Re: [time-nuts] Interesting white elephant on *bay
Hi David: I have an earlier version, see: http://www.pacificsites.com/~brooke/5001a/5001A.html The block diagram matches the GPS spec ICD-200 and the boards are made using wire wrap and standard ICs. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com David I. Emery wrote: Ebay item 130064070991 should interest some members of the group I think. Not clear how one controls it (does it have an ethernet port somewhere ?) Fun and games could happen with this thing in the wrong hands... ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 5345A
Hi Rick: Is there a way to know about the type of aging up front. For example what crystal makers have only micro cracks as the aging mechanism? For what starting date? My guess is that there are plenty of crystals that have aging that's mainly due to contamination or other causes that the better makers have eliminated. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Rick Karlquist wrote: Hal Murray wrote: I thought aging was generally uni-directional and reasonably predictable if you had enough data. Does it wander in both directions? This is probably on the list of the 10 greatest myths about crystal oscillators. Many decades ago, there were systematic aging effects such as you speak of. I remember learning as a youth that glass crystals age up and metal crystals age down. Over the years, any such systematic effects have been analyzed one by one to understand the root cause, and then the process has been fixed to get rid of that aging effect. What we are now left with are tiny cracks and crevasses that grow sporadically like a crack in an auto windshield. At least that is what we think is going on. The process people, like my friends Charles Adams and Jack Kusters, have worked themselves out of a job had taken retirement, because, like the efficient stock market theory, there is no predictability to the aging data. It is truly a random walk down Wall Street or in this case a random walk in time. Oscillators will age in one direction for a while but may then age in the opposite direction for while for no particular reason. Not only that, but crystals will jump a part in 1E^9 or so every so often. I've never seen a 10811 crystal without jumps if you wait long enough. I don't know of any other crystal makers who claim to not have jumps. Rick Karlquist N6RK ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS orthodontics: sawteeth hanging bridges - theeffect of time averaging
Hi Ulrich: Your M12+T plot ends at a little over a day (100k seconds) and the stability is on the order of 4E-13. But Cesium and other oscillators can be better than this. So how do you check them, use longer averaging time? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Ulrich Bangert wrote: Brooks, Excel computed that the unaveraged correction data had a standard deviation of 8.4 nsec, which is consistent with the actual measured 9.5 nsec rms jitter reported by Rich Hambly (Dec 06, PTTI paper by Clark and Hambly, p. 15). Even if this scientifical improvement has not found its way into Excel: A certain Mr. Allan has shown that the standard deviaton is NOT the appropiate measure for noise processes in oscillators. Therefore he had to find a new statitistics on its own. If you don't own a software to calculate ADEV and other relevant statistical measures with you may download one for free from my homepage: http://www.ulrich-bangert.de/plotter.zip But the question remains what time averaging is needed to reduce the sawtooth/bridge jitter from a typical +/-15 nsec to something negligible, perhaps +/-1 nsec? Have a look to http://www.ulrich-bangert.de/html/photo_gallery_44.html If you can read it it will immediatly give you the answer to your questions: in order to get to a certain precision draw a horizontal line at this precisision on the vertical axis and at the two crossing points read the necessary time for SAW corrected and uncorrected data on the horizontal axis. Nevertheless, pardon to contradict you: One simply has NO choice to average this long or to average that long. You have to set the regulation loop time constant up to exactly where the OCXO's tau-sigma-diagram meets the receiver's tau-sigma. Every loop time constant different from that is a faulty design and nothing else. The regulation loop dynamics may be improved a bit by pre-averaging the phase data before they are fed into the loop but not by computing the arithmetic mean over a time but by a gliding exponential average as is explained in detail in the PRS-10's handbook. Due to stability reasons even this time constant of this pre-filter is more or less fixed to abt. 1/3 the main loop's time constant. Regards Ulrich Bangert,DF6JB -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Brooks Shera Gesendet: Donnerstag, 21. Dezember 2006 18:50 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] GPS orthodontics: sawteeth hanging bridges - theeffect of time averaging Recently there has been some mention of the influence of 1pps sawtooth and hanging bridges jitter on the performance of a GPSDO. It would seem to me that the jitter must average to zero in the long run, for if it did not the 1pps signal would drift away from its relation to UTC. But the question remains what time averaging is needed to reduce the sawtooth/bridge jitter from a typical +/-15 nsec to something negligible, perhaps +/-1 nsec? To explore this I used TAC32 to record the 1 pps sawtooth correction message from a Motorola M12+ receiver for about 1 hour, during which time many bridges occurred (1). Excel's statistical toolbox was then used to examine the data. Excel computed that the unaveraged correction data had a standard deviation of 8.4 nsec, which is consistent with the actual measured 9.5 nsec rms jitter reported by Rich Hambly (Dec 06, PTTI paper by Clark and Hambly, p. 15). Averaging the sawtooth/bridge correction data for several averaging times produced the following results (2): Avg TimeStandard Deviation Residual Jitter none 8.4 nsec +/- 15 nsec 30 sec1.53+/- 4.3 100 sec 0.79+/- 2.2 300 sec 0.33+/- 0.7 It is evident that jitter is greatly reduced with a bit of time-averaging. In addition, the hanging bridges quickly disappeared into the residual jitter of the smoothed data. It appears to me that a typical GPSDO, which has an integration time in the range of 100's to many 1000's of sec is not likely to be impaired by the sawtooth/bridge noise of a GPS rcvr. A GPS-based clock is a different story since a precise 1pps timing signal without time averaging would be desirable. In summary, it appears that 1pps sawtooth/bridge noise can be ignored for a GPSDO. In some designs it may even be helpful by introducing further deterministic randomness to the phase measurement process. Regards, Brooks (1) the M12+ correction-message resolution is 1 nsec and this seems adequate for a jitter statistics investigation. But as a check, I compared the correction message data with the actual 1 pps jitter measured with a 5370B TIC, a PRS10 and a M12
Re: [time-nuts] GPS orthodontics: sawteeth hanging bridges - theeffect of time averaging
