
minus the frequencies of interest for comparison.  The normal DMTD
oscillator could then be called the second local oscillator or second
injection

One side effect of this approach is that common mode variations on the
oscillators being compared will either be enhanced or reduced because
those effects are inverted in frequency for the lower frequency.  I
haven't run the math to prove this, but it looks like it'll be
proportional to the ratio of their frequencies. 

I need to think more about the impact of variations between the first
and second LOs. 

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Re: [time-nuts] DMTD for different input frequencies

2010-11-22 Thread Oz, in DFW

On 11/22/2010 7:22 AM, Oz, in DFW wrote:
 On 11/14/2010 12:08 PM, Magnus Danielson wrote:
 In the first stage, the input signals is mixed by the
 Magnus,

 I'm writing you directly because I want to avoid a nitpicking flame war

Well, apparently I screwed up and didn't write you directly. 

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Re: [time-nuts] Hyperterminal with variable baud rate

2010-11-22 Thread Oz, in DFW

On 11/18/2010 2:32 PM, Elio Corbolante wrote:
 From: Hal Murray hmur...@megapathdsl.net
 Are there any terminal programs out there that allow you to select rates 
 other than the standard values?
 You can use the wonderful Tera Term (http://ttssh2.sourceforge.jp/):
 it accepts nonstandard values in the speed parameter.
 I verified it with an oscilloscope.

 _  Elio.
PuTTY has a serial mode that does this as well.  As long as the rate is
115200 divided by an integer, it works.

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Re: [time-nuts] Frequency referenced temperature regulator

2010-11-08 Thread Oz-in-DFW



On 11/8/2010 9:04 AM, Poul-Henning Kamp wrote:
 But since I happen to have access to much more stable frequencies
 than voltages, I thought of a different way:

 1. Mount a X-tal-osc with really lousy tempco inside the enclosure.

 2. Compare its output to a stable reference frequency.

 3. Use the output of the phase comparator to drive the Peltier.

 It is basically a PLL where temperature is used as EFC...

 Has anybody tried that ?
It's been my experience that oscillators with really lousy temperature
performance have really lousy repeatability as well.   I'm never delved
into why this is true, but I suspect it's a number of things and not
limited to the quartz resonator.

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Re: [time-nuts] Determining Time-Nut infection severity

2010-10-25 Thread Oz-in-DFW



On 10/25/2010 11:49 AM, Bill Hawkins wrote:
 It would take an extraordinary ego to believe that anyone would
 care about your exact time of death.
or be sufficiently obsessive-compulsive...  Oh. Wait.

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Re: [time-nuts] Febo.com SSL certificate expired

2010-10-18 Thread Oz-in-DFW



On 10/18/2010 6:54 AM, Dr. David Kirkby wrote:
 On 10/18/10 03:21 AM, Oz-in-DFW wrote:
 I used these guys for $9:

 http://www.cheapssls.com/comodo-ssl-certificates/positivessl.html

 It was worth it to not have to walk people through accepting a
 self-signed cert.

 But the more people that fork out, the less common self-signed
 certificates become, so the more the inclination of people to shell
 out for these things.

 Not only that, but it's $9 this year, and more next year. Each year
 you have to mess around with the certificate.

 In contrast Micky Mouse can be persuaded to sign one for 10 years
 (perhaps even longer) for $0.00.

 Dave
I understand all of this and ran with a self-signed cert for several
years. The fact is that several of my customers needed support to make
this work, and more than one of their IT departments don't allow self
signed certs.  It's a tradeoff like so many other things. 

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Re: [time-nuts] Febo.com SSL certificate expired

2010-10-17 Thread Oz-in-DFW

   I used these guys for $9:

http://www.cheapssls.com/comodo-ssl-certificates/positivessl.html

It was worth it to not have to walk people through accepting a
self-signed cert.


On 10/15/2010 2:36 AM, David C. Partridge wrote:
 Subject says all

 Dave


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Re: [time-nuts] 60 KHz Receiver

2010-10-05 Thread Oz-in-DFW



On 10/5/2010 3:59 PM, paul swed wrote:
 Well crazy as it sounds if you are at 100 KC you might just want 1 loran
 tower in a chain or even fewer. You only need 1 station not 3. Timing rcvrs
 worked on one signal.
Frequency recovery works with master only, timing requires ranging data,
so three stations are required to locate the receiver.

