[time-nuts] TV Signals as a frequency reference
Hal Murray (hmur...@megapathdsl.net) said:
"Roughly 40 years ago, a friend showed me a NBS booklet describing a scheme
for distributing time via TV. I forget the details. It was a cooperative
project with one of the major networks. NBS published the propagation delays
which changed occasionally as the phone companies providing the underlying
links rerouted things.
This is an IEEE article from 1972 that looks like a good fit:
Nationwide Precise Time and Frequency
Distribution Utilizing an Active Code Within
Network Television Broadcasts
DAVID A. HOWE
https://www.researchgate.net/publication/3092613";
I was a TV Broadcast Engineer in the 70s. There were a number of
schemes for transmitting frequency standard information via the TV
signal. One used the VITS signal referenced above. Another used a
cesium standard to control the 3.58 MHz (actually 3.579545454... MHz)
color burst signal. There were several articles in the hobbyist
press at the time on using this for a standard. You had to be
careful to use a network program, however; most local station could
not afford a cesium reference for something like that. (Actually,
the station I worked for had one but it was used for controlling the
transmitter frequency. Long story). Now that analog TV has gone
away, so have these signals.
Francis Grosz
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[time-nuts] Looking for Austron manual
I recently obtained an older Austron 1210 and am looking for a manual. I don't have the nameplate but the front panel is inscribed "Austron 1210 Crystal Clock", with no letter suffix. The battery tray cover has a date of "August 12 1985" stamped on it, and it has the analog clock. Unfortunately it is in rather rough shape and it looks like somebody attempted to modify it in some way. Apparently the oscillator has been replaced; it's now an Austron 1150 with a date of 3/85 on it. I'd really like to restore it as close to original condition as possible, or at least working properly. If anyone has a manual for this version or a pointer to it I'd really appreciate it. I have the manual for the "D" version but apparently this is considerably different. Thanks in advance for any help! Francis Grosz, K5FBG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Looking for Austron manual
I recently obtained an older Austron 1210 and am looking for a manual. I don't have the nameplate but the front panel is inscribed "Austron 1210 Crystal Clock", with no letter suffix. The battery tray cover has a date of "August 12 1985" stamped on it, and it has the analog clock. Unfortunately it is in rather rough shape and it looks like somebody attempted to modify it in some way. Apparently the oscillator has been replaced; it's now an Austron 1150 with a date of 3/85 on it. I'd really like to restore it as close to original condition as possible, or at least working properly. If anyone has a manual for this version or a pointer to it I'd really appreciate it. I have the manual for the "D" version but apparently this is considerably different. Thanks in advance for any help! Francis Grosz, K5FBG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Looking for Austron manual
I recently obtained an older Austron 1210 and am looking for a manual. I don't have the nameplate but the front panel is inscribed "Austron 1210 Crystal Clock", with no letter suffix. The battery tray cover has a date of "August 12 1985" stamped on it, and it has the analog clock. Unfortunately it is in rather rough shape and it looks like somebody attempted to modify it in some way. Apparently the oscillator has been replaced; it's now an Austron 1150 with a date of 3/85 on it. I'd really like to restore it as close to original condition as possible, or at least working properly. If anyone has a manual for this version or a pointer to it I'd really appreciate it. I have the manual for the "D" version but apparently this is considerably different. Thanks in advance for any help! Francis Grosz, K5FBG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 1 PPS users?