Hi Bruce: OK so the plot at will level off at about 5E-14. Suppose that I'm now using the SR620 to make averages of 5,000 seconds and plotting those where the inputs are from an M12+T and a FTS4060 Cesium standard. At 5,000 seconds Ulrich's plot shows about 4E-12. Does that mean with a perfect standard I would expect to see noise of about 4E-12? So I should set the averaging to about 1E6 seconds (11 days)? to get the best possible result? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Dr Bruce Griffiths wrote: Brooke Clarke wrote: Hi Ulrich: Your M12+T plot ends at a little over a day (100k seconds) and the stability is on the order of 4E-13. But Cesium and other oscillators can be better than this. So how do you check them, use longer averaging time? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Ulrich Bangert wrote: Brooks, Excel computed that the unaveraged correction data had a standard deviation of 8.4 nsec, which is consistent with the actual measured 9.5 nsec rms jitter reported by Rich Hambly (Dec 06, PTTI paper by Clark and Hambly, p. 15). Even if this scientifical improvement has not found its way into Excel: A certain Mr. Allan has shown that the standard deviaton is NOT the appropiate measure for noise processes in oscillators. Therefore he had to find a new statitistics on its own. If you don't own a software to calculate ADEV and other relevant statistical measures with you may download one for free from my homepage: http://www.ulrich-bangert.de/plotter.zip But the question remains what time averaging is needed to reduce the sawtooth/bridge jitter from a typical +/-15 nsec to something negligible, perhaps +/-1 nsec? Have a look to http://www.ulrich-bangert.de/html/photo_gallery_44.html If you can read it it will immediatly give you the answer to your questions: in order to get to a certain precision draw a horizontal line at this precisision on the vertical axis and at the two crossing points read the necessary time for SAW corrected and uncorrected data on the horizontal axis. Nevertheless, pardon to contradict you: One simply has NO choice to average this long or to average that long. You have to set the regulation loop time constant up to exactly where the OCXO's tau-sigma-diagram meets the receiver's tau-sigma. Every loop time constant different from that is a faulty design and nothing else. The regulation loop dynamics may be improved a bit by pre-averaging the phase data before they are fed into the loop but not by computing the arithmetic mean over a time but by a gliding exponential average as is explained in detail in the PRS-10's handbook. Due to stability reasons even this time constant of this pre-filter is more or less fixed to abt. 1/3 the main loop's time constant. Regards Ulrich Bangert,DF6JB -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Brooks Shera Gesendet: Donnerstag, 21. Dezember 2006 18:50 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] GPS orthodontics: sawteeth hanging bridges - theeffect of time averaging Recently there has been some mention of the influence of 1pps sawtooth and hanging bridges jitter on the performance of a GPSDO. It would seem to me that the jitter must average to zero in the long run, for if it did not the 1pps signal would drift away from its relation to UTC. But the question remains what time averaging is needed to reduce the sawtooth/bridge jitter from a typical +/-15 nsec to something negligible, perhaps +/-1 nsec? To explore this I used TAC32 to record the 1 pps sawtooth correction message from a Motorola M12+ receiver for about 1 hour, during which time many bridges occurred (1). Excel's statistical toolbox was then used to examine the data. Excel computed that the unaveraged correction data had a standard deviation of 8.4 nsec, which is consistent with the actual measured 9.5 nsec rms jitter reported by Rich Hambly (Dec 06, PTTI paper by Clark and Hambly, p. 15). Averaging the sawtooth/bridge correction data for several averaging times produced the following results (2): Avg TimeStandard Deviation Residual Jitter none 8.4 nsec +/- 15 nsec 30 sec1.53+/- 4.3 100 sec 0.79+/- 2.2 300 sec 0.33+/- 0.7 It is evident that jitter is greatly reduced with a bit of time-averaging. In addition, the hanging bridges quickly disappeared into the residual jitter of the smoothed data. It appears to me that a typical GPSDO, which has
Re: [time-nuts] GPS orthodontics: sawteeth hanging bridges- theeffect of time averaging
Hi Tom: The goal is to get the C field set. If by using only 5,000 seconds I'm not getting the full precision of the GPS system, then a longer averaging time would allow more accurate setting, nes pa? Have Fun, Brooke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Tom Van Baak wrote: Suppose that I'm now using the SR620 to make averages of 5,000 seconds and plotting those where the inputs are from an M12+T and a FTS4060 Cesium standard. At 5,000 seconds Ulrich's plot shows about 4E-12. Does that mean with a perfect standard I would expect to see noise of about 4E-12? So I should set the averaging to about 1E6 seconds (11 days)? to get the best possible result? You should continue to use 5000 second averagesare fine. When you use various ADEV programs they will be able to plot at 5000 s and any multiples of 5000 s, including 1e6. Have Fun, Brooke Clarke - Original Message - From: Brooke Clarke [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Friday, December 22, 2006 14:27 Subject: Re: [time-nuts] GPS orthodontics: sawteeth hanging bridges- theeffect of time averaging Hi Bruce: OK so the plot at will level off at about 5E-14. Suppose that I'm now using the SR620 to make averages of 5,000 seconds and plotting those where the inputs are from an M12+T and a FTS4060 Cesium standard. At 5,000 seconds Ulrich's plot shows about 4E-12. Does that mean with a perfect standard I would expect to see noise of about 4E-12? So I should set the averaging to about 1E6 seconds (11 days)? to get the best possible result? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Dr Bruce Griffiths wrote: Brooke Clarke wrote: Hi Ulrich: Your M12+T plot ends at a little over a day (100k seconds) and the stability is on the order of 4E-13. But Cesium and other oscillators can be better than this. So how do you check them, use longer averaging time? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Ulrich Bangert wrote: Brooks, Excel computed that the unaveraged correction data had a standard deviation of 8.4 nsec, which is consistent with the actual measured 9.5 nsec rms jitter reported by Rich Hambly (Dec 06, PTTI paper by Clark and Hambly, p. 15). Even if this scientifical improvement has not found its way into Excel: A certain Mr. Allan has shown that the standard deviaton is NOT the appropiate measure for noise processes in oscillators. Therefore he had to find a new statitistics on its own. If you don't own a software to calculate ADEV and other relevant statistical measures with you may download one for free from my homepage: http://www.ulrich-bangert.de/plotter.zip But the question remains what time averaging is needed to reduce the sawtooth/bridge jitter from a typical +/-15 nsec to something negligible, perhaps +/-1 nsec? Have a look to http://www.ulrich-bangert.de/html/photo_gallery_44.html If you can read it it will immediatly give you the answer to your questions: in order to get to a certain precision draw a horizontal line at this precisision on the vertical axis and at the two crossing points read the necessary time for SAW corrected and uncorrected data on the horizontal axis. Nevertheless, pardon to contradict you: One simply has NO choice to average this long or to average that long. You have to set the regulation loop time constant up to exactly where the OCXO's tau-sigma-diagram meets the receiver's tau-sigma. Every loop time constant different from that is a faulty design and nothing else. The regulation loop dynamics may be improved a bit by pre-averaging the phase data before they are fed into the loop but not by computing the arithmetic mean over a time but by a gliding exponential average as is explained in detail in the PRS-10's handbook. Due to stability reasons even this time constant of this pre-filter is more or less fixed to abt. 1/3 the main loop's time constant. Regards Ulrich Bangert,DF6JB -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Brooks Shera Gesendet: Donnerstag, 21. Dezember 2006 18:50 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] GPS orthodontics: sawteeth hanging bridges - theeffect of time averaging Recently there has been some mention of the influence of 1pps sawtooth and hanging bridges jitter on the performance of a GPSDO. It would seem to me that the jitter must average to zero in the long run, for if it did not the 1pps signal would drift away from its relation to UTC. But the question remains what time averaging is needed
