Re: [time-nuts] Why are 1PPS signals so skinny?
Jenny Craig? ___ 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] Faster than light of a different type
Hal, Excellent comment! In some sense, success is related to the number of people signed up. Yes, in the same sense that happiness is related to the money you have. It is possible to have too many or too much. Human nature includes Look at me, Ma. Look at me! Most pros can stifle that. People grow out of behaviors at different times, or not ever. The bigger the list, the more people under the skirts of the bell curve. Seems like many lists where members are acquainted with Ohm's law will fall into audiophile bashing at the drop of an extravagantly priced widget. Possibly to show the group I'm smarter than that! A possible way to select messages that stay on topic is to filter out those that don't have time in the text. If you believe your message is on-topic but time isn't mentioned, add Ob time-nuts: (Obligatory) and some words about time. It won't get them all because the word is common, but it might slow them down. I have wondered if part of the problem is that the list is set to only reply to the list. You have to work to get an individual address for an individual reply. Every list seems to have people who don't or can't edit their replies. I get the whole list first and skim it to find the interesting bits, then read them and let the rest go to an Outlook archive. I have trouble throwing away things that might be useful some day. Bill Hawkins -Original Message- From: Hal Murray Sent: Monday, May 07, 2012 10:45 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Faster than light of a different type c...@employees.org said: one more thing, people need to learn to hit the delete key if they don't like a particular email. get over it. I don't think that's a reasonable approach. Yes, of course, we should all be more tolerant. But that's only half the story. There is an interesting problem with technical discussion lists, bboards, usenet groups, web forums, whatevers. In some sense, success is related to the number of people signed up. On the other hand, once you get enough people, the signal to noise ratio often falls off a cliff. A (strong) hint of the problem is bursts of noise like the recent events here. The problem with saying just-hit-delete is that many of the people with technical skills/opinions/ideas that I want to hear from are not very tolerant of low signal/noise. So they leave the group rather than pound on their delete key. I think there is a fundamental truth for this area. It may be a physical constant. It's at least a good PhD topic. For any large list there will be some amount of traffic (like this message) that is grumbling about the bad traffic on the list. At best, it's the list operator/moderator occasionally (preemptively?) reminding people to stay on topic. It's something like 1/e for the max throughput of an Aloha network. If you beat up on the noisy people so they are less noisy, the list will grow to include enough new people to fill in the spots that were previously quiet. It would be interesting to study the timing of the noise bursts and/or the relation to people signing up or leaving a list. I've seen similar problems in standards groups. Initially, the group is full of smart geeks with good ideas. They are cooperating to try to solve an interesting problem. Then some not-so-sharp guy gets sent to make sure his company's products are blessed. As the group turns to politics, the smart guys leave, their company sends a lawyer to replace them, and things spiral downhill. -- One thing that might help is if everybody would get in the habit of scanning all their mail before responding to anything. The idea is that if a discussion explodes while you are sleeping (or away from your mail for whatever reason), you will learn that a topic has exploded before you contribute your wise-ass or me-too comment. Even if your answer is technical and valuable, you might notice that somebody has already said exactly what you were about to say. -- These are my opinions, not necessarily my employer's. I hate spam. ___ 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] Interesting paper: Don't GPSD' your Rb...
Here is a different tactic for disciplining Rb from GPS/TXCO - Consider the relatively (relative to a second) long stability of an Rb oscillator and the not-so-good stability of GPS. Perhaps using 1 PPS for a sampling period for stabilizing Rb is way too short. Maybe 1000 seconds is better. That's way too long for an analog integrator to do, so a microcomputer is required. Count the Rb and GPS 1 PPS signals for 1000 counts of Rb 1 PPS. You'll need to interpolate between 1 PPS GPS intervals to the level of accuracy required, so maybe we count cycles of 10 MHz from the GPS, using as many registers (cascaded integer counters) as required for 1 E10 (or more) counts (2540BE400 hex). At the end of 1000 seconds, use the difference between the lowest counter reading and 0xEB400 (times an appropriate gain) to tweak the value for the DAC doing the fine correction to the control voltage or current. Use the upper counters for a sanity check on the reading. As may be evident, I have never tried to discipline an Rb, but I am well aware of the effect of sample time on the control of a long time constant loop. True, the effect is strongest when dead time dominates the time constant, but that is not the case here. Still, I think there is value in using a long sampling time for the control action. Comments accepted with enthusiasm. Bill Hawkins ___ 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] Interesting paper: Don't GPSD' your Rb...
Thanks for the analysis, Magnus. A few other time constants might be interesting - When a step change is made to the control voltage or current, how long does it take for the oscillator to settle down to a new value? Is it instantaneous compared to a second? Do different components in different oscillators affect the settling time? It is not useful to make the next change before the last one is complete, at least for sampled systems. Using counters filters the change rather than taking a sample. Bill Hawkins -Original Message- From: Magnus Danielson Sent: Sunday, May 06, 2012 4:45 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Interesting paper: Don't GPSD' your Rb... On 05/06/2012 09:01 PM, Bill Hawkins wrote: Here is a different tactic for disciplining Rb from GPS/TXCO - Consider the relatively (relative to a second) long stability of an Rb oscillator and the not-so-good stability of GPS. Perhaps using 1 PPS for a sampling period for stabilizing Rb is way too short. Maybe 1000 seconds is better. That's way too long for an analog integrator to do, so a microcomputer is required. Using analog integrator for 1 PPS stuff is hardish and your performance will most probably suffer. You want your integrator to be digital as it is clearly a better memory over time. However, this is not to be confused with the time-constant, which should be much higher than 1000 s to use the stability of the rubidium where the GPS noise is worse. See PRS-10 manual for good illustration. Count the Rb and GPS 1 PPS signals for 1000 counts of Rb 1 PPS. You'll need to interpolate between 1 PPS GPS intervals to the level of accuracy required, so maybe we count cycles of 10 MHz from the GPS, using as many registers (cascaded integer counters) as required for 1 E10 (or more) counts (2540BE400 hex). At the end of 1000 seconds, use the difference between the lowest counter reading and 0xEB400 (times an appropriate gain) to tweak the value for the DAC doing the fine correction to the control voltage or current. Use the upper counters for a sanity check on the reading. Why wait with the updates of the DAC? By incrementally average for each second I think you get a smoother transitions. You sure want time-constants in excess of 1000 s, but you can achieve that by using 1 s updates. Again, read the PRS-10 manual for a fairly good description. As may be evident, I have never tried to discipline an Rb, but I am well aware of the effect of sample time on the control of a long time constant loop. True, the effect is strongest when dead time dominates the time constant, but that is not the case here. Still, I think there is value in using a long sampling time for the control action. I fail to see the benefit, and I have many times learned the hard way to see the downside of too low update rate. Comments accepted with enthusiasm. :) 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. ___ 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] Oh dear
Swiss-made? FEI 5660? PRS10? US $5,995? Oh, dear indeed. Nice to know the fiscal predators have predators to bite 'em. Bill Hawkins -Original Message- From: Jim Palfreyman Sent: Sunday, May 06, 2012 9:40 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Oh dear http://www.ebay.com.au/itm/Antelope-Audio-Isochrone-10M-Rubidium-Atomic-Cloc k-/270809581736?pt=LH_DefaultDomain_0hash=item3f0d8248a8 Make sure you read the description to discover what it's being sold for. My chuckle for the day. Jim Palfreyman ___ 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] parking lot location (was2 (Spoofing))
[Parking lot location details deleted] While clearly not spam, the only other time Mr. Darlington's name appears in this group in the 12,459 low noise messages since 12/31/2010 was the following: -Original Message- From: Robert Darlington Sent: Tuesday, October 04, 2011 4:07 PM To: j...@quikus.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 2 (Spoofing) So that no more goes out to the list. It does nothing to stop the problem. I'd have to look at the headers but based on what I'm hearing it sounds like his mail server is wide open, OR, somebody on the same network/isp is spamming. -Bob On Tue, Oct 4, 2011 at 2:54 PM, J. Forster j...@quikus.com wrote: I agree with that picture. The sad thing is that the spammer can do it to Jeff essentially forever. There is little that can be done, other than change his email address, because the spammer has both his email address and a list of sites where that email address is trusted. As a Moderator (not of this group) I immediately moderate any such spamming email addresses, so at least no further spam goes out. Best, -John From the looks of it: 1. The bad guys imported/stole Jeff's address book (via social networking ABI hijack, or PC infection). 2. The bad guys then spammed (from 84.27.224.19 in the Netherlands) to the contacts they stole from Jeff's address book (and spoofing as Jeff). This is troubling because it could happen to any one of us (if we have an address book and it gets hijacked). Per John's previous message, I would be leery of social network ABI (Address Book Import) for one thing. -Greg - Original Message - From: Chuck Harris cfhar...@erols.com Sent: Tuesday, October 04, 2011 2:04 PM Subject: Re: [time-nuts] 2 (Spoofing) I'm not convinced. Notice that the to: line contains a list of addresses that look like they would belong in a time-nut's address book. That wouldn't be beneficial, or necessary if the spammer was spoofing his way into febo's servers. I think this came from a spambot running on jeff's machine, and it emailed the payload to as many places as it dared... one of them happened to be the time-nuts address used for posting messages. -Chuck Harris gbusg wrote: The spam message in question was apparently spoofed and did not originate from Jeff's PC. In the message header, note the Originating-IP was [84.27.224.19]. That IP address originates from a server at [Netherlands Groningen Ziggo B.v]. Jeff's actual IP address (which I won't repeat here) is significantly different and is located in the U.S.A. Chuck, I think somehow the spoofers have overcome the obstacle you mention, unfortunately. (Otherwise how did the user of the Netherlands server manage to get spam through to our group?) -Greg This is the message that started it all: -Original Message- From: jeffh...@comcast.net Sent: Tuesday, October 04, 2011 4:42 AM To: lrode...@yahoo.com; ronru...@mindspring.com; smbi...@verizon.net; stacie...@comcast.net; time-nuts@febo.com; tryto...@gmail.com; warrensjmail-...@yahoo.com Subject: [time-nuts] 2 Have ever been to the best on-line shop? This is it! [link to a French ceramic pottery shop deleted]. End of old messages happens here. OB timenuts: Time hung heavy on my hands. Bill Hawkins ___ 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] To remove membership
Looked at the unsubscribe instruction link to see why Roy couldn't unsubscribe, IE 8 said there was a certificate error, unsafe to visit this site. Overrode that, got the site with a red banner from IE 8 about the certificate, was told that this is a high signal to noise group. Ironic, that, amidst the noise about Chinese scopes. Might want to fix the certificate so unsubscribers can do so. OB timenuts: Time marches on. Bill Hawkins -Original Message- From: Roy Phillips Sent: Wednesday, April 18, 2012 12:39 PM To: time-nuts@febo.com Subject: [time-nuts] To remove membership ___ 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] Antenna Restrictions...
I can tell you that the vent stack exists solely to prevent siphoning water out of J and P traps while water is running. When high winds produce a lower pressure at the roof vent than in the house, the traps will be sucked dry and you'll have to refill them to prevent odor in the house when the wind dies down. Yes, the sewer gases can be sucked out of the sewer, and sniffed in the breeze on the ground or deck below and downwind of the vent. Burt is right. Time marches on. Bill Hawkins -Original Message- From: Burt I. Weiner Sent: Sunday, April 15, 2012 8:45 PM To: time-nuts@febo.com Subject: [time-nuts] Antenna Restrictions... I can tell you from first hand experience - Do not restrict the air flow of a roof vent associated with plumbing, especially if it's associated with the Loo. Burt, K6OQK On 4/15/2012 5:41 AM, Chuck Harris wrote: Yes, but you GPS antenna surely would notice the infusion with various fumes and chemicals that come from the vent pipe. Remember, the vent is open to the sewer, its purpose is to prevent pressure build up in the sewer from blowing (or sucking) the water out of the various traps and letting sewer gas into the house. Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ 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] Improving performance of a GPS antenna...?
