Re: [time-nuts] 10811's

[bownes]

Is there a quick and dirty summary of which are the "good" 10811's? Otherwise, 
I clearly need to go through my collection and characterize them! :)

I should probably do that anyway...



> On Nov 17, 2014, at 21:50, Bob Camp  wrote:
> 
> Hi
> 
> As best anybody can tell, the improved phase noise and ADEV 10811’s came out 
> of a screening / select process. There is a finite chance that a “normal part 
> number” 10811 could be as good as or better than a part from one of the 
> “better part number” versions.
> 
> Bob
> 
>> On Nov 17, 2014, at 9:42 PM, John Allen  wrote:
>> 
>> As you all know, but has not been mentioned, is that there are many versions
>> of the venerable 10811, which different specifications, including phase
>> noise and stability.
>> 
>> 
>> 
>> The well known HP document 90027-1 lists many of them, and thanks to TVB, it
>> is here:
>> 
>> http://www.leapsecond.com/museum/10811a/90027-1.pdf
>> 
>> 
>> 
>> The contents include
>> 
>> 1 10811D/E Crystal Oscillators 2 10811D/E Option 001  3 10811D/E Option 002
>> 4 10811D/E Option 003  5 10811D/E Option 100 
>> 
>> 6 10811-60111 7 10811-60109 8 10811-60209 9 10811-60211 10 10811-60102 11
>> 05071-60219 12 10811-60158 13 10811-60160 
>> 
>> 14 10811-60164
>> 
>> 
>> 
>> I hope that this is helpful. Regards, John K1AE
>> 
>> 
>> 
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Re: [time-nuts] GPS in the news

[bownes]

I read the article and thought it would make for an interesting crowd sourced 
project if the sensitivity is large enough to build a distributed sensor 
network with GPSDOs. 



> On Nov 18, 2014, at 17:15, Magnus Danielson  
> wrote:
> 
> Hi Charles and Joe,
> 
> Read this, and hopefully you get smarter than from the write-up you linked:
> http://arxiv.org/pdf/1311.1244v2.pdf
> 
> I could not find any attempt at sensitivity scale required, and thus the 
> feasability of actually detecting these deviations.
> 
> From a quick look at it, I have a kind of notion of what they imply one 
> should look for, but it's not really well described exactly what to expect, 
> but maybe it becomes clearer on a quality read-through. It is more suggestive 
> than detailed method proposing, enough to show the idea, but not enough to 
> implement it, it needs the engineering on top of it.
> 
> Cheers,
> Magnus
> 
>> On 11/18/2014 03:12 PM, Joseph Gray wrote:
>> Yes, I read that yesterday. It will be interesting to hear what the
>> outcome of the study is.
>> 
>> Joe Gray
>> W5JG
>> 
>> 
>> On Tue, Nov 18, 2014 at 4:59 AM, Charles Steinmetz
>>  wrote:
>>> Dark matter the source of GPS irregularities?
>>> 
>>> 
>>> 
>>> Best regards,
>>> 
>>> Charles
>>> 
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Re: [time-nuts] Set time on Solaris computer from HP 58503A

[bownes]

> On Dec 14, 2014, at 07:42, Dr. David Kirkby (Kirkby Microwave Ltd) 
>  wrote:
> 
>> On 14 December 2014 at 11:57, Hal Murray  

> 
> That command works.
> 
> How do you reboot - apart from of course powering the thing off?
> 

# shutdown -y -i6 -g0

Or

# reboot

Or

# init 6

Bob
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[time-nuts] HP Agilent 5061A Cesium Beam Frequency Standard

[bownes]

If anyone happens to be looking for a 5061A in the Bay Area this might be a 
good deal. 

Bob

View item:
HP Agilent 5061A Cesium Beam Frequency Standard

End Time: Feb 20, 2015, 18:32:56 EST




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

[bownes]

All interesting solutions. 

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. 

As such, I'd be hard pressed to go with such a solution for Mark's problem. 

Soekris single board PCs are still out there, have a decent ecosystem, and are 
pretty rugged. Hard to beat for the budget requested. And decent GPS NTP 
implementations are documented. 

Failing that a nice used Symetricomm :)




> On May 12, 2015, at 21:09, Mark Spencer  wrote:
> 
> Thanks.   Yep running an extra Dc to Dc converter is an option but we already 
> have access to clean 28 and 13.8 VDC supplies with some extra capacity.  We 
> could likely provide up to a 100 watts of power for this system (I doubt it 
> would need that much.)
> 
> The hold over requirement is in the range of several hours.   The temperature 
> swings could be fairly large (ie. cold soak outside at minus 35C, then inside 
> a heated garage, plus what ever temperature the equipment bay rises to when 
> the vehicle has been operating for some time probably less than 85 deg C.) 
> mounting the equipment in locations other than the equipment bay would likely 
> result in lower max temperatures.
> 
> I'm not sure about the cooling capacity of the equipment bay, but there are 
> other areas with climate control systems where this device could be installed 
> if needed.  I'm fairly comfortable that a device that generated up to 100 
> watts of heat could be accommodated (ie, I would assume all of the electrical 
> power going into the device gets turned into heat) but would need to double 
> check this.
> 
> The size is somewhat flexible.
> 
> To a certain extent the requirements could be adjusted to fit an existing 
> COTS product that was perceived as generally suited to the application.   As 
> this is a one off requirement, that will be in use for a limited time some 
> limitations can be worked around or lived with.
> 
> The budget could be several thousand dollars.
> 
> I thought about a Raspberry Pi type of solution, but need to factor in the 
> cost of my time or that of someone else, plus there is a strong desire to 
> either drop in a COTS "black box" or use a laptop.
> 
> Thanks for the comments.
> 
> 
> Sent from my iPad
> 
>> On 2015-05-12, at 3:54 PM, Pete Stephenson  wrote:
>> 
>>> On Tue, May 12, 2015 at 7:11 PM, Mark Spencer  
>>> wrote:
>>> Hi sorry for a possibly OT post.
>>> Has anyone had practical experience with small commercially available time 
>>> servers / ntp servers suitable for mobile  use in a vehicle.
>> 
>> I don't know about any commercially-available products, but it sounds
>> like it'd be pretty straightforward to do with a Raspberry Pi or
>> something similar if you don't mind a little bit of DIY.
>> 
>> What constraints do you have on budget, size, power requirements, and 
>> cooling?
>> 
>>> The use case is I am in need of an accurate (ie.  within 100 ms) time 
>>> source for several pc's in moving vehicle.Being able to run directly 
>>> off a 13.8 or 28 VDC  source would be a major plus but AC power is also 
>>> available.
>> 
>> The Pi runs on 5V DC. DC-DC buck converters that can convert 7-35V to
>> 5V DC are cheap, efficient, and widely available. Shouldn't be a
>> problem.
>> 
>>> Hold over if there are gaps in GPS coverage is also a major plus.
>> 
>> How long would you need holdover? Seconds or minutes (e.g. driving
>> through a tunnel)? Hours? Days? Would the computers in the vehicle be
>> subject to large temperature shifts?
>> 
>> A Pi should be able to handle +/- 100ms of holdover in the
>> minutes-to-hours range using NTP.
>> 
>>> We already have a GPS with a 1 pps output, but an integrated box with it's 
>>> own GPS would be best.
>> 
>> A tiny integrated module like the Adafruit Ultimate GPS breakout[1] is
>> cheap, handy, and emits a 1PPS signal. It's also extremely small and
>> can be purchased in "hat" form[2] that mounts directly to the Pi.
>> 
>> Cheers!
>> -Pete
>> 
>> [1] https://www.adafruit.com/products/746
>> [2] https://www.adafruit.com/products/2324
>> 
>> -- 
>> Pete Stephenson
>> 
>>> On Tue, May 12, 2015 at 7:11 PM, Mark Spencer  
>>> wrote:
>>> Hi sorry for a possibly OT post.
>>> Has anyone had practical experience with small commercially available time 
>>> servers / ntp servers suitable for mobile  use in a vehicle.
>>> 
>>> The use case is I am in need of an accurate (ie.  within 100 ms) time 
>>> source for several pc's in moving vehicle.Being able to run directly 
>>> of

Re: [time-nuts] KS-24361 "NO GPS" - again

[bownes]

Typically the pins are two or three lengths. 

The longest pins are ground, the next are power, then signal pins. Quite often 
used for things that are hot swapped. Take a look at a USB cable for example. 





> On May 29, 2015, at 19:01, Chuck Harris  wrote:
> 
> Thees units were made for the phone company, and phone companies
> are big on "hot-swapping" modules.  The shorter pins are shortened
> to make sure that their circuit doesn't make contact until the
> longer pins have made contact.  Don't "fix" them!
> 
> -Chuck Harris
> 
> billriches wrote:
>> Hi Ulli,
>> 
>> I heard some comments that the short jumper cable between the two units
>> would make an intermittent connection.  You will notice that some of the
>> pins in the connector are shorter than the others and hopefully that is the
>> problem.  I don't know if the plugs are wired 1 to 1, 2 to 2 and so forth
>> but you could figure that out and make up another cable and try it.
>> Hopefully your problem will be as simple as a bad cable.  I have had two of
>> those systems running 24/7 for almost a year and have had no problems.
>> 
>> 73,
>> 
>> Bill, WA2DVU
>> Cape May
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Re: [time-nuts] Thunderbolt/Arduino RS232 Interface Issue

[bownes]

Swap the tx and rx lines on the Arduino. Swap back to reconnect to PC. 



> On Jun 3, 2015, at 10:51, Chris Albertson  wrote:
> 
> In the RS-232 world devices are either DTE or DCE.  You need one of
> each on each end of the line if using a normal straight cable.To
> connect two like devices you need a crossover cable (AKA "null modem")
>From the sounds of it I'm guessing the PC is a DCE and the Arduino
> and Thunderbolt are both DTE.
> 
>> On Tue, Jun 2, 2015 at 9:38 PM, Dan Quigley  wrote:
>> Hello,
>> 
>> I'm integrating an Arduino (Due/Mega have tried both) with a surplus 
>> Thunderbolt and need some advice.
>> 
>> The Thunderbolt is a known working unit (supplies 10Mhz to my HPSDR rig) and 
>> the serial interface works fine between it and a PC.  I've read the coverage 
>> about this kind of integration (and some of the archived discussions on this 
>> board) and am employing a commercially available MAX232-based "shield" 
>> (RS232 V2) to handle the level translations.  Just three lines (RX/TX/GND) 
>> are  used.  The MAX232 circuit is working, reliably passing data between the 
>> Arduino and a PC.
>> 
>> With the Thunderbolt is connected to the MAX232 no data passes.  Activity 
>> LEDs on the non-RS232 of the MAX232 circuit show no activity when the 
>> Thunderbolt is providing data, indicating the MAX232 is not performing the 
>> intended level translation.  I've scoped the RX/TX lines coming from the 
>> Thunderbolt both when connected to the Arduino and not.  There is a distinct 
>> difference. When disconnected, the pulses are about 10.3v and nice, crisp 
>> and square.  Connected, the pulses are ~50% lower in voltage (4.1v) showing 
>> an exponential rise in voltage and trace noise.
>> 
>> I'm pretty much stumped at the moment and wonder if anyone can offer a 
>> suggestion or thoughts on a direction to take.
>> 
>> Thanks in advance,
>> Dan Quigley (N7HQ)
>> 
>> 
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> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] How did they distribute time in the old days?

[bownes]

And to tie this back to the UPS thread, at university, the Simplex clock sync 
signal made our Vax 11/730 TOD clock run wy fast. 
I never figured out if it was using line frequency zero crossings for seconds 
or if it was leaking as DEC fixed it not long after it was installed. (And it 
was moved to a different phase of the power system than the clocks...)



> On Oct 14, 2015, at 15:55, Jim Harman  wrote:
> 
> The Western Union clocks were still in use at broadcast stations in the
> early 1970s. One problem was that the reset pulse and resulting jump in
> time would come exactly on the hour, when you were trying to synchronize
> with a network news broadcast that began at the network's version of 00:00.
> 
> ABC and I presume the other networks would send a tone 10 seconds before
> their program started, By listening to the network on the "Cue" channel,
> you would have a pretty good idea of when the news would start.
> 
> Another system in wide use around then and still somewhat today for
> controlling the clocks in a large building was sold by Simplex. The
> building would have a master clock (set manually by the custodian or
> whoever) that pumped out tones at about 3 KHz over the power lines. These
> signals would come out a couple of minutes before the hour, presumably to
> avoid problems with events scheduled on the hour. The slave clocks were
> designed to run a little fast, and would wait at 58:00 until they received
> a tone to restart. I believe there was a special tone that would make the
> clock run "fast forward," to deal with longer adjustments for power outages
> and DST.
> 
> One drawback of this system is that the tones sometimes leak into audio
> equipment, and in a quiet room they are often audible through the
> fluorescent light ballasts.
> 
> On Wed, Oct 14, 2015 at 12:42 PM, Nick Sayer via time-nuts <
> time-nuts@febo.com> wrote:
> 
>> 
>> 
>> 
>> The WU standard time service goes back further than the turn of the 20th
>> century. It started in 1870.
>> 
>> --
> 
> --Jim Harman
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Re: [time-nuts] New Member + Basic Questions

[bownes]

The 8640 will lock to an external 5Mhz reference. That's what the BNC in the 
heatsink is for. At least that is where it is on mine. 

The trick is doing a good divide by two. 

However, that said, the 8640 tops out at ~1024MHz, which if you get interested 
in even the lower microwaves, is not quite enough. 



Bob
KI2L

> On Jan 11, 2016, at 09:47, Rob Sherwood.  wrote:
> 
> The HP 8647A may be the worst signal generator HP ever made.  The 8656B won't 
> even go down low enough in level to make a noise floor measurement on a 
> modern transceiver.  Sure you can add external attenuation, but you won't 
> know about how much leakage is occurring.  Otherwise why wouldn't HP have 
> added another 15 dB attenuation in the box? That is why I mentioned the 
> 8657B.  Yes the 8662A's reliability issue is the power supply.  No question 
> not a starter generator.  The 8642A was never intended for field repair, but 
> it is the only generator with low enough phase noise to test top radios 
> today, and something a ham could afford. Again, not the first sig gen that 
> should be on your list 
> 
> Rob, NC0B
> Sent from my iPad
> 
>> On Jan 11, 2016, at 8:01 AM, "Nathan Johnson"  wrote:
>> 
>> 
>> 
>> I really appreciate all the help. I really like that Ref0 combination, I 
>> don't
>> see any Ref1s available right now, but you are saying that any decent
>> GPS+Arduino can substitute? Should I be looking in the archives for that, or 
>> is
>> there a website?
>> Minor clarification to my earlier post about the signal gen, I am aware that 
>> the
>> 8640 won't lock to an external reference. I had intended that to read
>> 8640-something or 50-something. I'm watching an 8647 and an 8656b on the 
>> usual
>> site at the moment. That 8662 looks beautiful, but it's a huge investment 
>> for a
>> piece of old gear that has a reputation for being a bit... Cranky and
>> opinionated. I have no practical need for that now, so I won't sign up for 
>> that
>> kind of challenge until I do.
>> I'm quite familiar with how this stuff multiplies, I have a Tektronix scope
>> collection, and have been a lurker on the TekScopes list for about a year. 
>> There
>> is a running joke on that list about "scope acquisition disorder". I'm pretty
>> sure that I'm infected, but I only have 5 scopes in the house at the moment, 
>> so
>> it's not that bad... Yet!
>> 
>> Nathan KK4REY
>> Sent using CloudMagic Email
>> [https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2]
>> On Mon, Jan 11, 2016 at 04:28, Discussion of precise time and frequency
>> measurement  wrote:
>> Good thread everyone.
>> Nathan you have received a lot of wisdom and humor today.
>> Yes for sub $200 you can be in good shape.
>> If lucent remember a Ref0 needs an arduino and a good GPS 1 PPS.
>> Though frankly even neo6s play well.
>> If a Ref1 it has a GPS in and no need for the arduino. The $175 gets you a
>> ref1 and ref0 combo that tie together usually with a cable thats shipped
>> with the units.
>> Mine were brand spanking new. NOS.
>> Good luck.
>> To Ron o yes no shed or anything but the gear builds up. Darn thing is
>> this stuff actually last longer then an iPhone99X due out tomorrow I am
>> sure.
>> Paul
>> WB8TSL
>> 
>>> On Sun, Jan 10, 2016 at 4:31 PM, Rob Sherwood.  wrote:
>>> 
>>> Paul,
>>> 
>>> Your last paragraph was a hoot. A ham friend of mine recently rented a
>>> storage shed to keep all his spare test equipment and parts units. Another
>>> ham friend used to have four storage units to store all his "stuff". The
>>> disease is not curable with either time or antibiotics.
>>> 
>>> My XYL will have to deal with two homes with labs and ham shacks, 7
>>> towers, 13 yagis, etc. when I am SK. Need I say more.
>>> 
>>> Rob
>>> NC0B
>>> 
>>> -Original Message-
>>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed
>>> Sent: Sunday, January 10, 2016 1:56 PM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] New Member + Basic Questions
>>> 
>>> 
>>> 
>>> Nathan,
>>> Bob shared a link for the Lucent units and a great amount of detail has
>>> been shared on Time-nuts about them. They will do what you want. The Ref0
>>> requires a external GPS receiver and another Time-Nuts Arduino. It works
>>> really well and the quality of the ref0 seems to be that of the 1pps
>>> feeding it.
>>> But they also make a no brainer pair that has a ref0 and ref1 that has a
>>> built in GPS receiver. They were $175 but they go all over the place in
>>> price. But it does just work.
>>> Trace-ability is an interesting word around this group. From your
>>> description not sure thats really a need. Accept for the oven oscillator
>>> they all are great and yes even really good oven oscillators are great and
>>> can actually be amazing. Not cheap at all though.
>>> You describe your counter and sig gen they have a resolution of .1Hz so
>>> going further isn't really all that helpful.
>>> Now

Re: [time-nuts] HP 5372A advice

[bownes]

Has anyone published a summary of the differences between the '71 & '72?


> On Jan 20, 2016, at 15:11, Poul-Henning Kamp  wrote:
> 
> 
> In message <569fde69.2020...@rubidium.dyndns.org>, Magnus Danielson writes:
> 
>> Good, then I have not remembered completely wrong.
> 
> The 5371 and 5373 manuals are not without relevance either, and
> don't overlook the app-notes and the HPJ (1989-02) articles either.
> 
> -- 
> 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] Fast risetime pulse generator

[bownes]

Maybe a krytron? If you are able to get one anyway. ;)

> On Apr 13, 2016, at 18:32, David  wrote:
> 
>> On Wed, 13 Apr 2016 00:03:03 -0500, you wrote:
>> 
>> ...
>> 
>> If you are building up something, you probably want a SRD (step
>> recovery diode) or tunnel diode. But both may be hard to find and
>> expensive these days.
> 
> Step recovery diodes are very similar in construction to varactor
> diodes so the later can be used in step recovery applications with
> qualification.
> 
> I have also seen the 1N4148 used as a step recovery diode when driven
> by an avalanche pulser but I do not know if it was qualified.
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Re: [time-nuts] RG6 or LMR400 for GPS Antenna (Symmetricom 58532A and T-bolt)

[bownes]

N connectors should never need to 'lubed'. Properly assembled they are 
waterproof. Same goes for BNC. That's what the rubber gasket on the mating 
surface is for. Metrology grade Ns don't have the gasket but you shouldn't need 
it on your metrology bench. :)

That being said, it never hurts to wrapped up with coax seal tape. 

> On Apr 20, 2016, at 21:03, Ryan Stasel  wrote:
> 
> Bob/Paul,
> 
> Thanks. And there's the rub... Who knows what the specs are on "generic" RG6 
> QS. I'll see what my seller wants for their LMR400, but otherwise yeah, RG6 
> is just easier. I have both compression and crimp connectors for it, 
> including some RG6 N-connectors (yeah, they're probably for LMR300, but they 
> work). 
> 
> Other question: any tips for the exterior N connection? I can "weatherproof" 
> the actual cable-connector crimp, but I'm curious if anyone bothers to "lube" 
> the N connector to keep moisture from otherwise seizing it up. 
> 
> Thanks!
> 
> Ryan Stasel
> IT Operations Manager, SOJC
> University of Oregon
> 
> Sent from my iPhone
> 
>> On Apr 20, 2016, at 17:00, Bob Camp  wrote:
>> 
>> Hi
>> 
>> RG-6 Quad Shield should be fine as long as it’s meeting the published specs. 
>> The advantage of LRM-400 is that you likely *know* where it came from and 
>> what the specs are. 
>> 
>> If you decide to split the antenna between GPSDO’s, a powered splitter is a 
>> really good idea. Each time you split another 2 ways, you loose 3 db. Get at 
>> least a 4 way splitter ….
>> 
>> Bob
>> 
>>> On Apr 20, 2016, at 4:41 PM, Ryan Stasel  wrote:
>>> 
>>> All, 
>>> 
>>> I’m going to be installing a “permanent” antenna at home, and will need a 
>>> run of about 100ft to get from my workstation, to the mast I’ll be mounting 
>>> the antenna on (Symmetricom 58532A). I’ve seen some indication that both 
>>> the antenna and the Trimble Thunderbolt won’t have any issues with running 
>>> over 75ohm cable, but thought I’d ask the “experts” whether I’d be better 
>>> off with some RG6 Quad-shield, or LMR400 (I’ve got a local source that 
>>> doesn’t know what LMR400 is, or what it’s worth)? 
>>> 
>>> Obviously I’d prefer to run and crimp RG6, but if I’d be better off with 
>>> LMR400, I’d rather run that now than go back into the crawlspace again. =)
>>> 
>>> Also, if it helps, I’ll probably have a Symmetricom/HP 58516A at/near the 
>>> T-bolt so I can experiment with other GPS(DO)s as well (especially one of 
>>> the JRMiller boards I bought and built (but never finished) ages ago). 
>>> Which brings the question, will the T-bolt provide the oomph needed to 
>>> power that splitter and the antenna over that length of cable? 
>>> 
>>> Thanks! 
>>> 
>>> -Ryan Stasel
>>> 
>>> 
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Re: [time-nuts] Using a frequency synthesizer replacement for motherboard oscillator

[bownes]

It all depends on what clock your talking about. Any given PC probably has more 
than one oscillator onboard.
Generally there will be one for the CPU, one for the display circuitry, and 
probably one for the real time clock.