[time-nuts] Time Interval Averaging: Theory, Problems, and Solutions
Hi Bruce: How to get a copy? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com /Time Interval Averaging: Theory, Problems, and Solutions/, David Chu, HP Journal June 1974 pp12-15. Bruce ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Looking for QST Jan 1990 Article on Crystal S, Q R testing By DeMaw
Hi: I'm looking for the subject article on crystal testing, or any other articles on testing crystals. This is more related to knowing if a given crystal is alive than characterizing it, i.e. a Crystal Activity Meter type thing. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Looking for QST Jan 1990 Article on Crystal S, Q R testing By DeMaw
Hi Mike: I've received an email asking about where to purchase a crystal activity meter and although I have a hand held unit, see: http://www.pacificsites.com/~brooke/Xam.html don't want to part with it. This is an older unit that uses PNP transistors. I'm now thinking about how to build one using a PIC and to that end would like to see what's in the subject article. So if you would email a copy to mailto:[EMAIL PROTECTED] that sure would help. The final product should be a hand held battery powered easy to use device. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Mike Feher wrote: Brooke - In that case why do not just use a signal generator like an 8640B with the crystal in series with the hot lead and then the other side of the crystal terminated in 1K or so. Then you can put a scope across the 1K resistor and watch the scope as you tune across the suspected resonant frequency. I have done this a lot when I was not sure of the crystal frequency, or, if it was working or not. Real simple to do. If all else fails, I am sure I have the QST you mentioned, and could scan the relevant pages for you. I also have a military crystal activity meter that does do a full characterization, but, it is big and bulky, and, I hardly ever use it. 73 Merry Christmas - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brooke Clarke Sent: Wednesday, December 20, 2006 5:15 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Looking for QST Jan 1990 Article on Crystal S,Q R testing By DeMaw Hi: I'm looking for the subject article on crystal testing, or any other articles on testing crystals. This is more related to knowing if a given crystal is alive than characterizing it, i.e. a Crystal Activity Meter type thing. Have Fun, Brooke Clarke ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
Hi Brendan: It's my take that there are two aspects of the Brooks (no relation) design that need to be addressed for optimum operation: 1. the filter time constants of the stock design are not correct for a Rb oscillator, and that can be fixed by getting a custom PIC from Brooks. 2. the TIC although suitable for use with the older Motorola GPS receivers is not optimum for use with the newer M12+T receivers. There is not a fix for this now, but maybe in 2007. Keep in mind that this design does work and that the above items relate to optimization not bug fixes. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Brendan Minish wrote: My original Question has sparked off quite an interesting discussion and I learnt a lot Since it seems that the Brooks Shera Project is not the optimum way of GPS disciplining a Rubidium Oscillator can anyone here point me in the direction of other DIY projects (or even ideas) that might yield a better result. 73 Brendan EI6IZ ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
Hi Brendan: It's interesting that the PRS10 can time stamp the 1 PPS input with a resolution of 10 ns. I wonder how they do that. http://www.thinksrs.com/downloads/PDFs/Catalog/PRS10c.pdf When I picked up my PRS10 at the factory during the tour I learned that the 10 MHz oscillator in the PRS10 was an improved version of the SC10. There's an Allan plot for the PRS10 at: http://www.thinksrs.com/products/PRS10.htm - overall PRS10 page http://www.thinksrs.com/assets/instr/PRS10/PRS10diag2.htm - Just the plot Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Brendan Minish wrote: On Tue, 2006-12-19 at 11:05 -0800, Brooke Clarke wrote: Hi Brendan: Keep in mind that this design does work and that the above items relate to optimization not bug fixes. I currently have the Brooks Shera design disciplining my LPRO-101 without any mods and using the ADC connected directly however the gain is not high enough for the small EFC range of the LPRO. It does work, it will keep it locked OK even with the longest time-constant and the figures appear to make 'sense'. I guess that with the excellent stability of the Rubidium Oscillator the lack of loop gain may even be an advantage as it will reduce sensitivity to other sources of short and medium term error I certainly intend trying the modified PIC software to improve gain and lengthen the filter time. I would however be most interested in building and comparing with an alternative discipline arrangement Anyone care to comment on projects based around the SRS PRS10 module and how it fares out in the scheme of things ? 73 Brendan EI6IZ ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] LPRO-101 with Brooks Shera's GPS locking circuit
Hi Ulrich: I think the answer is what other low cost options are available? I would like to have a more modern TIC capability to add to the clock I'm working on. But although there's been a lot of discussion about different ways of making TIC measurements, it's not clear to me how to do it on a budget. For example the TIC232 circuit by Richard H McCorkle is easy to implement, but how good is it's noise floor. See: http://www.piclist.com/techref/member/RHM-SSS-SC4/TIC232.htm Then there's the low cost frequency counting TIC that appeared in QEX that we know trades performance for low cost so it's not a candidate. Any ideas on what circuits have a noise floor that's compatible with the M12+T or it's newer equivalents and at the same time are in the low cost category? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Ulrich Bangert wrote: Tom, . What I wanted to explain is the Shera concept noise floor is a factor 20 above what a modern receiver can deliver (again inc. the sawtoth correction). And yes, you are right: There were different numbers when this concept was thought out! And exactly because different number were there when this concept was thougt out I am going to ask why people still built it today. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 5334 oscillator performance