Folks, One thing that is sometimes poorly understood is that on a power system real power flow (Watts)is primarily determined by phase; voltage determines reactive power flow (VARs). This means power system operators are very interested in the phase difference between the two ends of a transmission line, for example. GPS has made it possible to measure this accurately even over long distances using purpose-built instruments. Google "Phasor Measurement Units" got more information. Francis Grosz -- Message: 2 Date: Mon, 19 Dec 2016 11:46:41 -0500 From: Bob Camp To: Tom Van Baak , Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 1PPS users? Message-ID: Content-Type: text/plain; charset=utf-8 Hi > On Dec 19, 2016, at 10:11 AM, Tom Van Baak wrote: > >> I believe the power industry is using GPS provided time to stamp power >> events for analysis as well. > > Chris, > > Yes, in fact one of the first applications of hp's SmartClock was just that: > > "Accurate Transmission Line Fault Location Using Synchronized Sampling" > http://leapsecond.com/hpan/an1276-1.pdf There is an FCS paper that pre-dates that by about a decade. The guys at Quebec Hydro set up GPS to monitor the phase state in their main distribution network and wrote the paper. I dont have an FCS DVD handy to dig it up. I also have no idea if there is a copy outside a pay wall. They went into a bit more detail on what they saw. It gives you a bit better feel for how it works in the real world. Bob > > > Bob, > > For more background on 1PPS and time synchronization see: > > "GPS and Precision Timing Applications" > http://www.hpmemoryproject.org/an/pdf/an_1272.pdf > > "The Global Positioning System and HP SmartClock" > http://www.hpl.hp.com/hpjournal/96dec/dec96a9.pdf > > Other useful hp app notes for time nuts: > http://leapsecond.com/hpan/list.htm > > /tvb > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] The home time-lab
Jim,
IIRC, the IBM 360 mod 91 was one that used a MG set. I think it also
required chilled distilled water for cooling. Those were indeed the
days of "Big Iron".
Francis Grosz
>Date: Mon, 25 Jul 2016 21:04:58 -0700
>From: jimlux
>To: time-nuts@febo.com
>Subject: Re: [time-nuts] The home time-lab
>Message-ID:
>Content-Type: text/plain; charset=utf-8; format=flowed
>On 7/25/16 6:55 AM, 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
>we had a system like this to turn 60 Hz into 50 Hz with a toothed belt
>drive between synchronous motor and synchronous generator. It whined..
>"Satan's Siren" is what we called it.
>
>IBM mainframes used a similar scheme but I can't remember the details.
>
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[time-nuts] IFCS Repeaters
If you are at IFCS in New Orleans and want to use a repeater, my first recommendation would be the 444.200 machine if you have 70 cm and alternatively the 146.86 2-meter machine. Francis Grosz, K5FBG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 1968 Scientific American Magazine: Cesium ClockStandards
If you go to the amasci.com link they have a CD with all of the Amateur Scientist columns in it. It was amazing what some of those guys did way back then in a garage or basement. - Message: 6 Date: Wed, 10 Dec 2014 10:20:16 -0500 From: Paul Alfille To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 1968 Scientific American Magazine: Cesium ClockStandards Message-ID: Content-Type: text/plain; charset=UTF-8 That link leads to "Semester At Sea" -- but a little googling finds something useful: http://amasci.com/ I think the biggest loss from Scientific America was Martin Garners Mathematics Puzzles. Everything from LISP to Conway's Game of Life... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] "The GPS navigation is the weakest point,"
As the engineer quoted in the article says, Iran is not Afghanistan or Pakistan. Unfortunately Americans aren't very good in geography or history and we tend to lump everybody in that part of the world together, and so forget that Iran was once called Persia and the Persian Empire at one time conquered a large part of the world. We forget this at our peril. Francis >From: Joe Leikhim >To: 'Discussion of precise time and frequency measurement' > >Subject: Re: [time-nuts] "The GPS navigation is the weakest point," >Message-ID: <4eea874c.8060...@leikhim.com> >Content-Type: text/plain; charset=ISO-8859-1; format=flowed > >This mindset is an example why the US is falling so far behind the rest of the >world, not only in technology but in the >diplomacy game. In 1980 I worked for >a very smart engineering manager who told me he studied electrical engineering >>by the light of a gasoline lantern in a tent in Turkey. > >"US officials skeptical of Iran's capabilities blame a malfunction, but so far >can't explain how Iran acquired the drone >intact. One American analyst >ridiculed Iran's capability, telling Defense News that the loss was like >dropping a Ferrari >into an ox-cart technology culture." > >-- >Joe Leikhim ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] gravity controlled pendulumn clock?