My first job was in a blasting cap plant in 1960. Raw materials and finished product were kept in earthen bunkers separated by a distance that would prevent an explosion in one from propagating (the distances were found by experience). Tall, grounded masts were spaced among the bunkers to prevent strikes by lightning. There is a 45 degree cone of protection from the top of the mast to the ground. This is based on British Navy experience with sail masts of warships between 1793 and 1847. There were 220 strikes reported in that time. 2/3 of them struck the top masts. Only 1 in 50 struck the hull below the masts. See the report at http://www.lightningsafety.com/nlsi_lhm/conventionalLPT.pdf and search the PDF for cone of protection Then again, this outfit says the cone is a myth http://www.lightningsafety.com/index.html All I know is that we never lost a bunker in the 5 years I was there. We did have thunderstorms near Kingston, NY, 90 miles above NYC. The safety department tested the mast grounds with an instrument like a megger that used two probes driven in the ground (IIRC) to measure less than a tenth of an ohm resistance to ground. Looking back on it, I don't think anything would survive a direct hit on the mast. It was more a matter of the mast misdirecting the leader of the strike to look elsewhere for ground. Or, given the small numbers, maybe it was probability that saved us, like snapping your fingers to keep the tigers away in North America. Lightning arrestors for lead-ins are still a very good investment. Bill Hawkins PS- The worst explosion I remember there was the day a new technician took a few pounds of scrap powder to the burning grounds. It was supposed to be mixed with ten times as much sawdust to make it burn instead of detonate. He got the proportions backwards. The explosion got the attention of everybody in the plant. -Original Message- From: Chris Albertson Sent: Wednesday, April 04, 2012 12:53 PM People will argue that if you ground the pole it then will become a lightning magnet That thinking is 180 degrees backward. A pole becomes a lightning magnet if it is allowed to charge above ground potential. So for most of us who don't live in Florida a #10 wire clamped to the mast and run off to a ground rod is good enough. ___ 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] 60Hz More or Less
Ed, Your old signal generator frequency is regulated by stable components. The power grid frequency cannot be regulated because it is distributed over thousands of generators. Mathematical models are not stable, as people switch loads on and off. Regulation is done by human dispatchers calling generation plants and requesting more or less power from the variable power generators. Most boilers are fixed loaded at their most efficient operating point. It is quite amazing that the entire system usually averages out to 60 alternations per second per day. Sorry I can't look at your results, but I don't have time to play with operating systems that are constantly being improved. I tried Ubuntu and went back to Microsoft. Then again, I'm leery of things that show up on April First. Bill Hawkins -Original Message- From: Ed Mersich Sent: Sunday, April 01, 2012 5:18 PM At the moment I am thinking about modifying a DC-AC inverter and syncing it to an audio oscillator, (don't laugh, my Heathkit 30 year old audio generator is way better, more stable, than the grid). ___ 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] New to the list
Hi, George Is there anything that distinguishes you from the thousand others on this list? What is there about time that interests you? That makes you a nut? Do you lean towards theory or the soldering iron? Is bit twiddling your interest? Assuming that you have followed human nature and collected stuff that might be interesting, what have you collected? Who will throw it in the dumpster when you die? If you are completely new to this, where would you like to start? Something cheap from an auction site or a new hydrogen maser? Don't mind me, I've been around too long. Bill Hawkins -Original Message- From: George Allen Sent: Tuesday, March 13, 2012 9:26 PM Just a note to let you know that George, K2CM, has joined the list. George K2CM, Vestal, NY ___ 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] Questions about Austron 5000 Loran C receiver
Andy, I'm truly sorry this didn't go anywhere, in spite of Forster's attempt to hijack the thread. You got more replies from heavy hitters than I ever did. (Excuse me, Magnus, if you do not consider yourself as a heavy hitter.) What you have is a device that has a CRT display and Nixie displays, an antenna connection, and several 50 pin connectors. A creative bit banger could make a marvelous display from this unit. Truly creative bit bangers are hard to find these days. Have I challenged anybody here? Andy is one of the good guys. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Andy Lokken Sent: Saturday, March 03, 2012 10:09 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Questions about Austron 5000 Loran C receiver Thanks to all who replied. I think I'm in over my head with this one. There are far easier ways for me to try to receive Loran C, and I have no shortage of projects. So... Forgive me if this is not allowed on this reflector... Free to a good home (after shipping): One Austron 5000 Loran C receiver. Untested. Decent physical condx. See earlier post from me for a link to photos. If interested, please contact me off list. -Andy ___ 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] MINOS Status on Measuring Neutrino Velocity
Hi, Marvin Congratulations on receiving the funding to keep the experiment alive and to get the right equipment. I've thought of our conversation in early November many times. Is it coincidence that your posting arrives on the same day that a 60 nS error was found in the OPERA experiment? Bill Hawkins b...@iaxs.net -Original Message- From: Marvin Marshak Sent: Wednesday, February 22, 2012 2:08 PM To: time-nuts@febo.com Subject: [time-nuts] MINOS Status on Measuring Neutrino Velocity The MINOS Collaboration has made progress in its effort to use the Fermilab to Soudan MN neutrino beam to investigate the effect reported by the OPERA Collaboration of neutrinos travelling faster than the speed of light. The current MINOS methodology has two parts: (1) to retrospectively analyze data collected since 2005 with timing established by Truetime XL-AK GPS units and (2) to use new data to be collected during March and April 2012 with significantly enhanced timing instrumentation. The retrospective analysis will include considerably more data and improved analysis algorithms, compared with the observations published by MINOS in 2007. In this email, I will focus on the new instrumentation. MINOS now has three timing stations. The first station is located at a point called MI-60, which is at the Fermilab Main Injector in Batavia IL, an accelerator that produces the proton beam that eventually results in the neutrino beam. The MI-60 station monitors the antecedent proton flux as a function of time. The second station is located in the MINOS Neutrino Near Detector, which is approximately 1 km from the proton target. The third station is located at the MINOS Neutrino Far Detector in Soudan MN, approximately 735 km from the proton target. Each timing station includes an HP5071A cesium clock, installed with help from the U.S. Naval Observatory; a Novatel dual-frequency code and carrier phase GPS receiver, modified by and installed with help from NIST; and multiple Agilent 53230A time interval/frequency counters. Each station also has ancillary hardware, including distribution amplifiers, optical fiber links, temperature stabilization chambers and monitoring computers. Each station also has instrumentation to measure and monitor changes in propagation delays in the various cables and optical fiber links, particularly the long ones between surface GPS receivers and the deep underground detectors. An additional HP 5071A will be used for round trip travel between Fermilab and Soudan. The clock synchronization between the two ends of the beam will also be checked using other methods with help from USNO and NIST. I expect to describe these methods later when arrangements are more complete. These stations enable three inter-station measurements: . MI-60 to Near Detector: Most distance travelled by charged particles; should be very close to speed of light. . MI-60 to Far Detector: Almost entirely neutrino propagation delay. . Near Detector to Far Detector: Entirely neutrino propagation delay. We have just started operating the HP5071A cesium clocks in the last few days and are interested in suggestions for optimal operation and monitoring of these units. The HP5071As can be controlled and read out via a serial connection, and the device has many operating parameters it can report. Which of those parameters are most useful for long-term monitoring of the clock stability? Are there subtle problems in using these units? The next few months should produce interesting results and I will try to keep the list informed on progress. Marvin L. Marshak College of Science and Engineering Professor Morse-Alumni Professor University of Minnesota 116 Church Street SE Minneapolis MN 55455 612-624-1312 612-624-4578 (fax) ___ 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] Neutrinos faster than light update
Ah, Didier, that link is to a thread started in September, 2011. Do I have to sort through the 1000+ comments to find something recent? Bill Hawkins -Original Message- From: Didier Juges Sent: Wednesday, February 22, 2012 5:20 PM http://science.slashdot.org/story/11/09/22/1841217/cern-experiment-indicates -faster-than-light-neutrinos?sdsrc=rel Looks like they found the problem! Didier KO4BB ___ 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] Low-long-term-drift clock for board level integration?
What you are looking for is the Caesium standard on a chip that is presently only available for mostly military projects. This will become available as war surplus after WW III. But if you are going to correct it with NTP, a simple crystal oscillator will do. If you're using NTP, why do you need to initially set it to GPS accuracy? Your best solution is to maintain the GPS antenna and only use GPS to discipline a good crystal oscillator. Do you plan to regulate the ambient and power environment to some degree of accuracy? Note that 10 microseconds is 1 part in 10E5. The folks on this list deal in parts per 10E12. $300 will buy you a standalone GPS receiver that does parts in 10E9, but it is bigger than a circuit board. Can you use a standalone receiver to always generate a 10 MHz signal or pulse per second signal that is distributed to all of the measurement devices in a facility? Bill Hawkins, who has ideas but is not a professional -Original Message- From: Bill Woodcock Sent: Sunday, February 19, 2012 5:57 PM Hi. This is my first posting to this list, and I'm not a timekeeping engineer, so my apologies in advance for my ignorance in this area. I'm building a small device to do one-way delay measurements through network. Once I'm done with prototyping, I'm planning a production run of several hundred of the devices. They'll have a GPS receiver, probably a Trimble Resolution SMT, and they have a bit of battery so they can initially go outdoors for ~30 minutes to get a good fix, but then they get taken indoors and plugged into the network, and probably never get a clear view of a GPS or GLONASS satellite again. - From that point forward (and we hope the devices will have an operational life of at least ten years) they'll be dependent on their internal clock and NTP, but we really need them to stay synchronized to within 100 microseconds. 10 microseconds would be ideal, but 100 would be acceptable. And in order to be useful, they need to stay synchronized at that level of precision essentially forever. My plan, such as it is, was just to get the best clock I could find within budget, integrate it onto the motherboard we're laying out as the system clock, and depend on NTPd to do the right thing with it. Anyone have any thoughts or advice on clocks I could use that would be, say, under USD 300 in quantity 500, and would be optimized for minimal long-term drift? Power-use is not particularly constrained. It needs to be integrated onto our board, but space isn't too constrained either. I'm also happy to pay for a few consulting hours if people want to give me detailed advice on a professional basis. Thanks, -Bill ___ 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] GPS fade out, Sat/Sun
Nothing in Minnesota. Probably just the local terrorist cell tuning up the jammers for the big event on Valentine's day. Or a Light Squared test . . . Bill Hawkins -Original Message- From: paul swed Sent: Monday, February 13, 2012 7:52 AM None on the east coast Said Jackson saidj...@aol.com wrote: No outtage down here in Los Gatos. Hal Murray hmur...@megapathdsl.net wrote: I'm in California (Silicon Valley). It was about Sat noon-midnight local time, 8PM Sat to 8AM Sun UTC. A TBolt and Z3801A went into holdover. The TFOM on the Z3801A jumped up to 4 for a while. ___ 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] science projects
Fellow time scientists, Here's my view of the difference between science and engineering: Someone with better measuring equipment finds a discrepant result while verifying some physical law or accepted truth. That person needs to know the existing truths and create ideas about testing the new result. Questions are formed and hypotheses proposed. Initial testing is done and a paper published for all to see, but not, we hope, like Pons and Fleischmann's paper on cold fusion. Other scientists familiar with the nature of the problem try to verify each hypothesis with their own experiments. Positive results cause someone to propose a theory that explains the results so well that they become accepted truths. A technologist follows the progress of new theories and thinks of ways that they might be applied to life's problems, like renewable energy and uncontrolled growth, or like taking more money from the little people to make the incurably power hungry a bit more powerful than their rivals. If marketing studies show a positive return on investment, engineers are turned loose to solve the problems revealed as the details of building or manufacturing the new thing are studied. It is really difficult to find new problems in the physical sciences. One of the frontiers is brain science - how does any brain work. The human brain is most puzzling, because there are no instruments that provide a clear view of the workings of a living brain. See 101 Theory Drive by Terry McDermott for a description of one man's research into long term memory (no relationship, and so on). A time nut might be intrigued by the various frequencies that show up in brain waves. The Theta wave (about 3-8 Hz) is essential to memory, as described in McDermott's book. It is also essential to language processing, as hearing or speech. Why? What else does that? There are many oscillators in the brain. At least one of them is good enough that I can sometimes cancel my alarm just before it goes off. Bill Hawkins ___ 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] ANFSCD - Synchronizing time in home video recorders
Thanks for the info, Clint. Seems like the only way to get my four Panasonic DVRs to synchronize time is to analyze the I/O of the micro in the DVR, write interface and HMI specs, and replace the micro with one that can talk to my SNTP server. (Added two DVRs back when NASA was launching shuttles.) This would have the added benefit of fixing the scheduling bugs and make finalizing automatic for a full disk, rather than the five clicks it takes now. One day, the lack of sync every week will get to me, and I'll start this project, but I don't think I'll live to finish it. Bill Hawkins -Original Message- From: Clint Turner Sent: Thursday, February 02, 2012 4:10 PM -%- Off subject stuff snipped I, too, have an older (Philips) DVR that has lost its time sync since the analogs went dark. For a while, I used the XDS time code that happened to be in the vertical interval of one of its standard definition DTV PBS station's sub-channels (received on a set-top box and modulated onto a TV channel to which the DVR would look for its time code) but this has code since been dropped. Before I discovered this, I dug up the line 21 (IIRC) code specifications and noted that even a PIC could probably generate the proper code, synchronized either from a GPS or a WWVB receiver. I'd thought about putting it on multiple lines and then RF modulating it for the DVR to see, but lost enthusiasm after I discovered the time code on the sub-channel. Since that went away (about a year ago) I've just remembered to set the clock once a month, not being able to quickly find the specs for the time code again online... 73, Clint KA7OEI ___ 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] New Rubidium Frequency Standard Group
Staying on the topic of the thread, I also found the list clogging up with fixes for a cheap rubidium device (wouldn't call it a standard). Outlook told me that there were 10,350 messages in the time-nuts folder since it was archived at the end of 2010. I used Find for 5680 and got 900 messages, starting with Feb 2011 warnings about their frequency errors. Then I used Select All and Delete to remove 9% of the folder. How about a new list for eBay finds that are a waste of money, like the Lucent XO and Rb 15 MHz boxes? Maybe time-rats or time-junk Bill Hawkins Tobacco, coffee, alcohol, hashish, strychnine, are weak dilutions; the surest poison is time. Ralph Waldo Emerson, Jan 1862 -Original Message- From: Chris Albertson Sent: Thursday, February 02, 2012 10:03 AM If anyone wants all the FE5580A mail to go to one place make a filter in your email reader. Tell it to place anything sent from the TN list with FE5680 in the header or text to go into a special folder or otherwise be tagged as fe5680 related. I think this happens all the time -- people talk about whatever is new. Eventually $40 fe5680s will not be new. On Thu, Feb 2, 2012 at 5:57 AM, Rich (Buckeye) kq...@bex.net wrote: I have only been a member of the time-nuts group for a short while. It seems like 75% of the posts here have to do with the FE-5680A Rubidium Frequency Standards and their use and modification. This seems like the most popular subject and takes up a lot of the group's bandwidth. There is a new Yahoo Group called Rubidium that just was recently started. I wonder if all the Rubidium traffic and posts would be better at that group. Send posts to : rubi...@yahoogroups.com Just a suggestion. Tnx ___ 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] ANFSCD - Synchronizing time in home video recorders
And now for something completely different: Here I am with all of this precision time equipment, and I still have to manually set time on the Digital Video Recorders (DVR) because the TV channels that used to send a time code that the DVR understood no longer do so. Seems like it died when digital broadcasting replaced analog. Does anyone know how to make the DVR act as if it is seeing a code with the correct time of day? Failing that, can the crystal that determines time for the DVR be adjusted? Surely, some time-nut has solved this problem . . . Bill Hawkins Time is a great teacher, but unfortunately it kills all its pupils. Hector Berlioz, before 1869 ___ 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] FTL neutrinos or timing error - where did the energy come from
The January 28th Science News has an editorial by Tom Siegfried that points out that neutrinos were predicted to conserve the energy in radioactive beta decay. The OPERA results show unbalanced energy in the other direction. The pions that decay and create neutrinos do not have enough energy to get them past the speed of light. Either energy is coming from somewhere new, or something is wrong with the speed measurement apparatus. Then again, it could be something undiscovered about the propagation velocity of neutrinos in the crust of the Earth. Something like the velocity gain of spacecraft diving into a planet's gravity well and escaping again. More details are in the article on page 9, Neutrino parents set speed limits subtitle FTL flight would violate conservation laws. The article refers to a paper by Xiaojun Bi in the Dec 9 Physical Review of Letters. Just when you thought there were no new physics to be discovered, time appears to be out of joint. Bill Hawkins As Yogi Berra once said, It's tough to make predictions, especially about the future. ___ 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] US Army Frequency Standard
Amazing, the things that can be picked out of the noise. I have one of these frequency standards, but it belonged to the US Dept. of Commerce, during the period 1965 to 1970 when the DoC was given the weather bureau, named Environmental Science Services (ESSA). It was last calibrated 9-27-72, after ESSA became NOAA. The schematic on the cover of the cable box, inside the door, has the schematic for Frequency Standard TS-65C/FMQ-1 The box contains two cables, one with a PL-259 and one with a BNC connector. The name tag says Type 2509-2 Ser 140 made by American Time Products in New York, licensed under Western Electric patents. ATP made timing chart devices for setting the correct rate for a wrist or pocket watch. Google has nothing for ATP, but a search for TS-65C/FMQ-1 has one by Newton Time Products, which had negative search results. My device works, 60 Hz reads 60.06, which is 0.1%, but the 10 and 20 Hz ranges unaccountably have no output. Abe Books has a manual for $5. Since I'm cleaning out, this mechanical marvel is yours for the cost of shipping 24 pounds in a 12x12x20 box from Minneapolis 55438. It goes on the scrap truck Thursday if no one wants old stuff, as usual. Bill Hawkins ___ 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] hijacking threads
Well, I just got out of the shower and had this thought: There are people who hijack a thread *without* changing the Subject. Tension is caused by noble goals meeting human imperfection. So it goes. Oh, look at the time! Gotta run . . . Bill Hawkins -Original Message- From: Attila Kinali Sent: Monday, January 23, 2012 10:18 AM But lets close this topic. Everyone now knows that there is a difference between pressing reply and deleting the subject line and starting a new mail using compose. No need for any more OT talk :-) ___ 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] finding time astronomically.