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[time-nuts] Spread Spectrum LF Time Code (Was: 60 KHz Receiver)

2010-10-05 Thread Oz-in-DFW



On 10/5/2010 5:14 PM, WB6BNQ wrote:
 Poul,

 Please explain to me how spread spectrum would enhance any process of 
 frequency or
 time recovery ?
I can see a lot of reasons, but it's an answer requiring lots of
thought.  I'm not certain that it'd be an advantage.  Some things that
come to mind are:

   1. non-gaussian interferers would be reduced by the spread processing
  gain. (Yay!)
   2. With a long enough code you can discriminate against multipath
  (skywave.) as well as Loran - really limiting diurnal shift.
   3. With a high chip rate you can potentially get really fine time
  resolution. 
   4. Most of the processing goes right to bits - Moore's law becomes
  our buddy.

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Re: [time-nuts] Next Generation Time/Frequency Standards May Require Provisions Preventing Vertical Displacement

2010-09-30 Thread Oz-in-DFW



On 9/30/2010 8:43 AM, jimlux wrote:

 how stable?  
The parts are generally  ~ 1 ppm over temp and another ppm or two aging.

 I'm sort of curious, I wonder what sort of temperature range
 cellphones are expected to really work over..
depends on the vendor to some extent.  Not all standards spec an
operating temp range.  The bottom end is usually -20 or -40 C though not
at full spec, and -40 is pretty rare. 
 (not necessarily what they're specified for, but what the designers
 see as the sweet spot).. It's not like people carry their phones in
 pocket on the back of a backpack in -40 weather.
Most phones are not specified to operate this cold.  Even standards that
specify operating temperature range are often not fully complied with.

 I wonder if they're like pager receivers in some sense (e.g. they're
 on all the time, waiting for a call)
No, a lot of effort is spent in letting them spend most of their time in
standby and only wake up every second (or few seconds.)  Most modern
pagers do the same thing.  They indicate to the receiver when they will
be sending data, and when they will be sending device addresses
(generally called the paging interval for cellphones and pagers both.)

 And, as the phone heats up as you transmit, how much does the
 frequency change?
Once the phone is participating in the network it's locked to it.  At
that point the only thing we care about in the TCXO is short term (~
1sec) drift and that's WAY better than 1 ppm. If you are transmitting
you are still receiving several times a second and getting frequency
offset updates at the same rate.  It's closed loop.

 It's a real cost sensitive huge volume market, so the specs for a
 cellphone reference oscillator could be highly tailored to a specific
 application.
Yup, and stamped out in the millions per month so they are really
cheap.  Well under a buck. Most are just a slab of silicon, a slab of
quartz, and a package.  All oscillator functions and compensation are
provided in a custom bit of CMOS with EEPROM or fuse programmable
compensation memory.  I didn't think this was possible, but I saw one
yesterday in a GS that was in an SSOT-23 package.  Sheesh.

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Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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[time-nuts] Mostly Relevant: Comic

2010-09-28 Thread Oz-in-DFW

 Committee to Decide on How Long a Second Should Be...

http://comics.com/f_minus/2010-09-28/

A not quite layman's view

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mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] NIST chief on NPR right now! Tune in to science Friday :)

2010-09-24 Thread Oz-in-DFW

The recorded version is here:

http://podcastdownload.npr.org/anon.npr-podcasts/podcast/510221/129942724/npr_129942724.mp3

On 9/24/2010 1:10 PM, GMail / AnalogAficionado wrote:
Hope this makes it through from my phone...

- Chad.

On Sep 22, 2010, at 9:09, Bob Camp li...@rtty.us wrote:

The 3.0 firmware is one way to make sure you don't get one of the early
ocxo's. The later designs certainly worked better.

I haven't seen any of the original red label ocxo's show up for quite a
while, so they all may be gone by now.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Mark Sims
Sent: Wednesday, September 22, 2010 12:03 PM
To: time-nuts@febo.com
Subject: [time-nuts] Looking for good, cheap, external reference

I don't think the firmware on the Tbolt makes much difference in
performance. (The older firmware even has a couple more features in it).

Units with the 3.0 firmware are newer and have a much greater chance of
having the poor temperature sensor which definitely has a bad effect on
performance. If I had my choice of two units (both with the good
oscillator) I'd definitely pick the older one.