Presuming you are talking about the CPU clock, it should be fairly 
straightforward to find the oscillator package on the motherboard find the pin 
with clock output and feed your clock input there.

On Nov 30, 2012, at 16:59, Bob Camp  wrote:

> Hi
> 
> It's most commonly done with things like a Soekris 45xx series board. You 
> don't need anything very exotic for the frequency conversion. The jitter in 
> the PC is way worse than what the external chips will be creating. 
> 
> The real question is - what is the "magic frequency" on the particular mother 
> board you are going to modify? Once upon a time they all were a pretty 
> predictable 14.xxx MHz. These days, who knows what's going in where…
> 
> Bob
> 
> On Nov 30, 2012, at 4:55 PM, Sarah White  wrote:
> 
>> Has anyone ever used a TAPR clock block or other frequency synthesizer
>> to sort the clock drift / timing problems on a regular computer? I'll
>> probably end up with a used dell or IBM workstation for this purpose.
>> 
>> Recently, I came across a low-cost frequency synthesizer capable of
>> using a 10mhz frequency reference (planning on using the thunderbolt
>> GPSDO I'm working with once I manage to sort out the temperature issues)
>> 
>> http://www.tapr.org/~n8ur/Clock-Block_Manual.pdf
>> 
>> ^ TAPR "Clock Block" has an installation example for how to do what I'm
>> planning with a Soekris net4501 low-cost / low-power embedded device...
>> 
>> What I'm hoping to figure out is how to do the same, except on a proper
>> computer such as the local used ones I'm able to get for less than $200
>> with 2ghz with 30GB hard disk, 512mb or more ram, etc. So I figure this
>> should be fine for what I'm planning.
>> 
>> Example of what I'm trying to do, though based on the low-power embedded
>> Soekris net4501 system from the TAPR manual's example section:
>> 
>> http://www.febo.com/time-freq/ntp/soekris/index.html
>> 
>> ^Aren't those the photos from clock block frequency synthesizer manual?
>> 
>> Again, I'm wondering if anyone has opinions or experience about doing
>> such things with NOT an embedded system (as I said, can get a nice 2ghz
>> or so machine for less than $200 locally at a brick and mortar shop
>> within walking distance)
>> 
>> Thanks in advance,
>> Sarah
>> 
>> 
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Re: [time-nuts] GPS DO Alternatives

[bownes]

I've only been following this thread distantly, however, I have been playing 
with arduinos quite a bit of late. 

If you wanted to incorporate one as the processor of choice in a new design, 
the cost is quite low, under $4.00us for the processor in quantity one. I've 
used one in a new design in the last week and it really simplified life. 

As to the capabilities, remember that pretty  much any AVR chip can run the 
arduino code. The atmega128 has more oomph for about the same price for 
example. 

Additionally, if you don't like the language for the arduino, C takes about 5 
minutes to get running. 

Bob

On Dec 8, 2012, at 17:52, Jim Lux  wrote:

> On 12/8/12 9:30 AM, johncr...@aol.com wrote:
>> 
>> 
>> Instead the discussion has centered on what microprocessor (of a hundred
>> that would work)
>> and how to eliminate "glue" logic and and a few analog parts to save
>> money. This is silly - silicon is
>> CHEAP.
> 
> Silicon is cheap, but for one-off fabrication by a hobbyist that isn't always 
> the case.  As was mentioned in a couple of the mails in the long discussion, 
> for a single person to build something like this requires a combination of 
> skills and materials. Someone may be fine at software, but doesn't want to 
> fabricate circuitry, or vice versa.
> 
> So, there was discussion of what could you do that would literally be "plug 
> and play" with minimal hardware design and assembly required (so the playing 
> would be with software).
> 
> 
> This isn't an unusual scenario.. The AMSAT folks have run into it vis a vis 
> ground stations. So have others (APRS).  A colleague of mine (N5BF) comments 
> that what you really need is something where someone can "impulse buy" enough 
> to do something useful fairly quickly.  The "kit idea": buying $100 worth of 
> parts and then having to spend 6 weeks assembling and testing means that lots 
> of people will have $100 parts bags sitting on a shelf, unused.  You'd be 
> better off selling a $200 assembled and tested widget.  Yes, you won't sell 
> quite as many, but a LOT more of them will be actually used than those bags 
> o'parts.
> 
> 
> A particularly attractive model is where you have a hardware component that 
> is delivered pretty much ready to go, with basic software, and the "fooling 
> around" is with changes in the software or parameters. For the GPSDO world, 
> this might be experimenting with different filters and holdover strategies, 
> or maybe tuning it to work with your particular OCXO.
> 
> This is why the Arduino is so popular.  No or minimal soldering required, a 
> wealth of simple software that almost does what you need it to, be it 
> monitoring the temperature of your beer fermentation, turning on and off 
> sprinklers or whatever.
> 
> Anything where the software is quite complex, that will inhibit 
> experimentation, unless there's a lot of documentation of the theory of 
> operation and software design, and the software has to be written to 
> facilitate modification.   For the Arduino, the limited amount of storage 
> sort of self limits the complexity of applications.  Once you move into the 
> PC world it gets a lot harder.  And realistically, a lot of hobby written 
> software doesn't have a good architecture or underlying design.  It sort of 
> just growed in place with successive modifications to add features, etc.  And 
> it works, but it's not very easy to figure out how to modify it.
> 
> 
> 
> 
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Re: [time-nuts] suggestions for free samples from AD

[bownes]

You can generally get free samples of moderate cost from a vendors website. 
Mini-circuits and Hittite are the notable exceptions. 

On Jan 5, 2013, at 20:42, Lizeth Norman  wrote:

> Gentlemen:
> My experience is that if you place an order of some substance,
> assistance will be forthcoming.
> Some of the interesting parts only come by the reel   :-(~
> Was hoping that they might be persuaded to comp me one or two..
> I'm a hobbyist and as such don't try an hide it.
> Norm
> 
> On Sat, Jan 5, 2013 at 7:59 PM, Bob Camp  wrote:
>> Hi
>> 
>> Which brings up the standard caution to always be very honest about just 
>> what you plan to do with the stuff. "Inventing" a day job is not a good idea…
>> 
>> Bob
>> 
>> On Jan 5, 2013, at 6:49 PM, Didier Juges  wrote:
>> 
>>> "These days there's a trick where you can "borrow" things like dev boards.
>>> As long as you don't trash them, there's no charge. Often they seem to
>>> forget you have them…."
>>> 
>>> These tricks work best when you actually use that kind of product in your
>>> day job and the sales rep has the hope of eventually getting a sale.
>>> As a hobbyist, it is much much harder.
>>> 
>>> 
>>> On Sat, Jan 5, 2013 at 3:36 PM, Bob Camp  wrote:
>>> 
 Hi
 
 These days there's a trick where you can "borrow" things like dev boards.
 As long as you don't trash them, there's no charge. Often they seem to
 forget you have them….
 
 Bob
 
 On Jan 5, 2013, at 4:29 PM, Lizeth Norman  wrote:
 
> Bob,
> May have a little pull because I want to purchase two dev boards. It's
> a few hundred, so they may be persuaded to actually chat with me.
> Hence the idea of looking for a few cool parts
> Norm
> 
> On Sat, Jan 5, 2013 at 3:48 PM, Bob Camp  wrote:
>> Hi
>> 
>> If you happen to know your local Analog sales guy, he can be a big help
 in situations like this.
>> 
>> Bob
>> 
>> On Jan 5, 2013, at 2:28 PM, Lizeth Norman 
 wrote:
>> 
>>> Hi all!
>>> Title says it all. I have to place an order and need to fill up the
>>> sample bag limit.
>>> Suggestions??
>>> 73 es HNY de Norm n3ykf
>>> 
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Re: [time-nuts] Z3801A trouble

[bownes]

That is exactly what mine does when it has marginal power on the 48v input. You 
may find that 50-52vdc works. 

On Jan 13, 2013, at 0:14, Joseph Gray  wrote:

> After many years of faithful service, my Z3801A has stopped working.
> It seems to be going through a loop at powerup. All of the LEDs blink
> at once, then they blink in order, left to right. After several
> seconds, this is repeated. I'll have to clear the bench of the project
> I was working on so I can take the Z3801A apart.
> 
> Joe Gray
> W5JG
> 
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Re: [time-nuts] Needed: The Real Serial USB Fix

[bownes]

The problem with the Ethernet adapters is the lack of software support on the 
OS side. I'd have gone to that long ago if I could point any bit if software at 
a serial port that was actually on a terminal server out on the ip fabric. 

On Jan 27, 2013, at 12:30, Peter Gottlieb  wrote:

> At work we simply use multi port serial cards (*no* USB intermediary) or 
> Ethernet to serial adapters.  Any use of USB for critical test equipment was 
> pretty much banned here years ago.
> 
> 
> On 1/27/2013 8:47 AM, Stan, W1LE wrote:
>> Hello The Net:
>> 
>> Yes, I have had the mouse problem, but the more serious issue is when I run 
>> multiple (3) instances of Lady Heather
>> (latest version at KE5FX) and after awhile none of the times agree and the 
>> problem only gets worse with time.
>> I have tried the multiple USB to RS232 adapters into motherboard USB ports 
>> and I have tried a multi USB port PCI card.
>> 
>> Any solutions with this problem ?
>> 
>> Stan, W1LECape CodFN41sr
>> 
>> 
>> 
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>> 
>> -
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 10.0.1430 / Virus Database: 2639/5561 - Release Date: 01/27/13
> 
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Re: [time-nuts] Nifty "MINI TIC" for DMTD

[bownes]

Used is definitely the way to go. My stereo zoom scope was $15!

On Feb 8, 2013, at 16:12, "DaveH"  wrote:

> Check to see if there are any tech auctions in your area.
> 
> Picked up a nice scope with stand and illuminator for $90 in the Seattle
> area.
> 
> Dave
> 
>> -Original Message-
>> From: time-nuts-boun...@febo.com 
>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Dan Kemppainen
>> Sent: Friday, February 08, 2013 12:25
>> To: time-nuts@febo.com
>> Subject: [time-nuts] Nifty "MINI TIC" for DMTD
>> 
>> We do 0603 and 0402 with IC's at .5mm lead spacing all day 
>> long. Under 
>> stereo zoom, it's not an issue. We have 50+ year old techs who build 
>> this stuff all day...
>> 
>> We have one of these on every bench. At around $700 new for the 3x to 
>> 90x Zoom it's not bad. But may be prohibitive for home use. I can 
>> highly recommend adding a .5x bottom lens, as this increases your 
>> working distance by a factor of two...
>> http://truevisionmicroscopes.com/category/products/boom-mounte
>> d-normal-microscope/
>> 
>> Once you go surface mount, you'll never want to do through hole again!
>> 
>> Dan
>> 
>> 
>> On 2/8/2013 12:00 PM, time-nuts-requ...@febo.com wrote:
>>> Message: 4
>>> Date: Fri, 08 Feb 2013 10:45:21 +0100
>>> From: Volker Esper
>>> To: Discussion of precise time and frequency measurement
>>>
>>> Subject: Re: [time-nuts] Nifty "MINI TIC" for DMTD
>>> Message-ID:<5114c931.2070...@t-online.de>
>>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>> 
>>> 
>>> I bought a stereo microscope some days before and I agree
>> with Bob. I
>>> keep building non-RF projects the classical way (through
>> hole) but if it
>>> comes to radio frequency I prefer SMD since high frequency
>> is easier to
>>> handle. Can you tinker with the idea of buying a stereo
>> microscope? It's
>>> absolute fun to easily solder those miniature parts!
>>> 
>>> Volker - DF9PL
>> 
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Re: [time-nuts] OT - DC-10 gyros

[bownes]

On Mar 27, 2013, at 22:54, Jim Lux  wrote:

> On 3/27/13 3:20 PM, Bob Camp wrote:
> 
> 
> Of course, for the more mechanically inclined.. what about a big flywheel 
> driving an alternator.  You might be able to rejigger a car alternator.  I 
> don't recall how many poles they have..

A motor driving a flywheel driving an alternator/generator is called a motor 
generator set. Some implementations are called a diesel electric locomotive. We 
used to use them as power conditioners for Cray class supercomputers. Also used 
by many home machinists to generate 3 phase from single phase power. 

Car alternators are generally 3 phase internally. Don't know if you could get 
28vac out tho. 
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Re: [time-nuts] apple Xcode

[bownes]

Oh, you can do it, but you really need to know what you're doing.


As the prev poster said, it depends on what you are doing. Simple compiles are 
straightforward, autoconf if its a bit more complex, use Xcode.

If you are doing work on an app that needs a GUI, Xcode makes it easy. 


On May 20, 2013, at 13:39, Chris Albertson  wrote:

> If you are going to produce Mac or IOS apps you don't have a choice.  You
> pretty much have to use it.If you are building portable apps I tend to
> just use terminal sessions and a text editor and GNU's "autoconf" to create
> the .configure files.
> 
> Depends on what you are doing
> 
> 
> On Mon, May 20, 2013 at 9:53 AM, Don Latham  wrote:
> 
>> Have any tnuts used the Apple Xcode programming setup? If so, quick
>> comments?
>> tnx Don
>> 
>> 
>> 
>> --
>> "Neither the voice of authority nor the weight of reason and argument
>> are as significant as experiment, for thence comes quiet to the mind."
>> De Erroribus Medicorum, R. Bacon, 13th century.
>> "If you don't know what it is, don't poke it."
>> Ghost in the Shell
>> 
>> 
>> Dr. Don Latham AJ7LL
>> Six Mile Systems LLP
>> 17850 Six Mile Road
>> POB 134
>> Huson, MT, 59846
>> VOX 406-626-4304
>> www.lightningforensics.com
>> www.sixmilesystems.com
>> 
>> 
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> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Follow-up question re: microcontroller families

[bownes]

I use the Arduino as a rapid prototype development platform. I build the 
application and the hardware on the Arduino and then move the cpu to a 
standalone board. You can also use the Arduino as a programmer much like 
someone else suggested. 

Bob

On May 26, 2013, at 13:19, Chris Albertson  wrote:

> A fan controller (8-pin DIP package) is simple enough to build on perf
> board.  But mostly I agree that it is best to buy these on PCBs.  You can
> use them right out of the box.   I do have an Arduino and it's advantage is
> that you can build very fast.   I had a device that measured the resistance
> across a pot and displayed the value on a 2x16 LCD working about 40 minutes
> after I got the Arduino un-boxed.  It is easy and fast.   But they cost a
> few $$
> 
> A cheaper alternative I think I like is TI's "launchpads"  They come on
> little credit card sized PCBs and the concept of very much the same as
> Arduino.  TI sells several.  One is a $13 ARM Cortex M4.  It is a complete
> development system.  The other is a MSP430 version for $10.  But with the
> MSP versionyou can remove the uP after it is programmer if you like, or
> leave it on the board.   These prices include shipping.  $13 is good pice
> for an ARM on a breakout board.
> 
> They also sell an assortment of  "booster boards" that plug in and provide
> all kinds of interfaces, pretty much the same concept as Arduino "shields"
> 
> More info here:
> /launchpad/overview_head.html
> 
> On Sun, May 26, 2013 at 9:18 AM, Jim Lux  wrote:
>> On 5/26/13 9:00 AM, Chris Albertson wrote:
 
 But for many applications, the inevitable overhead
 (power, heat, external components, OS, etc) simply
 eliminates the gain of having a better/faster CPU.
 
 Sometimes I end up using a 6 or 8 pin PIC with only
 a few lines of code to to solve complex problems where
 a (F)PGA/CPLD design would be a lot of work and a
 16/32bit microcontroller simply overkill.
>>> 
>>> 
>>> 
>>> As it turns out there are a LOT more simple jobs than there are
>>> complex jobs.  This is why they make and sel a lot motr 8-t
>>> controllers than they sell 32-bit controllers.
>>> 
>>> For example I want to control the cooling fan for a rubidium
>>> oscillator's heat sink.   I only need three pins, 1) the temperature
>>> sensor, 2) Fan tachometer pulse, fan voltage.  A $1 "tiny AVR" 8-pin
>>> chip can handle this just fine and we are talking about 20 lines of
>>> code maybe after the pins are set up.  Using an ARM and running an OS
>>> would be silly overkill.
>> 
>> The other thing is packaging and peripherals..not to mention development
>> time.  It might be more "cost effective" (where cost is some complex
>> conglomeration of your time and money) to always use the same part, even
> if
>> overkill.
>> 
>> Some people are happy to layout a new PCB, get it fabbed (or make it
>> themselves) or deadbug it.  Others might want a board with terminal
> strips.
>> Or you might want something that you have a box for or maybe you like
>> mounting it inside.
>> 
>> 
>> I think everyone has their favorites, and most folks tend to have
> relatively
>> few candidates at any given time (it's difficult to switch among various
>> processors on a day to day basis).  Right now, I tend to use Matlab on PCs
>> for big things, with some python.  For smaller needs, I've been using lots
>> of Arduino Uno R3s and Teensy3s, because of the packaging.  Both using the
>> Arduino semi-C tool chain and also the non-arduino compilers.  (having a
> USB
>> boot loader, etc, does make life easier).
>> 
>> I've used PICs and Rabbits in the not too recent past, but the Rabbits
> don't
>> have as nice a development environment, and there's no equivalent of the
> $20
>> Arduino, nor the plethora of cheap interfaces to things like relays and
> what
>> not.
>> 
>> I haven't looked much at whether a low cost PIC on a board with
> peripherals
>> is available. They've always been a "build a circuit" either with
> perfboard,
>> deadbug, or small PCB, and that makes it take a few more hours or days.
>> 
>> For the "I want to finish the project this weekend starting Saturday
>> afternoon", the whole arduino world is pretty convenient, at least as far
> as
>> getting the hardware put together and a first load of software running.
>> 
>> 
>> 
>> 
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> 
> 
> --
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Follow-up question re: microcontroller families

[bownes]

For making a blinking LEDs, it is hard to beat a 74LS74. However, a PIC, is 
probably less expensive! :)

On May 26, 2013, at 13:33, Bob Camp  wrote:

> Hi
> 
> If you head over to the auction sites and do a bit of creative digging / 
> bidding, the Arduino clones are amazingly cheap. They easily beat the $12 or 
> so Freescale and TI demo boards by a wide margin cost wise. Bang for the buck 
> wise, indeed the demo boards win out. For blinking a LED, running out of 
> horsepower isn't a major concern with any of them. 
> 
> Bob
> 
> On May 26, 2013, at 1:19 PM, Chris Albertson  
> wrote:
> 
>> A fan controller (8-pin DIP package) is simple enough to build on perf
>> board.  But mostly I agree that it is best to buy these on PCBs.  You can
>> use them right out of the box.   I do have an Arduino and it's advantage is
>> that you can build very fast.   I had a device that measured the resistance
>> across a pot and displayed the value on a 2x16 LCD working about 40 minutes
>> after I got the Arduino un-boxed.  It is easy and fast.   But they cost a
>> few $$
>> 
>> A cheaper alternative I think I like is TI's "launchpads"  They come on
>> little credit card sized PCBs and the concept of very much the same as
>> Arduino.  TI sells several.  One is a $13 ARM Cortex M4.  It is a complete
>> development system.  The other is a MSP430 version for $10.  But with the
>> MSP versionyou can remove the uP after it is programmer if you like, or
>> leave it on the board.   These prices include shipping.  $13 is good pice
>> for an ARM on a breakout board.
>> 
>> They also sell an assortment of  "booster boards" that plug in and provide
>> all kinds of interfaces, pretty much the same concept as Arduino "shields"
>> 
>> More info here:
>> /launchpad/overview_head.html
>> 
>> On Sun, May 26, 2013 at 9:18 AM, Jim Lux  wrote:
>>> On 5/26/13 9:00 AM, Chris Albertson wrote:
> 
> But for many applications, the inevitable overhead
> (power, heat, external components, OS, etc) simply
> eliminates the gain of having a better/faster CPU.
> 
> Sometimes I end up using a 6 or 8 pin PIC with only
> a few lines of code to to solve complex problems where
> a (F)PGA/CPLD design would be a lot of work and a
> 16/32bit microcontroller simply overkill.
 
 
 
 As it turns out there are a LOT more simple jobs than there are
 complex jobs.  This is why they make and sel a lot motr 8-t
 controllers than they sell 32-bit controllers.
 