Hi Colin: A year or so ago I purchased a number of unit oscillators form a number of sources like Digi-Key, Jameco, eBay, etc. These were all XOs, not TCXOs. Some had no markings some were from well known makers. Almost all of them showed high aging rates indicating leaking packages, i.e. they were slowing down and the rate was not getting smaller. You might want to run the unit in a temperature controlled environment for a few days to be sure it's not defective. I did this using a lunch bucket which is an insulated cylinder with an opening of about 5 and about 6 deep. I used a home brewed heater set to the turnover temperature of the XO. Does the 5334 have an external reference input? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Colin Bradley wrote: I recently took one of my 5334A’s off of the house standard to lend to a friend. I thought it a good idea to check the onboard oscillator before lending it out. Both of my 5334A’s lack Opt 10 oscillators. This particular unit was almost 40Hz high in frequency. I tried to set it to frequency and had trouble getting it closer than 2Hz. The set-ability was very poor. I checked the service manual and found that HP only specified a final frequency within 8Hz. I can now see why. I then turned the instrument off for 12 hours. The next day I powered the unit back up. The oscillator was 20Hz higher than where I had measured it at shutdown the night before. It took well over an hour for it to re-stabilize and overshot the previous set point by 2Hz. At this point I decided to lend a Heathkit IM-2420 to the friend and continued experiments with the 5334A. I now took the second 5334A down and ran the same tests on it. This instrument was somewhat better but still shared many of the problems the first unit. 1) 60+ minutes to stabilize after power-up. Oscillators would start out 9 – 19Hz high and settle in at +- 1Hz. 2) Poor retrace at turn on. Final settling frequency can vary by 1Hz. 3) Poor set-ability due to the ceramic trimmer. 4) Oscillator pulling of 2 – 3Hz when I connected another counter to the rear panel oscillator jack. The oscillator buffer is on the same ECL chip as the oscillator. After looking at the circuit I decided that a new TCXO would be a better solution than trying to modify the existing circuit for better performance. Since these units are used at room temp most of the time, I need not worry about a wide temp range specification. I set the following goals for the replacement oscillator. 1) Improvement of stability by an order of magnitude and set-ability of two orders of magnitude. 2) Replacement to be built on a circuit board that would mount in the oven oscillator connector on the main circuit board. 3) Use of the full time 24vdc at this connector to power the oscillator at all times. Use of an on-card battery supply for oscillator backup. 4) Cheap 5) Use of readily available TCXO oscillator module. After checking Mouser and Digi-Key I settled on a Mouser supplied FOX801BE 10mHz unit @ $13.46. to start my experiments. This oscillator draws only 2ma. and frequency is set by an external trim pot. I would be interested in the experiences of others with respect to the performance of their non-oven 5334’s (or 5328’s) and ideas that support the design goals. Thanks Colin Do you Yahoo!? Everyone is raving about the all-new Yahoo! Mail beta. http://new.mail.yahoo.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Austron 1210D-03 Battery Pack Ideas
Hi Mike: http://www.batteryspace.com has a number of Ni-Cad and Ni-MH cells. It's a good idea to replace with the same chemistry so that the charger works properly. Most modern batteries have a capacity that's much higher than batteries 10 or 20 years ago, so getting the exact same size is not so important. Better to make up a smaller battery but that has about the same number of cells and Amp-Hour capacity. Note that many cells are available with pre welded tabs to simplify making up a battery pack. They also have a number of pre assembled battery packs, one of which may be just what you need. I see that John already has posted that the battery was 12 F cells each speced as 1.2 Volts and 7 AH. This is less than a modern D cell. Battery Space also carries Universal chargers that are the Burp type which are in my opinion the only way to go. http://www.batteryspace.com/index.asp?PageAction=VIEWCATSCategory=944 - some 12 and 14.4 Volt packs. But if a 2x6 configuration is not correct then combine some smaller packs like: http://www.batteryspace.com/index.asp?PageAction=VIEWCATSCategory=943 If you make an online order use the discount code:batteryspace for a little off. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Mike Feher wrote: BTW, John, I meant to ask you this before when you mentioned this clock, but what did you decide to do about the backup batteries, if anything? I have not found a source for those 1.5 size NiCd D cells that were in there. The clock of course works fine without them, but, it would be nice to get it back to original. I may just have to go with external backup batteries. - 73 - Mike Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Ackermann N8UR Sent: Monday, November 06, 2006 3:02 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 10811A/B OCXO OP/SRV manual is onlineat hparchive.com Not HP, but it seems that manuals for Austron gear are always hard to find. At the moment, I'd like to find one for the 1210D portable clock. John Jack Hudler wrote: Thanks John, I wonder if the group has any requests. I'm working on a personal project to scan a considerable archive of documentation. It has required me to write a lot of custom OCR software and I thought I would try it on my favorite source first. What's the most requested or desired manual or manuals? Jack -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Miles Sent: Monday, November 06, 2006 1:34 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 10811A/B OCXO OP/SRV manual is onlineathparchive.com Re: [time-nuts] HP 5060A option 004Wow, that is a NICE scan. Thanks for that contribution. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Earth: An Oscillator and Frequency Standard
Hi Tom: Thanks for the lab test report on the earth frequency standard. Since there are a number of frequency/time standards that have much better performance I'd like to find a way to directly measure the performance of the earth standard. I've thought about a telescope looking at stars or maybe a photo detector to look at the light from the closest star to the earth frequency standard. Do you have any ideas on how to make these measurements? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Tom Van Baak wrote: Anyway, how do you compute the Allan Deviation of a sun dial? Oh, God, now someone's going to do it... John Well, yes, thanks for asking! I did it a year ago. The lab report on earth, including Allan deviation is at: http://www.leapsecond.com/museum/earth/ /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 5 MHz Frequency Doubler