Folks, Actually, the USGS goes around measuring the local gravitational constant in various places. There was a gravimeter set up in the basement of one of the local universities a few years back doing just that. And some time ago, the U.S. spent a fair amount of time, money and effort (presumably as did the Soviet Union and others) mapping the Earth's external gravitational field to correct for its effect on ballistic missile trajectory. Probably still do. Francis On Dec 12, 2011, at 5:19 PM, Magnus Danielson wrote: > On 12/12/2011 01:37 AM, Jim Lux wrote: >> On 12/11/11 4:04 PM, Tom Van Baak wrote: >> >>> GCPC -- gravity controlled pendulum clock (elevation) >>> >> >> >> intriguing. From your parenthetical remark, I'm assuming you move the >> whole assembly up and down to adjust the speed? >> >> I was thinking about a huge mass that moves around? >> >> let's see.. period is proportional to sqrt(1/g) >> >> g is proportional to 1/r^2, so period is proportional to r. >> >> Earth is roughly 7000 km radius, so moving it 1 meter higher or lower >> changes the period by 1part in 7million... interesting. > > Hmm... how does the near-field gravitational pull behave? > > The far-field is surely r^-2, but wonder about the near-field effect. > > Need to grab some paper and pen and convince myself. > > Cheers, > Magnus > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] FS: HP 59309A
Sal, It's also a relatively simple mod to rearrange things in the 59309A to accept the 1 pps input from a GPSDO. I no longer have my unit for the exact reference, but it simply involved lifting one side of a capacitor and connecting it to the external DC BNC on the back. Feed in the 1 pps, set the clock, and you're good. Francis --- From: SAL CORNACCHIA To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FS: HP 59309A Hi Don, ? Can You share with me and the group on making the 10 MHz input adapital. ? Thank You ? Best regards, Sal C. Cornacchia Electronic RF Microwave Engineer (Ret.) From: Don Latham To: Discussion of precise time and frequency measurement Sent: Wednesday, October 26, 2011 12:07:48 AM Subject: Re: [time-nuts] FS: HP 59309A in addition, they are? readily adaptible to 10 MHz input using the external power bnc and a cmos decimal counter chip. Don J. Forster > A look at the manual implies that it can be switch set for 365 or 366 > days. > > A nice unit, but I've already got one. > > Best, > > -John > > ==- > > >> Hello Everyone, >> >> Currently only for the Time-Nuts, I have an HP59309A HP-IB Digital >> Clock >> for sale. This one has Option H04, otherwise known as Option 001, >> which >> offers a Julian Calendar (0-366 day-of-year indication) instead of the >> regular Month/Day. >> >> The unit is functional, clean and in quite good shape, with the >> expected >> light scratches and blemishes on the top/bottom/sides typical of a >> used >> unit. The front is pretty clean. Price is $90 + shipping. Please >> contact >> me directly. >> >> >> Thanks, >> >> Bert, VE2ZAZ >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Weird TEC data
Hi, Scott, They track because most of Arkansas is part of the Eastern Interconnection and the transmission systems are tied together through that. The general shape follows the loading of the system; that is, as the load increases throughout the day the alternators slip behind; as it decreases they advance. They try to keep the system frequency accurate to +/- 0.02 Hz. but that integrates out to a worst case of 72 cycles slip or advance/hour. PNNL has developed the Grid Friendly Grid Monitor software and you can use that to watch the frequency and accumulated phase error of the Western Interconnection. Here in New Orleans a friend in the power company who was interested in its history told me a story. In the very early days, frequency control was pretty poor and it was hard to keep up with the changing load. So by 5 PM every day, every electric clock in the city was 10 or 15 minutes slow. So overnight they'd speed up the system and so by 8 AM the next morning every electric clock would be 10 or 15 minutes fast because the total slip during the day was 20 or 30 minutes. Today we'd consider that absolutely unacceptable (even for non-Time Nuts), but back then it just was. Still, elimination of TEC is idiotic. I had occasion recently to talk to a couple of very high-level power systems people and they thought it was crazy as well. Like elimination of leap seconds, we'll just have to see. Francis >Message: 7 >Date: Tue, 02 Aug 2011 21:18:17 -0500 >From: Scott Newell >To: time-nuts@febo.com >Subject: [time-nuts] Weird TEC data >Message-ID: <848527.81129...@smtp109.prem.mail.sp1.yahoo.com> >Content-Type: text/plain; charset="us-ascii"; format=flowed > >Here's the latest plot from my TEC test rigs. Y-axis is phase error >(in 60 Hz cycles), X-axis is time in MJD. The plot starts at 7AM local time. > >http://n5tnl.com/tec/tec_test_01.png > >Same serial connected embedded hardware, timestamped on the receipt >of first character. One machine (red line) is a Sun running debian, >the other (green line) is a Dell PC, also running debian. Both >running ntp, of course. One is located in a fairly large city (by >Arkansas standards!), the other is out in a small country >town. Different utility providers. > >The general shape and bumps in the plots track nicely, but I'm >wondering why there's so many cycles difference after 36 hours. > >Comments? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] No more 60Hz! TEC Elimination