---
-There are several cheaper ones for sale but make sure you get the 3.0
firmware
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--
mailto:o...@ozindfw.net
Oz
POB 93167
Southlake, TX 76092 (Near DFW Airport)

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[time-nuts] Drake DSR-2 Receiver manual

2010-09-16 Thread Oz-in-DFW



On 9/16/2010 5:58 PM, Murray Greenman wrote:
 I know this is a bit off-topic, but I wonder if any of you guys have
 available the manual for the old (1970s) Drake DSR-2 receiver?

 I've you are able to send me a PDF copy, I'd be most grateful.

 73,
 Murray ZL1BPU


I'd also post this on Manual_Exchange(@yahoogroups.com, and I just did)

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] Homebrew WWVB TX simulator?

2010-09-14 Thread Oz-in-DFW



On 9/14/2010 5:27 PM, Hal Murray wrote:
  Is there a secret NTP++ protocol that I've
 missed out on? 
Yes, but I can't tell you  ;-)

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] Timing Distribution in Mountainous Terrain



On 9/9/2010 12:49 PM, k6...@comcast.net wrote:
 Ralph-- 

 As far as getting a signal through mountainous terrain, look at NVIS antennas 
 for HF -- we use them for Field Day for just that kind of communications, 200 
 - 300 miles in mountainous terrain. Figuring out propagation delays is going 
 to be interesting with NVIS though. 

 73 de Bob K6RTM 
 --
Actually, it's not too hard. layer sounding for single site DF has been
pretty well documented for a long time.  Getting it with accuracy to 15
feet is probably impossible though.

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] Timing Distribution in Mountainous Terrain



On 9/9/2010 2:03 PM, Ralph Smith wrote:
 1e-11 only buys you 3000 seconds of drift before blowing the 30 ns budget.
 Without going to cesium we will most likely need some form of mutually
 visible synchronization. 
Is Cesium even enough?  The requirement looks like about 6 parts in
10e-14.  That's hydrogen maser territory isn't it? 

Given the application you could probably achieve this with fiber
back-haul that you continually range and jitter filter to achieve that
resolution.  Not gonna be off the shelf, though.  Your could probably
layer data transmission on top of this.

Why not just periodically release a metalized weather balloon as a
calibration target, or use one to lift a calibrated reflector in the
event of an outage?  Or pick a conventionally tracked target as a
calibration source?

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] Timing Distribution in Mountainous Terrain



On 9/10/2010 7:26 AM, Ralph Smith wrote:
 On Sep 10, 2010, at 7:50 AM, J. L. Trantham wrote:

 Loran was used as an area navigation method in aviation for many years.  It
 was available nation wide with a number of chains.  I had assumed that the
 area of interest was the Rocky's but if the Appalachians, even better.
 The site currently under consideration is in Colorado. Only problem with 
 Loran, of course, is that is has been killed, thus the operative word was 
 above. If the design and approach bears out it could be deployed over a much 
 wider scale.

 Ralph 
Even if LORAN was alive it wouldn't meet the requirement.  You'd still
have 20-30 M position uncertainty in a differental application - way
more than your 30 ns.   I thiink that dropping LORAN was a really big
mistake, but it wouldn't meet this need.   I used to see several 100 ns
of time drift and jitter when I was in San Antonio and watching Boise
City, OK (~600 Mi)

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] Timing Distribution in Mountainous Terrain



On 9/10/2010 12:26 PM, Stanley Reynolds wrote:
 On the crazy side another common view object is the lunar laser ranging 
 retroreflector array. Has been improvements in cost of lasers and telescopes 
 in 
 the past 41 years and it doesn't appear to be headed for shutdown anytime 
 soon.

 Stanley 
Can they even shut this down?  I thought it was passive.  Last I heard
they were worried about it becoming unusable as the loss was rising,
presumably because of dust accretion.  But even that seems to have
stabilized.