It might be useful to determine the rate of the sun's movement at the ends of the analemma. There is a passage grave north of Dublin, Ireland, that has a long passage from a shadow box above the entrance to a spiral carving on the rear wall. Light shines on the carving at the winter solstice. The waiting list to see this event fills up with New Agers about a year before the event. I asked our guide if that wasn't very hard on people who could only see the event on one day if that day was cloudy. Oh, no, she said. The event happens for 3-4 days on either side of the solstice. Of course, a passage grave is not the same as a shadow cast by a fine wire on a microscope. It might take a few years to locate it properly. Are there any timenuts that want to be buried in a passage grave? Bill Hawkins -Original Message- From: Chris Albertson Sent: Monday, January 23, 2012 8:40 PM On Mon, Jan 23, 2012 at 6:07 PM, J. Forster j...@quikus.com wrote: I think you'd want a slit, not a pin hole. The pin hole would be better but it would only work one day a year. Actually two days per year, unless it was adjusted for the summer or winter solstice, then it'd be one. I still think it is one. because there are not an integer number of days per year so you don't get and exact repeat in 6 months. Maybe a pin hole would only work once ever? I don't know. To work the pinhole has to exactly line up with the detector at the exact same time of day. But I'm not liking slits either because I can't see how to adjust them to exact vertical. I'm back to the first thing I thought of, a wire with a large weight. Then you measure the light curve as shadow of the wire sweeps over the detector. ___ 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] HP 3575A Gain-Phase meter
Mark, Google gives this link as top of the list, and it does explain it. http://www.amplifier.cd/Test_Equipment/Hewlett_Packard/HP_meter/HP3575A.htm Very useful for Bode plots, but it doesn't do frequency stability. Bill Hawkins -Original Message- From: Mark C. Stephens Sent: Friday, January 20, 2012 9:10 PM To: time-nuts@febo.com Subject: [time-nuts] HP 3575A Gain-Phase meter Hello Folks, I have the chance to get hold of a 3575A, a HP Gain-Phase meter, would it be any use for me as a time nutcase? Many thanks, Mark ___ 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] ISA bus computers for auction GPIB hackers
The twists of fate have left me with four IBM 365 desktop computers from about 1998. Each has a 200 MHz Pentium Pro, 128 MB of 32 bit memory, new (in 2003) 10 GB disk (bios limited to 8455 MB) with Win 98SE and fixes, floppy drive and slow CD-Rom drive. All of them work. The IBM design uses an LPX motherboard with a vertical backplane for the card slots. There are 4 ISA slots and 3 PCI slots, but it's ISA or PCI for a total of four cards. Each comes with a SVGA video card, sound card, and a 10 Mb/s Ethernet card. The motherboard has one each serial and parallel port, and a USB 1.0 port. Power consumption is a mere 65 watts. I was going to use them for GPIB for Racal-Dana 199x counters, but never got around to assembling everything. Now it's time to shed the equipment collection to be able to move to smaller quarters, as time takes its toll on the body. Any or all of them are available for pickup at 55438 near Minneapolis, Minnesota. For shipping I will use a service to pack and ship, which will be reasonable but not cheap. I need to know by Jan 24, before they join the rest of the stuff in a storage locker on a junk truck. Bill Hawkins ___ 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] Intro Q: Racal-Dana 1991 or 1992 Counter ?
IMHO, the RACAL 1992 is an excellent frequency and phase tool, with its 9 digit display. The Phase AB feature allows fine comparison of two 10 MHz inputs. Don't know the 91. The cure for time-nuttery is to get old, and realize that your collection of equipment will prevent you from being able to move to assisted living. Bill Hawkins -Original Message- From: cfo Sent: Thursday, January 19, 2012 2:58 PM Hello Nuts I'm a Danish radio ham , and have recently picked up electronics again. I'm programming AVR ARM controllers , and doing some basic electronics stuff. I am rusty in analog electronics , and even have to lookup how to calculate a base resistor on a bjt. --%--- snip And now back to the Racal-Dana 1991 or 1992 Counter question. I might need a TIC , and the HP5070 + shipping is to much. So i was wondering about one of the above mentioned Racal's. I have a nice offer on a 1991 , but can get a 1992 also ? Witch one would you recommend for general Nut usage. 73 de OZ1FTG CFO Ps: I suppose the above sounds familiar. Has anyone found a cure the yet ___ 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] Toys for time-nuts in old-folks home
Just so, Chris. Another possibility is loss of interest in time, which has become the enemy. I've become fascinated with the workings of the brain, and how that has affected aspects of civilization. Maybe I can write a book, before I can't. Bill Hawkins -Original Message- From: Chris Albertson Sent: Thursday, January 19, 2012 9:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Toys for time-nuts in old-folks home On Thu, Jan 19, 2012 at 6:53 PM, Hal Murray wrote: The cure for time-nuttery is to get old, and realize that your collection of equipment will prevent you from being able to move to assisted living. You mean you can't take it with you?! It will (hopefully) be a long time before I get to that point, because it sounds boring already. Suppose you are moving into an old folks home where you have limited space. What toys would you take with you? How would you decide? Technology will have moved by them. I would have zero use for a lot of the stuff I have not. So my answer would be the future version of an iPad and not much more I was at a presentation today where they have some space qualified TN stuff Like a cesium clock and an Rb. These were old because of the time it takes tho quality something to use in space. Also I say a current chip scale atomic clock that was a few millimeters cube. My point is that in years from now the $39 Rb form China will be inside a tiny package the size of a 2N transistor and interface directly with your iPad. You will keep the parts in a used medicine bottle. Think about the reduction in size and cost for the last 20 years. This will happen again in the next 20. In 20 years the chip scale clocks will be on eBay for $40 each. Chris Albertson Redondo Beach, California ___ 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] Storage locker cleanout
To anyone in the Minneapolis area: Collected a lot of stuff from eBay during the last decade, to keep me busy in retirement. Turned out that need never arose. Now I can't afford to keep an 8x8 storage locker anymore, so it must be empty by the end of this month. There are many rack-mount time code generators, most by Datum. They're 1, 2, and 3 rack units high. All have 5 and +/- 12 or 15 VDC compact power supplies. The 3 and 5U units have 1 MHz crystals in ovens. All have 9 digit led displays, and all speak IRIG. Thumbwheels are used to preset the digits. None have GPS receivers. There are time instruments by HP, as well as Tek scopes and other fine old vacuum tube items. All of what's in the locker is free for pickup at 6200 W Old Shakopee Road in Bloomington, MN. Things that are not free include a pair of Z3801As with HP cone antennas and 50 feet of RG8U cable and a Ratelco 48 VDC positive ground power supply. There's a 2 KVA sine wave Liebert computer UPS that requires eight 12V batteries, as large as you like. Then there's three HP 3335 synthesizers (200 Hz to 80 MHz) that I need to test. Two of them work, IIRC. One has Telco outputs. Pictures available from b...@iaxs.net, or call 952 835-6840. Bill Hawkins ___ 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] Spoofing..
If you follow the link to get an offline PDF, you get the whole magazine in 32 MB. The result is interesting, but some of us would be better off downloading at night. This is the wrong list to start a discussion of your blinding Internet connection speed. Bill Hawkins -Original Message- From: Rob Kimberley Sent: Wednesday, January 11, 2012 11:44 AM There is an interesting article in this month's GPS World on spoofing. http://www.nxtbook.com/nxtbooks/questex/gps0112/#/28 Rob Kimberley ___ 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] Spoofing..
Hello, WHAT??? Rob, that was a simple warning to people who might not be expecting to tie up their machine while 32 megabytes downloaded. The magazine was very interesting. Thanks for posting the link. Bill Hawkins P.S. I did not mean you, Rob, when I said your speed. I was trying to head off an OT thread by others. Such is email. -Original Message- From: Rob Kimberley Sent: Wednesday, January 11, 2012 1:57 PM -Original Message- From: Bill Hawkins Sent: 11 January 2012 19:03 If you follow the link to get an offline PDF, you get the whole magazine in 32 MB. The result is interesting, but some of us would be better off downloading at night. This is the wrong list to start a discussion of your blinding Internet connection speed. Bill Hawkins -Original Message- From: Rob Kimberley Sent: Wednesday, January 11, 2012 11:44 AM There is an interesting article in this month's GPS World on spoofing. http://www.nxtbook.com/nxtbooks/questex/gps0112/#/28 Rob Kimberley ___ 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] Question re neutrinos and GPS
Tom, I had to look up traveling clock synchronization to get a better understanding, and found this link: http://www.newtonphysics.on.ca/einstein/chapter9.html The idea that Qz (time on the quartz clock, no?) drops out in the subtraction seems to me to require Qz to be invariant. That seems beyond the capability of quartz at the required error of one microsecond during the many hours that it will take to transport Q between CERN and LNGS. Plenty of time for cracks to propagate or chips fall off. Why do you say we can ignore such effects? Thanks for any enlightenment. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Sunday, January 08, 2012 9:11 AM To: iov...@inwind.it Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Question re neutrinos and GPS what about swapping the Cs clocks between CERN and LNGS without re- synchronizing them, and repeating the neutrino test? Antonio I8IOV Right, typically when you perform a traveling clock experiment you don't touch the clocks -- you don't need to synchronize or resynchronize anything. The key point is the difference in time from A to B, or A to B to A. This is accomplished with a time interval counter and you do the subtraction with a calculator. Imagine that you have two Rb in your house and wish to compare their times. If they are too far apart to use a long cable, one trick is to use a traveling quartz clock and TIC. You measure Rb1-Qz and then walk to the other clock in order to measure Rb2-Qz. Ignoring effects like drift in quartz or counter, the time of the quartz drops out of the calculation of Rb2-Rb1. Make sense? So there's no mathematical requirement for synchronization of the traveling clock. And there's also a practical reason why you don't precisely synchronize or resynchronize -- most Cs have a 100 ns granularity on their 1PPS sync input. /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] Solstice Puzzle
Just read decimal seconds... Now that's interesting. It would be like visiting another country that uses a different temperature scale. After a while you'd be able to relate the numbers to your own sense of temperature. Similarly, you'd be able to relate the count of seconds to your sense of time of day. You'd be the only one on the block (and maybe in your house) that could look at the seconds count and know the time of day. There would have to be a reset message from the lowest order block when the seconds roll over at midnight. Ah, and a pushbutton to tell the low order block to add a leap second at midnight. Neat puzzle. Has anyone come up with an arrangement that would make it useful to separate the blocks? If they are separate, each has to have its own power supply. Or you could use RF to supply enough power to a nanoprocessor and a liquid crystal digit. Modulate the RF with 1 PPS and you can clock the simultaneous change of the digits. Although, there is a certain charm to watching the change propagate at some low serial message baud rate. Head or tail deletion is a pretty good idea, too. Bill Hawkins -Original Message- From: Jim Lux Sent: Saturday, December 17, 2011 10:54 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Solstice Puzzle On 12/16/11 10:04 PM, Neville Michie wrote: At this time of the year many people look for frivolous puzzles to solve. If you impose the minor requirement that you cast off the shackles of Babylon and sexigesimality.. and just read decimal seconds. Each block has a divide by 10 driving the display. it has a LED on the left side, and a photosensor on the right side. If the box detects pulses coming in from the sensor it uses those to drive the counter, if it detects nothing, it uses an internal 1 pps source. In any event sensor on the right, emitter on the left, is the basic strategy. The one widget detecting nothing uses an internal oscillator. You could have it send an entire timecode (in HH:MM:SS form), and receiver blocks just have to count where they are in the chain to know which digits to display. A simple way would be to do head or tail deletion [where the] right hand unit sends out SMMHH. Each block displays the first byte, sends the remaining ones on. ___ 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,
MIC CHECK! It is time to occupy this thread with something that is time-nutty. The previous thread on gravity control of a pendulum clock was hijacked by Jim Palfreyman to a conflict on the metric system, that led to something completely off topic continuing under the SAME SUBJECT. Now John Forster seeks to introduce military conflict into this list with the false drone that the US deliberately let the Iranians have. Of course we came up with a story to make them believe they did it. Does that have anything to do with leap seconds? Determining the speed of neutrinos? Pushing back the limits of accuracy of atomic time? Using an ancient GPSB program to activate a board found on eBay? Searching for the perfect divider? John Ackerman, this list is too large. It needs pruning. We need more people to occupy this list with stuff that is on topic, rather than be driven away by people who crave conflict. Best wishes to all as the solemnity of the solstice approaches. The solstice, at least, is about real planetary time. Have at it, while you can. Bill Hawkins -Original Message- From: J. Forster Sent: Thursday, December 15, 2011 3:10 PM To: time-nuts@febo.com; vintage-military-ra...@yahoogroups.com Cc: armyrad...@yahoogroups.com Subject: [time-nuts] The GPS navigation is the weakest point, Iran hijacked US drone, claims Iranian engineer Tells Christian Science Monitor that CIA's spy aircraft was 'spoofed' into landing in enemy territory instead of its home base in Afghanistan Iran guided the CIA's lost stealth drone to an intact landing inside hostile territory by exploiting a navigational weakness long-known to the US military, according to an Iranian engineer now working on the captured drone's systems inside Iran. ___ 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?