Hi Christopher: You might have a look at Mini Circuits MK-3, see: http://www.minicircuits.com/MK-3.pdf My guess is that it contains a monolithic bridge diode circuit and a couple of balun transformers. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Christopher Hoover wrote: Hey 'nuts, I'm looking for a good design for a 5 MHz frequency doubler. The Wenzel Blue Tops HF doubler is said to be based on a low phase noise, public-domain NIST design: http://www.bluetops.com/Modules/lnhd.htm http://www.bluetops.com/Modules/lnhd.htm The LNHD is a fixed-frequency HF doubler based on a public-domain design developed by the National Institute of Standards and Technology (NIST http://www.boulder.nist.gov/timefreq/ ) for superlative phase noise performance. Can anyone point me at a this design? I haven't had any luck finding it on the web. I'm open to suggestions on other doubler designs, as well. -ch ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 5 MHz Frequency Doubler
Hi Rex: I think the 4 diode bridge circuit shown on the left of Fig 2 is the Mini Circuits MK-3. Note the fundamental and third harmonic suppression on the MK-3. http://www.minicircuits.com/MK-3.pdf Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Rex wrote: On Wed, 25 Oct 2006 23:13:55 -0700, Christopher Hoover [EMAIL PROTECTED] wrote: Hey 'nuts, I'm looking for a good design for a 5 MHz frequency doubler. The Wenzel Blue Tops HF doubler is said to be based on a low phase noise, public-domain NIST design: http://www.bluetops.com/Modules/lnhd.htm http://www.bluetops.com/Modules/lnhd.htm The LNHD is a fixed-frequency HF doubler based on a public-domain design developed by the National Institute of Standards and Technology (NIST http://www.boulder.nist.gov/timefreq/ ) for superlative phase noise performance. Can anyone point me at a this design? I haven't had any luck finding it on the web. I'm open to suggestions on other doubler designs, as well. -ch Not a specific answer to the question, but I've been planning to try the Simple 2-diode doubler in this article... http://www.wenzel.com/pdffiles/diodedbl.pdf What say the experts? How does it stack up to the JFET design being discussed? Also, I'm visually oriented; finding it hard to follow the JFET discussion. Any pointer to a schematic of an implementation? ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 5 MHz Frequency Doubler
Hi Brian: rtHz is Root Hertz. On the newer HP (Agilent) Spectrum Analyzers you can display directly in rtHz, but there is no standard ASCII display character for that so they use xx/Hz where xx is something like uV. So although the display appears to be saying uV per Hertz it's really uV per root Hz. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com [EMAIL PROTECTED] wrote: For what my 2 cents are worth. I've used the Wenzel design diode based multiplier many times and have had very good results with regards to close-in as well as far phase noise. A simple schematic of my circuit application can be found at: http://www.mgef.org/images/134-5_to_10MHz_doubler_Ver_II.gif -Brian, WA1ZMS On Wed, 25 Oct 2006 23:13:55 -0700, Christopher Hoover [EMAIL PROTECTED] wrote: Hey 'nuts, I'm looking for a good design for a 5 MHz frequency doubler. The Wenzel Blue Tops HF doubler is said to be based on a low phase noise, public-domain NIST design: http://www.bluetops.com/Modules/lnhd.htm http://www.bluetops.com/Modules/lnhd.htm The LNHD is a fixed-frequency HF doubler based on a public-domain design developed by the National Institute of Standards and Technology (NIST http://www.boulder.nist.gov/timefreq/ ) for superlative phase noise performance. Can anyone point me at a this design? I haven't had any luck finding it on the web. I'm open to suggestions on other doubler designs, as well. -ch ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] HP-IB Commands or Manual for 59309A Digital Clock
Hi: I'm looking for the HP-IB commands (or better a manual) for the HP 59309A Digital Clock. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FW: HP-IB Commands or Manual for 59309A Digital Clock
Hi Daun: I found the sticker on the bottom of my clock, (although your image is much much easier to read than the actual size one) but it's not at all clear what some of it means. For example: Setup Instruction 3) Set Front Panel switch to Int or Ext, but my clock has no front panel switch. Operating Instruction E) Send Start code from table 2 to synchronize clock with Reference Clock. What does that mean? Also there are DIP switches inside whose function I sure would like to know. Having Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Daun Yeagley wrote: Hi Brooke I sent a response through the list, but the attachment was a tad large. (I'm sure John would pass it though!) Anyway, I thought I'd save some time and send you the bigger file anyway. Original text pasted here: Hi Brooke Turns out I have one of these on my shelf and it has a label on the bottom with the codes. I've probably got a manual out in my barn, but those of you that know about my manual stash realize that it would take a monumental effort to dig it out. (I keep threatening to have a manual party one of these days to rescue them and sort them all out). In the meanwhile, I set it on my scanner, and attached is the result. (I have it in higher resolution as well, but know it would difficult to get it through that way, but if you need it that way I can get with you off list to make it happen) regards, Daun N8ASB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brooke Clarke Sent: Monday, October 23, 2006 9:43 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP-IB Commands or Manual for 59309A Digital Clock Hi: I'm looking for the HP-IB commands (or better a manual) for the HP 59309A Digital Clock. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FW: HP-IB Commands or Manual for 59309A DigitalClock
Hi Tom: Thanks. Knowing about the secret door sure makes a difference. Having Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Tom Van Baak wrote: Setup Instruction 3) Set Front Panel switch to Int or Ext, but my clock has no front panel switch. There are a whole set of cute switches behind the bottom half of the front panel. Open the panel from that tiny square cut-out on the lower left corner. http://www.leapsecond.com/museum/hp59309a/open-front1.jpg http://www.leapsecond.com/museum/hp59309a/open-front2.jpg Operating Instruction E) Send Start code from table 2 to synchronize clock with Reference Clock. What does that mean? You stop the clock with the P command; then set the date and time with repeated D, H, M, and S commands; then start the clock with the T command. Also there are DIP switches inside whose function I sure would like to know. Let me dig out my manual... /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Features of a Precision Clock?
Hi Bill: On the to do list is a version based on Richard McCorkle's RS232 Time Interval counter. For a minimum cost version a different PIC is needed than the 16F88 used in the Current Version (PC4). Once the TI counter is part of the clock then all kinds of neat things can be done. I'll keep in the looking at the mains. In the PC4 there's a software TI counter good to 1 ms that can be used to trim the Real Time Clock chip. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Bill Hawkins wrote: How about a version that works from the 50/60 Hz power frequency with a 1 PPS output and internal micro clock oscillator? Great for watching the power grid lose time and regain it as the power generated vs. consumed balance varies. If the power line PPS lags behind at an increasing rate, it's time to turn off the air conditioner and run all those clock ovens on battery before the under-frequency relays start cascading. Of course, you need the precision version for comparison. Does anybody in this group look at power line frequency drift? Bill Hawkins ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Features of a Precision Clock?