 For example I want to control the cooling fan for a rubidium
 oscillator's heat sink.   I only need three pins, 1) the temperature
 sensor, 2) Fan tachometer pulse, fan voltage.  A $1 "tiny AVR" 8-pin
 chip can handle this just fine and we are talking about 20 lines of
 code maybe after the pins are set up.  Using an ARM and running an OS
 would be silly overkill.
>>> 
>>> The other thing is packaging and peripherals..not to mention development
>>> time.  It might be more "cost effective" (where cost is some complex
>>> conglomeration of your time and money) to always use the same part, even
>> if
>>> overkill.
>>> 
>>> Some people are happy to layout a new PCB, get it fabbed (or make it
>>> themselves) or deadbug it.  Others might want a board with terminal
>> strips.
>>> Or you might want something that you have a box for or maybe you like
>>> mounting it inside.
>>> 
>>> 
>>> I think everyone has their favorites, and most folks tend to have
>> relatively
>>> few candidates at any given time (it's difficult to switch among various
>>> processors on a day to day basis).  Right now, I tend to use Matlab on PCs
>>> for big things, with some python.  For smaller needs, I've been using lots
>>> of Arduino Uno R3s and Teensy3s, because of the packaging.  Both using the
>>> Arduino semi-C tool chain and also the non-arduino compilers.  (having a
>> USB
>>> boot loader, etc, does make life easier).
>>> 
>>> I've used PICs and Rabbits in the not too recent past, but the Rabbits
>> don't
>>> have as nice a development environment, and there's no equivalent of the
>> $20
>>> Arduino, nor the plethora of cheap interfaces to things like relays and
>> what
>>> not.
>>> 
>>> I haven't looked much at whether a low cost PIC on a board with
>> peripherals
>>> is available. They've always been a "build a circuit" either with
>> perfboard,
>>> deadbug, or small PCB, and that makes it take a few more hours or days.
>>> 
>>> For the "I want to finish the project this weekend starting Saturday
>>> afternoon", the whole arduino world is pretty convenient, at least as far
>> as
>>> getting the hardware put together and a first load of software running.
>>> 
>>> 
>>> 
>>> 
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Re: [time-nuts] GPSDO & Crystal Aging

[bownes]

Interesting idea. It might be an interesting experiment to couple a large 
number of inexpensive xtals to see how it impacts effects such as sudden 
changes in a single xtal. 

With sufficient monitoring of each one, you could even tune the coupling to 
amplify/attenuate the results of the 'good' and 'bad' ones over some interval. 

Of course, what effect this has on things like phase noise, drift, and so on is 
a whole different matter. 

Bob

> On Apr 11, 2014, at 14:14, "Richard (Rick) Karlquist"  
> wrote:
> 
>> On 4/11/2014 11:04 AM, Hal Murray wrote:
>> 
>> How many would you need?  Is 3 enough?
>> 
>> How well could you do with several low(er) cost oscillators relative to one
>> good but expensive one?  It might be an interesting experiment in a nutty
>> sort of way.
> 
> My guess would be 3 would be a minimum, so you
> could have a majority vote.  Len Cutler's group
> actually built an experimental ensemble of 9 or
> 10, but it didn't seem to come to fruition.
> For this to make any sense, you would need to be
> able to cherry pick 9 or 10 really good oscillators.
> However, there was no way to get the production
> line to sign on to this.
> 
> David Allan had
> this interesting concept to the effect that if
> you had a sufficient number of wristwatches
> (maybe 1000) and you averaged them together
> you could somehow get a quality clock, or at
> least 31.6 times better.  Kind of like the
> notion of 1000 monkeys with 1000 typewriters...
> 
> Rick
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Re: [time-nuts] hp 54600a and rs-232

[bownes]

"Framing error" or "override" sounds like a parity or stop bit issues. Have you 
changed those at all? 7E2 often works when 8N1 is specified. 

> On Apr 22, 2014, at 10:34, "Collins, Graham"  wrote:
> 
> Thank you Thomas,
> 
> I have that document but it wasn't of much help. I spent much time over the 
> weekend reading through the various hp documents for this scope and 
> interfaces but it did not shed any light on the subject.
> 
> Cheers, Graham
> 
> 
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of Tom Knox
> Sent: April-22-14 10:28 AM
> To: Time-Nuts
> Subject: Re: [time-nuts] hp 54600a and rs-232
> 
> This may help: 
> http://cp.literature.agilent.com/litweb/pdf/54652-97004.pdf
> 
> Thomas Knox
> 
> 
> 
>> From: coll...@navcanada.ca
>> To: time-nuts@febo.com
>> Date: Tue, 22 Apr 2014 07:21:22 -0400
>> Subject: [time-nuts] hp 54600a and rs-232
>> 
>> While only related to time nuttery in the sense of the hp 54600a being an 
>> instrument (oscilloscope) which we nuts might use make some meaningful 
>> measurements, I am hoping that members of this list vast knowledge of many 
>> such instruments may be able to help or at least point me in the right 
>> direction.
>> 
>> I recently obtained a hp 54600a digital oscilloscope in very good condition 
>> and while not a modern whiz bang high bandwidth and high speed instrument it 
>> is quite capable and compliments my old Tektronix 5440 scope quite nicely.
>> 
>> My 54600a has the basic RS-232 interface module which seems to work OK. I am 
>> able to select "print screen" and send data from the scope to an HP plotter 
>> or printer - computer actually which collects the data stream and converts 
>> the hgl data into a png file using a simple script.
>> 
>> However, my attempts at getting the scope to respond to commands via the 
>> RS-232 serial interface are for naught. I am using a USB to RS-232 converter 
>> and an appropriate null modem cable. I don't have a proper serial port to 
>> try however.
>> 
>> When I send commands to the scope it will display "framing error" or 
>> "overrun" or "rs-232 error (113)" or "rs-232 error (118)" (I can't find 
>> either error code listed in the hp documents).
>> 
>> Being able to capture a "screen dump" is my primary concern and I am able to 
>> do so, controlling the scope via rs-232 as I might using a gpib/hpib 
>> interface is only secondary  but still, it would be nice to know why my 
>> limited attempts have so far not worked.
>> 
>> Ideas? Comments? Suggestions?
>> 
>> 
>> Cheers, Graham ve3gtc
>> 
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Re: [time-nuts] GPSDO standard interface?

[bownes]

Well, I built one of the ve2zaz units, and it has a. Pretty well defined serial 
interface. On the other hand, the one I use most has a PIC and an LCD, no 
serial interface. 

> On Jun 25, 2014, at 20:10, Bob Stewart  wrote:
> 
> In an offline communication, I suddenly realized that I hadn't given any 
> thought to the user interface for my GPSDO.  Is there an accepted standard 
> interface for GPSDOs, or is that a murky Microsoft-esque world of patents and 
> lawyers?
> 
> 
> Bob - AE6RV
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Re: [time-nuts] Time Code Units Available

[bownes]

Walter,

If the two datachron units and the datum 9300 are still available, I would be 
most interested. 

Thanks!
Bob

> On Jul 8, 2014, at 17:08, walter shawlee 2  wrote:
> 
> (very sorry for the first file size! Here's a smaller one)
> 
> Since there were several requests for more details, here's the various*time 
> code units *we have, numbers following in () are *quantities*. Sorry, the 
> fluke 207-1 VLF receiver is gone.
> 
> A pic is attached to show some units and the condition (very good), and 
> here's a list of what I found in one building.
> 
> There are probably more elsewhere, but I have to search further later. I 
> remain mystified as to *why* I thought we needed all these at some earlier 
> time.  We also have a huge quantity of stabilized/TCXO oscillator modules if 
> interested. probably more fun to snorkel through them in person, however.
> 
> *TRAK:*
> 
> 8400 Time Code Translator/Generator
> 
> 8390 Time Code Generator (2)
> 
> 8392 Countdown Reader
> 
> 8397-4 Time Code Translator (3)
> 
> 8397-8 Time Code Translator (2)
> 
> *OTHERS:*
> 
> Kinemetrics/Truetime 60DC NBS Time (WWVB)
> 
> Kinemetrics/Truetime 468DC NBS Time (Satellite)
> 
> (*I believe these are complete receivers, but both need antennas I do not 
> have*)
> 
> KODE Inc. TCU
> 
> DATACHRON 3700 CDU (Large display) ($40)
> 
> DATACHRON 3070 Time Code Translator/Generator
> 
> Anadex Counter CF-601R (seems to be second counters w/plasma displays) (2)
> 
> Datum 9300 Time Code Generator/Translator ($25)
> 
> ODETICS 285 Time Code Unit
> 
> Time Code Generators are $50 each, Translators/Displays are $30 each.
> the Kinemetrics and Odetics units are $50 each.
> all are as-is, as shown in the pic. shipping is extra.
> If you are coming up for the August 1/2 Free Stuff session,
> we will toss some of these into the free pile!
> 
> all the best,
> walter
> 
> -- 
> Walter Shawlee 2, President
> Sphere Research Corporation
> 3394 Sunnyside Rd.,  West Kelowna,  BC
> V1Z 2V4  CANADA  Phone: (250) 769-1834
> walt...@sphere.bc.ca
> WS2: We're all in one boat, no matter how it looks to you
> 
> 
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[time-nuts] MIT Flea

[bownes]

Apologies for to those not in New England or not going to the Flea. 

I'm heading out to the MIT Flea at oh-freaking-dark in the morning and I know 
there are often several time nuts who go. If you happen to see a guy wander by 
in a Horton Emergency Vehicles hat looking very tired, say Hi!
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Re: [time-nuts] Oscilloquartz 3210 Cesium Standard

[bownes]

Careful Chris, it sounds like you are developing the symptoms of the Vintage 
strain of the time nuts infection. Next thing you know, you will be looking at 
tall clocks. 

Bob, who is debating the wisdom of non invasively synchronizing the family 
heirloom tall clock to the new cesium clock...

> On Aug 28, 2014, at 10:33, Chris  wrote:
> 
>> On 08/28/14 05:03, Javier Herrero wrote:
>> Hello,
>> 
>> Here is the manual I've. I have also some other documentations, and some
>> Oscilloquartz software for the OSA-5585, but I don't know if they are
>> very useful.
>> 
>> Regards,
>> 
>> Javier
> 
> Hi Javier,
> 
> Thanks for that and for the other replies. The 3210 looks like quite an early 
> design, with no sign of microprocessors at all. There's a 8 slot card cage 
> with a load of discrete analog circuitry, 741 op amps etc and a couple of 
> boards full of 14 / 16 pin ssi cmos / ttl devices, which I guess would be the 
> synthesiser logic and perhaps a state machine style startup sequencer. Apart 
> from that, the rest is power supply related and what looks like an alarm 
> board with optoisolator discete outputs to a 25 way D connector. The step 
> recovery diode (?) multiplier into the microwave cavity is a really neat gold 
> plated assembly with what looks like a 50r termination (setup tap for 
> spectrum analyser ?) and an adjustment trimmer, but am not touching that or 
> the many trimpots on the boards or any adjustments until I have more info. 
> The tube is from FTS, part number / model 7101.
> 
> It seems strange that the 2nd harmonic, meter #9, is zero, since even with a 
> tube approaching eol, one would expect at least some indication, which is why 
> I think there may be an electronic fault. Perhaps the hv power supply module 
> feeding the electron multiplier. Will try to measure that, but the area 
> around the tube is really heavily rivetted and screwed down in all 
> directions. Looks like a lot of the left hand side of the case will need to 
> be disassembled just to get at the tube connections. It also had the battery 
> backup option, with 4 sets of 3 x cyclon type cells, but with a date code of 
> 1984, are seriously dead and have been removed.
> 
> This time nuts things seems to be a growing interest and wonder if there is a 
> cure ? :-). Recently bought a 1970's era Tracor 304D rubidium standard. 
> Again, no lock, but a very well engineered and screwed together piece of kit 
> and should be fixable. Collection now includes the Z3816, from Ebay US around 
> 7 years ago, a Z3815 currently being repackaged, an HP103 with open circuit 
> oven heater elements and the 3210...
> 
> Regards,
> 
> Chris
> 
> 
> 
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Re: [time-nuts] 5370 processor boards available

[bownes]

At that point, why not just remove the few remaining HP parts and put them in a 
new enclosure? :)



> On Oct 8, 2014, at 10:29, Pete Lancashire  wrote:
> 
> One future project would be to replace the front panel with a LCD/Touch
> Panel
> 
> 
> 
>> On Wed, Oct 8, 2014 at 6:56 AM, Chuck Harris  wrote:
>> 
>> Hi Magnus,
>> 
>> As one of the charter users of the board, I know that.  I was hoping
>> that some of the other users might elaborate on what John's board has
>> done for them that they wouldn't have done otherwise.
>> 
>> The addition of a BBB inside of a 5370 just reeks of future capabilities,
>> and possibilities.  How have these opportunities been exploited?
>> 
>> I quite enjoy being able to run my 5370 in the lab when I am in my
>> office... but that is a luxury, not a need... for me.
>> 
>> -Chuck Harris
>> 
>> Magnus Danielson wrote:
>> 
>>> Hi Chuck,
>>> 
>>> The benefit is that you can use Ethernet straight into the 5370, you can
>>> get much
>>> higher sampling rates and well, we can have fun hacking up more
>>> functionalities into
>>> the 5370 native support if we like to.
>>> 
>>> Cheers,
>>> Magnus
>>> 
 On 10/08/2014 02:46 PM, Chuck Harris wrote:
 
 Hi John,
 
 Can you share with the group any interesting applications this
 new processor board has enabled?
 
 Other than turning the 5370A into a capable replacement for the
 5370B...
 
 -Chuck Harris
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Re: [time-nuts] GPS, USGS Early Earthquake Warning

[bownes]

WIWAUG (when I was an under grad), it was explained to me that the seismometers 
were log scale and basically don't clip. When you get into a big event, the 
last few decimal places just don't matter. 

We also used differential GPS across known fault lines to measure slip both 
over time and during events, which are often 'step' slips of a bit at a time 
over the course of the event, which may last seconds or hours. 

Bob




On Apr 28, 2012, at 18:32, "Tom Van Baak"  wrote:

> Brooke,
> 
> Right, an overloaded accelerometer is a problem -- if you have
> only one or a few of them.
> 
> But the beauty of using cellular sites is that you have hundreds
> or thousands of them across populated areas; so it's no problem
> if the a bunch of sensors near the epicenter overload. A clipped
> signal is not worthless; at least you know something big happened
> there; you can rely on slightly more distant cell tower sensors to
> get readings a few seconds later that are less clipped or not clipped
> at all. (There's another solution I heard about -- using smartphones
> as a tiered network of synchronized accelerometers).
> 
> A high rate GPS solution sounds really cool to me but I bet its also
> far more expensive.
> 
> Related to that, are there any seismometer experts on the list? I've
> always wondered why they don't augment the extremely sensitive
> detectors with less sensitive detectors? Of course a really good
> detector will overload; so just co-locate cheap detectors that are 40
> and 80 dB less sensitive. That way you get a clean signal no matter
> how close or far the epicenter is from the detector.
> 
> /tvb
> 
> - Original Message - From: "Brooke Clarke" 
> To: "Tom Van Baak" ; "Discussion of precise time and 
> frequency measurement" 
> Sent: Saturday, April 28, 2012 2:49 PM
> Subject: Re: [time-nuts] GPS, USGS Early Earthquake Warning
> 
> 
>> Hi Tom:
>> The USGS talk was the first time I'd heard about the need to look at an 
>> earthquake as happening along some length of fault line.  For the big quake 
>> in Japan the forecast software assumed a point source for the quake and that 
>> cause them to under estimate the magnitude and get other things wrong.  GPS 
>> is part of the solution to get better results.
>> In the S. CA example he showed a 180 mile long rupture of the San Andreas 
>> fault.  At 2 miles a second the quake would last about 90 seconds.
>> Accelerometers that are not right on top of the fault will be overloaded 
>> with signals coming from each location where there's a fracture and so the 
>> data will be nearly impossible to untangle in a short time frame.  But a GPS 
>> receiver will show a DC displacement that unambiguous.
>> Have Fun,
>> Brooke Clarke
> 
> 
> 
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Re: [time-nuts] US 5065A standby battery cell source?

[bownes]

I get my tabbed batteries from Batteries America. Decent prices and good 
quality. 



On Jul 1, 2012, at 19:41, Dan Rae  wrote:

> All this discussion of the excellence of these Rb units reminds me that 
> another cell must have died in my battery pack since the slightest glitch in 
> the power here now makes the green light go out.  The last time a cell died I 
> just took it out since it actually seems to work well enough with 20 instead 
> of the specified 21, but another one seems to have gone high resistance.
> 
> So, my question is: where might be a good place in the US to get tabbed NiMH 
> AA cells to replace the battery in mine?   I am currently using generic 
> Chinese ones, but am not at all happy with their longevity.
> 
> And this one came from eBay, quite a bit less than $500 because it looked 
> filthy, but it took a lot of patience to find it and a bit of TLC to get it 
> going, but it has been working superbly for about four years now.
> 
> Dan
> 
> 
> 
> 
> 
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Re: [time-nuts] [OT]: HP-5061A and a dust bunny.....

[bownes]

I understand this event perfectly. Our feline owners leave us presents on an 
occasional basis. Usually we find them straight away, but when we can't, ninja 
nose wife takes over.

For some reason, however, they tend to only leave the back half of the dead 
rabbit. My spouse says it is because the back half must taste like a$$.
 
To make it time relevant, why is it the cats only bring things at precisely 
4:30 AM? I'm pretty sure they are not WWV compliant.

Thanks,



On Jul 8, 2012, at 16:50, "Brian, WA1ZMS"  wrote:

> This was such a crazy event that I have to share this with somebody.
> 
> 
> 
> I started to notice an odd smell in the ham shack/lab yesterday night.
> 
> Now we had a bad weather storm and was one of 2.5 Million homes
> 
> without AC power for 5 days.  So the generators were pressed into
> 
> service and kept the lab cool with a 9,000BTU room air conditioner.
> 
> 
> 
> My first thought was mold in the temporary A/C unit. But after the
> 
> family came home from church it was very clear that it was much
> 
> worse than a simple mold issue. It was the smell of a dead rodent.
> 
> It had to be. I recognized it by then.
> 
> 
> 
> So the hunt was on!  Where was the dead mouse or mole that
> 
> one of our cats must have dragged in through the pet door?
> 
> 
> 
> The astute may already know the answer:  In the bottom of a
> 
> rack where an HP-5061A lives was not only the typical “dust
> 
> bunnies” that often collect in such areas…….BUT……..
> there was also a dead rabbit! 
> 
> 
> 
> BTW….All 3 cats have been interviewed and none will admit to
> 
> being involved in any way.
> 
> 
> 
> 
> 
> -Brian, WA1ZMS/4
> 
> Forest, VA ßwhere the AC mains are back on and the venting
> 
> of the shack/lab continues with an outside air temp of 38C.
> 
> No kidding!  What’s worse the heat or the smell? Both will kill
> 
> you.
> 
> 
> 
> 
> 
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Re: [time-nuts] Thunderbolt mounting

[bownes]

I've oft considered bolting one to the cement wall in my basement, which is a 
very nice, very stable 57deg F just to see how it holds. 



On Jul 13, 2012, at 14:36, "Don Latham"  wrote:

> You can get one of these at any large truck stop :-)
> Don
> 
> Peter Gottlieb
>  Now I
>>   suppose one could put it into a highly insulated container with a
>>   bidirectional Peltier temperature controller (I have some larger
>>   examples of those), but really was wondering if there was an easier
>> way
>>   than that.
>> 
>> 
>>   On 07/13/12, Azelio Boriani wrote:
>> 
>>   Peltier cooler on top of the OCXO or on top of the TBolt?
>>   On Fri, Jul 13, 2012 at 9:54 AM, Chuck Forsberg WA7KGX N2469R
>>   <[1]c...@omen.com>wrote:
>>> How about a thermostatically controlled Peltier cooler?
>>> 
>>> 
>>> --
>>> Chuck Forsberg WA7KGX N2469R [2]c...@omen.com [3]www.omen.com
>>> Developer of Industrial ZMODEM(Tm) for Embedded Applications
>>> Omen Technology Inc "The High Reliability Software"
>>> 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430
>>> 
>>> 
>>> 
>>> 
>>> __**_
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>> References
>> 
>>   1. mailto:c...@omen.com
>>   2. mailto:c...@omen.com
>>   3. http://www.omen.com/
>>   4. mailto:time-nuts@febo.com
>>   5. https://www.febo.com/cgi-bin/**
>>   6. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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> 
> 
> -- 
> "Neither the voice of authority nor the weight of reason and argument
> are as significant as experiment, for thence comes quiet to the mind."
> R. Bacon
> "If you don't know what it is, don't poke it."
> Ghost in the Shell
> 
> 
> Dr. Don Latham AJ7LL
> Six Mile Systems LLP
> 17850 Six Mile Road
> POB 134
> Huson, MT, 59846
> VOX 406-626-4304
> www.lightningforensics.com
> www.sixmilesystems.com
> 
> 
> 
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Re: [time-nuts] Thunderbolt mounting

[bownes]

As someone pointed out, it is dependent on where you are, as well as a number 
of other factors. 

I've got a nice chunk of concrete tied to bedrock about 10' below the surface 
with a thermal variation that is below the threshold of the thermometer i have 
there.

  Since I need to put something else on the concrete block (seismograph) I 
thought it might be interesting to toss a frequency std on it a well. 

Yet another project...:)



On Jul 13, 2012, at 20:25, Neville Michie  wrote:

> 
> You have to go deep into the ground to get stability.
> At 15 metres deep there is a lovely pure sine wave of about 0.3C P-P.
> I measured it on the roof of a cave, its period one year.
> My design for the bolt is to put it in a 1/4 inch thick aluminium box which 
> is held at a constant temperature by a fan. Switching control is good enough 
> as the 
> thermal diffusivity of 1/4 inch aluminium will attenuate any spectral 
> components shorter than 
> a minute. The aluminium box is so conductive that the box is isothermal, so 
> once the bolt 
> has established its internal temperature gradients, nothing changes.
> cheers, 
> Neville Michie
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Re: [time-nuts] Lightsquared questionfor SFO area....