Let's see, arguably the most accurate pendulum clock was the Shortt clock. It was good to 200 microseconds/day, or about 2 E-9, where you could see the effect of the moon and the sun, just. Suppose I have one of those beauties in my basement, with the requisite apparatus to compare it to a Caesium clock disciplined by GPS. Suppose my wife drives her 3000 pound car out of the garage, about 20 feet away. What will be the affect of that local change in mass? Could I discipline a Shortt clock to GPS by using a PLL that slid a one ton mass along the basement floor near the free pendulum? Sliding the one ton mass is left as an exercise for the reader, as is installing it in the basement. Yours in search of more perfect knowledge outside my field, Bill Hawkins ___ 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] looking for data on time code display
Fascinating. I also have one of these with slight differences, but it does have a Fort Meade tag. Bought it from a guy on the BoatAnchors list in Atlanta in the dim past. The HTID number is H9823180065821, NSN 664500DISPLAY, User ID STWA104 The rotary switch adds a 160 KHz position. The two switches are marked CODE POLARITY and POWER ON. The rear panel has a 4 pin circular jack labeled AUX and a 24 pin rectangular connector marked PARALLEL. A partly torn tag taped to the top says Made by TRAK, Model ?? 2234/U, SN 517. A plastic envelope contained a DD Form 1348-1A release/receipt document from the Defense Reutilization Marketing Office at Meade. It released 5 of these units worth $1500 each, dated 1-29-98, ship from H98231 (in HTID number above) to SX1213 (marketing office?). Somewhere I'd heard that these units were for locating times on tape recordings of intercepts. The different filter frequencies are for different tape speeds, from high speed search to fine positioning. The code might be IRIG but it could just as easily be something the NSA invented for the purpose. I bought it because I'd visited the NSA museum at Fort Meade and seen the code breaking machines. I didn't find them intimidating at all. The gift shop would sell me a jacket with NSA logos, but I didn't know where I would wear it. There is a certain cachet to having a box that was used by top secret agents to decode radio intercepts. Bill Hawkins P.S. I'd recommend doing some signal tracing from the Input connector. We have no idea what signal levels were used, if it wasn't IRIG. I never found time to do that. -Original Message- From: ed breya Sent: Sunday, December 11, 2011 2:12 PM I looked at your first post again and noticed there were apparently lots of TTL circuitry, so it could be an IRIG code receiver, and you should be able talk to it. If you don't have a source readily available, you may be able to fool it into responding a little to gibberish applied from a modulated signal generator, just to see if it's functional. Ed ___ 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] Line Voltage frequency Interface morphed to batteries
I should have been more direct. What does a charged flash capacitor have to do with safety concerns for low voltage batteries touching the tongue? You can have the last word. It's time I moved on. Bill Hawkins -Original Message- From: J. Forster Sent: Monday, November 28, 2011 10:28 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Line Voltage frequency Interface morphed to batteries Hey, John, got any idea of the DC to DC converter that charged that capacitor? 1 transistor, 1 transformer. The photoflash cap is 80uF 330 VDC. What voltage did it put out? I presume 250-300 VDC. If you really want to know I can measure it. Or the time it took to charge it? Maybe 2-5 seconds. E = 1/2 C [uF] * V [KV} * V [KV] The energy stored is 1/2* 80 * 0.25 *0.25 = 2.5 J @ 250 VDC An external medical defibrillator is roughly 40 to 120 J. -John = Guarantee that you won't light a flash tube with 1.5 VDC. Move on. Bill Hawkins -Original Message- From: J. Forster Sent: Monday, November 28, 2011 9:43 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Line Voltage frequency Interface morphed to batteries Recently, I took an old disposable 35mm film camera appart. It had a flash, powered by a 1.5 V carbon-zinc AA battery. Inadvertantly, I got across the terminals of the flash capacitor and got a hell of a shock. Had the current gone through the right (wrong?) place, I could well be dead. -John ___ 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 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] Line Voltage frequency Interface morphed to batteries
Every time I follow a school bus that stops at a railroad crossing and opens its doors to stop, look, and listen - even though there is no sign with crossed bars saying Stop, Look, and Listen and there are many flashing red lights when a train approaches - I think of politicians who would not put their name to a bill that compromised children's safety, in any way real or imagined. Lawyers are responsible for the death of common sense in the USA. Trial lawyers, that is. Now, a 9 volt battery has a few centimeters between terminals, if that. It is commonly accepted that electrocution needs a path through the heart to succeed, as well as many milliamps. GFCI outlets trip at about 5 mA. Pain begins at 10 mA. You would be hard pressed to get those currents anywhere on the human body, never mind through the heart, with 9 VDC. There is a reason why someone using a defibrillator shouts, Clear. There was a time, before the internet, when most people were ashamed to venture opinions on things they didn't know about, so they stayed quiet. The anonymity of the Internet has made it possible for people to share their ignorance with no shame, and we are poorer for it. Notice the obligatory use of the word time in the above paragraph. In the words of another organization for another reason, Move on. Bill Hawkins OTOH, I remember being very afraid, at 6 years old, when my father told me it was OK to touch the terminals of a car battery. I'd heard that electricity killed, but I had no idea of the magnitudes involved. ___ 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] Line Voltage frequency Interface morphed to batteries
Hey, John, got any idea of the DC to DC converter that charged that capacitor? What voltage did it put out? Or the time it took to charge it? Guarantee that you won't light a flash tube with 1.5 VDC. Move on. Bill Hawkins -Original Message- From: J. Forster Sent: Monday, November 28, 2011 9:43 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Line Voltage frequency Interface morphed to batteries Recently, I took an old disposable 35mm film camera appart. It had a flash, powered by a 1.5 V carbon-zinc AA battery. Inadvertantly, I got across the terminals of the flash capacitor and got a hell of a shock. Had the current gone through the right (wrong?) place, I could well be dead. -John ___ 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] Using Thyme for Stuffed Mushrooms
Stuffed mushrooms are a fine holiday treat. Begin with a box of baby Portabella (Crimini) mushrooms. You know, the ones that start out as spores in a soil of horse manure and hay in a dark, moist limestone cave. The young mushrooms dream of becoming large, but one day the cave is filled with light and men with sharp knives cut them off at the knees. That's what you buy at the store. Clean out the stems and the gills to make room for the stuffing. For ten 5 cm mushrooms, you need 15 to 20 cm of a medium carrot and a stalk of celery, finely chopped. Include some onion if you like; the mushrooms are beyond caring. Sautee them with a clove of finely chopped garlic and add a pinch or two of dried thyme. Cool, then blend with Panko bread crumbs and shredded Parmesan to taste. Stuff the mushrooms and bake at 165 C for 10 minutes, then 3 minutes under the broiler. Make time to enjoy the product with a suitable wine. This is really a great use of your thyme. Oh, wait - this isn't the thyme-nuts list. Never mind. Bill Hawkins The above was intended to entertain. Please don't be offended. ___ 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] The GPS velocity of light versus neutrinos
A good friend, who has written a lot of excellent real-time software, maintains that that it is impossible to find all of the systematic errors in something as complex as the GPS system. The error is small, 60 ns in 2.4 ms, about 3 E-5, for OPERA or 8 E-5 for MINOS. Has anyone measured the speed of light with GPS clocks in the same way that neutrinos are measured - say between mountain tops? Another way would be to get a common view light flash from a magnesium flare on a high altitude rocket. There's a lot at stake here. Many physicists will prematurely wear out their brains looking for the answer. Bill Hawkins b...@iaxs.net (already on all the spam lists) ___ 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] Power grid experiment may drive Americas clocks cuckoo ?
Yet another example of what a reporter can do when the facts are not understood. The speculative headline is catchy but dead wrong. Back when it was written last summer, there was a plan to deregulate the frequency. The reason it was even proposed is that most clocks now are battery powered and are regulated by crystal oscillators. Power frequency regulation is complicated. Generating plants are told how much power to generate by a central dispatcher. Individual plants do not have precise control of generator frequency because the synchronous generators tied to the common distribution network would fight each other. Presently, the act of changing the amount of power generated in a plant carries the risk of tripping a generator off-line, which can cascade to other generators and other plants due to the step change in power on the network. The networks are too big, and they are designed to fail to protect themselves. Last I knew, the test had been cancelled. Bill Hawkins -Original Message- From: Craig S McCartney Sent: Wednesday, November 16, 2011 8:49 PM Yet another challenge to proper time-keeping. I think that I will re-calibrate the sundial in my yard and declare it Montalvo Road Time (MRT) and darn to those who disagree! http://www.sltrib.com/sltrib/utes/52072031-68/clocks-power-grid-electric .html.csp Craig McCartney 160 Montalvo Road Palomar Park, CA 94062 ___ 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] HP5370B - Err 02, but way off topic
It's late, and my defenses are down. I agree that we could learn a lot, had we the capacity to do so, but not from crayons. They have no neurons at all, so they learn nothing. The child that has many boxes and sorts each color into a box teaches them nothing. A better allegory would concern human empathy. Those who have it can deal with the fact that no two people are alike. Those who don't would rule the rest of us without understanding the differences. That's evolution in action. Bill Hawkins -Original Message- From: Bob Smither Sent: Tuesday, October 25, 2011 11:32 PM Bob Smither, PhD Circuit Concepts, Inc. = We could learn a lot from crayons: some are sharp,some are pretty, some are dull, some have weird names, and all are different colors ... but they all have to learn to live in the same box. = ___ 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] SLIP vs Ethernet for NTP
Fascinating thread. Poul-Henning Kamp mentions contact prell. Google can't find it. Even quoted, I get shampoo and people with that name. I understand well contact bounce and contact dwell, but what is the meaning of prell? Bill Hawkins -Original Message- From: Poul-Henning Kamp Sent: Sunday, October 23, 2011 1:40 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] SLIP vs Ethernet for NTP In message 4ea45815.5080...@earthlink.net, Jim Lux writes: I'd have to go back to some pretty old databooks, but I'll bet the x8 thing has been around since the 70s. Why 8, and not 4, is a better question... The original standards text describes this in some detail, but I can't remember which one of them it was (Not V.24, possibly V.28 ?) Since the other end might be electromechanical, the system had to be imune to a rate tolerance in the several %, as well as flank-jitter and contact prell. With 4x oversampling, your sampling point on the start bit would be somewhere in the [37.5...62.5]% interval. A 2.5% rate difference would eat 25% over 10 symbols, and you would be left with +/-12.5% for jitter/prell. 8x oversampling gives you +/-18.75%, a full 50% better. It was argued at the time, that the sampling point of the start bit should be 75% into the start bit, because the prell is not symmetric, but this was not adopted. -- 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. ___ 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] Sneaky Errors
This is the famous man who has two watches does not know what time it is problem. Lucent solved it for telecom with the RFTGm (Reference Frequency and Timing Generator) equipment, consisting of GPS disciplined OXO and Rubidium oscillator modules that continuously checked each other via 1 PPS and 10 MHz links. The frame housing the oscillator units selected one or the other for distribution to six connectors. Sadly, the output is 15 MHz. Otherwise, the only solution is more watches, preferably by different manufacturers. In some ways, this reminds me of the ancient parity check for memory locations. Parity is not used anymore for commercial computers, because a memory error is usually not alone, and errors soon make the computer lose its way and halt. In this case, plan on the TB either running correctly or failing due to some alarm. Alarms must be monitored, of course. You could set up a time interval counter to show the phase between the two outputs. The Racal-Dana 1992 does that at 10 MHz. Out of curiosity, what would be the consequences of a steadily increasing phase error? Would it offend your sense of perfection or would it have real consequences? Bill Hawkins -Original Message- From: David VanHorn Sent: Wednesday, October 19, 2011 2:47 PM I have two thunderbolts, set up so that I can switch over to the backup unit if the primary fails. All is well with that, but what could I do to detect a less obvious failure, like 9.99 MHz output? If they disagree, I don't know how to resolve which is correct. ___ 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] Sneaky Errors
Seems to me that 200 ns is 720 degrees of phase error, which is a lot. A person handy with logic circuits could build a simple phase detector with a flip-flop and an RC filter with a tenth second time constant. An analog circuit could detect 360 degree rollover and set off alarm bells. Note that you still have the two-watch problem. Two equal divider chips ahead of the flip-flop could allow larger errors before rollover. The error may reverse itself and run the phase error down, and then reverse again as the two ovens cycle at different rates. This would be normal behavior, unworthy of an alarm. An additional challenge would be to build logic to select the oscillator output to be distributed, then compare the output to the output of three oscillators in three phase detectors. The device that had phase rollover would put itself in standby, alarm, and leave you with the two watch problem. Perfection demands many oscillators with a voting system. Long winter nights could be spent solving these problems. I'm too old for that stuff. (I also post the most recent ideas first, so as not to reread old ideas.) Bill Hawkins -Original Message- From: David VanHorn Sent: Wednesday, October 19, 2011 5:58 PM Magnus said (note the attribution), Steadily increasing phase error is to let there be a frequency error. Frequency is the derivate of phase, so it comes with the territory. So a 200 ns per second phase drift would provide a frequency error of 2 Hz on your 10 MHz. Can't have one without the other. I understand, I'm just saying that if the absolute phase is wandering a bit over tens of seconds, it's NOT an issue. ___ 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] Lucent RFTG-m-XO GPSDO
Hi, K4CLE A while ago, I invested $600 in two pairs of the GPSDO and LPRO units. Intended to replace a pair of 48 volt Z3801 receivers with 24 volt units. Put them in the project pile for lack of drawings and software, where they have languished. Their value has dropped, but I'd still like to have 24 volt receivers with software like GPSCon that can do SNTP. RS422 is no problem. Please let me know if you find drawings and software. Copies are worth more than postage to me. Bill Hawkins -Original Message- From: k4...@aol.com Sent: Sunday, October 09, 2011 1:41 PM I will look for my drawings on this unit and send copies to you. And I know I have the software too, just need to find it! I have read in some of the notes here on time-nuts that people may be able to use RS232 for communicating with the RFTG units. But it was designed for RS422 and I would suggest you use RS422 for best results. I use a little RS422-4S232 converter which has worked fine for me. The early units had FRS rubidiums in them. The LPRO was used in the newer units. So, you have the more recent design. ___ 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] AF General says White House pressured him tochangeLightSquared testimony
What is a story about a pot calling a kettle black doing on this list? ___ 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] Buzzing 5061B
Another possibility: The 5061B ovens initially draw too much power for the UPS, charged or not. Try plugging the standard into the wall until it heats up, then transfer it to the UPS. If the standard buzzes when it is plugged into the wall, it is not a problem in the UPS. Let it warm up anyway and see if the buzzing stops. This is what I'd do, and I've never lost a 5061B yet - but then, I've never owned one. Did have a 5065 and some other Caesium standard, both with high initial heater currents. Bill Hawkins -Original Message- From: Erno Peres Sent: Saturday, September 03, 2011 6:23 AM looks like the UPS battery and the 5061B draws too much currenttogether just charge-up the UPS and when it is OK plug the other unit in ___ 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] UTC and the speed of light?