Hi: I've got the Precision Clock to work and have some questions about the priority of the features. As it is now the clock allows user selection of the input frequency at power up that determines the instruction clock for the PIC micro controller. The choices are 2.5, 5, 10 or 20 Mhz. The clock displays on line one HH:MM:SS and on line two Day of Week, , Mon, Day of Month. The leap year testing uses the 4, 100 and 400 year rules and so you can determine the day of the week for any Georgian calendar (1583 onwards) date. Setting is by means of 4 buttons, Right, Left, Increment, Decrement. This is very intuitive and quick. During setting the clock continues to keep time. Also a new data field to the right of the seconds appears as 4 hex digits to allow moving the LED/1 PPS output pulse in 1 ms steps. If the input frequency fails then all the fields that can blink do blink and the clock stops. Pressing and holding Right or Left for a few seconds clears the blinking and restarts the clock using the input frequency that was selected at power up. For more see: http://www.pacificsites.com/~brooke/PRC68COM.shtml#PC3 Now for the possible next features to be added. It would be nice to get some feel for how important they are: (1) Synchronize the 1 PPS output rising edge to be near a 1 PPS input pulse on a one time basis (the 1 PPS edge will have an error of a few instruction cycles which are each 4/Fin long). If this was done the manual setting would be removed. (2) Add another mode of operation where the clock runs on it's internal RC oscillator and the timing is determined by an external 1 PPS that needs to always be connected. (3) Add a backup Real Time Clock with it's own coin cell battery to allow using the clock in a portable application and allow the clock to be shipped while running. The chip has a 0.1 ppm aging trim capability and there could be a provision to automatically trim it when one of the above precision input frequencies is applied for maybe a day. Then when the input frequency is disconnected the clock would continue to tell the time. There are also many options for alarms. (4) Other displays such as fractional Julian Day number, fractional Modified Julian Day number. sidereal time, or ??? I don't think there's enough memory for all of the above, probably only one or two of them so I'm hoping to get some input on the priorities. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Features of a Precision Clock?
Hi James: Can you point me to an example Bulletin C? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com James Maynard wrote: On receipt of Bulletin C, can you arm this clock to display the upcoming leap second? That's a feature that I would desire. Brooke Clarke wrote: Hi: I've got the Precision Clock to work and have some questions about the priority of the features. As it is now the clock allows user selection of the input frequency at power up that determines the instruction clock for the PIC micro controller. The choices are 2.5, 5, 10 or 20 Mhz. The clock displays on line one HH:MM:SS and on line two Day of Week, , Mon, Day of Month. The leap year testing uses the 4, 100 and 400 year rules and so you can determine the day of the week for any Georgian calendar (1583 onwards) date. Setting is by means of 4 buttons, Right, Left, Increment, Decrement. This is very intuitive and quick. During setting the clock continues to keep time. Also a new data field to the right of the seconds appears as 4 hex digits to allow moving the LED/1 PPS output pulse in 1 ms steps. If the input frequency fails then all the fields that can blink do blink and the clock stops. Pressing and holding Right or Left for a few seconds clears the blinking and restarts the clock using the input frequency that was selected at power up. For more see: http://www.pacificsites.com/~brooke/PRC68COM.shtml#PC3 Now for the possible next features to be added. It would be nice to get some feel for how important they are: (1) Synchronize the 1 PPS output rising edge to be near a 1 PPS input pulse on a one time basis (the 1 PPS edge will have an error of a few instruction cycles which are each 4/Fin long). If this was done the manual setting would be removed. (2) Add another mode of operation where the clock runs on it's internal RC oscillator and the timing is determined by an external 1 PPS that needs to always be connected. (3) Add a backup Real Time Clock with it's own coin cell battery to allow using the clock in a portable application and allow the clock to be shipped while running. The chip has a 0.1 ppm aging trim capability and there could be a provision to automatically trim it when one of the above precision input frequencies is applied for maybe a day. Then when the input frequency is disconnected the clock would continue to tell the time. There are also many options for alarms. (4) Other displays such as fractional Julian Day number, fractional Modified Julian Day number. sidereal time, or ??? I don't think there's enough memory for all of the above, probably only one or two of them so I'm hoping to get some input on the priorities. Have Fun, Brooke Clarke ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Interesting Graphical Clock
Hi: http://www.fetmar.org/bookClock/ Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Re Danjon Astrolabe
Hi Tom: With an atomic quality clock it should be possible to measure the period of the earth every day using the sun and/or stars and see how far from 86400 seconds it is. I too have been thinking of how to use the sun in a precision way. Since UTC is close (UTC1 is better) to the sun's movement it should be possible to make a clock that's within 0.1 seconds based on the sun's position. If using the sun then just using 4 (East, South, West Up) small solar panels mounted to the face of a cube might work. It's easier if the cube is really square and sitting on a level surface and rotated so that one face is aligned with true North. Although you could measure the current from each panel and calculate the sun's position, it might be enough to pre calculate ratios and note the time when those ratios occur. But as you know the Equation of Time complicates the relation between the sun's position and UTC. For sundials the EOT is taken as fixed by day of year, but for precision work you need to compute it for the actual day in question, although taking into account where in the leap year cycle you are may be enough for 0.1 seconds. Maybe it's about the same as calculating UTC based on sidereal time from a star sight? Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Tom Van Baak wrote: I'm interested in automatically measuring the earth's period by looking close to straight up with a fixed telescope. Here's a related idea for you; a modern digital sundial. Two different ways to implement it: 1) Aim a webcam on a standard sundial and write some image processing software that at the pixel level monitors the amount of shadow in real-time compared to PC time (UTC). By the end of a day, you'd have enough samples to have nailed down solar time quite accurately. Collecting data over weeks or months would be even more revealing. Fun math and programming problem. 2) Instead of a fixed base, gnomon, and slowly moving shadow like almost all sundials, you put a stepper or servo motor/encoder on the base. Then place matched photodiodes on either side of the gnomon and steer the whole sundial for constant *minimum* shadow. In real-time, a PC or microcontroller monitors the photodiodes, keeps the sundial in position, and logs continuous position data (as a function of UTC). At the end of the day your precise measure of solar time drops out of this data. At night it extrapolates where it should aim the sundial for sunrise. Again, collecting days or weeks of data gives you even greater precision. 2b) Do the same using a PC-controlled telescope, where software constantly adjusts Az-El to maximize the measured brightness of the filtered sun through the eyepiece/CCD. /tvb http://www.LeapSecond.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Re Danjon Astrolabe