[bownes]

Interesting that they use jammers. The guys on the ambulances just wrap the 
antennas with the foil from burger wrappers or the like. 



On Jul 28, 2012, at 0:34, Jim Lux  wrote:

> On 7/27/12 6:42 PM, Brian, WA1ZMS wrote:
>> Does anyone know if there is ANY recent active Lightsquared testing taking
>> place in the SFO area of the US?
>> 
>> 
> 
> Very unlikely.. they've lost their experimental license.
> 
>> 
>> I'm dealing with a day-job issue with GPS clocks in the Bay Area showing
>> "GPS unlocked" errors from 3rd party equipment.
>> 
>> 
> 
> 
> there are myriad sources of interference out there.  Jammers are a BIG 
> problem in urban areas (truckers and cab drivers use them to defeat their GPS 
> based tracking systems and time clocks).
> 
> there's a great set of articles over the past few months in GPS World about 
> it.
> 
> 
>> 
>> 
>> 
>> 
>> 
>> -Brian, WA1ZMS
>> 
>> 
>> 
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Re: [time-nuts] Cables dor 10 mHz

[bownes]

Not only do i remember the frozen yellow hose, I still have my vampire tap 
drill/tool...now finding it may be another matter...:)



On Jul 30, 2012, at 18:53, Chris Albertson  wrote:

> On Mon, Jul 30, 2012 at 12:41 PM, Sylvain Munaut <246...@gmail.com> wrote:
>>> 10 mHz
>> 
>> Please use MHz   ...
>> 
>> 10 mHz is 10 milli-hertz, ie 1 cycle every 10 second.
>> 
>> 
>> An yes, ethernet not being coax cables, I'd expect them to act as
>> antennas quite a bit ...
> 
> He said "old" Ethernet cables so I assume he meant 10Base2 cable which
> is RG58 with BNC connections.
> 
> Or the even older 10Base5 cable.   But the old 10Base5 would never
> leak.  It was made from RG8 but with an additional shield braid cover
> and they never cut it, signals were taken with "vampire taps". Or at
> the feed end where they used type N connections.   I wonder how many
> people here remember the old 10base5 stuff.  We used to call it
> "Frozen yellow garden hose".  It was a perfect description.  I think
> it was about 1980. And I still remember being astounded when I saw
> that a "vampire tap" could work.
> 
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Re: [time-nuts] Modern motherboard with RS232 port

[bownes]

Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump that  
to 2.01. 







On Aug 19, 2012, at 13:06, Chris Albertson  wrote:

> This sounds like a newer version of the board I use.   The thing to check
> is if the CPU heat sink has a fan or not.  Having no fan indicates that the
> CPU is not using much power.  It also removes a common failure point.
> 
> To reduce power even more.  On an NTP server you can unplug the keyboard,
> mouse and monitor and if you have other servers on the LAN configure one as
> a "boot server" and have it run TFTP then your NTP server does not need a
> disk drive.  It can run off a "RAM disk".  This makes it very fast, even
> faster than a SSD and it saves some cash.  Makes backup easy too as there
> is nothing to backup if there is no local storage.  If you don't have a
> TFTP server use a small notebook size disk drive. Even a 80GB drive is
> overkill.  You can also boot from a USB thumb drive and run a RAM disk.
> 
> It is worth it to look at your electric bill to find how much you pay for
> power.  Here I'm at $0.21 per KWH.  A full size PC server can use 250W or
> more.  There are 8760 hours in a year so you get $460 per year to run that
> 250W PC.  The little Atom will pay for itself in just a few months.  The
> first time I did that calculation, my "power hogs" where given away.
> 
> 
> 
> 
> On Sun, Aug 19, 2012 at 7:42 AM, Stan, W1LE  wrote:
> 
>> Hello The Net,
>> 
>> For your consideration:
>> 
>> The INTEL model DN2800mt ITX mother board uses a ATOM CPU and
>> draws about 11 watts of AC power when configured as:
>> (I have not measured DC power yet.)
>> 
>> 30 GB OCZ Nocti mSATA solid state drive,
>> WIN7 pro, 64 bit, USB keyboard and mouse
>> APEX MI-0008 case.
>> 
>> Also has:
>> parallel port available on mother board, you extend to a connector
>> RS232 serial port available on mother board, you extend to a connector
>> a single DC power supply from 11 to 19 V DC.
>> 1 each PCIe expansion port, I will use with a premium 4 channel sound card
>> SATA ports available for HDD/SDD,
>> USB ports are available,
>> Motherboard sound, and Gigalan.
>> 
>> I have not played with NTP, (yet), but it sounds like a decent time nut
>> technical challenge.
>> 
>> My application is for a remote site with only 13V DC power available from
>> PV/batteries.
>> Then use fiber ethernet to get off site.
>> 
>> The INTEL website would have further details.
>> 
>> Stan, W1LECape Cod   FN41sr
>> 
>> 
>> 
>> 
>> z
>> 
>> 
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> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Modern motherboard with RS232 port

[bownes]

It comes w ntp out of the box if you run fedora. 



On Aug 19, 2012, at 20:21, Bob Camp  wrote:

> Hi
> 
> The pi doesn't have a conventional serial port. It does have a TTL serial on 
> the 28 pin connector. There are also IRQ pins on the same connector. Since 
> they go directly to the CPU chip, hardware latency should be pretty good. It 
> should interface directly to a TTL output gps receiver like a LEA-6T. You 
> probably would need to tune up a driver to get it to work. Since it's Linux, 
> you should be able to get some sort of ntp running on it. AFIK there are no 
> neat counters like on a 45xx board. You also don't have a well tuned ntp 
> since it's LInux.
> 
> Bob
> 
> On Aug 19, 2012, at 1:31 PM, Chris Albertson  
> wrote:
> 
>> On Sun, Aug 19, 2012 at 10:16 AM, bownes  wrote:
>> 
>>> Why not just use a raspberry pi? Uses a whole 2w at idle. Ntp might bump
>>> that  to 2.01.
>>> 
>>> 
>>> 
>> You certainly could run ntpd on that box.  But I wonder how the PPS is
>> supported in hardware?   What is the standard deviation of interrupt
>> latency on the DCD pin on the serial port.  Perhaps some one who has a "pi"
>> could measure this.   All the data should be in the system log as each PPS
>> is time stamped and written to the log.   If the DCD pin is polled you are
>> not going to get decent results.  Maybe someone could read the PPS drive
>> code.
>> 
>> -- 
>> 
>> Chris Albertson
>> Redondo Beach, California
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Re: [time-nuts] Modern motherboard with RS232 port

[bownes]

Agreed. Just pointing out there isn't a big porting effort to get ntpd itself 
up and running. 


On Aug 19, 2012, at 22:24, Chris Albertson  wrote:

> On Sun, Aug 19, 2012 at 6:49 PM, bownes  wrote:
> 
>> It comes w ntp out of the box if you run fedora.
>> 
>> 
> You can run NTP without a Pulse Per Second (PPS) driver.  It will work just
> fine.   Most NTP installations don't use PPS.  But if you want to connect a
> GPS receiver and use it for precision timing you must have PPS support.  So
> having a working NTP out of the box is not enough.
> 
> 
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Hi Power LED Light power supply...

[bownes]

The local sandwich shop that I frequent recently switched to LED lighting. When 
I walk up to the counter I can see the flicker when people's hands are moving.

The same applies for LED taillights when a vehicle is moving as well as newer 
LED tower lighting.

Bob



On Sep 18, 2012, at 13:15, Hal Murray  wrote:

> 
> li...@rtty.us said:
>> There are a *lot* of TV's out there that refresh at 60 Hz or less. 
> 
> Many years ago, we had a busted fluorescent light at work.  I could see the 
> flicker out of the corner of my eye.  I found it annoying, so I'm a firm 
> believer that some people can see flicker in some conditions.  (Fortunately, 
> it was in a location where I didn't spend much time.)
> 
> Direct vision was not a problem.  I assumed the lamp was running at 60 Hz 
> rather than 120 and that peripheral vision was better at detecting 
> flicker/motion.
> 
> 
> Wiki has an interesting page on this stuff:
>  http://en.wikipedia.org/wiki/Flicker_fusion_threshold
> 
> the rod cells of the human eye have a faster response time than the cone 
> cells, so flicker can be sensed in peripheral vision at higher frequencies 
> than in foveal vision
> 
> But also:
> The maximum fusion frequency for rod-mediated vision reaches a plateau at 
> about 15 Hz, whereas cones reach a plateau, observable only at very high 
> illumination intensities, of about 60 Hz
> (I think that is backwards from the previous line.  I'd guess somebody typoed 
> rods-cones.)
> 
> Note that LEDs without diffusion are high-illumination, so I'm not surprised 
> if some people report flicker troubles.  It would be interesting to 
> investigate some examples.  I wonder if they are 120 Hz or 60 Hz?
> 
> 
> More wiki:
> 
> For the purposes of presenting moving images, the human flicker fusion 
> threshold is usually taken as 16 hertz (Hz). In actual practice, movies are 
> recorded at 24 frames per second, and TV cameras operate at 25 or 30 frames 
> per second, depending on the TV system used.
> 
> Even though motion may seem to be continuous at 25 or 30 frame/s, the 
> brightness may still seem to flicker objectionably. By showing each frame 
> twice in cinema projection (48 Hz), and using interlace in television (50 or 
> 60 Hz), a reasonable margin of error for unusual viewing conditions is 
> achieved in minimising subjective flicker effects.
> 
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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Re: [time-nuts] GPS Jammer

[bownes]

Many folks.

The paranoid tinfoil hat crowd

Folks who are concerned that law enforcement has placed a GPS tracker on their 
car. 

Truckers avoiding log enforcement

Truckers who want to sleep rather than drive. 

Ambulance drivers who want to sleep but claim to have been held up at hospital. 

Emergency services personnel (fire,ems,law enforcement) who want to take the 
company vehicle where they are not supposed to.


Just a few of the many I can think of!

On Oct 3, 2012, at 0:40, "Ron Ward"  wrote:

> Hi:
> Other than a terrorist, who would want to jam GPS?
> Ron
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Magnus Danielson
> Sent: Tuesday, October 02, 2012 2:28 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] GPS Jammer
> 
> On 10/02/2012 11:05 PM, John Lofgren wrote:
>> The 0.5 W and + 10 dBm numbers in the specs don't work out.  +10 dBm is 10
> mW.  I suspect that the 1/2 watt is really the DC input power.
> 
> Now, that makes sense.
> 
>> And, I'd agree about the range.  +10 dBm into a dipole at 10 meters gets
> you about -44 dBm at the receiver antenna in a free-space model.  That's
> really loud compared to the nominal -130 to -140 dBm you'd hear from the
> satellites.
> 
> Indeed. Even for 10 mW it was not reasonable. No wonders that "1-10 m 
> jammers" cause such grief to DHS. Serious overkill.
> 
> Cheers,
> Magnus
> 
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> 
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Re: [time-nuts] OT question about liquid cooling

[bownes]

BWIWY (back when I was young) we needed a dummy load for a supercomputer (think 
Cray YMP size) that drew many many kw. 

Our test load was about 250' of 3/4" copper tubing coiled at about 12" dia and 
1" spacing. The load was varied by changing where the + and - leads were bolted 
onto the coil with u bolts. 

The whole mess was cooled by running water through it. A hose barb on the input 
connected up to the cold water supply and the output was run into a drain. You 
had too little resistance dialed in when all thy came out the output end was 
steam. :)

Anyway such a test load could be replicated using 1/4" ice machine copper 
tubing available at the hardware store, some hose clamps, and or hose barbs.

Bob

On Oct 3, 2012, at 19:35, Tom Harris  wrote:

> My day job is large industrial power supplies. The test racks have large
> resistive loads with big fans exhausting to the outside. Cheap & simple.
> Safety is by several strings of temperature cutouts wired in series. We
> usually get work experience students in to wire them up.
> 
> Tip: to make a funny valued power resistor, just get the next value up and
> wrap some nichrome wire around it to bring it down to the correct value.
> 
> I met an engineer who made a battery charger for one of our submarines.
> This was tested by putting the load bank in a dumpmaster, and keeping it
> filled up with water using a firehose!
> 
> On 4 October 2012 02:01, Javier Herrero  wrote:
> 
>> Hello all,
>> 
>> Please excuse me for the OT, but since this list is plenty of very
>> knowledgeable colleagues, I'm tempted to ask...
>> 
>> I need to cool several resistive loads, in the order of 5kW, and I plan to
>> use a cold plate and a liquid-to-liquid heat exchanger like the Lytron
>> LCS-20, but this unit is quite big, and an overkill (it has 20kW
>> capability).
>> 
>> If someone could suggest me a smaller liquid-to-liquid heat exchanger, and
>> preferably a rack mount unit (and share any experience), it would be most
>> welcome.
>> 
>> Since this has not too much to do with time and frequency, please answer
>> off list.
>> 
>> Thank you very much! Best regards,
>> 
>> Javier
>> 
>> 
>> 
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> 
> 
> -- 
> 
> Tom Harris 
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[time-nuts] Tracking NTP displacement and correlation between two clients.

[bownes]

It had to happen eventually. Time Nut interest overlapped with $DAY_JOB.  

Due to reasons I really can't go into, a systems user is concerned with the 
displacement of two servers from the same pair of stratum 2 NTP servers. 

I'm convinced that it really isn an issue as long as the two systems in 
question remain within a few 10's of ms. However, I have no off the shelf 
method of collecting and correlating the data. Before I go out and invent the 
wheel, I thought I would check and see if anyone has done such a thing and 
saved the scripts and whatnot. 


Thanks!
Bob
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Re: [time-nuts] Tracking NTP displacement and correlation betweentwo clients.

[bownes]

Comments inline. 

On Oct 5, 2012, at 18:26, Hal Murray  wrote:

> 
> bow...@gmail.com said:
>> The problem is that they start in sync and over the course of a day drift
>> that far apart despite having NTP running. We're not sure why NTP isn't
>> correcting it along the way. Though at this point, we are looking at a
>> firmware bug.
> 
> I wouldn't think of it as two systems drifting apart, but rather at least one 
> system with a broken clock.
> 

Correct. 

> Is it only one system that is broken?
> 

Sort of. There are several systems consisting of a matched pair of nodes. In 
each case, one of the two wanders out into the weeds. But not every pair has 
one that goes south. 

In this case, four systems, 8 nodes, all identical hw (sequential sn's even), 
identical iLOM/DRAC, same software the entire length of the stack. 

Installing the latest firmware patch appears to have solved the problem. I'll 
know next week. 


> How many systems do you have running the same firmware?



> Normally, if ntpd is off by more than 128 ms, it will step the clock.  That 
> puts a line in the log file.  So it's more than a bit strange that the clocks 
> get off by many seconds.
> 

My thinking exactly. But it wasn't. I was hoping to use some tools to watch it 
drift off. 

> I'd double check that ntpd really is still running.

It is. 

> Are your drift-apart systems using only your 2 local stratum-2 servers?  If 
> so, that may be the problem.  If those servers don't agree, which one do you 
> believe?  (There is endless discussion in the NTP community about how many 
> servers you need.  3 lets you out-vote 1 bad guy.  4 lets you out-vote a bad 
> guy if one of them is down. ...)
> 

Two NTP servers agree. They even agree with my S1 at home. :)

Thanks for all the help folks. It looks like it was a firmware bug, even if I 
can't explain how the firmware was causing the NTP clock to be off. 

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Re: [time-nuts] Antique 5061A option 004

[bownes]

Boy am I glad I didn't go to either!

On Oct 15, 2012, at 17:30, "David I. Emery"  wrote:

>In a mad moment at the NEARFest flea this weekend I grabbed
> a 5061A for $250.   Poor thing was getting wet in the rain and needed
> a home.  Really really heavy to carry to the car, however...
> 
>It has a high performance option 004 CBT in it (late SN
> 3112A02887 dated 05/93).   And a 10811-60109 OCXO.   Option 3 whatever
> that is, and H29 too.   Seems to have a BNC marked C field...
> 
>Chassis SN is 2002A01710 but a number of the modules have  late
> series numbers such as 2740 for the synth, 2652 for the oven controller,
> and 2448 for the AC amp..
> 
>The unit obviously came from the Naval Observatory (similar
> to Paul Swed's I presume)... has a sticker on it.
> 
>Looks superficially as if it was upgraded various times -
> wondering if anyone could suggest where a manual that would cover the
> OCXO mod and others on into the 90s might be had (Artek ?) 
> 
>I have yet to fire it up (gotta dig out a power cord I have
> somewhere in the way back junque)... but FWIW (not much I am sure) I was
> told it would lock "after a while".
> 
>I suppose it is time to see if it will pump down and have any
> measurable beam current - I guess at least possible that a CBT that
> young might still have a tiny bit of life left.
> 
>A question - I assume the OCXO is 10 MHz (I think all 10811s
> are) and thus it obviously must be easily possible to provide a 10 MHz
> output. Is there a point to attach a SMA to BNC for this ?
> 
>It is my first Cesium, now I guess I officially have the
> disease, all those Rbs and GPSDOs being just prodromal syndromes...
> 
>I also grabbed a PRS10 at the flea (that was pretty cheap
> at $50) and wonder where I might land a PBBT adapter for it cheap
> too... I'd rather see if it works OK before investing in a new one
> first... and that connector is a bear.
> 
> 
> -- 
>  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
> 02493
> "An empty zombie mind with a forlorn barely readable weatherbeaten
> 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
> celebration of what could have been, but wasn't and is not to be now either."
> 
> 
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Re: [time-nuts] RasberryPi, timing and GPS receivers

[bownes]

By the way, you need not use a USB serial adapter. Several folks are doing PPS 
on the gpio pins. 

Take a look here 

https://github.com/davidk/adafruit-raspberrypi-linux-pps

And here

http://www.frambozenbier.org/index.php/raspi-community-news/4439-george-lu-on-ntp-pps

On Oct 16, 2012, at 22:03, x...@darksmile.net wrote:

> The miniITX mobos are quite impressive.
> There is no argument there.
> 
> However, My simple idea was this:
> 
> Since I want to keep time at 3 separate locations
> and wanted stratum 1 NTP, I didn't want overkill.
> 
> Actually my reason for 3 different locations is simple:
> Internet is flakey some places and sometimes just down.
> I'd like to have correct time no matter what
> happens to the internet.
> 
> The other thing I want to do is create a very small footprint
> NTP server that basically looks like 3-4 cartons of
> cigarettes stacked on top of each other.
> 
> Maybe even have the power supply on the bottom
> of the stack.
> 
> I don't know if I'll be able to do this
> but this is the general idea.
> 
> I think maybe something like this:
> 
> GPS Receiver + antenna connector
> ---
> Interface board
> ---
> CPU main board
> ---
> Shield board (mostly ground plane)
> ---
> Power supply
> ---
> 
> If I could put this in a nice aluminum
> case I think it would look beautiful.
> 
> -G
> 
> Quoting Chris Albertson :
> 
>> On Tue, Oct 16, 2012 at 4:37 PM, Hal Murray  wrote:
>>> 
 One does NOT need a dedicated server for NTP.  NTP can run on a linux 
 system
 that is also a web and mail server or on e  linux desktop system that you
 use for web surfing and web browse ring, just as long as the box stays
 running and you don't turn it off.
>>> 
>>> It's been discussed before, but probably worth repeating.
>>> 
>>> Don't overlook the cost of power.  If you have an old power-hungry CPU that
>>> you use for mail and web, leaving it on all the time can cost a lot.
>> 
>> Yes.  You are right.  that is why I posted a like to this
>> http://www.newegg.com/Product/Product.aspx?Item=N82E16813121442
>> this board uses very little power and as you say will pay for itself
>> quickly.  You can reast your hand of the heat sink and notice there is
>> no fan.  It uses just a few watts. and can run VMware, and multiple
>> servers
>> 
>> 
>>> The
>>> payoff time for replacing it with a low power system can be as low as a year
>>> or two.
>>> 
>>> 
>>> --
>>> These are my opinions.  I hate spam.
>>> 
>>> 
>>> 
>>> 
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 
>> 
>> 
>> --
>> 
>> Chris Albertson
>> Redondo Beach, California
>> 
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> 
> 
> 
> 
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Re: [time-nuts] Nifty "MINI TIC" for DMTD work

[bownes]

+1 please!

On Nov 19, 2012, at 16:23, mcqu...@sonic.net wrote:

>> 
>> "MINI-TIC" for DMTD work
>> 
>> 
>> Hi Everyone!
>> 
>> I've been testing a Miniature 2 channel TIC that Bert Kehren and Juerg
>> Koegel
>> and Richard Mc Corkle have designed.
> 
> 
> Please add my name to the list!
> Thank you,
> Dave
> 
> 
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Re: [time-nuts] EIP545A 18GHz counter query

[bownes]

You can also overdrive a mmic and get good results. That is what I'm using as 
the oscillator for my 1.296 GHz beacon. 