Folks, The Pacific Northwest National Laboratory has a couple of "Grid Monitor" tools as part of their "Gridwise" program that you can download. This gives a pretty good high resolution look at the grid frequency. (This is the frequency of the Western Interconnect.) If you're interested, check out http://gridwise.pnnl.gov/technologies/transactive_controls.stm The download buttons plus a link to a pdf on the program are in the bar on the right side under "Transactive". While not the accumulated error due to TEC elimination, it will allow you to see how far off things get, not to mention see any large disturbances. There might be some interesting viewing there this summer. There is also more info available on their "Gridwise" program. Francis Grosz ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Another incermental improvement in atomic clocks
Timekeeping errors will be further reduced by
better accounting for the effect of blackbody radiation
on atomic clocks. See
http://www.rdmag.com/News/2011/05/General-Science-Physics-Developing-An-Accurate-Means-For-Computing/?et_cid=1511177&et_rid=54735850&linkid=http%3a%2f%2fwww.rdmag.com%2fNews%2f2011%2f05%2fGeneral-Science-Physics-Developing-An-Accurate-Means-For-Computing%2f
Francis Grosz
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Re: [time-nuts] homebrew H maser
I think the book referred to is The Scientific American Book of Projects for the Amateur Scientist by C. L. Stong (no "r' in Stong) I too used to just read it - great book. It's a collection of some of "The Amateur Scientist" columns by Stong from Scientific American magazine. Unfortunately it's out of print and used copies can be a bit pricey or hard to find. There is a great deal available, however - a complete collection of all of "The Amateur Scientist" columns ever published on a CD for $27. If anyone is interested, the link is http://www.brightscience.com/ Francis -- Original Message > Date: Tue, 31 Aug 2010 18:06:38 +0200 > From: Attila Kinali > Subject: Re: [time-nuts] homebrew H maser > To: j...@quik.com, Discussion of precise time and frequency > measurement > Message-ID: <20100831180638.16e4c656.att...@kinali.ch> > Content-Type: text/plain; charset=US-ASCII > > On Sun, 29 Aug 2010 10:11:47 -0700 (PDT) > "J. Forster" wrote: > >> I used to read Strong's book as bedtime reading. > > And which book would that be, for those who have not read it? > > Attila Kinali ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 'Discussion of precise time and frequency measurement'
Joe,
If you have an analog 'scope with delayed sweep, set it up with the main
time base
showing the 90 MHz signal in a convenient way (say 1 cycle/div) and then
use the delay to look at the signal some time later (after the initial trigger)
with
the modulation on and off. Any phase or frequency modulation should be pretty
obvious then. (Note: Use delayed sweep, NOT delayed trigger; i.e., "B starts
after delay", not "B triggerable after delay".)
Francis Grosz
Original Message
---
It's been a long week and it's only Tuesday.
How can I prove that the A3 assembly is, in fact, phase modulating? In
other words, how can I prove that the 90 MHz signal from the A3 assembly to
J1 on the A4 assembly is phase modulated by the 137 Hz signal?
I have looked at the output of the A3 assembly at the cable to J1 on the A4
assembly (A4P1) with an oscilloscope and a spectrum analyzer with Mod On and
Mod Off and can see no difference. Likewise, on a functioning unit, I can
not see any difference there either. Are there proper ways to set up the
scope or SA to focus on this issue?
Short of fabricating a 'phase detector', how can I prove that the A3 unit is
functioning in my 'problem child' unit. If I have to fabricate a 'phase
detector', how easy (or difficult) is that?
Thanks,
Joe
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[time-nuts] 60 Hz timing
And IIRC, DEC defined 1/60 second as a "jiffy"; it was also used to do task
switching on the time-sharing systems (e.g., PDP-10 AKA DECsystem-10).
Francis Grosz
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