Hi Bruce: I'm interested in automatically measuring the earth's period by looking close to straight up with a fixed telescope. There are automatic star trackers that can see stars in the day time so the only time you would not see the star is when there's cloud cover. By using a reticule it should be possible to detect individual stars and discriminate other bright objects. I've started a web page on Stellar Time Keeping at: http://www.pacificsites.com/~brooke/StellarTime.shtml although many of the patents linked on that page are aimed at satellite navigation there are a couple designed for surveying on the earth. But if the position of the instrument is known then you can get the time of star meridian crossing. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Dr Bruce Griffiths wrote: In article 44D8C0BB.1030608 at pacific.net https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts, Brooke Clarke brooke at pacific.net https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts writes /Hi Geoff: // //Thanks for the reference to Geodesy. Do you know if the first edition //has the Danjon information? //I ask because the second editions are rather pricey and the 3rd and 4th //are not available at all. //Could someone on this list make a copy of the Danjon section? // /I'm quoting from memory about the workings of the Danjon Astrolabe - the book was borrowed from my local library, and I don't remember which edition it was. Nor can I quote chapter and verse, I fear - although I will attempt to re-borrow the book, and copy the relevant section. Later this week, I hope. AFAIR, the discussion was of the workings of various instruments for determination of time from the stars, together with ways to mitigate the systematic errors in each instrument. Personal equation figured large in all this, which is why the PZT was preferred. -- Geoff Powell The explanation of the operation of the Danjon Astrolabe is somewhat oversimplified. There was a motor driven optical mechanism that was used to keep the 2 stellar images superimposed for some time so that a sequence of observations could be taken on a single star. This significantly reduced the personal equation on the measurements obtained with this impersonal version of the astrolabe. I remember a book on Astrometry (sorry cant remember the title) that had detailed cross sections of the astrolabe together with a very detailed description of how it worked. A modified version of the Dajon Astrolabe is currently in use at Santiago Chile for Solar astrometry. Bruce ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Looking for good SR620 setup to compare GPS and rubidium
Hi David: The most straight forward way is to make a time interval measurement between the two 1 PPS signals. It's good to use a BNC-T connector at the SR620 front panel and a scope so that you can set the trigger levels at 50%. If both sources are TTL (0 to 5 volts open circuit) and you use the 50 Ohm termination in the SR620 then the pk-pk will be 2.5 volts and a trigger level of 1.25 volts works well. By setting SAMPLE SIZE size to some number like 500 (seconds since your have 1 PPS input) you can then DISPLAY either MEAN or JITTER. The latter is a very good indication of what's going on. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com David Forbes wrote: Folks, We have a rubidium oscillator in a laboratory here that is ripe for calibration against a primary standard. We have installed a Datum 9390 GPS receiver next to it as well as an SR620 counter. Can any of you recommend a good operating mode to make the SR620 reveal the rubidium drift rate in a reasonably short time a couple days is OK) so that we may adjust it to near zero? We have both 10 MHz and 1PPS available from both sources. We don't currently have a logging computer connected to the SR620, but we can do that if needed. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Trimble Receiver TRANS II and ACE II
Hi Philip: It's been my experience that each manufacture of GPS receivers has their own proprietary command language that gets used in all that manufacturers products. Some products implement commands that others do not, but the core commands stay the same. So you might just get from the Trimble web page documentation on a receiver that is close. My Trimpack web page is at: http://www.pacificsites.com/~brooke/Trimpack.shtml Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com [EMAIL PROTECTED] wrote: Dear Sirs Can anybody help with the TRANS II and ACE II I am looking for user / operation manual and programming manual for both units and perhaps if anybody has a Service type information Circuit Diagrams parts list etc.. Used in a Truetime GPS-DC and XL-AK Truetime receivers If anybody can help please reply to my email address [EMAIL PROTECTED] Best Regards Philip A Davies ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] An example of phase noise
Hi John: It's my understanding that the lowest jitter comes about when the highest output divisor is used. In case of ties use the lowest VCO divisor. See: http://www.pacificsites.com/~brooke/BTSG.shtml Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Ackermann N8UR wrote: Poul-Henning Kamp said the following on 08/20/2006 02:37 PM: In message [EMAIL PROTECTED], John Ackermann N8UR writes: Thought this might be interesting. I took a spectrum analyzer shot of my ICS525 Clock-Block synthesizer at 250MHz, and overlaid it with a shot of an RF signal generator (Marconi 2202A) at the same frequency, and using the same reference source. The 2202A is designed for bench use and isn't noted for particularly good phase noise, but you can see the dramatic difference between the two units (the ICS525 is in red, the 2202A in cyan). That's why the Clock-Block isn't recommended for RF use! Have you played with the various PLL configurations that give the same output frequency to see what difference they make ? No, I haven't done that. In this case, all three results from the calculator (lowest error, jitter, and current) used the same jumper settings, and I haven't messed with the formulas to come up with other possibilities. However, some other experiments indicate that the phase noise is better when only the V divisors are used; using the R and particularly S divisors results in quite a bit more noise. If you look at the phase noise plots at http://www.febo.com/time-freq/hardware/ICS525/index.html you can see the difference between a simple divisor configuration and a more complex one. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Distribution amplifier
Hi Magnus: I use satellite splitters and amps for GPS, see: http://www.pacificsites.com/~brooke/4GPS.shtml Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Magnus Danielson wrote: Hi! In need of a GPS distribution amplifier. Any ideas? (Ebay isn't good for this) Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Enhancing the TIC232 code for better data