The question has both a frequency and a counter part, as does any clock. The frequency shift with gravity has been nicely addressed by tvb and others. The counter of the frequency is subject to phase shift caused by the speed of light and the distance to the measured source. Each counter must be given an initial value of time in order to be called a clock. There can be no correction done at the source of the frequency. The user must make a distance/speed of light correction for his (rarely her) location. Try this old analogy. There is one clock in the center of town. It's pendulum is the only source of frequency. If you can't see the clock, then the bell is your only source of time. Different citizens at different distances will not hear the bell at the same time because of the speed of sound. If some of the citizens had astoundingly precise wristwatches, really fast reaction times, and different large distances from the bell, they would be surprised when they met at the monthly Gentleman's Time Club gathering to see that their watches did not match. Eventually Isaac Galilei would discover the speed of sound and deduce the reason for the offsets. Then the gentlemen would periodically meet under the clock tower to set their watches, and reckon the distances to their homes by the time offset. Bill Hawkins, who recently read Neal Stephenson's Quicksilver. ___ 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] LightSquared squabble raises questions about political games
Guys, Yes, the games are political. No, politics is not the subject of this list. I've stopped being curious about things I can't fix. Bill Hawkins ___ 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] Weird TEC data
Could you please explain how transformer phase lags could jump? As I understand synchronous generators tied to a common grid, it is not possible for them to have large phase angle differences under normal conditions. Losing a whole cycle would cause forces that could damage the machine. What that means is, that if the two locations representing the red and green traces are on the same grid then there should be less than one cycle difference between them at all times. NTP can't be causing the jumps because the difference increases with time. You would see the displayed time difference change as well. Since that is not the result that you have, it is time to calibrate your equipment. I'd start with the line frequency sensor looking for dropped cycles. It's possible that different computers running different other programs could drop different numbers of points. What are they doing when the steep drops in difference occur? Is anyone else running a similar experiment? Bill Hawkins -Original Message- From: Poul-Henning Kamp Sent: Thursday, August 04, 2011 1:13 AM The jumps in the difference looks a lot like transformer phase-lag in the grid, but the real test is to collect more data and see if you ever see the difference move the other way. ___ 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] MIT RADIATION LABORATORY SERIES 1940-1945 (28 VOLS) on eBay
Y'know, as an MIT grad I once coveted that series. But now that I am 93, I don't give a damn, you see. (Harry Belafonte, on sex education) (actually, I'm 73) So there's $900 that won't be leaving my wallet and aiding the economy by circulating. What does this have to do with time, you ask? Why, only that the passage of time alters men's passions. Bill Hawkins -Original Message- From: Mike Feher Sent: Tuesday, July 12, 2011 9:21 PM A guy is offering a complete set item # 320727122967 on eBay. I already have one complete set and lots of duplicates, otherwise I would jump at it. I like the hard copy a lot better than trying to read them on-line. Regards - Mike ___ 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] More 60 Hz data/graphs
Hal, That's good stuff. Sadly, I've got to convert UTC to your local time to interpret the results, so I haven't done it. Tom's MJD will be even worse. The reason is that the loads that cause frequency droop occur during workdays. Lost cycles are made up at night, so I need to know when local day and night occur. At the present time (before July 15th), the power dispatching center for an area tries to end the day (perhaps at 7 AM) with exactly 60x60x60x24 cycles of power generated. This keeps the clocks on time, and balances the power budget for the day - no extra cycles given away and no cycles stolen from other areas. The Time Error Correction (TEC) elimination experiment (to find out who notices the loss) is motivated by the number of frequency excursion (not trip) errors that occur when dispatch requests a correction. It costs the generating plants money (nothing else drives change today) to increase power on demand - in fuel and stress on the equipment. With any luck, my next message will be about the frequency control problem. Bill Hawkins -Original Message- From: Hal Murray Sent: Sunday, July 03, 2011 11:15 PM I've moved the 60 Hz stuff from http://www.megapathdsl.net/~hmurray/time-nuts/ to http://www.megapathdsl.net/~hmurray/time-nuts/60Hz/ -- The main graph is now up to sightly over 4 days. http://www.megapathdsl.net/~hmurray/time-nuts/60Hz/60Hz.png Peak-to-peak is almost 8 seconds. The slew rate is pretty fast in a few places. 1 second in 1/2 hour at hour 64. 4 seconds in 3 hours at hour 13. 2.5 seconds in 3 hours at hour 44. 7 seconds in 7 hours at hour 91. -- ___ 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 - control
Group, The effort to track power line frequency changes is laudable. I think the effort to determine the stiffness of the network by measuring the phase angle between GPS time and local line zero crossings is most interesting. But the following is about the frequency control problem. The main problem is that the amount of power that is stored in the distribution system is negligible. The generating station has no information about load changes until after they have happened. There is no lag time that allows derivative action to compensate. If the generating station is on an island with no connection to any grid, you can use a proportional controller with integral action to control the generator speed by manipulating the fuel valve to the engine. This can hold the generator quite close to your desired line frequency. But because it is feedback control, an error must be sensed before the fuel valve moves - cycles can be lost. It is still necessary to manually bias the fuel valve to match the error between the cycles generated and the GPS cycles elapsed. When generating stations are synchronously synchronized by the distribution network, a new problem arises. The stations can not all use integral action and maintain stable control. In fact, only one integral controller may be on such a network. The integral control comes from the area dispatcher, who integrates the cycles generated and compares them to the cycles to maintain 60.000+ cycles per second (in the degenerate West). I am not clear on how the dispatcher allocates frequency error to the area stations, or how they react to commands to change. But it seems to me that this is a control problem that can be solved without undue stress on the generating equipment. Perhaps it is as simple as a setpoint rate of change limit (can't be, 3000 people would have thought of that.) We welcome your comments with Enthusiasm. The references below are important. Bill Hawkins -Original Message- On Fri, Jun 24, 2011 at 7:02 PM, Bob Kupiec bobkup...@comcast.net wrote: AP: Power grid change may disrupt clocks - http://news.yahoo.com/s/ap/20110624/ap_on_hi_te/us_sci_power_clocks Time Error Correction Elimination - http://www.nerc.com/page.php?cid=6|386 NERC Report - June 14 - http://www.nerc.com/files/NERC_TEC_Field_Trial_Webinar_061411.pdf ___ 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, How do I discipline 120VAC 60Hz from a UPS
Group, My plan for precision 60 Hz was to use a Caesium standard and an HP 3320B synthesizer. At about that time, some 200 watt amplifiers became available on eBay. They were designed for public buildings to do elevator music or emergency announcements. Accordingly, they ran on 120 VAC 60 Hz or 28 VDC. 24 VDC was fine but wouldn't quite deliver 200 watts. I bought two. The transformers are large, and have 70.7 volt line outputs. Low voltage boost transformers can get closer to 120 VAC if turning up the volume won't do it. Never got around to it, and need to lighten the load on the basement floor. The Caesium standard has been sold. Please write to b...@iaxs.net for details. I'm in Minneapolis, MN. Also have a Liebert 2 KW sine wave UPS that requires 96 VDC. Bought eight 12V 33 AH batteries for it to keep the time rack running. Six of them died with shorted cells after 6 years, so the Liebert is available. Bill Hawkins ___ 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] 60 Hz measurement party- big sync motors
Will, and the rest of you fascinated by power distribution, A big synchronous motor allows its power factor to be changed by changing the field current for a given load. The motor can be adjusted to look like a resistive load instead of inductive, or even capacitive to correct plant power factor. Look it up. Industrial power consumers are charged extra for power factors less than unity because the distribution system must carry more current for the same watts as the power factor departs from unity. Induction motors have inductive power factors because there must be slip between the rotating field and the speed of the rotor. Synchronous motors don't have slip, just phase angle. Zero angle looks like a resistive load, yes? The compressors don't have to run in sync. Best, Bill Hawkins (who heaves a nostalgic sigh just thinking about those fine old engines of progress) -Original Message- From: Will Matney Sent: Sunday, June 26, 2011 1:11 PM To: time-nuts@febo.com Subject: Re: [time-nuts] 60 Hz measurement party I quite like your generator description of huge rotating lumps of copper-ensnarled iron. It brings me back to around 20 years ago, when I was a plant electrician at an older railcar manufacturer. They had huge open-frame synchronous motors, from around the 1930's, that ran their air compressors, and why they used this type of motor is anybodies guess. If I remember right, they were rated at around 200 HP, or so, and were about 8 feet in diameter. The rotor shaft was mounted on huge babbit bearings upon concrete pillars, and about 1/3 of the motor sat in a pit in the concrete floor. I used to have to repair the brushes on the slip rings constantly, until I talked the boss into adding a shunt across the n.o. contacts on the 250 Vdc contactors to quench any arcing. The motors stator itself ran on 4160 Vac. Would the other compressors have to run in sync somehow, as all of them had these motors, just some a little smaller than the others? They drove large single cylinder compressors that fed something like a 6 inch air line (pipe). However, they all did not run at once, and they only did when there was a larger demand for air. Timing is the only thing I can lay this to, and was wondering about it. Best, Will ___ 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] Replacing electrolytics - any disadvantages of high temp ones?
Group, During my days of interest in antique radios, I learned that the dielectric between aluminum plates was formed by passing current in one direction to build up an oxide coating on the plates, which became the dielectric. The thickness is directly proportional to working voltage and inversely proportional to capacitance. As we learned from reforming old caps, the oxide thins when there is no voltage on the cap, but can be restored by passing several milliamps through the cap. Applying rated voltage before it was formed would destroy the cap by welding spots of the plates together. I'm not sure that this applies to modern caps. As to the temperature rating, a high temp cap run in a cool environment will be as unhappy as someone transplanted from Miami to Minneapolis in the winter. It may work, but it will be very unhappy - so it depends on your empathy for the cap. There ought to be a way to work precision time into this thread, but I can't think of one. Bill Hawkins -Original Message- From: Poul-Henning Kamp Sent: Tuesday, June 21, 2011 2:40 PM In message 4e008a73.50...@erols.com, Chuck Harris writes: and yet, I find that some electrolytic capacitors that have been run at lower than normal voltage improve markedly when reformed by applying rated voltage through a 10K resistor for a couple of hours. I noticed in a datasheet at one point, that the capacity only was warranted above a certain percentage of rated voltage. No explanation was given. ___ 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] please un subscribe Pete to Time Nuts
Which Pete? If it's you, use the link that follows To unsubscribe, go to at the bottom of this page. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pete Rawson Sent: Thursday, June 02, 2011 1:11 PM To: time-nuts@febo.com Subject: [time-nuts] please un subscribe Pete to Time Nuts Please unsubscribe Pete to time nuts. ___ 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] What are these towers?
Bob, Since Minneapolis is finally warming up enough for weeds to grow, I liken threads like these towers to weeds in the lawn. A good way to prevent lawn weeds is to have grass so thick that the seeds won't grow. Translate lawn to this list and grass to on-topic messages. Wish I had one to share, but I'm considering moving on to a new hobby. Bill Hawkins -Original Message- From: Robert Darlington Sent: Saturday, May 21, 2011 1:31 AM Guys, I gotta ask, what does this have to do with time keeping? Am I missing something? -Bob ___ 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] Results parts selection + commercial assembly poll?
As I recall, the thread looked like marketing research for a profitable product, not design research for the benefit of list members. Part of the problem is that this list discourages off-list discussion by not providing the individual's email address. If the original poll request gave the sender's address and made it clear that their mailer's Reply key was the wrong thing to use, we might not be having this discussion. You can reply to me at b...@iaxs.net. I'm already on all of the spam lists, and Red Condor filters all of the spam. Bill Hawkins -Original Message- From: Bob Bownes Sent: Monday, May 16, 2011 12:15 PM I was more wondering why the discussion never moved, not why the project discussion died here. But this is probably enough bandwidth wasted again. :) ___ 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] Atomic clock on a chip
That's a good link. Here's another, to a video presentation that gets into the details of the Symmetricom CSAC. http://www.brainshark.com/Steve_FatSymmetricom/vu?pi=691826191dm=5pause=1; appKey=77 Bill Hawkins -Original Message- From: James Fournier Sent: Wednesday, May 11, 2011 9:25 PM http://www.smartertechnology.com/c/a/Technology-For-Change/Smarter-Atomic-Cl ock-on-a-Chip-Debuts/ ___ 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] 60hz disciplined watch (really?)