Bob

On Nov 27, 2012, at 15:45, Ed Palmer  wrote:

> Hi Don,
> 
> Yes, I've heard of SRDs.  I think every Rb standard uses them.  I recently 
> purchased a YIG Multiplier that includes an SRD followed by a YIG filter.  
> But, from my reading, there are some significant issues that you run into 
> when driving an SRD.  I'm still playing with mine.
> 
> Ed
> 
> On 11/27/2012 2:15 PM, Don Latham wrote:
>> snip
>>> I'm in the same position as you regarding testing at high frequencies.
>>> You might be able to get a signal at the second or third harmonic of
>>> your generator by cranking the level to the maximum and then using the
>>> counter's Band 3 frequency limits feature to only look at that
>>> frequency.
>> snip
>> You can also get a step recovery diode and generate a bunch of harmonics...
>> DonL
> 
> 
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[time-nuts] MIT Flea & HP 5328

[bownes]

Apologies to those not in or around Boston tomorrow. You can ignore this msg. 

I'll be at the flea tomorrow selling off a 5328 with 10811 OXCO & 15GHz 
prescaler and a few other goodies.

I seem to recall that there are generally a few of us in attendance. Perhaps we 
could have an impromptu gathering of time nuts at say, 11 AM? 

Bob
KI2L
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[time-nuts] Datum 105242-001 pinout

[bownes]

My Google fu is weak tonight. 

I'm out in the field getting ready for the ARRL VHF/UHF contest. Thought I'd 
bring along the bits for my 10GHz transverter and assemble it during the 
downtime. 

But I'm being thwarted. 

Does anyone have the pinout for  the six pin Datum 10Mhz oscillators?

Thanks! 
Bob
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[time-nuts] HP 4352A

[bownes]

I just asked over on the HP equipment list, but time nuts had a thread on the 
4352 a while back...

 Has anyone got a service manual for the  4352A? The B version is out there in 
the wild, but the A version seems to have gone MIA. 

Additionally, should anyone have either a 11636B power divider or 8471e#004 
peak detector surplus to their needs, please let me know as the 4352A I got 
last week is missing both. 

There are, however, three more left on eBay from a vendor outside LA. They are 
all missing the power divider and peak detector however. But for $130, I 
figured it was worth a gamble. 

I suspect that any power divider good to 4GHz and peak detector good to the 
same can be made to work pretty well though. If I can't find the peak detector, 
 I may try substituting a linear power detector since I have a drawer full. 

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

[bownes]

Aside from using the toaster oven reflow controller from SparkFun? 

> On Jun 23, 2016, at 21:28, Jay Grizzard  wrote:
> 
>> On Thu, Jun 23, 2016 at 11:28:00PM +, Mark Sims wrote:
>> A usable re-flow oven can be had for $300.
> 
> Do you (or anyone) have suggestions for usable reflow ovens in this price
> range? Every time I've gone looking on Amazon, I've found ovens which
> (according to reviews) had cycle timers were *horribly* off, to the point
> they would sometimes burn boards by keeping them at peak temperature 
> for 2x - 3x as long as they were programmed to. Though you can work
> around that if you really want to, this really doesn't meet my definition
> of "usable".
> 
> Am I missing some obvious cheapie oven without these types of problems?
> 
> -j
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Re: [time-nuts] pick and place problems/design (was: OT stuffing boards)

[bownes]

And try to tell transistor A from transistor B from diode C when they are all 
upside down. 

A moving head design can be made to pick up parts off of reels on all four 
sides. But it takes more table space. Which is money. 

As someone else said, you need Z rotation, which isn't as easy as it sounds 
when using pneumatics to pick up the part. 

Moving table design sounds like a recipe for shaking the parts off the solder 
pads. I've not had good luck with solder paste staying tacky for long. In which 
case you are dispensing paste then sticking part. Not a deal breaker but slow. 

> On Jun 25, 2016, at 04:12, Adrian Godwin  wrote:
> 
> Many parts can't be recognised visually. Capacitors are the obvious example.
> 
> On Sat, Jun 25, 2016 at 6:11 AM, Chris Albertson 
> wrote:
> 
>> The ideal hobby use pick and place machine would be very different
>> from a commercial machine.  Lets say I want one board made.   What I
>> want to minimize is my time.  With a conventional machine by FAR most
>> of my time is spent setting the machine up.  In fact setup is so slow
>> that for smaller PCBs I could do it with tweezers in a fifth of the
>> time needed to set up the machine.
>> 
>> So a hobby machine must be designed such that you could get it going
>> in nearly zero time.   In the ideal case you drop the parts all mixed
>> up, (but right side up) in a small tray.  They are mixed and in random
>> orientation.  then you give the machine your PCB design file (not a
>> special pick and place file) and then a vision system IDs the parts.
>> Today vision is dirt cheap.
>> 
>> But the 3D printer needs one more degree of freedom.  It must be able
>> to rotate the part (or the PCB) as it is unlikely the part on the tape
>> or tray only needs translation to the PCB, likely ration is required
>> in almost all cases.
>> 
>> I think a hobby machine would only be successful if it could reduce
>> the setup time to nearly zero and for that it would need a really good
>> vision system that could hunt down randomly placed parts.  It would
>> have to work pretty much like you or I would do the job manually.  But
>> we have software like openCV and good "board cams" with M7
>> interchangeable lenses for $35.  A vision system actually saves a ton
>> of money because the machine need not be so precise as vision closes a
>> feedback loop.
>> 
>> Also how many hobbyists are going to have reels of parts?  I might buy
>> some parts by the dozen but most no more than about 4 or 6 at a time.
>> I don't want a large machine.  It should have a working surface, a
>> white melamine table about 12 inches square and I place the PCB to be
>> stuffed and all the parts on the same foot square table at any random
>> location then press the "go" button.  The camera scans the table.
>> This kind of machine would be horrible for production work but a one
>> foot cube machine that required zero setup is what most of us want.
>> 
>> Going a little farther.  I'd like this SAME machine to actually make
>> the PCB too.  A 3D printer could route the copper and drill holes and
>> print the solder resist plastic too.
>> 
>>> On Fri, Jun 24, 2016 at 8:56 PM, Attila Kinali  wrote:
>>> On Fri, 24 Jun 2016 13:59:58 -0500
>>> "Graham / KE9H"  wrote:
>>> 
 Lots of problems to be solved...
>>> 
>>> Most of these problems are easy:
>>> 
 How do you take loose parts or cut tape or tape reels
>>> 
>>> You don't. No loose parts with any kind of pick&place machine.
>>> As for cut tape, these can be taped on an empty reel to make
>>> them compatible. Everything has to be in a tray, reel or similar.
>>> 
 and get the right
 part out, and into the chuck, oriented in the right direction?
>>> 
>>> Orientation is defined by the reel/tray the parts come in.
>>> This is also documented in the datasheet, usually.
>>> 
 How many different kinds of parts, sizes, shapes, pin counts, IC
 footprints, can you handle at once?
>>> 
>>> As many as there is space around the machine :-)
>>> 
 How do you know it is the correct part?
>>> 
>>> You put it manually in the right feeder and double check that it
>>> fits the programming.
>>> 
 How do you know where the "+" end, or "pin 1" is?
>>> 
>>> This comes with the orientation of the part in the reel/tray.
>>> 
 How do you know that there actually is a part in the chuck?
>>> 
>>> Your trays are guaranteed to be non-empty by manually loading them.
>>> 
 How do you know the part in the chuck is oriented the way you expected
>> it?
>>> 
>>> The manufacturer guarantees that the reels/trays are loaded correctly.
>>> 
 How do you know where the footprint on the circuit board is located?
>> (to a
 few thousandths.)
>>> 
>>> This is provided by the pick&place file. Usually its 3-5 digits after the
>>> decimal point, when using mm. But as I wrote before, you don't have to
>>> place part hyper exact. Being within 0.1-0.3 of the pitch of the part
>>> is usually enough. Surface tension does the rest.
>>> 
>>>

Re: [time-nuts] Good GPSDO on eBay?

[bownes]

To paraphrase a few other folks, taking on the task of building your own, even 
using the VE2ZAZ board as a basis is a very educational experience. It will 
teach you an enormous amount. There are lessons in control systems, phase and 
frequency locked loops, oven controllers, phase and frequency measurement, and 
doubtless lots of things I've overlooked. 

Well worth the effort. 

> On Jul 9, 2016, at 23:06, Bob Stewart  wrote:
> 
> But, as a starter GPSDO, probably anything is good.  Frequency accuracy, even 
> if a fraction of a Hz off, is all you're looking for at first.  I bought one 
> of Bert Zauhar's (VE2ZAZ) circuit boards and chips for my first one.  It was 
> a good experience.  And when I was done, I had a GPSDO that was as good as 
> most of what you find on ebay in the bargain basement, but at a much lower 
> cost.  But then you need a case, and something to compare it to, and 
> something even better, and then you're a time-nut.
> 
> But 
> 
> 
> At 04:40 PM 7/9/2016, Richard Mogford wrote:
>> This looks like a good beginner's GPSDO on eBay: 172148560746
>> 
>> "This is GPS Disciplined Clock made with trimble GPSDO Board.Full 
>> tested by Agilent 53132A with US-012 option and Ex-ref from trimble 
>> thunderbolt GPSDO."
>> 
>> 
>>   The seller says it has a sine wave output and is accurate from
>>   10e-11 to 10e-12.
>> 
>> Any thoughts?
>> 
>> Richard
>> 
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> 
> 
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Re: [time-nuts] The home time-lab

[bownes]

Or the current version:

Large AC motor driving a LARGE flywheel with an AC (and/or -48VDC) generator on 
the other side feeding a very large battery plant. If mains drops more than 1/2 
cycle it connects the turbine and starts it up. 

We had a 5MW one at $OLD_GIG for feeding our supercomputer factory. 

It was rumored that at least one customer location kept one of their turbines 
(redundant) idling at all times because they could not afford to loose a data 
set. 



> On Jul 25, 2016, at 09:55, Bob Camp  wrote:
> 
> Hi
> 
> If you go back far enough in time …. there is another alternative:
> 
>   Big rectifier bank, turning AC into DC, often off of multiple phases or 
> sources. 
> 
>   Big DC motor running into a fairly large flywheel. 
> 
>   AC generator (or in some cases DC generators) running off of the shaft
> 
>   A tuning fork (yes state of the art timing) based control on the AC 
> output frequency  
> 
>   A saturated reactor control loop on the generator side, same thing on 
> the motor side.
> 
> Wonderfull stuff. State of the art UPS for your shipboard computer in 1962. 
> Ear muffs anyone? 
> 
> Bob
> 
> 
> 
>> On Jul 25, 2016, at 8:39 AM, Charles Steinmetz  wrote:
>> 
>> Chris wrote:
>> 
>>> I've never thought UPS were a good idea for anything but a computer
>>> that needs to shut down gracefully.   For your use you need something
>>> that cleans up the AC mains power.
>> 
>> A proper "online" (or "double conversion") UPS does just that.  It always 
>> provides cleanly-generated sine-wave power from a DC-AC converter.  Most 
>> will even deliver crystal-controlled power (i.e., non-synchronous with the 
>> AC line) in several frequency increments, if you desire, as well as a choice 
>> of regulated output voltages.  (For obvious reasons, they are usually 
>> operated synchronously.)
>> 
>> They are *much* more effective than ferroresonant supplies at removing 
>> glitches from the mains supply.
>> 
>> You must be referring to "offline" backup supplies.
>> 
>> Best regards,
>> 
>> Charles
>> 
>> 
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Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

[bownes]

A second here or there is a very big deal to those of us in the financial and 
database worlds. 

Aside from the well known instances involving electronic trading I have 
customers fighting over cabinet positions and cable lengths to place processors 
closer to disk drives and on switch paths with 10ns less latency. 





> On Jul 25, 2016, at 16:57, Mark Sims  wrote:
> 
> Apple's new file system timestamps files with nanosecond resolution.   A lot 
> of Linux file systems also do that now.   The nanosecond ain't what it used 
> to be...  I can imagine people wanting picosecond timestamps in the near 
> future.  Who knows,  maybe we'll have something like NTP compensating for 
> light-speed delay for the gap between the read/write heads and disk surface 
> (assuming we still use heads and surfaces)  ; -)
> 
> Except that you still have the issue of “what time did this file get 
> changed”. To most of us, that’s not really a big deal. A second either way … 
> who cares.   
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Re: [time-nuts] [LEAPSECS] Leap second to be introduced at midnight UTC December 31 this year

[bownes]

We've been dealing with speed of light issues for over 20 years in the 
financial world. And telecom. 

Someone recently built a new fiber route from Chicago to NY because it was just 
a touch shorter. The distances are down to hundredths of a ms. 

> On Jul 25, 2016, at 17:41, Bob Camp  wrote:
> 
> Hi
> 
> In these days of computers trading with computers, the whole issue of “who 
> did what when” can 
> result in major money trading hands. I’m sure that at some point the 
> financial markets will have to
> deal with light speed issues and geography if they have not already.  
> 
> Bob
> 
>> On Jul 25, 2016, at 4:57 PM, Mark Sims  wrote:
>> 
>> Apple's new file system timestamps files with nanosecond resolution.   A lot 
>> of Linux file systems also do that now.   The nanosecond ain't what it used 
>> to be...  I can imagine people wanting picosecond timestamps in the near 
>> future.  Who knows,  maybe we'll have something like NTP compensating for 
>> light-speed delay for the gap between the read/write heads and disk surface 
>> (assuming we still use heads and surfaces)  ; -)
>> 
>> Except that you still have the issue of “what time did this file get 
>> changed”. To most of us, that’s not really a big deal. A second either way … 
>> who cares. 
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Re: [time-nuts] Shera revisted

[bownes]

There are also some nice cypresses semiconductor parts that are similar and 
have a really nice dev environment. 
Basically a core surrounded by programmable logic. Code in C ore close to it. 



> On Aug 11, 2016, at 07:06, Bob Camp  wrote:
> 
> Hi
> 
> To your earlier point, there are a number of fairly low cost boards with 
> Zynq’s on them. 
> They aren’t into the $5 range, but they are not that much more than one of 
> the Beagle 
> boards. 
> 
> Bob
> 
> 
>> On Aug 10, 2016, at 11:18 PM, Chris Albertson  
>> wrote:
>> 
>> Thanks for pointing out the Zynq.  Wow you get a dual core ARM and an
>> FPGA all in one package.   It seems overkill for a GPSDO but not the
>> type you are making as you can transferring the time out of the GPSDO
>> using PTP.
>> 
>> The Zyng looks to the the perfect platform for low-cost SDR.
>> 
>> On Wed, Aug 10, 2016 at 2:30 PM, Joakim Langlet
>>  wrote:
>>> Dear time-nuts,
>>> 
>>> My name is Joakim Langlet (SM0OET) and I just recently joined this list. As
>>> Brooks Shera was mentioned, I remembered that I was referenced in the
>>> footnotes of the original article in the QST - July 1998. It feels almost
>>> historical now. Brooks bought a few OCXOs from me.
>>> 
>>> I am currently working on a GPS stabilized OCXO.
>>> It is based on a Xilinx Zynq FPGA as the processor and counter arrangement.
>>> The hardware is starting to take shape. The control voltage of a 20 MHz OCXO
>>> is set by a DAC coupling from which I hope to set the voltage in very small
>>> steps.
>>> The OCXO has a CMOS level output which is converted to LVDS and is wired to
>>> the FPGA board. The Xilinx Zynq take a minimum frequency of 19 MHz as input
>>> to the PLL of the clock tile. My intention is to scale up the clock to some
>>> where a bit over 200 MHz to be fed to the counters.The 1 PPS from the GPS
>>> receiver is also fed into the FPGA to gate the counters.
>>> 
>>> The reason for my choice of processor is that I want to run Linux on it in
>>> order benefit from the large software base. Time distribution using PTPv2
>>> and a nice web-application to visualize and control what is going on inside
>>> is part of the intended concept.
>>> 
>>> I still have a long way to the finish line but I will try to present some
>>> results as I proceed.
>>> 
>>> I am following what is written on this list with great interest. It feels
>>> good to know that I am not the only nut 
>>> 
>>> BR/
>>> Joakim
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>> 
>> 
>> 
>> -- 
>> 
>> Chris Albertson
>> Redondo Beach, California
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Re: [time-nuts] DIY VNA design

[bownes]

Comment inline


> On Aug 21, 2016, at 18:59, Dr. David Kirkby (Kirkby Microwave Ltd) 
>  wrote:
> 
> I am not convinced that this is time-nuts related,  although I am sure many
> time-nuts either have a VNA or would like one. Such a project needs its own
> forum.
> 

v...@yahoogroups.com would be the place. 

The intersection of HP equipment && Time-Nuts && VNWA mailing lists is >> 1 :)

> 
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Re: [time-nuts] Need 10 MHz for DSN space-probe hunting

[bownes]

Just shipped out three new systems for $DAY_JOB to Goldstone, Madrid and 
Canberra. 

Love it when work and time nuts intersect. 



> On Sep 13, 2016, at 17:35, Andy ZL3AG  wrote:
> 
> 
> That sounds like fun!
> 
> Do they have a mailing list they hang out on?
> 
> https://eyes.nasa.gov/dsn/dsn.html
> 
> 
> 
>> On 14/09/2016, at 5:04 AM, Mike Baker wrote:
>> 
>> Hello, Time-Nutters--
>> 
>> Full disclosure--  I am a complete newbie at understanding the
>> intricacies of generating a really stable, low phase noise, accurate
>> frequency reference for microwave reception up around the 8 GHz
>> DSN (Deep Space Network) band.  I have been following the back
>> and forth comments on the Time-Nuts list about improving the
>> Trimble T-bolt's 10 MHz output but confess that most of it is pretty
>> much deeper technical voo-doo than I am comfortable with.
> 
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[time-nuts] IRIG-B for OS X

[bownes]

Has anyone seen an IRIG-B generator for OS X sound port?

I know there is one for the PC in NTP, but thought I would ask before diving in 
to that asp pit. 

Bob
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Re: [time-nuts] Thinking outside the box a super reference

[bownes]

Not to mention there is not so sensitive film, sensitive film and really 
sensitive film. 

Good old orthographic film took minutes in bright light. 



> On Nov 4, 2016, at 20:24, Poul-Henning Kamp  wrote:
> 
> 
> In message , David writes:
> 
>> Various online sources say that natural rubidium is radioactive enough
>> to fog photographic film in 1 to 2 months but that is also the case
>> with unprocessed uranium ore so I would not worry about it at all.
> 
> Yes, that sounds about right for an isotope with a 40 billion years
> half-life.
> 
> 1 to 2 months is a LNG time for photographic film.
> 
> -- 
> 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] Linux PPS clues?

[bownes]

I suspect the multitasking aspect of the OS will give you far more jitter than 
one could cope with. 

> On Nov 4, 2016, at 22:46, Casey L. Jones  wrote:
> 
> Maybe you could use something like a serial to parallel converter chip or the 
> serial port input of a microcontroller. You could feed in a constant string 
> of zeros until an event, and then feed in a one to the stream when the event 
> occurs. You could save the stream of ones and zeros in memory for maybe a 
> second, and then stamp the block with the time. Then you can have your main 
> CPU figure out the time of each event by knowing the bitrate and looking at 
> how many bits precede each one bit back to the beginning of the block. The 
> blocks would likely be largely zeros, and would thus compress really well if 
> you decide to not even bother converting the format of the blocks to a 
> timestamp format. The advantage of this scheme is that it could probably have 
> a sampling rate far higher than a timestamping process, without overstressing 
> even many modestly powered processors.
> 
> Another way to synchronize your samples with GPS, at the cost of some sample 
> rate, is to use a two input multiplexer at your serial input and to take 
> every odd bit of your serial stream to be a sample of the pps output of your 
> GPS and every even bit to be the state of your event trigger. That way your 
> pps and data are interleaved in your bitstream for post processing.
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Re: [time-nuts] RPi/ beagle bone-like computer without video

[bownes]

Fits very nicely into a 5370 in fact. :)

> On Nov 30, 2016, at 17:12, Graham / KE9H  wrote:
> 
> The BeagleBone Green is a BeagleBone Black with the HDMI and video chip
> removed.
> 
> Mouser Part number *Mouser Part #: *713-102010027, $39, In stock.
> 
> 
> Makes a great little headless server.
> 
> --- Graham
> 
> ==
> 
>> On Wed, Nov 30, 2016 at 3:51 PM, Clint Jay  wrote:
>> 
>> Raspberry Pi compute module? Maybe even a Pi Zero?
>> 
>>> On 30 Nov 2016 21:47, "Adrian Godwin"  wrote:
>>> 
>>> The tiny g3 routers are worth looking at. They have WiFi, Ethernet and
>> USB,
>>> cost very little and will usually run wrt54g Linux. Can be rather short
>> on
>>> memory though.
>>> 
 On 30 Nov 2016 8:43 p.m., "jimlux"  wrote:
 
 I'm looking for a small linux single board - similar to RPi or
>> Beaglebone
 Black, but don't need the HDMI, or video stuff.
 Preferably without weird connectors, and available for wide temperature
 ranges (it's for a data logger/collector in the field)
 
 What's out there?
 
 There's BBB in industrial flavor (-40 to +85C ) for $60-70
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Re: [time-nuts] Is there any Ubuntu/Linux Software for the Z3801A?

[bownes]

Walter,

You can always download VirtualBox and run a Windows system in there under 
Linux, OS X, Solaris, or whatever you like. It's free, and it works well. 

Oracle VM works too, but is probably overkill. 