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 





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Re: [time-nuts] Timing Distribution in Mountainous Terrain



On 9/10/2010 4:04 PM, Ralph Smith wrote:
 OK, stop me if this is really stupid. The initial site is in Colorado.
 Would it be possible to use WWV? In particular:

 1) Lock a reference to the carrier of one of the WWV signals
 2) Generate PPS off of WWV-locked reference
 3) Periodically send difference of GPSDO PPS and WWV-locked PPS home,
 along with GPS lock indication
 4) When GPS goes away do the math at home and correct for the timing drift
 of the GPSDO compared to WWV-locked reference

 There are probably several fatal flaws with this approach. In particular,
 the following are required:
 1) Ability to maintain constant lock to WWV
 2) Common-mode error. Will the propagation from WWV be similar enough for
 all stations to it be a practical common reference.
 3) Adequate resolution. Even if, for some reason 1 and 2 are possible,
 would the result be good enough to use.

 Like I say, probably completely unworkable, but what are your thoughts?

 Ralph

There are a number of problems I see with this, each of which is
sufficient to eliminate this as an option. 

   1. Propagation varies with temperature, humidity, and other
  atmospheric effects like dust content.  Over a several hundred
  mile path this is going to be at least an order of magnitude
  greater error term than the overall budget. 
   2. This is HF and skip paths are common.  The WWV wave form provides
  no mechanism for discriminating between ground and skywave.  LORAN
  accomplished this by using a short pulse.  The Skywave path was
  always later than the groundwave, and for most cases was
  completely distinct.  This can be 100s of microseconds.
   3. It's conceivable that you could have long-path propagation that
  makes a complete circuit of the earth - really long delays and no
  good way to know in the absence of a stable reference.  About 150
  milliseconds...
   4. Multipath with sky and ground waves adds yet another variable. 

And WWVB doesn't really fix much of this. 

-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 




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Re: [time-nuts] WeirdStuff tbolt $75 [eBay Link]

 Just to remove a variable seemingly causing confusion;

The ebay link is

http://cgi.ebay.com/300457580821

And still more than 10 available.


On 9/2/2010 12:02 PM, Peter Loron wrote:
 Umm, their eBay listing shows like $11 for US domestic shipping and
 $30 to Turkmenistan...seems pretty in line with reality...

 -Pete

-- 
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Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 




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Re: [time-nuts] WeirdStuff tbolt $75 [eBay Link]

 There are several packaged versions up for $100 and modest shipping.

On 9/2/2010 1:29 PM, Oz-in-DFW wrote:
 I'm guessing they had 18 and someone bought the last.

 On 9/2/2010 1:25 PM, Mark J. Blair wrote:
 On Sep 2, 2010, at 10:06 AM, Oz-in-DFW wrote:
 http://cgi.ebay.com/300457580821

 And still more than 10 available.
 That listing appears to have ended. If I had gotten there in time, I'd have 
 been tempted to buy a couple of them. My Thunderbolt is flaky (stops 
 outputting serial data or responding to serial commands after a period of 
 minutes to hours), so I could have tried out a couple others in hopes of 
 finding a reliable one, followed by harvesting OCXOs from the ones that 
 didn't make the cut.





 -- 
 mailto:o...@ozindfw.net
 Oz
 POB 93167 
 Southlake, TX 76092 (Near DFW Airport) 




-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 




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Re: [time-nuts] WeirdStuff tbolt $75 [eBay Link]

 Sorry, sorgot to include link;

http://cgi.ebay.com/330453047354

also more than 10 available.

On 9/2/2010 1:31 PM, Oz-in-DFW wrote:
 There are several packaged versions up for $100 and modest shipping.

 On 9/2/2010 1:29 PM, Oz-in-DFW wrote:
 I'm guessing they had 18 and someone bought the last.

 On 9/2/2010 1:25 PM, Mark J. Blair wrote:
 On Sep 2, 2010, at 10:06 AM, Oz-in-DFW wrote:
 http://cgi.ebay.com/300457580821

 And still more than 10 available.
 That listing appears to have ended. If I had gotten there in time, I'd have 
 been tempted to buy a couple of them. My Thunderbolt is flaky (stops 
 outputting serial data or responding to serial commands after a period of 
 minutes to hours), so I could have tried out a couple others in hopes of 
 finding a reliable one, followed by harvesting OCXOs from the ones that 
 didn't make the cut.





 -- 
 mailto:o...@ozindfw.net
 Oz
 POB 93167 
 Southlake, TX 76092 (Near DFW Airport) 




 -- 
 mailto:o...@ozindfw.net
 Oz
 POB 93167 
 Southlake, TX 76092 (Near DFW Airport) 




-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 




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Re: [time-nuts] Freestanding mast