Group, Google can't find anything for citizen ecodrive watch time sync 60 hz except a few where the k was left out of 60 khz. All of the watches that synched received WWVB at 60 KHz. The claim of 13 millisecond accuracy from line frequency is suspect. There is no control of the power grid to that accuracy. It is not possible. The weekly accuracy is measured in cycles. Variation during the day can be seconds, losing during the day and gaining at night. It seems to me that the filtering algorithm for 60 Hz would have severe underflow problems with floating point math in a low power processor. Bill Hawkins ___ 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] T.I. experimenting - newbie question
For extra points, test with the same long cable at different temperatures. Say from soaking in a 150 deg F oven and a zero degree freezer. Bill Hawkins ___ 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] T.I. experimenting - newbie question
I've always been partial to differential measurements. So many things fall out when you do the subtraction. Make short and long cables using the same wire and connectors. Measure the time delay for each. Subtract the short delay from the long delay to get Td. Subtract the length of the short cable from the length of the long cable to get Ld. The delay per unit length of cable is Td/Ld. If the connectors are a significant part of the delay, you can't use Td/(delay/unit length) to find the virtual end of the cable inside the connectors because the unit length delay changes in the connector. Try it with several different lengths of cable. If the unit length delay changes, something else is going on. Bill Hawkins ___ 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] Parts Selection
Haven't read all 33 replies, so I must be repeating at least one: Can't do it. Too old and shaky. Don't want to buy expensive equipment to equip myself to do it. Don't consider the micro to be a useful tool, unlike most on this list. Have no trouble with vacuum tube and 0.1 perf board parts. My solution to the 50/60 cycle line problem is a Z3801, a frequency synthesizer, and a 70 watt audio PA amplifier with 70 volt line output. Notice the clever way I've eliminated the bytes from previous messages . . . Bill Hawkins ___ 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] Datum Handbook of Time Code Formats
Well, Wizard, I'd love to read it, but I don't hand out personal details to unknown web sites. Bill Hawkins -Original Message- From: gandal...@aol.com Sent: Friday, March 11, 2011 8:38 PM I guess the title might just about say it all:-) This is another generous donation from Rob Kimberley who has made available a copy of the 1987 seventh printing of the Datum Inc. Handbook of Time Code Formats. The handbook includes descriptions and signal details of IRIG, NASA, and other time code formats as well as information on the WWV, WWVH, and WWVB, US Standard Time Broadcasts. It's a great source of information and available now from.. _http://rapidshare.com/files/452123988/Handbook_of_Time_Code_Formats.pdf_ (http://rapidshare.com/files/452123988/Handbook_of_Time_Code_Formats.pdf) As always, please feel free to distribute/upload this in as many directions as possible. regards Nigel GM8PZR ___ 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] Datum Handbook of Time Code Formats
Wizard, they want my name and email address. That can be sold to anybody to use on their mailing list of pushy offers. They offer a service that I do not want. James, I do not see a slow download button or the file name. I assume I have to give them name and email before I see anything that I can use. I am still using IE6 and ignoring people who want me to upgrade to the new, advertiser-friendly IE8. The web was always supposed to be backward compatible, but the prices paid for user information are changing that. If that's what I'm up against, then I'll live without it. Not that my buying habits would do them any good, as I run away from ads with dancing baloney (blinking, repeating, or adverdramas). I'd like to hear from anyone who has made it available as a plain old document for download. Bill Hawkins -Original Message- From: James Fournier Sent: Friday, March 11, 2011 9:09 PM You don't need to, click the slow download button at wait about 40 sec. On Fri, Mar 11, 2011 at 10:02 PM, Bill Hawkins b...@iaxs.net wrote: Well, Wizard, I'd love to read it, but I don't hand out personal details to unknown web sites. Bill Hawkins -Original Message- From: gandal...@aol.com Sent: Friday, March 11, 2011 8:38 PM I guess the title might just about say it all:-) This is another generous donation from Rob Kimberley who has made available a copy of the 1987 seventh printing of the Datum Inc. Handbook of Time Code Formats. The handbook includes descriptions and signal details of IRIG, NASA, and other time code formats as well as information on the WWV, WWVH, and WWVB, US Standard Time Broadcasts. It's a great source of information and available now from.. _http://rapidshare.com/files/452123988/Handbook_of_Time_Code_Formats.pdf_ (http://rapidshare.com/files/452123988/Handbook_of_Time_Code_Formats.pdf) As always, please feel free to distribute/upload this in as many directions as possible. regards Nigel GM8PZR ___ 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] Smithsonian Museum web page on time
And now for something completely different . . . A comic strip called 4Kids made reference to this web site: http://americanhistory.si.edu/ontime/ It gives a sound-bite overview, with pictures, of time in the U.S. from 1700 to about 2006. The history is interesting, particularly the railroads and time zones, but there is nothing touching our kind of time until the last article, Splitting Seconds. There are no details at all. Maybe they need help. Then again, I dropped my Smithsonian membership when it became clear that stuff that could not be understood by a liberal arts dropout was being removed from the magazine and the museum. The site credits the book On Time: How America Has Learned to Live by the Clock by Carlene E. Stephens and The Smithsonian Institution for it's information. And now back to the regularly scheduled hardware and software discussions. Bill Hawkins ___ 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] Tool Needed to Access my Timer Battery
Well, this thread caused me to dig out a Girard-Perregaux Gyromatic 39 jewel self-winder that my father gave me in the late fifties, after his trip to Switzerland. To your point, the face just has five horizontal lines that cross it. There are no numbers except for the day window. The ends of the lines mark the hours. It has a second hand. There are no marks at 6 and 12. Sadly, the dial crystal is acrylic, and badly scratched. But maybe that would work for you to make things even fuzzier - if, that is, the watch was for sale. Bill Hawkins (who would not like to show up for a train on the wrong side of the 10 minute tolerance.) -Original Message- From: J. Forster Sent: Wednesday, February 16, 2011 2:05 PM - snip - Since then, I've discovered I really don't need to know time to much better than +/- 10 minutes. FWIW, -John ___ 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] Why do crystals go bad?
Group, Jim Garland on the boatanch...@theporch.com list asked about crystals: A 22.5MHz crystal (HC-5 case) in my homebrew receiver, built about forty years ago, no longer oscillates. It seems to be purely an age-related problem. It is in a standard solid state circuit which bandswitches six crystals, and the other five work just fine. I wonder what causes a crystal to stop working, and whether it is possible to repair them? I've repaired dead 100kHz calibrator crystals, and hamband crystals in FT-243 cases, by cleaning off the brass pressure plates, but am not sure if one can do this on thin high crystals. As I recall, the metal electrodes are evaporated onto the sides of the element. 73, Jim W8ZR One of the replies was: Broken families, drugs, drink... the normal, I suppose. John K5MO Scott Robinson asked: Receiver crystals aren't getting beaten up by high power, but something has killed a lot of them in my R-390A and Drake R-4A. Curiously yours, Scott And Roy Morgan asked: I have a 1960's frequency standard from a Nike site: the Sulzer Oscillator and would like to find tech into on it. Any help appreciated. Bill Hawkins ___ 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] GC-1000 Clock Cap Choice?
Thanks, I needed that (wiping off the cold water [I hope] from the
deluge delivered).
Indeed, there is nothing special about 60 Hz (even though Hertz
never resonated anything at 60 cycles per second) filter capacitors.
There is nothing special about 100 and 1000 cps PLLs either. A good
plastic cap should be fine. I'd be more worried about the resistors,
unless the PLL caps were electrolytics. The output filters should be
low pass, which are not particularly critical.
Disclaimer: I don't have a GC-1000 manual or schematic. Most of this
is based on the outcome of shotgunning the caps in an R-390 class
receiver. Brooke's tables of marked versus measured capacities sure
do indicate the need for replacement, but not with anything exotic.
Bill Hawkins
P.S. You don't know that he'll be dead in 20 years, but there is a
high probability that he'll be beyond caring. I mean, if an interviewer
asked you what was the most important thing that happened to you during
your life, the one that you would like to live over before you die,
would you name the day you got your GC-1000 working?
Was this a troll? You decide . . .
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of WB6BNQ
Sent: Sunday, January 16, 2011 7:41 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GC-1000 Clock Cap Choice?
Brooke,
WTF ! Just replace them with the same type as was in there. That will give
you
another 20 or so years and by then you will be dead and won't give a damn.
The only critical (for that time) component would be the TC loop
capacitors for
the 567 PLL's. They should be silver mica types (good enough tempco for the
567's), but knowing heathkit they might have just used common disk ceramic
types
(bad for tempco).
All these other people going crazy with all the {RE} engineering crack me
up. No
thought as to what is really needed to fix the item. All they truly do is
create
a given level of noise that exceeds the original expectations of this list.
Well, one other thought . . . . . but I would hate to accuse you of
trolling,
73BillWB6BNQ
Brooke Clarke wrote:
Hi:
More than half the electrolytic caps in this Heathkit GC-1000 Most
Accurate Clock are bad and I'm trying to come up with modern replacements.
http://www.prc68.com/I/HeathkitGC1000.shtml#Rx
The Tone Decoder board uses a couple of NE567 PLL ICs to capture the 100
Hz and 1000 Hz WWV tones. Heathkit used Tantalum caps for the PLL
output filter. I'd think something like a low loss electrolytic or
plastic cap would be better.
http://www.prc68.com/I/HeathkitGC1000.shtml#TB
Also how about using Aluminum Organic Polymer caps (where there are
replacements) instead of the plain electrolytic caps?
The plan is to replace all the electrolytic and tantalum caps since the
ones that are now OK may fail in the near future.
Any thoughts?
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
___
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Re: [time-nuts] Archiving Data
Seems to me there's at least three things going on. 1. People need meaningful work. It is more satisfying to re-invent from ignorance than to learn that something has been done several times before. Either way, the effect on the orbits of stars is not measurable. It only matters to a human. 2. Yes, we can no longer build a Saturn 5 rocket, but why would we want to? Technology moved on, and we still ride the crest of the wave, even as some seek the bleeding edge. Does anyone seriously believe that hidden or destroyed in Tesla's papers is the secret for a death ray? Anyone that understands the laws of physics, that is. 3. Most human brains are genetically programmed to detect loss of a mate, or children, or helpful friends. If not, we wouldn't notice, and lose chances for survival. This sense of loss gets connected to other brain areas to a variable extent. I hate to lose useful or clever artifacts, and so my basement has spilled over into a storage locker. Now I'm at an age where I can't keep them because they'll be hauled to the dump when I die. Others do not share my love for those things. Who would pay the shipping for a fine old Tektronix 500 series scope? Anybody that's tried to invent categories for things knows that it isn't perfect. What I'd file under one name, someone else would file under another if there were any ambiguity at all. Google shows that data might as well be buried in some salt cave unless you can come up with the key words that will find it. Thanks for caring, Perrier, but humans aren't capable of storing everything so it can be retrieved. Especially not when languages are different. George Shultz (Peanuts) did a cartoon of Snoopy saying, Sometimes I've just got to bite a cat. Next panel, But then I just lie down and forget about it. Last panel, That's real maturity. Not saying any one is immature, just that feelings pass as life goes on. Bill Hawkins -Original Message- From: Perry Sandeen Sent: Friday, January 07, 2011 2:59 PM I apologize in advance for my long posting apology accepted - So where am I going with all this? Glad you asked. No one knows if their or others data will lead to a new discovery or process. Da Vinci certainly didn't. It can however; lead to learning that can then can be taken to the next level of knowledge and invention. Words cannot express my gratefulness to those who have taken the considerable effort and expense to post science information and support technical lists such as this on the net as well as the posters who have kindly shared their knowledge with us. I just hope it doesn't get lost. End of Rant. I now get off my soapbox and return you to your normal programming. Regards, Perrier ___ 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] Archiving Data
Well, Perry, you were right. The thread has drifted into technology when the real challenge is the catalog for all that has gone before. But perhaps that is not within this group's charter. History Channel did a reasonable presentation of the Knights Templar, within their tabloid guidelines, tonight. Talk about massive amounts of information being concealed before and especially after 1307. Time (the subject of this group) keeps on slipping into the future, leaving hints of things lost in its wake. Sorry I couldn't work any chips or programs into this posting. At least we do have an archive, although the subjects do mutate from the subject lines. Bill Hawkins -Original Message- From: Perry Sandeen Sent: Friday, January 07, 2011 2:59 PM --- big Snip % --- So where am I going with all this? Glad you asked. No one knows if their or others data will lead to a new discovery or process. Da Vinci certainly didn't. It can however; lead to learning that can then can be taken to the next level of knowledge and invention. ___ 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] Problems with Garmin - maybe we should cut them a little slack
It's a slow day at the end of too many holidays in series, counting Solstice. Pardon me for slacking off and getting way off track ... I have asked three different map services for the location of a restaurant and gotten three different answers within a mile of each other. So I called the restaurant and found out how to get there. All this without asking an automotive device that uses GPS technology to know where it is, but is quite unable to ask for other opinions and converge on the right answer. And certainly not to call the destination to ask for directions. I rely on an automotive device to tell me where I am, not how to get to some destination. Like as not, Lola (from the song Whatever Lola wants, Lola gets) will thread me through a series of complex turns because the route is an inch shorter than taking the bypass. Happy new year, and may you prepare for your trips rather than trusting your route decisions to a device that was designed to look good in ads. There has to be an accuracy disclaimer somewhere. Bill Hawkins -Original Message- From: J. Forster Sent: Friday, December 31, 2010 11:00 AM My concern is a major industrial building complex and all the visitors that get misdirected to the wrong end of a long road every day. -John === And who sent this, John? Maybe we should cut these cartographers a little slack. When you consider that Garmin will sell you a map update of the entire northern hemisphere for eighty bucks, we perhaps shouldn't get too wadded up if they miss the exact location of my little bungalow by a couple of hundred feet. After all, we're not talking about GPS error here, but address designation. And there are quite a few little bungalows in all of North America... Bill ___ 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] GPS Antenna -Receiver Mutual Interference...
Well, I have two HP conical antennas 4 feet apart and just below the roof level, with an elevation cutoff of 30 degrees for the large and growing oak trees on 3 sides. Fifty feet of RG-8 each connects to two Z3801A receivers. I've had no trouble in a dozen years, here in Minneapolis. T1 to GPS runs at about +4E-008 for both from GPSCon. My son runs a 50' deep sea fishing boat out of Ocean City, MD. It has two GPS navigation antennas less than 4 feet apart up on the signal mast. It also has portable GPS receivers used by fishermen who want to learn his fishing spots, but these are about 10' away. He has had no trouble with navigation. What would be the symptoms of interference? A disturbance in PPS signals at the 10E-12 level? Bill Hawkins -Original Message- From: shali...@gmail.com Sent: Monday, January 03, 2011 1:50 PM The additional advantage is to give you diversity and some immunity against multipath (at least it reduces the probability that both receivers will be affected at the same time due to weird constellation issues or local interference). But it now creates an issue which is how do you know who is right when both receivers don't agree... Didier KO4BB -Original Message- From: Rob Kimberley r...@timing-consultants.com Sender: time-nuts-boun...@febo.com Yes, I've seen this. On installations in the past, when we were putting up dual GPS systems, we always put them at least 10 metres apart. What is actually best practice, is to put one at one end of building and the other one at the other end. Rob Kimberley -Original Message- From: Mark J. Blair Sent: 03 January 2011 2:19 AM On Dec 30, 2010, at 6:53 PM, Burt I. Weiner wrote: Has anyone run into a situation where two GPS Navigation type Antenna/Receivers interfere with each other? It's possible that LO leakage from one is jamming the other. When doing mobile GPS receiver testing at work with a single antenna feeding multiple receivers through a splitter, we sometimes had to insert attenuators in each receiver's antenna feed to keep them from jamming each other. ___ 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] Us Time Nuts and... Wrist Watches.