Bob

> On Dec 1, 2016, at 13:07, walter shawlee 2  wrote:
> 
> After re-working the lab I have my Z3801A in, I realized there's no windows
> computers left anywhere near there.  Is there any monitoring software that 
> will run on my 16.04 Ubuntu Linux machines?  I have the Z3801A with an 
> external antenna, that drives a 10Mhz distribution amp for optional external 
> references around the lab. I don't have anything looking at it, however, so I 
> am not sure if that is actually correcting the GPSDO or I am seeing the raw 
> oscillator, which si pretty good by itself.  The other shop counters have 
> externally NIST-cal'd hp 10811A's in them, so they are pretty accurate 
> anyway, but I am curious to know the real story.
> 
> I also have a re-cycled rubidium module and ovenized oscillator cal'd to NIST 
> in tandem as another check source I put together this year.  I'm just looking 
> for external validation of those last few figures. I guess that is an 
> occupational problem of having too many sources and counters, one is never 
> really totally certain. kind of a local quantum cloud of measurement 
> uncertainty.
> 
> I was able to get those surplus DeLorme GPS pucks running under Ubuntu, I ran 
> VMware to host an XP install, then tracked down the XP-only serial emulator 
> needed to read the USB puck interface, and ta-da, it works. Hideously 
> complicated way to see if they were good, but I was curious to know.  No 
> VMware in that lab, however, so looking for a native app to read the Z3801A
> 
> any useful Z3801A software suggestions appreciated,
> all the best,
> walter
> 
> -- 
> Walter Shawlee 2, President
> Sphere Research Corporation
> 3394 Sunnyside Rd.,  West Kelowna,  BC
> V1Z 2V4  CANADA  Phone: (250) 769-1834
> walt...@sphere.bc.ca
> WS2: We're all in one boat, no matter how it looks to you.
> Love is all you need. (John Lennon)
> But, that doesn't mean other things don't come in handy. (WS2)
> 
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Re: [time-nuts] [OT} audiophile outlets.....

[bownes]

And there is your product. The GPSDO derived 44.1 kHz reference!

I only ask for a 10% royalty.:)

On Jun 19, 2013, at 20:54, Tom Knox  wrote:

> I wonder what is the best way to obtain 44.1KHz from a 5-10MHz reference.
> 
> Thomas Knox
> 
> 
> 
>> Date: Wed, 19 Jun 2013 15:14:17 -0600
>> From: alanh...@gmail.com
>> To: j...@quikus.com; time-nuts@febo.com
>> Subject: Re: [time-nuts] [OT} audiophile outlets.
>> 
>> Rb or Cs locked 50/60 Hz AC power might still be an available niche
>> although I didn't do much of a search.
>> Alan
>> 
>> 
>> On Wed, Jun 19, 2013 at 11:52 AM, J. Forster  wrote:
>> 
>>> How about a Rb or Cs standard to control the sampling rate of the DACs in
>>> your CD player so you always have perfect pitch and no wow or flutter?
>>> 
>>> Oh, it's already being done and sold to Audiophools  never mind!
>>> 
>>> -John
>>> 
>>> 
>>> 
>>> 
 Simple, just think of the next snake oil.  There's always more.
 
 
 On 6/18/2013 10:33 PM, Brian, WA1ZMS wrote:
> What's gets me is that I didn't think of this snake oil first.
> Had I thought of it first I could own a PTI H-MASER by now.   :- )
> 
> -Brian, WA1ZMS
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Didier Juges
> Sent: Tuesday, June 18, 2013 10:01 PM
> To: n...@verizon.net; Discussion of precise time and frequency
> measurement
> Subject: Re: [time-nuts] HP and other equipment failure
> 
> "audiophile outlets"
> 
> You've got to be kidding but not even.
> 
> At least, nobody is forcing anybody to buy them...
> 
> Didier
> 
> Peter Gottlieb  wrote:
> 
>> The current distortion from simple transformer-rectifier-capacitor
>> power supplies contains a lot of third harmonic content.  In a 3 phase
>> system (as are all distribution systems for commercial and industrial)
>> the third harmonic ADDS in the neutral, or creates circulating currents
>> in a delta configuration.  These currents, as you mention, can get very
>> large and were the cause of many
>> 
>> transformer explosions in cities as these power supplies became common.
>> The
>> transformer designs had to be improved, but the PFC supplies make a big
>> difference.
>> 
>> How many of you have looked at the power line waveform, especially in
>> an industrial or commercial area?  Doesn't look much like a sine wave,
>> does it?  So it's pretty funny to see audiophile outlets
>> (http://www.dedicatedaudio.com/power_outlets).
>> 
>> Peter
>> 
>> 
>> 
>> 
>> On 6/15/2013 6:56 PM, stan, W1LE wrote:
>>> PFC to me is power factor correction, not only the classical power
>> factor to
>>> minimize (VAR) volt-amp reactive component,  but also to remove the
>>> harmonic load  current imposd on the
>> electrical power
>>> system.
>>> A '90's onward technique. in th 80's and 90's without the harmonic
>> load
>>> current reduction and having
>>>  a few 100 end items of equipment, each withtheir own  a switch mode
>> power
>>> supplly,
>>>  it was not uncommon to find hundreds of amps of the third harmonc on
>> neutra,
>>>   in the electrical power distribution system.
>>> 
>>> Could be a serious EMC problem if you were dealing with voice grade
>> channels.
>>> And people safety issues.
>>> 
>>> Stan, W1LE   Cape Cod
>>> 
>>> 
>>> 
>>> On 15-Jun-13 5:52 PM, J. L. Trantham wrote:
 Sorry for the interruption but what is 'PFC'?
 
 Thanks.
 
 Joe
 
 -Original Message-
 From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]
>> On
 Behalf Of Poul-Henning Kamp
 Sent: Saturday, June 15, 2013 4:09 PM
 To: Robert Atkinson; Discussion of precise time and frequency
>> measurement
 Cc: Perry Sandeen
 Subject: Re: [time-nuts] HP and other equipment failure
 
 In message
>> <1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com>,
 Robert  Atkinson writes:
 
> While I agree with everything else you say, you CAN have too much
> filter capacitance. At least where dc rectifier / filter
>> (smoothing)
> circuits are concerned. Increasing C causes increased ripple
>> current
> [...]
 And ripple current can be a major source of power-line frequency
>> noise in
 all electronics.
 
 The main reason why switchmode power-supplies today (can) outperform
>> linear
 power supplies with respect to noise, is because the legally
>> mandated PFC
 correction eliminates the bridge-rectifier ripple harmonics.
 
 I would not hessitate to use a good quality switchmode t

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

[bownes]

There are some good alternatives to krytrons. Just don't expect to be able to 
afford or export them. ;)


> On Dec 26, 2013, at 21:26, Bob Camp  wrote:
> 
> Hi
> 
> Unless you want run for < 1 second, that rules out a Krytron. 
> 
> Length of operation also impacts some of the other implementations. 
> 
> Bob
> 
>> On Dec 26, 2013, at 9:16 PM, ct1dmk  wrote:
>> 
>> Many thanks to all for the nice tips.
>> 
>> I may narrow down by saying a few more specs as suggested.
>> The pulse would see a somehow unknown load but for a start I
>> was suggested to have my source with 50ohm impedance so worst
>> case would be a short circuit and therefore the pulse would be a current 
>> pulse
>> and would have some 10Amp. Pulse length about 100ns so only some 0.5mJ 
>> energy that would die inside the pulse source( this would be the worst case).
>> The 100us repetition rate make a a very small duty cycle of 1/1000 so 
>> average power
>> maximum 5W.
>> 
>> Since the amplitude and timing parameters are to be controlled (pulse timing 
>> come from an FPGA) I really need a solution using that trivial switching 
>> element fet or bipolar (and can't really do a more exotic scheme if I cant 
>> electronically control the parameters) also I must use a transformer because 
>> these short pulse are to be superimposed to another voltage and a 
>> transformer becomes very handy to do that. I interrupt the wire and insert 
>> the secondary there to add the pulses.
>> 
>> The challenge I'm facing is on the device either RF FET or Biplolar tr etc. 
>> and
>> surrounding circuits, transformer, etc. this to achieve the 4ns (or 5ns).
>> (the transformer I have in mind is something very similar to those 
>> transformers
>> on the final stages of HF/VHF ham radio amps, coax cables and ferrite cores)
>> any suggestion regarding devices etc ?...
>> 
>> Thanks for all comments.
>> 
>> Luis Cupido.
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Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51

[bownes]

Those bolts would be whitworth. 



On Dec 15, 2011, at 14:43, "Steve ."  wrote:

> The laboratory where i work obviously reports results using the SI metric
> system. There is one exception though, and that is the energy side,
> specifically calorimetry. At first glance the calorimeters appear to
> normal(SI, that is). They take mass in terms of the gram, measure
> temperature by degree Celsius, and internal calibration is stored as
> calories.
> 
> The exception is the result is reported in BTU/ pound!  How's that for
> mixing systems?
> 
> On the electronics side of things it's even worse. Technical documents
> mixing and matching between systems. It's very common to see specifications
> cited partially in MKS and CGS with no correction terms.
> FYI:
> MKS = Milimeter Kilogram Second
> CGS = Centimeter Gram Second
> 
> I've seen two other systems, but their names are eluding me at this time.
> Also, I've come across bolts that are not SI, nor SAE. I believe they are
> considered a british thread but i'm not certain.
> 
> Steve
> 
> On Thu, Dec 15, 2011 at 1:15 PM, Don Latham  wrote:
> 
>> What I find interesting is that the first push for standardization, at
>> least for machine threads, came from the manufacture of arms, the
>> Springfield Armory, at the time of the Civil war. At that time, threads
>> were a mixture of the then fledgling metric system (French) and a
>> conglomeration of American threads. Thread shapes were quite different
>> as well. The next big standardization came from- you got it- the
>> automotive industry (SAE is of course Society of Automotive Engineers),
>> and I guess, only a guess, that the reluctance to change to metric
>> really came from the automobile industry. At one time, the Volvo had
>> SAE, Metric, and Whitworth fasteners in it, and not too long ago at
>> that.
>> So, I think that manufacturing inertia rather than the housewife might
>> be to blame for the US still being SAE and all that implies. As bolts
>> go, so do the rest of the measurements.
>> Don
>> 
>> 
>> Chris Albertson
>>> On Thu, Dec 15, 2011 at 9:29 AM, Dan Kemppainen 
>>> wrote:
 
 On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote:
> 
> It's not like metric is totally absent.  We drink 2 liter cokes and
> defend
> ourselves with 9mm pistols.   Our cars use mostly metric parts.  Even
> ham
> radio operators, arguably the most jingoistic and set in the past
> bunch
> around, get on the 80, 40, and 20 METER bands.
 
 
 I agree with you, and funnily enough the rest of the NATO world uses
 7.62mm
 and 5.56mm rifles. (Both were originally based on standard inch sized
 rifle
 cartridges designed in the US)
 
 The problem in converting to metric would require replacing a lot of
 tools.
 For example Mills, lathes, and other machining tools and measurement
 devices
 are expensive, and last for decades.
>>> 
>>> Can you point one even ONE machine shop in the US that can make metric
>>> parts?  Those guys would have gone out of business years ago.   Also
>>> how many are still using hand cranks and reading veneer scales?   Even
>>> small one man ships are using CNC now.
>>> 
>>> The US is slowly converting.  It will take a long time.  Even now if
>>> you go to Home Depot and look at plywood you see the better (non
>>> construction) grades sold in even millimeters with the inches being
>>> some odd number of 32nds approximation.   This will slowly creep into
>>> more and more products.
>>> 
>>> So the debate is silly.  If the US should convert???  No.  the only
>>> question is how fast are we converting and when will we be fully
>>> converted.   Not even if this will happen, it will.
>>> 
>>> 
>>> 
>>> 
>>> Chris Albertson
>>> Redondo Beach, California
>>> 
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>>> 
>>> 
>> 
>> 
>> --
>> "Neither the voice of authority nor the weight of reason and argument
>> are as significant as experiment, for thence comes quiet to the mind."
>> R. Bacon
>> "If you don't know what it is, don't poke it."
>> Ghost in the Shell
>> 
>> 
>> Dr. Don Latham AJ7LL
>> Six Mile Systems LLP
>> 17850 Six Mile Road
>> POB 134
>> Huson, MT, 59846
>> VOX 406-626-4304
>> www.lightningforensics.com
>> www.sixmilesystems.com
>> 
>> 
>> 
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Re: [time-nuts] line frequency website

[bownes]

Imagine a 3d map in which colour represents phase or frequency and Z 
displacement of the sample point represents voltage. 

Would make for a nice animation anyway. 



On Dec 30, 2011, at 17:47, shali...@gmail.com wrote:

> The problem is that while the frequency is going to be pretty much the same 
> anywhere on the same grid, the voltage is not. Knowing the voltage at some 
> point in your state (or another) is not all that useful. They may record it, 
> but I am not even sure it would be worth saving in a database.
> 
> Didier KO4BB
> 
> Sent from my BlackBerry Wireless thingy while I do other things...
> 
> -Original Message-
> From: David VanHorn 
> Sender: time-nuts-boun...@febo.com
> Date: Fri, 30 Dec 2011 10:13:38 
> To: Discussion of precise time and frequency measurement
> Reply-To: Discussion of precise time and frequency measurement
>
> Subject: Re: [time-nuts] line frequency website
> 
> 
> I would love to see something like that which plotted voltage.
> 
> 
> 
> From: time-nuts-boun...@febo.com [time-nuts-boun...@febo.com] On Behalf Of 
> Jim Lux [jim...@earthlink.net]
> Sent: Thursday, December 29, 2011 5:16 PM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] line frequency website
> 
> Check it out:
> 
> http://fnetpublic.utk.edu/tabledisplay.html
> 
> line frequency measurements updated once a second
> 
> Operated by the Power Information Technology Laboratory at the
> University of Tennessee, FNET is a low-cost, quickly deployable
> GPS-synchronized wide-area frequency measurement network. High dynamic
> accuracy Frequency Disturbance Recorders (FDRs) are used to measure the
> frequency, phase angle, and voltage of the power system at ordinay 120 V
> outlets. The measurement data are continuously transmitted via the
> Internet to the FNET servers hosted at the University of Tennessee and
> Virginia Tech. The Power IT Lab has developed several applications which
> use the FNET data to study the power system, including:
> 
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Re: [time-nuts] Speaking of shipments from China

[bownes]

It is one of those cost/benefit calculations. The cost of sorting the real 
gifts from the commerce <$100 labeled as gift probably wouldn't pay for itself. 

It is, of course illegal. The question is are we better off changing the 
enforcement or the law. Not to mention the cost of the latter. 

Makes you wonder what the time constant of legal change to behavior change is 
and how that varies with penalty magnitude. To pull things back to a discussion 
of time.  :)



On Dec 30, 2011, at 19:55, "Richard W. Solomon"  wrote:

> Was it really a gift ?? The U. S. Customs folks take a dim view on folks 
> lying on a Customs Declaration. 
> But, being realistic, it's so rampant that only by making a Federal Case 
> out of one will it ever stop. But, I am not holding my breath. 
> 
> 73 es HNY, Dick, W1KSZ
> 
> 
> -Original Message-
>> From: li...@lazygranch.com
>> Sent: Dec 30, 2011 4:41 PM
>> To: Discussion of precise time and frequency measurement 
>> Subject: [time-nuts] Speaking of shipments from China
>> 
>> I got a feebay shipment from China today. Duty? No problem, it was declared 
>> a gift. ;-)
>> 
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Re: [time-nuts] Getting my Rockwell D200 GPS to work

[bownes]

Step one...is the antenna in a location where it can see they sky?

Sorry if it is a stupid question but you already said it was plugged in. :)



On Jan 6, 2012, at 19:24, "Don Lewis"  wrote:

> Can someone please give me some pointers (my first time with a GPS module).
> 
> 
> 
> A little hand-holding, pls.
> 
> 
> 
> I bought three of these Rockwell D200 GPS receivers. (It's little GPS PWB
> with an antenna connector and pins for connecting to the RS232- PC)
> 
> 
> 
> All three 'appear' to work the same way (no apparent capture of satellites).
> 
> 
> 
> Here's what I have:
> 
> 
> 
> 1.VisualGPS installed and running.
> 2.A small USB-RS232 card installed and appears to be operational.
> 3.Small GPS active antenna plugged in.
> 4.VisualGPS monitor just repeatedly displays:
> $GPGGA,,0,00,,,*66
> 5.I think I understand this to be NMEA code to mean no satellites have
> been acquired.
> 6.The Rockwell D200 draws ~180ma (5V) with no antenna and ~190ma with
> the small active antenna plugged in.
> 
> 
> 
> What am I doing wrong?  Other than maybe cheap china gps' and antenna???
> But it is what I could afford and thought it would be cheap to learn on.
> 
> 
> 
> Thanks for your help.
> 
> 
> 
> -Don
> 
> 
> 
> 
> 
> 
> 
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Re: [time-nuts] Getting my Rockwell D200 GPS to work

[bownes]

It will certainly help to have visible sky and a metal ground plane. I have 
mine in a skylight in my office and they still only 'see' about half of the sky 
due to the slope of the skylight and living on the south side of a hill. 

So, putting one where it actually can see the sky and letting it sit for 20-60 
minutes would tell you something more. 


On Jan 6, 2012, at 19:54, "Don Lewis"  wrote:

> Maybe I didn't take positioning seriously.  
> 
> The antenna is currently on a shelf above my workbench, there is a
> ceiling and an upstairs above it. Then the roof.  
> 
> Is it very critical to be outside in order to 'see' the sky?  
> 
> I did take it out once and set the antenna on my car roof, but still no
> satellites.
> 
> 
> -Don
> 
> 
> 
> 
> 
> -
> 
> 
> 
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of bownes
> Sent: Friday, January 06, 2012 6:49 PM
> To: Discussion of precise time and frequency measurement
> Cc: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Getting my Rockwell D200 GPS to work
> 
> Step one...is the antenna in a location where it can see they sky?
> 
> Sorry if it is a stupid question but you already said it was plugged in. :)
> 
> 
> 
> On Jan 6, 2012, at 19:24, "Don Lewis"  wrote:
> 
>> Can someone please give me some pointers (my first time with a GPS
> module).
>> 
>> 
>> 
>> A little hand-holding, pls.
>> 
>> 
>> 
>> I bought three of these Rockwell D200 GPS receivers. (It's little GPS PWB
>> with an antenna connector and pins for connecting to the RS232- PC)
>> 
>> 
>> 
>> All three 'appear' to work the same way (no apparent capture of
> satellites).
>> 
>> 
>> 
>> Here's what I have:
>> 
>> 
>> 
>> 1.VisualGPS installed and running.
>> 2.A small USB-RS232 card installed and appears to be operational.
>> 3.Small GPS active antenna plugged in.
>> 4.VisualGPS monitor just repeatedly displays:
>> $GPGGA,,0,00,,,*66
>> 5.I think I understand this to be NMEA code to mean no satellites have
>> been acquired.
>> 6.The Rockwell D200 draws ~180ma (5V) with no antenna and ~190ma with
>> the small active antenna plugged in.
>> 
>> 
>> 
>> What am I doing wrong?  Other than maybe cheap china gps' and antenna???
>> But it is what I could afford and thought it would be cheap to learn on.
>> 
>> 
>> 
>> Thanks for your help.
>> 
>> 
>> 
>> -Don
>> 
>> 
>> 
>> 
>> 
>> 
>> 
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Re: [time-nuts] FE-5680A Mechanical Question

[bownes]

On Jan 13, 2012, at 17:51, Chris Albertson  wrote:

> 
> 
> I'm surprised that no one has built a GPIB controller from a uP.
> Electrically the GPIB is simple and slow by modern standards.
> 

Several have. That is basically what the prologix is.  There is another one you 
see on eBay quite often for about$60. 

The problem seems to be one of compatability and interpretation/implementation 
of the GPIB command set. For example, There is an NI gpib to USB as well, but 
it is not compatible with the Prologix. 

Bob
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Re: [time-nuts] nanoseconds in the news

[bownes]

There was a system in NJ with over 3000 ps2s in a supercomputer config. 

The financial industry's idea of high cost is a bit different than most. 

The price of your real time ticker feed from the exchanges is directly 
proportional to the associated network latency due to speed of light. 

Bob



On Feb 16, 2012, at 18:30, Tom Knox  wrote:

> 
> EndRun set up the system next door to the NYSE used by GS. I think EndRun has 
> a white paper on their site describing the ultimate in insider trading 
> systems. It has been the subject of a number of articles and a whistle 
> blowers case. Some believe it was responsible for a 1000 point "glitch" 
> several years ago.
> 
> Thomas Knox
> 
> 
>> From: namic...@gmail.com
>> Date: Fri, 17 Feb 2012 09:20:07 +1100
>> To: time-nuts@febo.com
>> Subject: Re: [time-nuts] nanoseconds in the news
>> 
>> Obviously no one is thinking big enough.
>> A hyper-super computer on either side of the Atlantic could run a model
>> of each of the stock markets which could be synchronised by frequent  
>> data transfer.
>> The learning power of these models would be very great, and they  
>> could deliver a real-time
>> estimate of the other markets that would be hundreds of milliseconds  
>> better that neutrinos.
>> The long term veracity of these computers could not be doubted, the  
>> noise in short terms
>> would be continually reduced.
>> A system like GPS could be used to synchronise them so they could  
>> give nanosecond response.
>> 
>> 
>> Would that not be great for huge spikes!
>> 
>> cheers,
>> Neville Michie
>> 
>> On 17/02/2012, at 9:07 AM, Peter Monta wrote:
>> 
 Time is money...
>>> 
>>> I wonder if long-distance neutrino links might be attractive to the
>>> financial community.  The SNRs are currently way too low, but with
>>> aggressive engineering, a link through the Earth would shave off many,
>>> many milliseconds (even at not greater than the speed of light :-) ).
>>> The cost would be very high though.
>>> 
>>> Cheers,
>>> Peter
>>> 
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Re: [time-nuts] Tek to HP conversion... Was: Re: Fwd: FE-5680A Contact FEI

[bownes]

Yup. Between the 1ghz 7000 series, the DSA602 w 1Ghz plug ins, and the 2236 
portable I don't expect I'll ever need to buy another scope. 



On Feb 17, 2012, at 16:36, "J. Forster"  wrote:

> Tek went into the toilet when Danaher bought them out.
> 
> I bought a TDS1002 and could not even get the PC software to download
> screen images, even after "registering".
> 
> However, registration sure did get me onto their spam list. It took at
> least a hald-dozed tries to get their spam to stop.
> 
> I have lusted after Tek since about 1962 and have over 100 of their
> instruments. The 7000 series and TM500 seriea are masterpieces.
> 
> But, never again.
> 
> YMMV,
> 
> -John
> 
> =
> 
> 
> 
> 
> 
> 
> 
>> I was a Tek aficionado for many many years. My first personal scope was a
>> tek, my first work scope was a Tek. I've owned at least half a dozen over
>> the decades. The three scopes I own today are Tek. But everything else on
>> my lab bench has changed over to HP (with the exception of a couple of
>> TM5006 mainframes full of specialty plugins).
>> 
>> The quality, availability, and most important to me, the consistency of HP
>> gear has been impressive. I've yet to go into a lab where the majority of
>> basic RF equipment, counters, sig gens, spectrum analyzers, etc was not
>> HP.
>> Unless they were lucky enough to have R&S.
>> 
>> The ability to get manuals, parts, and just plain guidance on the HP gear
>> has been great.
>> 
>> Now if I can score an HP Primary or GPSDO standard, I'll be happy.
>> 
>> 
>> On Fri, Feb 17, 2012 at 1:26 PM, paul swed  wrote:
>> 
>>> I believe in HPs case a unique situation occurred on the old gear.
>>> That is there were and are people at agilent willing to take the time to
>>> preserve their history. After all its still pretty fantastic stuff even
>>> at
>>> 20, 30, and yes I have a piece in the 40-50 years old era. Generally
>>> amazingly well built. I do know that when test and measurement was HP
>>> their
>>> support was top notch both for me professionally and personally. It did
>>> effect what I chose to buy for the business. But on the personal side
>>> they
>>> always helped I was above board about why I was calling.
>>> Ahhh for the good ole days.
>>> Regards
>>> Paul
>>> WB8TSL
>>> 
>>> 
>>> 
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>> 
> 
> 
> 
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Re: [time-nuts] Z3801A......????

[bownes]

Oh you are a bad bad man. 

I'll do some homework and see what a rational offer is, but suffice it to say, 
I'll probably take it. :)



On Feb 17, 2012, at 17:15, "Brian, WA1ZMS"  wrote:

> Bob-
> 
> I have a spare that i need to test and make sure all is OK.
> 
> Any interest?
> Make me an offer and it's yours after I get time to test is out.
> 
> 
> -Brian, WA1ZMS
> 
> On Feb 17, 2012, at 4:56 PM, bownes  wrote:
> 
> 
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Re: [time-nuts] How best to exchange Large files?

[bownes]

Wow. I just save it to an nfs share on the NAS. Then I can get to it from 
anywhere in the house/world...

Have not seen anyone use kermit or zmodem orsplit or rar or uuencode for a long 
long time. 





On Feb 21, 2012, at 18:59, Chris Albertson  wrote:

> On Tue, Feb 21, 2012 at 3:47 PM, Robert Darlington
>  wrote:
>> Gotcha.   Try using something like WinRAR to chunk up your file into
>> multiple parts or the UNIX "split" command.   In the very least that's
>> a way to get it to somebody that can reassemble it for distribution on
>> a web server.
> 
> That works but it is 100% manual.  Today we have software that will
> break up files, send the bits and reassemble them and will even let
> you shut off one of both computers and automatically restart.
> Torrent is the best known of these.It will just carry one in the
> background and if more people want the file it will take advantage of
> the added bandwidth.   With magnetic links you can send someone an
> email and say "click here for the file" and it will "just work".   No
> one has to slip or reassemble the file.
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> 
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Re: [time-nuts] LORAN-C at MIT

[bownes]

Yup. Once a month. Good sized parking lot plus four or five floors of a parking 
garage. Sounds like there were enough T-N there to have had a gathering! :)

I too looked at all the loran units and decided to pass. 

III



On Apr 15, 2012, at 17:45, "Don Latham"  wrote:

> Oh, I can't stand it...from my location in the sticks... really an MIT
> flea market??
> real surplus/excess electronics
> Nuttin' like that in western Montana.
> 'course we do have wide open spaces :-)
> Don
> 
> Rob Kimberley
>> Silly thought, but do you know if the 2100F units sold or not. I'm
>> interested at that price as Loran still good in UK (plus I used to sell
>> these when I worked for Austron, and would be nice to actually own one).
>> 
>> Rob Kimberley
>> 
>> -Original Message-
>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
>> Behalf Of J. Forster
>> Sent: 15 April 2012 19:41
>> To: time-nuts@febo.com
>> Subject: [time-nuts] LORAN-C at MIT
>> 
>> At the MIT Flea today, I saw 4x Austron 2100Fs for about $25 each. There
>> was
>> also a LORAN-C simulator and a Stanford LORAN-C unit for $200.
>> 
>> Seems the stuff is hitting the skids.
>> 
>> -John
>> 
>> 
>> 
>> 
>> 
>> 
>> ___
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>> 
>> 
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> 
> 
> -- 
> "Neither the voice of authority nor the weight of reason and argument
> are as significant as experiment, for thence comes quiet to the mind."
> R. Bacon
> "If you don't know what it is, don't poke it."
> Ghost in the Shell
> 
> 
> Dr. Don Latham AJ7LL
> Six Mile Systems LLP
> 17850 Six Mile Road
> POB 134
> Huson, MT, 59846
> VOX 406-626-4304
> www.lightningforensics.com
> www.sixmilesystems.com
> 
> 
> 
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Re: [time-nuts] Capacitor failures

[bownes]

A fine and accurate observation. I've been slowly replacing the loud 110v fans 
in my test equipment with new, higher cfm, quiet 12 vdc fans that probably 
won't last as long but make it possible to hear in my workshop. 



On Oct 21, 2010, at 11:59 PM, Perry Sandeen  wrote:

> Gents,
> 
> Over the years I’ve purchased 15 or so pieces of HP 3XXX and HP 5XXX series 
> of test equipment.  
> 
> All has worked well until a week ago my HP 3568B which had worked for years 
> smoked when I turned it on.  I had moved and had not powered it for a couple 
> of years.  Looking at the PS board I had failed to remove the long-dead NiCad 
> memory battery for some inexplicable reason since I had removed them on the 
> other six I have.  Several burned 1/10 tiny resistors and board lands.  This 
> will not be a fun fix.
> 
> I then stared to look at the various electrolytics in it and then in a few 
> other HP pieces.  Most seem to use computer grade screw terminal caps as the 
> initial PS filter.  But I noticed that on many of the daughter boards HP used 
> the familiar axial lead type of caps.  All seemed original.  
> 
> Most of my HP stuff is between 25 to 40 years old.  These original 
> electrolytics are on borrowed time.  That it works so well is a shining 
> tribute to the quality of the HP organization.
> 
> However I plan on replacing all the axial types in all of my HP equipment, 
> except for the tantalums, with new 105C, low ripple, high reliability types.  
> Fixing some HP boards is a PITA.
> 
> My logic is this.  The large amount of reasonably priced HP equipment that is 
> for sale is the result of the American electronic industry becoming almost 
> non-existent.
> 
> After WWII (the big one), sorry I couldn’t resist that,  all major American 
> cities had Surplus Row’s and there was a booming mail order business also.  
> We had seven major makers of Ham radio equipment.  It’s all gone.
> 
> So now on epay the low priced older HP equipment are the final remnants.  In 
> a few years they will be gone.  None of us can afford the new stuff.
> 
> To invest between $25 to $50 in new caps plus perhaps more or better cooling 
> fans to extend the equipments operation for another 20 or 30 years is fine by 
> me even though I probably won’t be around or care by then.
> 
> Regards,
> 
> Perrier
> 
> 
> 
> 
> 
> 
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Re: [time-nuts] Maintaining boatanchors (was Capacitor Failures)

[bownes]

Don't forget to scare up the appropriate programmer. Those are getting hard to 
come by too. 



On Oct 22, 2010, at 7:02 PM, Chuck Harris  wrote:

> I don't believe the parts are failing due to structural
> problems, but rather are just leaking down their buried charge.
> 
> It should be quite possible to refresh them by erasing them and
> reprogramming.
> 
> -Chuck Harris
> 
> Bob Camp wrote:
>> Hi
>> 
>> Find pin compatible replacement EPROM's while you still can. They don't make 
>> all those small / slow / multiple supply
>> / parts any more.  Saves building all sorts of strange adapter boards as 
>> well as re-shooting the memories.
>> 
>> Bob
>> 
>> 
>> On Oct 22, 2010, at 6:44 PM, Poul-Henning Kamp wrote:
>> 
>>> In 
>>> message<1498648302.205602.1287785250803.javamail.r...@sz0110a.emeryville.ca 
>>> .mail.comcast.net>,
>>> k6...@comcast.net writes:
>>> 
 What to do? Pop out the parts and rewrite them? Dump them to disk as well?
>>> 
>>> Make backup-copies while they have no problems.
>>> 
>>> -- 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] Maintaining boatanchors (was Capacitor Failures)

[bownes]

If you are going to worry about things at that level, then it is not just the 
memory devices, you'll be worrying about all the programmable parts such as 
PALs, GALs, and other eplds. Then you are really looking fort some exotic 
programmers. 

Ironically, I bought a standalone programmer many many moons ago to back up a 
set of 1702's that I was concerned about. A few months ago, while cleaning out 
the lab, I found a paper listing of the contents of said UVEPROMs. Not quite 
sure where the programmer went to. :)

On Oct 23, 2010, at 9:42 AM, Magnus Danielson  
wrote:

> Hi Chuck,
> 
> On 10/23/2010 03:01 PM, Chuck Harris wrote:
>> Hi Magnus,
>> 
>> I keep an old Toshiba 1963 486 based laptop in good working condition
>> to allow me to run my old ADVIN U84 DOS based programmer. I check it
>> out from time-to-time.
>> 
>> I can't do much about the mask rom'd parts, though I don't think they
>> have any higher of a failure rate than any other IC. The eprom based
>> controllers, can be a worry, but I can program most of them from the
>> 1980's on... assuming they aren't protected.
> 
> Some of the ROMed variants can actually be read just like their EPROM 
> variants.
> 
> While ROMed parts does not have the EPROM trapped charge aspect to failure 
> mode, they can fail for any other reason and this is an issue.
> 
>> There are a myriad of open source format converters available... things
>> that convert S to intel hex, etc... I seem to recall even writing some
>> of them...but that is a foggy memory by now.
> 
> Yes.
> 
>> I find my violins' EPROMS are very stable, and last centuries.
> 
> They don't have any, which helps.
> 
> Cheers,
> Magnus
> 
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Re: [time-nuts] Maintaining boatanchors (was Capacitor Failures)

[bownes]

Precicesly why I have a basement shelf or two dedicated to old datebooks. :)



On Oct 23, 2010, at 12:44 AM, Hal Murray  wrote:

> 

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Re: [time-nuts] Maintaining boatanchors

[bownes]

This makes me re-think arguing with my wife about tossing the 15 linear feet of 
three ring binders full of systems documentation sitting in the basement. 

But not for long. I'll keep what I don't have electronically I guess, but the 
SunOS 2.2 manual set can totally go in the trash. 

The field engineering manuals on the other hand, all stay. I actually used one 
from the early 80's a few weeks ago to build a discrete stepper motor 
controller rather than order the newfangled ic. 


On Oct 24, 2010, at 1:03 PM, Bob Camp  wrote:

>> ask to speak to the oldest engineer or srevice tech.
>> 

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Re: [time-nuts] Linux timekeeping / jiffy source

[bownes]

Unfortunately, there is no way to restart the kernel without going through a 
BIOS re initialization. 

Changing the run level restarts the init process but does not reload the 
kernel. 



On Dec 2, 2010, at 10:17 PM, mi...@flatsurface.com (Mike S) wrote:

> Anyone familiar with Linux kernel timekeeping?
> 
> I've recently upgraded a server to an AMD 890FX/SB850 based motherboard. 
> After doing so, I observed a large (in time-nut terms) inconsistency in 
> system timing, as seen in the rate of the system's Time Of Day clock.
> 
> Sync'ing to a local GPS locked NTP server, I see up to an 80 ppm spread 
> between reboots, which I've documented at 
> http://www.flatsurface.com/AMD_SB850/index.html . I'm running kernel 2.6.32 
> (Debian squeeze).
> 
> I think that kernel timekeeping ("jiffies") are linked to the "8254" timer in 
> the SB850 south bridge, but maybe it's the HPET in the 890FX north bridge. 
> Anyone know how to tell which the kernel is using for timekeeping?
> 
> Also, is it possible to restart the Linux kernel without a full reboot 
> (avoiding BIOS initialization), to see if it's a kernel or BIOS issue? I 
> don't believe a simple change of runlevel restarts the kernel from scratch.
> 
> I haven't seen this inconsistency on previous Intel or Serverworks based 
> motherboards, but I've seen this behavior on 890FX/SB850 motherboards from 
> two different manufacturers (although I think both use Award BIOS). 
> 
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Re: [time-nuts] Linux timekeeping / jiffy source

[bownes]

Thanks for the correction/education!



On Dec 3, 2010, at 2:17 AM, Christian Vogel  wrote:

> Hi bownes,
> 
>> Unfortunately, there is no way to restart the kernel without going through a 
>> BIOS re initialization.
> 
> actually, there is. It's called "kexec".
> 
> See, for example http://www.ibm.com/developerworks/linux/library/l-kexec.html 
> .
> 
> Greetings from Germany,
> 
>Chris
> 
> 
> 
> 
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Re: [time-nuts] Frequency counter recommendation

[bownes]

For me, at least, the purpose is twofold, to learn, and to get a better 
instrument. The idea of being able to discriminate between two inputs a few ps 
apart is fascinating and something I'd like to learn how it is done. 

The VNA is a good comparison. I have a nice scalar nw but would like a VNA. So 
I built one of the n2pk VNAs. Great experience, great instrument. And I know a 
lot more than I did before. 

I think this project could be done sans prescaler, e.g. good to at least a 
hundred MHz, two inputs, 10mhz timebase input, rs232 out ( with ftdi USB option 
for a couple of hundred dollars in kit form. Would that be great for everyone? 
No. But would at least 10 people buy one and/or participate in the project? 
Probably. Could a design be done that could support all those options someone 
specified? Probably. Would one person be willing to design them all? No way. 
Would all that stuff be less than a 5370? No way. Would I want one of these and 
a 5370? Probably. But that what makes us nuts, isn't it?

The other Bob



On Dec 18, 2010, at 9:39 PM, Bob Camp  wrote:

> Hi
> 
> If you are going to do a full boat implementation and work out all the 
> isolation issues and packaging, the question becomes:
> 
> Will it be better bang for the buck than a ~ $200 HP 5370?
> 
> Bob
> 
> 
> On Dec 17, 2010, at 9:29 AM, jimlux wrote:
> 
>> Interesting discussion..
>> comments interspersed
>> 
>> Chris Albertson wrote:
>>> Jumping ahead to design.  No one wants a serial RS232 interface. they
>>> don't even make computers with RS232 ports much any more.  Those guys
>>> that designed equipment that forced people to load costom USB drivers
>>> just did not think.  There is no need for that.  What you do is make
>>> you project appear to be some "standard" USB class and then the OS
>>> (Linux, Windows or Mac OSX) will already have a driver.   That VNA
>>> should have presented itself as a serial port.  And then the software
>>> could read from a serial port.  But of course there would be not
>>> physical RS232 device.
>>> If you have to select an interface I'd rather have any wireless type.
>>> WiFi or Bluetooth.
>> 
>> wireless interface and RF test equipment is a bad combination.  If you're 
>> trying to measure small scale performance (e.g. timing at 1E-10 levels), 
>> small amounts of RF leaking in/out causes problems.  This is one of the 
>> things that separates good test equipment from great equipment.  It's hard 
>> to get better than 100dB isolation from packaging, and if you're looking for 
>> things at the -150dBm level, something at 0dBm is huge.
>> 
>>> But if you are building a modular system you do NOT want to pick one.
>>> You just make a project standard to use (say) I2C, SPI, "two wire" ir
>>> whatever.  Then the counter module is controlled by i2c and if you
>>> want to connect it to a computer you build the USB module but if you
>>> want a stand alone no-computer instrument you build the "front panel"
>>> that has LED numbers.
>>> That is the entire ont is "modular", you avoid this kinds of decisions
>>> and allow for easy upgrade as technology changes.
>> 
>> 
>> IR/fiber optic interfaces are very intriguing.  Too bad that the plastic 
>> fiber stuff costs more than conventional wires/connectors.
>> 
>>> Other questions to resolve are "how many slices to cut the pie into".
>>> I would argue for "very small" single funtions bulding blocks so we
>>> don't have the HPSDR problem of years of time to design each one.
>> 
>> Against that: every connection causes potential troubles.  A better solution 
>> for the generalized case is to put multiple functions together, but don't 
>> necessarily connect them all. Think of the old IF strip chips. Oscillator, 
>> amplifiers, variable gain stages, detectors, all on the same chip but the 
>> ins and outs brought out to pins.  I don't think you want to bring them out 
>> to connectors, but, rather, provide a way to do interconnections, etc.
>> 
>> 
>> 
>>> Selecting a physical chassis to use willl take time.  I like the idea
>>> of using a disk enclosure because then you can buy a 1U or 8U rack or
>>> an old PC chassis, If you modual looks like a disk there are plenty of
>>> things it can fit into.
>> 
>> "old pc chassis" is a very limited life item in a particular configuration.  
>> do you mean my old IBM PC?  Or an AT? or a tower case? or a midsize case?
>> When you say disk drive size, do you mean "5 1/4" floppy/CD-ROM/DVD" or 
>> something else.
>> 
>> Packaging is going to be critical for high performance.  Look at boxes from 
>> COMPAC, for instance.
>> 
 From my experience, for something like this to take off one person has
>>> to take ownership of the project and run with it, make the web site,
>>> write some golas and build "something" that works.  Only then do other
>>> jump in and help.
>>> It really would be good to have a Time and Frequency Instrumentation
>>> Project as currently the state of the art seem to be that you simply
>>> buy someth

Re: [time-nuts] Frequency counter recommendation

[bownes]

That's kinda my point about using rs232. Serial to USB, serial to Ethernet  
adaptors will be available for  a good long while. 

Also why I like the idea of a standalone instrument that also has a pc 
interface of some sort.  Or a slot for a pc interface of whatever source I 
want. 

So how does one build the core counter with a start, a stop, and maybe a 10 MHz 
reference input with sub 5ps resolution and accuracy?



On Dec 19, 2010, at 3:50 PM, Bob Camp  wrote:

> Hi
> 
> The gotcha with caps is that they don't block RF very well. Of course if you 
> go high enough in frequency, not much can be blocked anyway. 
> 
> Opto isolated RS-232 is just a pair of cheap optos, a couple of diodes and a 
> few resistors and caps. It costs next to nothing and it will work just fine 
> for any speed you are likely to need in a counter.  Spend $4 on a USB to 
> serial adapter and throw it away when the next generation of driver signing 
> (or what ever) renders it obsolete. Replace it with one that likely costs 50 
> cents then. I won't go into the possibility that it might cost half a Euro or 
> $50 
> 
> Bob
> 
> 
> On Dec 19, 2010, at 12:01 PM, Poul-Henning Kamp wrote:
> 
>> In message <4d0e3080.1060...@earthlink.net>, jimlux writes:
>>> Bob Camp wrote:
>> 
>>> There are some nice solutions, though, using USB directly, which has the 
>>> advantage of providing a few watts of power.  Isolated DC/DC converters 
>>> are readily available.  you might be able to do transformer isolation of 
>>> the two data wires.
>> 
>> First: you want to use capacitors, not transformers.
>> 
>> Second: it is surprisingly tricky to get to work in practice, I have
>> only ever seen one device that managed to do so, and comply with
>> the USB standard, and the designer swore to never do it again.
>> 
>> People generally default to a small USB-enabled microcontroller
>> with an optocoupler to the real stuff.
>> 
>> -- 
>> 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] Form factor

[bownes]

I love those Hammond boxes until I have to pay the bill. The one for my n2pk 
VNA was about $28. 

But one of those as the primary enclosure with input boards and output boards 
that plug into a main board would be feasable if a tad expensive. 

Some modules lend themselves to plugins on a main board (output modules for 
example) while things that need to chain like input modules ( think pre amp 
followed by prescaler followed by trigger sense) don't. 