My favorite watch is to stand outside on a quiet night and watch the snow fall silently. It is a rare time-less moment. Best wishes for the solstice celebration of your choice, or as we used to say 60 years ago, Merry Christmas. Bill Hawkins -Original Message- From: Michael Poulos Sent: Friday, December 24, 2010 11:01 AM We all enjoy good accurate time keeping. :) What is your favorite watch? ___ 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] What is the best way to multiply a 10 Mhz
So, two doublers for 40 MHz and a tripler for 30 and then mix to get 70? What happens to phase noise when you do that? Is it as bad as a PLL? Seems like you ought to get adequate harmonic rejection. What about six mixers to get 20, 30, 40, 50, 60, and 70 MHz? Chips and tank coils are cheap, no? Bill Hawkins -Original Message- From: Burt I. Weiner Sent: Tuesday, December 21, 2010 1:39 PM It would seem the most jitter free way to do it would be to simply multiply it up like we used to do. Some reasonably Hi-Q LC circuits could make a nice flywheel and filter out other signals at the same time. Once you have it to the desired signal frequency you could condition it to clock your DDS. Am I missing something here? Wouldn't be the first time, ya know! Burt, K6OQK Subject: Re: [time-nuts] what is the best way to multiply a 10 Mhz signal? On 21/12/10 16:35, Stephen Farthing wrote: Hi everyone, I want to multiply the output from my Efratom 101 (10Mhz) to clock a DDS at 70 Mhz. Has anyone tried this? Regards, Steve G0XAR ___ 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] TAC/TDC
Just finished editing 25 papers on process control for FDA (Food and Drug Administration) regulated industries, so here are a few reflexive neuron firings. The FDA requires that the user requirements be captured first, in a way that can be understood by both the user and the vendor of the required hardware or software, but with no vendor contribution. Once agreement has been reached, the vendor prepares a functional specification that can be understood by the user and the people who will build the thing that is proposed. When the functional specification is approved, the technical team prepares design requirements and builds what the user needs (they hope). When built, it is tested against the design specification, then the functional spec, and finally the user spec. The user signs off on the last tests to accept the product. This only works when everybody is on familiar ground, and all of the technical principles (if not the details) are understood. Otherwise, you enter a design, prototype, and feedback cycle until the user and the vendor can agree on what the vendor will provide. Only then can the user write requirements that don't require transmutation of elements or time travel. Concisely, the requirements must refer to feasible design properties. They can't be kept separate until it is known that the thing can be done. After that, the FDA process (V-Model) assures a win-win result, if you have the people and the time to handle the documentation and negotiations. All IMHO, of course. Bill Hawkins -Original Message- From: Magnus Danielson Sent: Wednesday, December 15, 2010 3:50 PM %-- You mix requirements and sketch of design-idea. Keep requirements and proposed design properties separate. 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] Adjusting accuracy of a Casio G-Shock watch
Jim, I have such a watch, purchased in Singapore in Oct 2009. It is solar, but it has no radio connection. It is water-resistant to 20 atmospheres (bar). I don't wear it, but I keep it by a southern window. The back cover appears to be held on by four screws. I've not tried to open it. It's off by two hours and 91 seconds, over a year. It's possible that I didn't make the final time zone adjustment when I got back to Minnesota. What was the problem with getting the back off? Bill Hawkins -Original Message- From: Jim Palfreyman Sent: Tuesday, December 14, 2010 10:17 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Adjusting accuracy of a Casio G-Shock watch Fellow time-nuts. Over in another part of the internet is a group of people who love their Casio G-Shock watches. These digital watches have been around for decades and are built very well. The one I own is an atomic and solar model (i.e. no battery replacement). However being in Tasmania, I cannot receive the low frequency time signals. When I first received the watch it's accuracy was excellent. Under 10 seconds a year. I even posted on here about it. Since then though it has drifted somewhat. After a ton of internet searching on how to open the case and how to adjust these watches (this is non trivial as the models are all very different and no instructions existed for this model - the GW-810D) I have finally cracked it. Interestingly, the module has a pad that gives off a stepped square wave at 32768/48 Hz. So with well calibrated equipment (which we all have of course) it is trivial to adjust the trimmer to put the watch back to decent accuracy. Using the smallest adjustment of the trimmer that I could muster I could get it down to about 0.5 in 10^6 or 1 second in around 20 days. Not as good as when I got it - but I was probably just lucky. Over in mygshock.com they struggle with this sort of timing stuff - whereas my big deal was opening the case! Just posting in this in case anyone here is interesting in adjusting their G-Shock. Jim ___ 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] Adjusting accuracy of a Casio G-Shock watch
Referring to the post with the mechanical procedure, you determine the offset over a couple of weeks. When you open the watch to adjust it, you apply the offset to whatever frequency you find when you open the watch. I don't wear a watch when I sleep, and that becomes part of the offset to be corrected. Bill Hawkins -Original Message- From: Don Latham Sent: Wednesday, December 15, 2010 12:49 AM Might want to have the watch near body temp when you adjust? Don ___ 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] Got 60HZ?
The original question referred to a good squaring chip. Then we veered off into other ways to coax chips into delivering 60 Hz from 10 MHz. At the time, I thought there must be a way to buy European 50 Hz synchronous clocks, or digital clocks that use the line frequency. Here's an electromechanical solution. You'll need a small low voltage DC motor with good bearings, a disk that fits on the motor shaft that has been drilled or etched with two concentric circles of tiny holes, two light source and detector pairs to get pulses from the holes, PLL circuitry, and an amplifier to drive the motor. One circle of holes generates a frequency that can be phase locked to a standard your choice. The other circle generates a frequency that is a binary multiple of 60 Hz. 120 Hz is enough for a square wave output. A higher frequency is required to approximate a sine wave. For extra credit, add a copper disk to the motor shaft. Make one or more electromagnets so that the copper disk passes through the gap. Run the DC motor from a regulated voltage that makes the frequencies about 1% high. Arrange the PLL to drive the electromagnets to regulate the motor speed using the counter field generated in the copper disk. See if the copper disk can be made thin enough to also have the circles of holes. In return for some mechanical skills, you can avoid strange chips and arduous programming. Bill Hawkins -Original Message- From: Michael Poulos Sent: Wednesday, December 08, 2010 10:14 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Got 60HZ? Recently I bought a Efratom Ru frequency standard from eBay and a frequency divider chip that makes 1MHZ,100KHZ,25KHZ,10KHZ,100HZ and a 1HZ output. Today I thought of a way to make a nice 60HZ so you can use a mains-powered clock for the display (using amplifier and transformer wired backwards). But, now you'll need 60HZ. A European has it easy with 50HZ as you use a BASIC Stamp or Arduino to divide the 100HZ output. But for 60HZ I came up with a solution: You set up the Arduino to take the 10KHZ from the divider chip and program it to count off 83 pulses to flip an output. But wait! Unless you add a leap count every 3 flips of the output, it'll run fast. Assume at the start the Arduino output starts high then turns low: (83+83+84+83+83+84)*20 = 10,000 pulses = one second H__L__H__L__H__L Every output cycle and a half the voltage swing is a little over 1 percent longer because of the leap count. This means that the distortion adds a slight inaccuracy, not enough to upset New Year's revelers. But if you want a better 60HZ, try using the 100KHZ: (833+833+834+833+833+834)*20 = one second You see where this is going with leap counts. The ultimate of course is one really good Arduino and (after a hex inverter to amplify it) take the straight 10MHZ and apply this leap count technique: (8+8+83334+8+8+83334)*20 = one really accurately made 60HZ = one nice second, just the thing for a Nixie clock. :) Now, what is a good hex inverter to take the 10 million HZ of my rubidiom movement to feed a frequency divider chip (and later Arduino)? It needs to take the .5 of a volt sinewave and squarewave it and in a normal 14 pin DIP (breadboardable) package. ___ 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] Got 60HZ?
Have one of those FAA signal generators of vacuum tube vintage. There's a selector switch for about a dozen frequencies that mechanically moves the light detector to the right track. The eddy current brake was used in a synchro system to adjust the speed of the control transformer shaft, which generated the three-phase signal for rotating the antenna and all of the radar display sweeps. The electromagnet is quite large. A Hammond tone wheel might get you eight octaves of harmonics, or 2**8. No need for decayed dividers and their reset tricks, just straight flip-flops, all the way down. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Robert Atkinson Sent: Saturday, December 11, 2010 12:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Got 60HZ? Ahh, the tone wheel. make it a shaped slot, lamp and LDR and you can have a sinewave. Add a second sensor on an arm pivoted at the center of rotation and you have variable phase. A lot of early aircraft test signal (VOR / ILS) generators used this technique. metal disks and eddy current sensors were more common than optical. There was also the Hammond organ. If you want 50Hz clocks try ebay.co.uk or amazon.co.uk etc. Or I can supply for a small commisson ;-) Robert G8RPI. ___ 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] MBD /B
Darn, I was sure that was a coded message to space saying it was safe to bring the Mother Ship in because we were all distracted by tax cuts for the rich. Bill Hawkins -Original Message- From: Stan, W1LE Sent: Wednesday, December 08, 2010 7:32 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] MBD /B I figured out what I did wrong. I cross posted from the lowfer reflector. Please disregard. I will be more careful in the future. Stan, W1LE Cape Cod ** You are assuming that you have a future. ** ___ 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] Truetime dc 468 goes sat rcvr simulator basics working
There are also a lot of GPS hockey pucks that send the NMEA codes to map software in a laptop that are rapidly becoming obsolete. NMEA is adequate for the 468 display. Have three of them, to go with three NIB (except for the manual) DC 468 receivers. Don't need any of them. Bill Hawkins -Original Message- From: paul swed Sent: Monday, December 06, 2010 3:13 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Truetime dc 468 goes sat rcvr simulator basics working Justin, I might think quite a few time Nuts have these. So making progress have build a gps sat message decoder for the GPRMC sentence that gives time and data. I believe most GPS units put that sentence out. Have it decoding time and next is date. Maybe tonight. Then I have to glue this code into the simulator to set the clock. Next will be a update subroutine which is quite tricky as to how the updates done. ___ 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] OT [GPS Survey grade RX]
How accurate do you want the survey to be? What's your budget? A handheld GPS can give you 3 meters for 200-300 bucks. Bill Hawkins -Original Message- From: wa1...@att.net Sent: Saturday, December 04, 2010 6:57 PM I wish to survey some of my land here in the US. What used GPS receivers out there might be good candidates? I really don't want to haul a Z3801A out in the woods and run a self- survey unless the cost is too high. :-) -Brian, WA1ZMS ___ 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] Time Code generator
WWV is not necessarily audible at all times. 2.5 MHz seems a poor choice because it has 1/4 of the power at the higher frequencies, except 20 MHz. I went through a phase of acquiring Datum time code generators back in 2003. Thought I'd turn them into rack-mounted shack clocks, but never got around to it. These things generate and receive most IRIG frequencies, but IRIG B at 100 HZ is the most commonly used. They come in 1, 2, or 3 rack units height. They're built with late seventies parts on plug-in cards and weigh about 15-20 pounds. Some have crystal ovens at 1 MHz. Most can use an external 1 MHz. You have to preset the time of day and push a start button after a power cycle. Also have some IRIG clocks, which only decode an IRIG signal. I'd like to get these units to people who can use them, so shipping is going to be the main cost. Don't know what it takes to ship to Canada. Bill Hawkins b...@iaxs.net -Original Message- From: Collins, Graham Sent: Friday, December 03, 2010 6:28 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Time Code generator On another list to which I subscribe, the question was asked about the suitability of recording WWV 2.5mhz audio as one track when recording off the air signals of interest as a time reference. The person who asked the question didn't really state his intentions but they seem very similar to my immediate needs. That is, simply a time reference - that is the time, the start of the minute, and periodic references (i.e. seconds) between the announcements. It seems that recording the audio of something like WWV or CHU is ideal. However, another approach would be recording a more proper time code signal as you might have available from a precision clock. Of course, a decoder would also be required. A quick Google search turned up lots of leads which I have yet to sort through. In the interim I thought I would pose the question to the learned members of this group for their suggestions. Keep in mind KISS and that a very high degree of accuracy is not required. Is there an opensource/freeware PC app that will generate an appropriate time code signal that can be recorded on one track of an audio recorder (either PC based i.e. Audacity or standalone) that will also decode via soundcard or other input? Cheers, Graham ve3gtc ___ 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] Another GPS .. this is a true boatanchor
Looks like an early marine GPS navigation device, probably before WAAS. May have an NMEA output for other devices, like fish finders. Amazon has a VHS video of the operator's manual for $30 but only two left. Bill Hawkins -Original Message- From: Pete Lancashire Sent: Friday, December 03, 2010 4:31 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Another GPS .. this is a true boatanchor If too far off topic let me know, or is there a GPS-nuts list ? Raystar 920. I think i have 2 two, did find two antennas one new. http://petelancashire.com/gallery/main.php?g2_itemId=21152 This one may be fun to see if can make it run .. anyone with a manual ? -pete ___ 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] If there a FAQ
Chris, If you are familiar with vacuum tube stuff, I have a basket-case Beckman 905 WWV receiver that you can have for shipping. The radio was discarded because the 6AQ5 coupling capacitor got leaky and caused smoke to be released from the power transformer, which is otherwise OK. It was then sprayed with a fire extinguisher, which ruined the speaker but didn't get past the front panel. The 905 is a five channel crystal controlled dual conversion receiver. Information is available on the web. It's in a basket because I never got around to repairing it, after taking it apart. Actually, if you have a good communication receiver, you have all you need to set a 10 MHz crystal to 1E-8, if the adjustment has any stability. That's a ten second beat rate. Then you need to filter out the temperature variations, or fool around with NPO caps to compensate for temperature variations. Well maybe 1E-7, which is normal for WWV over the Rockies (sky- wave). Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson Sent: Sunday, November 28, 2010 11:42 PM To: j...@quik.com; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] If there a FAQ WWV at 10MHz is not bad at all. My current system is a cheap $0.75 10Mhz crystal tuned with a screwdriver on a veritable trimmer capacitor. I know I can zero-beat it by ear and get within a couple Hz out of 10MHz. That is better then 1E-6 simply by hand, ear and screwdriver. No computer. The trouble with a 60Khz signal is that a two cycle error gives a 1 in 30K error, I'm just looking to use it as a frequency standard, not caring at all about the data they transmit I figure my first upgrade is to replace the crystal with a temperature compensated oscilator chip. Now to go find one. -- = Chris Albertson Redondo Beach, California ___ 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] USB Low Cost GPS Timing Receiver
Brooke, Google says the SD-200 speaks 4800 baud NMEA at 1 second intervals. It is not clear whether the message is fixed of if it will reply to queries. Your question only concerned cost. Is one second accuracy adequate? Bill Hawkins -Original Message- From: bro...@pacific.net Sent: Friday, November 26, 2010 3:43 PM To: time-nuts@febo.com Subject: [time-nuts] USB Low Cost GPS Timing Receiver Hi: A friend is looking for a low cost GPS receiver to set the clock in the computer that controls his telescope mount. USB would be nice but is not a requirement. For example does eBay item 130456356506 set the computer clock? This GPS receiver for the Nikon has a mini-USB connector, but when connected to my computer is not recognized. http://www.prc68.com/I/Nikon.shtml#GPS Have Fun, Brooke Clarke ___ 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] OT: 5372A
What's this?? Has gold been discovered on the west coast again? Shall I cash in all my timenuts acquisitions for a pan and a donkey? :-) for the sarcasm impaired . . . Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Dave Mallery Sent: Sunday, November 21, 2010 7:09 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: 5372A planning to move to gold beach... 73 dave ___ 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] Do I have a defective thunderbolt?
It's normal. You have a defective unit. Have 8781 messages in timenuts here. Will start thinning it out by deleting threads for Thunderbolt and Lady heather. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Thursday, November 18, 2010 6:31 PM To: gera...@decampos.net; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Do I have a defective thunderbolt? You've mixed up the backslashes used by Windows with the forward slashes expected on the WEB. Links should be: http://www.decampos.net/LH/LH1.png http://www.decampos.net/LH/LH2.pnghttp://www.decampos.net/LH/LH2.png Bruce Geraldo Lino de Campos wrote: For some reason, the links didn´t include the suffix png. The correct linkas are www.decampos.net\LH\LH1.png www.decampos.net\LH\LH2.png On Wed, Nov 17, 2010 at 2:21 PM, Geraldo Lino de Campos gera...@decampos.net wrote: I have a thunderbolt acquired from TAPR. Almost every time the number of satellites change, there is an abrupt change in the DAC voltage as high as 1 mv, sometimes. See www.decampos.net\LH\LH1http://www.decampos.net/LH/LH1.png - a graph with time constant 200 and Damping 4. Using much higher values improve the situation, as can be seen in www.decampos.net\LH\LH2.pnghttp://www.decampos.net/LH/LH2.png, time constant 1000 and damping 100 (note the change in the DAC scale), but the jumps are still present. Is this normal, or I have a defective unit? The antenna is located in a window, with several buildings nearby, so the change in the number of satellites is frequent. -- gera...@decampos.net ___ 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] Temperature sensors and bridge amps
Rick, Is the double integrator actually a cascade of two controllers, where the primary controls the crystal temperature and its output sets the setpoint for a heater temperature controller? That's how industrial control handles the lag between a 5000 gallon reactor and its steam-heated jacket. There's a sensor and primary PID for the reactor contents (stirred) and a sensor and PID for the jacket temperature. When I said ambient I was thinking of the range that a military receiver like the R-390 was designed for. Seems to me that if the only disturbance to the crystal temperature is the ambient temperature, then you can lag ambient with enough insulation so that the internal controller can be slow enough to have adequate gain. There are disturbances within the internal loop that would have to be dealt with, such as the heater supply voltage and the offset voltage of the first error amplifier. We are going for stability, not accuracy, right? Bill Hawkins P.S. Really good story to wind up the loosing things thread. -Original Message- From: Richard Karlquist Sent: Saturday, November 13, 2010 3:24 PM Yes, E1938A. I was operating on limited sleep when I posted that. Rick On Sat 13/11/10 8:35 AM , Magnus Danielson wrote: On 11/13/2010 04:48 PM, Richard Karlquist wrote: The HP E9183A achieved 1 millidegree over -55 to +85C in a single oven. The time lag was dealt with by adding a double integrator to PID. I'd assume you would intend to write HP E1938A, right? Cheers, Magnus Rick Karlquist N6RK On Fri 12/11/10 8:26 AM , Bill Hawkins wrote: in the heater control loop. Of course, you can't get to a millidegree from ambient with just one oven. And you can't eliminate time lags if you have any thermal mass. ___ 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] Temperature sensors and bridge amps
As I understand it, the problem to be solved is stability to a millidegree or some such. That kind of accuracy is not required because the flat spot of crystal tempco is not narrow. +/- 1% would be accurate accuracy. For stability, you must remove all sources of variation. Self- heating is not a stability problem, it is an accuracy problem. Operating at the bridge null reduces the effect of bridge power variations. The challenge is to get enough gain from the low offset error amplifier to maintain the required error range without having so much gain that the loop is unstable. This usually means taking physical design steps to eliminate dead-time or lags in the heater control loop. Of course, you can't get to a millidegree from ambient with just one oven. And you can't eliminate time lags if you have any thermal mass. Note that you have the same loop stability problems if you use a crystal as the sensor and a counter as the detector. I worked for Rosemount (part of Emerson since 1976), a maker of industrial sensors including 100 ohm platinum. The four wire Kelvin connection offers the most accuracy, but frugal industry finds that a three wire connection is adequate for very long runs of cable. This connection puts a lead wire in both legs of the bridge. Bill Hawkins -Original Message- From: Bob Camp Sent: Friday, November 12, 2010 6:28 AM The 100 ohm standard for RTD's dates way back. The assumption was that you had it on a *long* run of cable (2 pair / sense leads of course). The insulation leakage was a bigger issue than anything else in the equation. On Nov 12, 2010, at 5:36 AM, Poul-Henning Kamp wrote: This was one of the things that I wondered about: How large currents are used ? Can't be too much because that would lead to self-heating... ___ 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] Frequency referenced temperature regulator
Nickel sensors are more stable than thermistors, but not as stable as platinum. The cost is more attractive than Pt, tho. I'd consider staying analog with a DC bridge and a PID control op-amp. You don't need a highly accurate voltage source for the bridge because null is null, whatever the excitation voltage. Of course, you'll want a stable null for the op-amp, too. You do need a highly stable set of bridge resistors for a stable temperature. In the old days, precision, stable resistors were wound on ceramic forms by soldering a loop of e.g. constantan wire to the lead wires at each end of the form. Then you pull the loop at the center so that you can wind it on the core in a non-inductive manner. Inductance doesn't matter, but you want to finish the winding with the center bent double and sticking out a few inches from the core. Attach the lead wires to a measuring device with sufficient precision and accuracy, and hope that the winding has slightly more resistance than you want. Now take a razor blade and short the center wires closer to the winding. The resistance should go down. When you find the spot that gives the right resistance, remove the insulation and solder the wires together. Don't even think of using any kind of variable resistor to adjust the bridge null. What you want is a stable temperature near the value that gives the least crystal tempco. Yes, this is also how to make a meter shunt, but you'll be using much finer wire. The best thing to do might be to find an antique precision resistance bridge. It will have many such resistors in it, and you might be able to avoid winding altogether. Please write for details. Bill Hawkins -Original Message- From: Perry Sandeen Sent: Wednesday, November 10, 2010 11:03 PM List, Looking for a stable temperature sensor I first went to YSI. They have sold their sensor products to. Measurement Specialties, Inc. Perusing their site I came upon a Ni1000 SOT temperature sensor. It is a nickel based unit that has a basic resistance of 1K ohms at 20 degrees C and rising to 1482 ohms at 80 degrees C. . It has close to a 6 ohm change per degree. I tried to find one of their distributors without success. Entering the part number in Google, I found it is also made by ZETEX. ZETEX calls it an IC TEMP SENSOR NI1000 SOT23-3. The Digi-Key catalog as part number is ZNI1000CT ND. They are $2.77 each. The ZETEX data sheet has a nice circuit for a digital thermometer. Perhaps a LM 331 precision voltage-to-frequency IC or using a change in a bridge circuit to a varactor on a VCXO might provide the lack of aging problems that exist with a thermistor when precisely trying to obtain a temperature-to-frequency conversion. ___ 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] Greenwich time ball
Antonio, American English is my mother tongue. Sometimes I use it to say silly things, but I beg no one's indulgence. I haven't heard anything silly from you yet. Bill Hawkins -Original Message- From: asma...@fc.up.pt Sent: Sunday, November 07, 2010 5:02 PM (English is not my mother tongue: please be indulgent...) Best regards, Antonio CT1TE ___ 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] Setting clocks 100 years ago
I remember the ball dropping at Greenwich at noon GMT, but that's because it was summer, and 1 PM BST. Makes you wonder how they interpolated the hour after the noon transit. Chronometers must have been pretty good by then, or there would have been no point to generating a time signal. The US Navy dropped the ball at noon when it dropped a ball. See http://wwp.greenwichmeantime.com/info/timeball.htm People who didn't have a ball and mast used a noon gun. These were also used inland. I remember seeing (on TV) one of them with an arrangement that use magnified light from the sun to light the fuse on the cannon. If you Google noon gun you will be flooded with information about the cannon on Signal Hill in Cape Town, SA. Use the advanced search to reject Cape Town and many other locations will appear. Bill Hawkins -Original Message- From: Rob Kimberley Sent: Friday, November 05, 2010 3:31 AM I thought the ball dropped at noon. Perhaps you were there in the summer, and they had advanced 1 hour for summertime (daylight savings). Rob K Bob Marinelli wrote: Hi Murray, Actually, the ball at Greenwich drops at 1:00 pm every day. For everyone who can get to London, the observatory is well worth at least a half day visit, they have several working Harrison clocks and yes you can set your wristwatch at 1:00 when the ball drops :) there is also a wonderful transit. Cheers, Bob On Nov 4, 2010, at 4:30 PM, Murray Greenman wrote: Once the transit was observed, a large ball on top of the building was dropped, indicating midday, and in some locations a cannon was also fired. Ships in port could observe the ball drop and hear the cannon. To this day the ball drops at midday at Greenwich. 73, Murray ZL1BPU ___ 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] Why .30 cal holes can't be seen at 800 yds...
And that is why lawyers have taken over the world - fear of the unknown. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Heathkid Sent: Thursday, November 04, 2010 8:46 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Why .30 cal holes can't be seen at 800 yds... I wasn't giving legal advice... just pointing out one can purchase the targets (not make them). Be legal and obey all laws... if you have to purchase through someone with a FFL make sure the transfer is legal (or even possible) and be responsible. Good advice Bob. But this did start out as a timing project thread. I just wanted to explain IF one can legally purchase these, they are available. I do not and did not suggest in any way that anyone makes explosives or do anything illegal. If someone is going to use these, I hope they have the smarts to know and understand the laws applicable to them. Always read and understand your local laws regarding purchase, ownership, and use of anything. I am not giving legal advice on anything. - Original Message - From: Robert Darlington rdarling...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, November 04, 2010 1:58 PM Subject: Re: [time-nuts] Why .30 cal holes can't be seen at 800 yds... Be careful about giving legal advice. These are not legal where I live. Making explosives in any quantity is legal at a federal level in all 50 states without any kind of license but those darn states and cities make laws to restrict that. Mixing tannerite turns it into a federally, state, and locally regulated explosive which means at a very minimum the federal laws apply. This means no transporting it, storing it, buying it, selling it, etc. without an ATF license (this would fall under manufacturing regs which are related to commerce, not a physical act of mixing). This means if you mix it at home and transport to a range, you go to prison. Mix at the range and hold onto it over night, you go to prison. Throw it down range, can't find it, get caught, go to prison. Google for the ATF Orange Book that covers almost anything you want to know on the subject but it's only at the federal level. Always check state and local laws before toying with this stuff. Prison doesn't sound like a lot of fun to me. Also, I noticed that the thread degenerated into nothing having to do with time measurement. I tend to restrict myself but felt I really needed to point out that legal in one place doesn't make it legal everywhere all of the time. -Bob (p.s. tannerite is flippin' awesome!) On Thu, Nov 4, 2010 at 11:23 AM, Heathkid heath...@heathkid.com wrote: Here are some exploding targets that are legal: http://www.tannerite.com/ A friend uses them and swears by them. On 11/3/2010 11:28 PM, jimlux wrote: Michael Conlen wrote: There's always nitroglycerin. I've heard it reacts well to vibration. nitromethane is much more readily available and also shock sensitive. Cyanoacrylate debonder. or glowplug fuel ___ 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 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 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] Setting clocks 100 years ago
Antonio, The earliest purpose for mechanical clocks was religious, so they appeared in church towers in the 1600's. They were set by sundials. The 1800's brought the telegraph and precision telescopes. Once it was possible to transmit time signals at near the speed of light, and to determine star crossings with millisecond precision, time could be synchronized among those clocks the could be set electrically. See Einstein's Clocks, Poincare's Maps: Empires of Time by Peter Louis Galison for a fascinating history of this era. Accurate maps could not be made without an accurate sense of time, provided by telegraph cables from a central clock in Paris. The accuracy of pendulum clocks increased dramatically once true time could be known, leading to the Riefler and Shortt free pendulum clocks, where the free pendulum swung in a vacuum. These mechanical marvels gave way to the crystal oscillator in the 1930's. Church clocks were fine with local sundial time until the railroads discovered the need to accurately schedule trains on the same track to avoid collisions, say in the 1850's. Central time standards were necessary to enforce a common sense of time over a wide geographic area, like the United States at the time. Paris had a pneumatic system for setting tower clocks across the city using pipes under the streets that carried pressure pulses from a central clock in 1880. Synchronization was done with star-crossing observatories and telegraph signals driven by precision clocks that could keep steady time between one night's star crossing and the next. One of these was Goodsell Observatory at Carleton College, in Northfield, Minnesota, USA. See http://www.carleton.edu/departments/PHAS/astro/pages/history2.html From the 1870s until the Second World War the Carleton observatory was among the best and most prominent in the United States. It set time for all the major railroads from Chicago to Seattle. I visited the observatory a few years ago with a group of time enthusiasts. The remains of the telegraph board that distributed time far and wide were still there, but our guides couldn't tell us anything about them. Several accurate pendulum clocks were set around the concrete base of the telescope on the floor below it, but they were not in good repair. There was a Riefler clock in the basement that was missing the lower vacuum chamber because someone drilling holes for a computer network had drilled through a wall without looking to see what was on the other side. Corrosion has had its way with the mechanism since then. The observatory building had been turned into classrooms and a faculty lounge in the room with the star crossing detector. No one seemed to know what they were treading on, or what prevented them from having more room. No one knew the purpose or value of the spare parts stores. I can't bear to go back there. In short, church bells stopped being the time standard about 300 years ago. Heck, 100 years is only 30 years after I was born. I used to think my grandfather, born in 1880, had seen a lot of change. Now I've seen a lot of change, and lately none of it seems to be for the better. Bill Hawkins I hope someone appreciates the last two hour's work . . . -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of iov...@inwind.it Sent: Thursday, November 04, 2010 4:47 PM To: time-nuts@febo.com Subject: [time-nuts] Setting clocks 100 years ago This evening I happened to hear the nearby church's bell tolling 10 pm, and thought that 100+ years ago this could have been the official time of the town, which maybe was used by people to set their own clocks (if any). But then I wondered, who told the priest what time was it? To what extent the clocks of two towns were expected to be close to one another? Does anybody know? Antonio I8IOV ___ 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] Why .30 cal holes can't be seen at 800 yds...
Group, I haven't been following this thread that won't die, but I've contributed to others :^) If the problem is that it is expensive to detect when a bullet hits a target half a mile away, then have I got a solution for you! Visit any friendly neighborhood terrorist supply store and buy a small quantity of PETN, or any other explosive that can be detonated by the impact of a bullet. Smear a coating of this over the area of the target that you intend to hit. When you hit the target, there will be a very bright flash with a very fast propagation velocity, which should be adequate for the average 10X scope and photosensor. No, I don't know where to find a terrorist supply store. Perhaps you can make do with the PETN in blasting caps, or brew up a batch of nitrogen tri-iodide, as any college freshman could do in the fifties. Or try the powders from a Very pistol flare. Yours for more creative solutions, Bill Hawkins ___ 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.