On Dec 21, 2010, at 1:29 AM, Chris Albertson  wrote:

>>> Eurocard has been one suggestion as a form factor. While I personally
>>> love Eurocard, the boards and connectors are expensive.
>>> 
>>> Stackble connectors are a pain in assembly.
>>> 
>>> Backplanes are inherently evil at high speeds.
>>> 
>>> Plugging everything into one main board makes that a critical design
>>> item and that much harder to upgrade.
> 
> I agree with all of the above.
> 
> I think what we want is simply a mechanical standard.  Something that
> will simply hold everything in place.
> 
> What if every module was in it's own metal box?  Each box has a
> forward or "user facing" panel that is tall and narrow and contains
> things like input jacks and status LEDs and a rear facing panel that
> is for power and module to module interconnect.Many of the
> modules, I assume would work as stand alone gadgets (a trigger is a
> usful device all by it self)  To assemble a system you place all the
> boxes like books on a shelf.  Maybe even some book end so they don't
> fall over.  But you might build a wood cabinet, put a handle on top
> and metal bumpers on the corners.  The wood cabinet would house the
> modules and also the power supply and the rats nest of interconnect
> wiresSo those who like to be neat can make nice wood cases and the
> rest of us can have a working system made of a half dozen boxea and
> cales all over the work bench
> 
> Here is an example of a module box
> http://www.hammondmfg.com/pdf/1455L1601.pdf
> 
> We would not have to specify a height or length, only the width needs
> to be uniform.  But in our case the width becomes height when you turn
> them on edge.   Some modules might need two PCBs and a wider box.  We
> should make a list of connectors to be used for power and so on for
> the rear pannel
> 
> I had previously suggested about the same thing but only to make the
> box the same size as a disk drive so we could use common existing
> racks.  I'd still prefer that but maybe these hammond boxes are more
> popular
> 
> 
> -- 
> =
> Chris Albertson
> Redondo Beach, California
> 
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Re: [time-nuts] Form factor

[bownes]

That would all depend upon the interconnect strategy, which hasn't reached 
consensus either. 

Based on the early module list, a bus probably isn't necessary, and individual 
ribbon cable and/or coax will do if speeds stay low. 



On Dec 21, 2010, at 2:34 PM, Bruce Griffiths  wrote:

> Another factor to consider is that ps stability requires using coax 
> connectors that are mechanically stable to within a few microns ie no BNCs.
> 
> Bruce
> 
> Don Latham wrote:
>> I agree about the ebay finds. Bad to design the boards form factor around
>> old chassis.
>> Maybe the thing is to find out from the electronic design how big the
>> board(s) will have to be or what the electronic footprint is, then go from
>> there? If the boards are designed so that idiosyncratic mounting is
>> possible, we can all mount them according to our own taste?
>> 
>> Don
>> 
>> Chris Albertson
>>   
>>> You can't plan a project like this around eBay junk.  How would you
>>> assemble
>>> 100 kits if each kit requires that you find a specific HP instrument on
>>> eBay?
>>> 
>>> If cost is a big issue then I'll go back to my first idea.  Make your PCB
>>> about
>>> the size os a disk drive.  Then yu get a llength od 1 x 1/4 inch aluminum
>>> L
>>> and bend it into a three sided "U" and attach it to three sides of the
>>> PCB.
>>> 
>>> The finished assembly should fit into any enclusre designed to hold SATA
>>> disk drives.  A PC case could work but there are nicer looking boxes, rack
>>> mount and diesktop
>>> 
>>> This trades a bit of metal working for the cost of a Hammond box.  But
>>> the metal work requires only a hack say and drill.
>>> 
>>> 
>>> 
>>> On Tue, Dec 21, 2010 at 8:35 AM, Bob Bownes  wrote:
>>> 
>>>> I do the same with Tek 500/500series instrumentation plugins. You can
>>>> get
>>>> the TM504 mainframe for<  $50 on ebay and scrap grade modules for<  $10.
>>>> Plus you get a linear power supply, backplane and already RF rated
>>>> enclosure.
>>>> 
>>>> On Tue, Dec 21, 2010 at 11:12 AM,  wrote:
>>>> 
>>>>   
>>>>> Hi
>>>>> One source of boxes to consider is old HP equipment, some is very
>>>>> reasonably priced, like 37203 for small boxes and a 59401A makes an
>>>>> ideal
>>>>>  housing
>>>>> for a Rb with clock GPS and backup power. Some times you can even use
>>>>>  part
>>>>> of the guts. I even went as far as repackaging my 5062C into a HP case
>>>>> of
>>>>> that generation, heresy in the eyes of some of you
>>>>> Bert Kehren   Miami
>>>>> 
>>>>> 
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>>>>> 
>>>>> 
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>>>>   
>>> 
>>> 
>>> --
>>> =
>>> Chris Albertson
>>> Redondo Beach, California
>>> 
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>>> 
>> 
>>   
> 
> 
> 
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Re: [time-nuts] Large Qty HP C-Beam Tubes available

[bownes]

Greg,
I'm going to be in the area next month and might be able to pick some up and 
redistribute them if that is of any assistance.  

If I can end up with a clock somehow, I'd be interested in that too. 

Bob


On Jan 15, 2011, at 12:33 PM, "J. Forster"  wrote:

> I doubt the shipping issue is really problematic. The amount of Cs is so
> small and so well contained it presents no real hazzard.
> 
> If you want to be on the safe side, pack the tubes really well and ship
> them UPS or FedEx Ground.
> 
> FWIW,
> 
> -John
> 
> =
> 
> 
>> Greg-
>> 
>> I, for one would be very willing to take a chance on one or two tubes
>> and see if there is any life left in them, but sadly I live in Va.
>> 
>> I have e-mailed a friend in Boulder to see if he ever heads out in
>> your direction but I don't think he does very often.
>> 
>> Please keep me in mind if you uncover a way to address the shipping
>> issue or if another steps up to buy the lot, as I would be willing to
>> contact them as well.
>> 
>> Regards,
>> -Brian Justin,  WA1ZMS
>> Forest, VA
>> 
>> 
>> On Jan 15, 2011, at 8:07 AM, "gbusg"  wrote:
>> 
>>> Regarding the various discussions regarding CS reservoir depletion...
>>> 
>>> I should probably mention that I'm helping the family of my friend,
>>> the late
>>> Chuck Norton (who owned Frequency Standards and Services in Colorado
>>> Springs) with their sale of the equipment Chuck had in his lab and
>>> inventory. We've been selling the more "generic" equipment on eBay,
>>> but
>>> holding some of the time & freq. stuff for now in case time-nuts
>>> folks want
>>> some of it.
>>> 
>>> There's a large qty of used (mostly HP) Cesium Beam Tubes. I didn't
>>> count
>>> them yet, but going by memory I'd say there might be 10 or 15 of them.
>>> Probably mostly for the HP 5060A and HP 5061A.
>>> 
>>> If anybody's interested, I can inventory the exact part numbers of
>>> those
>>> tubes for you. Keep in mind they're all used tubes in unknown
>>> condition. So
>>> we must assume they don't work. Probably they can be had for a very
>>> low,
>>> reasonable price - but the family says that, due to the DOT-SP11401
>>> paperwork & complications when shipping cesium beam tubes, they
>>> would prefer
>>> local pickup (in Colorado Springs) on the tubes. So that might make it
>>> difficult - unless someone will be passing through Colorado Springs,
>>> or they
>>> have suggestions on how to easily ship the tubes?
>>> 
>>> Contact me off list if for further information.
>>> 
>>> My best,
>>> Greg
>>> 
>>> 
>>> P.S. There are also quite a few HP 5061A and other similar time &
>>> frequency
>>> pieces (e.g., several HP 5087A, etc.).  I've not yet tested any of
>>> that
>>> stuff, so don't know the condition. Probably at least his main
>>> cesium beam
>>> standard (that was part of his NIST time & frequency service system)
>>> works
>>> well.
>>> 
>>> 
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> 
> 
> 
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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

[bownes]

Of the 2 lc orgs I administer or am a member of, and the roughly 8 other lc 
orgs I  interact with on a regular basis, only one uses lc certified gps equip. 
The others are all consumer grade or don't use gps. 

However, a slew of filings and letters from the lc community might not be a bad 
idea, if only to lay the groundwork for the inevitable lawsuits. 


On Feb 2, 2011, at 3:06 PM, Rex  wrote:

> On 2/2/2011 7:25 AM, jimlux wrote:
>> 
>> 
>> I got the impression that it wasn't modeled, but was an actual field test of 
>> some sort.  I'll have to go back and reread.
>> 
>> But, it's possible that the consumer receiver has better multipath and 
>> interference rejection, if only because it's newer. Aviation stuff takes 
>> longer to go through the approval cycle, so it tends to lag consumer 
>> electronics in terms of technology adoption.
>> 
>> 
> 
> From the paper submitted by the GPS manufactureres to the FCC
> http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030
> 
> it seems they simulated the Lightsquared signal with test equipment and made 
> measurements in an anechoic chamber of effects on GPS signal reception to a 
> couple of popular GPS receivers. Using this data they extrapolated real-world 
> effects with path loss calculations. Ironically, it probably wouldn't be 
> legal or safe to make the jamming measurements in a real, open space, 
> environment.
> 
> The paper says the Lightspeed transmitters can be up to around 15 kW EIRP in 
> a band right adjacent to GPS. I would think filtering out that signal to 
> avoid overload would be a daunting task.
> 
> 
> 
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Re: [time-nuts] From GPS World - Lightsquared has been given the goahead

[bownes]

Sorry. Life critical. Fire, ems, law enforcement, aviation, etc. 



On Feb 2, 2011, at 3:37 PM, Rex  wrote:

> On 2/2/2011 2:29 PM, bownes wrote:
>> Of the 2 lc orgs I administer or am a member of, and the roughly 8 other lc 
>> orgs I  interact with on a regular basis, only one uses lc certified gps 
>> equip. The others are all consumer grade or don't use gps.
>> 
>> However, a slew of filings and letters from the lc community might not be a 
>> bad idea, if only to lay the groundwork for the inevitable lawsuits.
>> 
>> 
> 
> Pardon my ignorance, but I can't immediately work out what you mean by 'lc'.
> 
> 
>> On Feb 2, 2011, at 3:06 PM, Rex  wrote:
>> 
>>> On 2/2/2011 7:25 AM, jimlux wrote:
>>>> 
>>>> I got the impression that it wasn't modeled, but was an actual field test 
>>>> of some sort.  I'll have to go back and reread.
>>>> 
>>>> But, it's possible that the consumer receiver has better multipath and 
>>>> interference rejection, if only because it's newer. Aviation stuff takes 
>>>> longer to go through the approval cycle, so it tends to lag consumer 
>>>> electronics in terms of technology adoption.
>>>> 
>>>> 
>>> From the paper submitted by the GPS manufactureres to the FCC
>>> http://www.gpsworld.com/gnss-system/signal-processing/lightsquared-jamming-report-11030
>>> 
>>> it seems they simulated the Lightsquared signal with test equipment and 
>>> made measurements in an anechoic chamber of effects on GPS signal reception 
>>> to a couple of popular GPS receivers. Using this data they extrapolated 
>>> real-world effects with path loss calculations. Ironically, it probably 
>>> wouldn't be legal or safe to make the jamming measurements in a real, open 
>>> space, environment.
>>> 
>>> The paper says the Lightspeed transmitters can be up to around 15 kW EIRP 
>>> in a band right adjacent to GPS. I would think filtering out that signal to 
>>> avoid overload would be a daunting task.
>>> 
>>> 
>>> 
>>> 
> 
> 
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Re: [time-nuts] time-nuts Digest, Vol 79, Issue 31

[bownes]

I've not seen 110v fans in 'ultraquiet'. 



On Feb 10, 2011, at 11:37 PM, "Rick Karlquist"  wrote:

> It isn't clear why you need to change to 12V fans.
> Why not "modern" 120V fans?
> 
> Rick
> 
> 
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Re: [time-nuts] Enclosure for Thunderbolt

[bownes]

James,

I used an old 1 u server case and it's accompanying power supply. The back 
panel was already punched for a db9. All I had to do was drill some holes for 
BNC output and sma for the antenna connector. 

The big win was the 2x16 backlit LCD panel on the front which I hooked up to a 
monitor unit like the one from ko4bb. 

http://www.ko4bb.com/Timing/GPSMonitor/

Stacks right on top of the rest of the gear. 


On Feb 22, 2011, at 9:05 PM, James Fournier  wrote:

> Does anyone have a recommendation for a nice instrument style enclosure to
> house a Trimble Thunderbolt and a matching Mean-Well power supply with a bit
> of room to spare for connectors and cabling? My goal is to package
> everything together into a proper looking instrument to stack on my bench.
> 
> Many Thanks, James
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Re: [time-nuts] T.I. experimenting - newbie question

[bownes]

Another interesting measurement would be to use the timebase output and 
external reference to compare the readings using the same timebase. 

Or are you already using a gpsdo?



On Apr 5, 2011, at 12:08 AM, Joseph Gray  wrote:

> I'm keeping the "newbie question" in the subject for those who wish to
> ignore this thread. To those who respond, your contribution to the
> diminution of my ignorance is appreciated :-)
> 
> I had borrowed two different 5328A counters. I just compared them,
> using the exact same coax, connectors and settings. Both units were
> warmed up for over one hour.
> 
> In my previous readings, I was averaging for 1 s and rounding to one
> decimal place. The following readings are averaged for 10 s and
> rounded to two decimal places. This seemed like a good place to round,
> as the readings were stable enough to this point.
> 
> Old 5328A (slide power switch):
> + + = 19.43 ns
> - - = 19.49 ns
> 
> Newer 5328A (toggle power switch):
> + + = 18.92 ns
> - - = 19.41 ns
> 
> The A and B inputs on the old unit match much more closely. If I
> average the readings of each unit, there is more than 200 ps
> difference between the old and new unit. How do I know which one is
> correct?
> 
> Joe Gray
> W5JG
> 
> On Mon, Apr 4, 2011 at 8:25 PM, Joseph Gray  wrote:
>> Hal,
>> 
>> Here are the results I got using your suggestion. The numbers may be a
>> bit different than last night as I'm not sure I'm using the same
>> cable.
>> 
>> A+, B+ = 18.9 ns
>> A-, B- = 19.4 ns
>> 
>> Obviously there is some difference in delay between the A and B
>> channels. Otherwise, the two numbers would have been identical -
>> correct?
>> 
>> If I take the average of the two readings, I get 19.05 ns, which is
>> more precise than the readings I'm taking. I'm rounding to the nearest
>> 0.1 ns on the readings.
>> 
>> A+, B- = 5014.6 ns
>> A-, B+ = 5023.5 ns
>> 
>> If I take the average of these two readings and subtract out the 5 us
>> for 1/2 period of the 100 KHz square wave, if get 19.15 ns. This
>> agrees very closely with the above average.
>> 
>> I haven't looked at the service manual for the 5328A yet, so I don't
>> know if I even have the proper equipment to attempt a calibration. In
>> the mean time, would you say that taking the average of the first two
>> readings is a valid method?
>> 
>> Joe Gray
>> W5JG
>> 
>> On Sun, Apr 3, 2011 at 7:18 PM, Hal Murray  wrote:
>>> 
>>> How about a square wave?  Start on one edge, stop on the next cycle.
>>> 
>>> You can play with start on rising edge, stop on falling and the reverse.
>>> They should add up to the total.
>> 
> 
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Re: [time-nuts] Selecting a used HP sweep/frequency generator

[bownes]

Thanks for the input folks. Based on what you all have said, my needs and the 
availability from a list member, I'm going to go with a 3325. 

I spent some time reading the manual this evening, which states that the 3325 
will output up to 20,999,999.99 hz on the front connector and up to about 60Mhz 
on the aux rear connector. That might just be a very useful feature. 

As a side note, the need here is for a sweeper that can be used in conjunction 
with a network analyzer at the lower frequencies. The function generation of 
things other than sine is just a bonus. 

Thanks again for all the advice. Another question follows in a new post, so as 
not to hijack this one. ;)

Bob



On Apr 14, 2011, at 10:07 PM, Gary Chatters  wrote:

> On 04/14/2011 02:03 PM, Poul-Henning Kamp wrote:
>> In message, Bob Bownes 
>> wri
>> tes:
>> 
>>> The candidates at present are the 3324 and 3325.
>> 
>> Don't overlook the 3336.
>> 
> 
> The 3336 would meet the OPs requirements.  Frequency coverage 10Hz to 21MHz 
> with phase continuous sweep.  AM and PM available.
> 
> The 3336 is sort of a companion to the 3586 selective level meter. There are 
> A/B/C versions with similar variations in input configuration. The 3336 can 
> be linked to the 3586 with an HPIB cable and track the frequency (the manual 
> says, I have not tried it yet).
> 
> The 3336 is not a function generator.  Only sine wave output.  It has an 
> input for 10MHz reference.
> 
> 
> The 3314A is a function generator and in some ways more versatile than the 
> 3336.  Sine, square and triangle outputs as well as burst (specify number of 
> cycles in each burst).  And only half the size of the 3336.
> 
> It does not have the precision setting capability of the 3336 (and some of 
> the others mentioned).
> 
> I have never gotten the Easter egg to work with the one I have access to.  It 
> looks like it is running, but no output.
> 
> User manuals for most of these are available on the Agilent web site.
> 
> 
> Gary
> 
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Re: [time-nuts] USB and Mouse conflict persists

[bownes]

I have this problem as well. The issue is that the USB com port shows up as a 
different number sometimes after a reboot and thus I must go in and manually 
disable the 'mouse' again. 

Quite annoying when trying to set up a system that just boots up and works. 



On May 11, 2011, at 9:51, brent evers  wrote:

> I believe you need to disable - not delete - the serial mouse in the
> device manager, else it just keeps reinstalling.
> 
> Brent
> KD4VMM
> 
> On Wed, May 11, 2011 at 9:42 AM, David J Taylor
>  wrote:
>>> Hello David,
>>> 
>>> The symptoms include: eratic mouse cursor that stabilizes (corrects)
>>> after I disconnect the USB port to the T'Bolt.
>>> 
>>> Stan, W1LE
>> 
>> There are some suggestions here, Stan:
>> 
>>  http://www.gpsmap.net/GarminHints.html#GPSR_ComputerMouse
>> 
>> The device names many differ, but the same principles apply.  It's likely as
>> Robert mentioned.
>> 
>> 73,
>> David - GM8ARV
>> --
>> SatSignal software - quality software written to your requirements
>> Web:  http://www.satsignal.eu
>> Email:  david-tay...@blueyonder.co.uk
>> 
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Re: [time-nuts] GPS interference and history...

[bownes]

That small hemispherical antenna could also have been 900mhz. I have one here @ 
home that is a combined gps/900mhz antenna from an ambulance tracking system. 


On Jun 10, 2011, at 22:01, Hal Murray  wrote:

> 
> li...@rtty.us said:
>> There's an enormous amount of gear out there that gets timing off of GPS. 
> 
> That's an interesting claim.  Does anybody have any data on the usage of GPS 
> for timing?
> 
> I assume there is one in every cell tower and one in every 911 call center.  
> Are there other large categories of users?
> 
> What would it cost to replace all of it?  If you wanted to do something like 
> that, what would "it" cover?  How about people like us running old recycled 
> gear?  (Z3801A, ThunderBolt, ...)
> 
> 
> I think I saw one last week.  It was on a river level measuring station on 
> the Sacramento River.  It was a small block building.  There was an antenna 
> pointing up into the sky.  I assume there is a satellite up there.  There was 
> also a small (~3 inch dia) hemisphere antenna. I assume it was GPS.  (They 
> had power going into the building (no solar panels) so it should have been 
> simple to get a phone line too.)
> 
> I'm not sure why they need GPS at the recording house.  They know where it is 
> so timing is the only use I can think of.  But they could also get that at 
> the receiving end.  Millisecond accuracy isn't helpful.  Second level 
> accuracy might be interesting if something breaks and you want to know when 
> the wave got to downstream stations.  The risetime is probably over a second.
> 
> 
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
> 
> 
> 
> 
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Re: [time-nuts] Am I the only Time Nut who doesn't wear a watch?

[bownes]

Guess I'm an oddball, I have my choice of about a dozen wrist bourn time pieces 
from the dresser. 

Hardly the best, but my favourite is a euro spec tag heurer chrono. 





On Jul 8, 2011, at 11:37, Pete Lancashire  wrote:

> I normally don't. Use to but one day it stopped working and never got
> it repaired.
> But then I have 20+ clocks at home and a Nixie(R) clock on my desk at work.
> 
> The only one I wear now on special events is a retirement gift to my 
> grandfather
> when he retired in the the late 60's.
> 
> How may factory workers get an engraved 17 jewel watch when they retire
> now days ?
> 
> -pete
> 
> On Fri, Jul 8, 2011 at 8:19 AM, John Green  wrote:
>> I haven't worn a wristwatch in maybe 30 years. I generally use my cellphone
>> or whatever timepiece that's handy. Or, I just guess. I don't wear my
>> wedding ring either. Jewelry of any kind bothers me.
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Re: [time-nuts] Defective Z3801 and strange PS board

[bownes]

My educated guess is that they expected to sell these to telcos, who 
traditionally run everything in a central office on -48v and running off of ac 
was an afterthought. 



On Jul 9, 2011, at 9:43, Marco IK1ODO  wrote:

> Hello group,
> 
> after many years (about 12, I think) of faithful continuous operation, my 
> Z3801 failed.
> I opened it, and found that there was no supply to the main PCB. The power 
> supply board in the Z3801 (and Z3805, 58503A, possibly all the series) is 
> marked 58503-60003. It is a very strange board. It seems to have a first 
> DC-DC converter taking 48V input, powering two other DC-DCs that work on 48V 
> (!), one supplying +5/+15/-15V to the main board, the other supplying 5V 4A 
> to a fourth DC-DC that drives the outer oven with up to 18V.
> Well, it is the first DC-DC that failed. I bypassed it, powering directly the 
> no. 2 and 3 from 48V, and all works again. The questions are: does a 
> schematic for that board exist? Anyone knows why such a complex power supply 
> architecture was adopted? It is not very energy-efficient, all those DC-DC 
> run hot.
> 
> 73 - Marco IK1ODO / AI4YF
> 
> 
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