Hi Bill Didier: I think that Richard is using the tvb divider on his 10 MHz reference to get to 1 PPS and that has a square wave output. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Bill Janssen wrote: Didier Juges wrote: Second thoughts about inverting the UTC 1PPS. I have read in a previous post that for most GPS receivers, only the leading edge of the 1PPS pulse is tightly controlled (and intended to be synchronous with the satellite signal), the falling edge is not. If this is true, we want to make sure we keep that edge the way it is and then invert the 1PPS from the DUT, if this is possible. Also, at least with my Jupiter receiver, the 1PPS is a fairly short pulse, not nearly 50% duty cycle, so inverting it might not give much improvement. Any thoughts? Didier Would it be feasible to clock a flip-flop with the pulse ? that would give a 50% duty cycle but with one pulse per two seconds. I hate to slow the signal but it might be feasible. Bill K7NOM ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Enhancing the TIC232 code for better data
Hi Didier: Neither. It's my understanding that Timer 1 is gated by the output of a 4046 phase detector and it's high time is determined by counting a 16 Mhz oscillator. The PIC internal Synchronization feature is set to off. Since Timer 1 is used as a 16 bit counter it will rollover in about 4 milli seconds. So the main program loop that executes much faster than that just polls the Timer 1 overflow bit and increments some more bytes to from a 4 or 5 byte accumulator (the accumulator needs to be large enough to hold counts corresponding to 256 seconds where the TI is 1 second). The falling edge of the same 4046 output is also used to generate an interrupt by using another PIC pin. This interrupt decrements another 1 byte counter that's set for the number of times a phase comparison will be made ( 1 to 256 comparisons) and since we are talking about 1 PPS signals it's also about how long the test sequence will run in seconds. Once the counter decrements to zero the measurement is finished and the 4 or 5 bytes are output. They are then divided by the number of measurements to get the actual measurement value. Since 16 Mhz has a period of 62.5 ns a single shot measurement would have that resolution, but if the number of measurements is 125 the resolution will be 0.5 ns. I'm not sure why it's better to zero Timer 1 after each interrupt rather than letting it accumulate the time intervals. Have Fun, Brooke PS I really like this idea. Didier Juges wrote: How do you measure the averaging time? Should we 1) measure the actual time that the phase data is being read (as I understand, that would be accumulating the time that the phase comparator output is high) and stop when we reach a certain count/time, or should it be 2) just elapsed time (periodic interrupt based on independent timer)? If it's 1, we need another counter, and if it's 2, we need another timer. Should there be an overflow check on both the 24 bit phase counter and the 32 bit accumulator? I am concerned that clearing the phase counter may introduce more jitter if it's not done at the right time. Since the counter is read from an ISR, there may be issues of latency. I am very interested as I am considering using a small proto Silabs PWB with an C8051F300 chip for the experiment. Didier KO4BB Richard H McCorkle wrote: Here is an insider tip for the Time-Nuts community: Although the Simple Time Interval Counter works quite well with it's present code, it was designed as a demonstration of adding Simple Commands to a program. The code can be enhanced for less noise in the data when being used in serious work by making a few modifications to the code. As designed a 32-bit phase counter accumulates multiple samples until the sample time is reached. Multiple gates of the clock to the phase counter has been shown to produce higher noise in the data than reading and resetting the phase counter on each sample and accumulating the samples in a separate register. By taking a 24-bit sample each second, adding it to a 32-bit accumulator, and clearing the phase counter before the next sample, less noise is introduced into the data giving improved results. To enhance the performance of the Simple Time Interval Counter for serious use make the following changes to the code: 1. Change the TMR1 overflow counter in the background routine to 8-bit making a 24-bit phase counter. 2. Define a separate 32-bit register as a phase accumulator. 3. Define a 32-bit add routine to add the 24-bit phase data to the 32-bit phase accumulator and clear the phase counter. 4. Modify the interrupt routine to read the phase counter, add the result to the 32-bit phase accumulator, and clear the phase counter on each interrupt. 5. Display and clear the 32-bit phase accumulator at the selected averaging time. By making these modifications to the Simple Time Interval Counter the modified TIC can provide cleaner data capable of analysis in the sub nanosecond range for use in serious timing work. . Enjoy! Richard H McCorkle ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SiLabs
Hi Randy: Would you elaborate on how TRAIM works. I thought that it acted like a switch and either allowed the 1 PPS output or turned it off. But you seem to be saying that it can remove a bad satellite from the solution and maintain the 1 PPS output. Is that the case? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Randy Warner wrote: Glenn, You're right. I would expect quite a bit of jitter. My comment about USB-Serial converters probably should not be on a timing news list. However, the 1PPS coming in on the DCD line of a standard serial port jitters too, but is still plenty accurate for loose timing systems like NTP servers who are only looking for millisecond type resolution. I think one of the main reasons we still sell a lot of timing receivers to these customers is really because of the TRAIM function. They really don't need ns type accuracy, but they DO want the receiver to alert them to large anomalies due to sick satellites, and to automatically remove the satellites from the solution. Randy ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Information on the Danjon Astrolab
Hi Geoff: Thanks for the reference to Geodesy. Do you know if the first edition has the Danjon information? I ask because the second editions are rather pricey and the 3rd and 4th are not available at all. Could someone on this list make a copy of the Danjon section? The PZT used a large pool of Mercury to define Up. The source of many errors was considered in the design and as far as I know were all eliminated. The PZT worked by exposing a glass plate at 4 known times. I think it was reversed for two of the exposures and then after development read on what amounted to a coordinate measuring machine. Then a number of corrections could be made depending on the geometric relation between the 4 points. The Dent Meridian Instrument or as he called it the Dipleidscope uses a couple of mirrors behind a clear glass and when the two reflections coincide the star is on the meridian. The manual gives a number of ways of aligning it, one of which depends on already knowing the time. See: http://www.pacificsites.com/~brooke/Dent.shtml But it's intended for visual use, not automated. Have Fun, Brooke Clarke Geoff Powell wrote: In article [EMAIL PROTECTED], Geoff Powell [EMAIL PROTECTED] writes Does anyone know how a Danjon Astrolabe works? snip Source for this - the book Geodesy by Bomford. Sorry, no ISBN or publisher (I'm typing from memory) Geodesy Bomford, Guy Clarendon Press, Oxford 2nd Edition (1965) (Out of Print) 3rd Edition (1971) ISBN 0198519192 (Out of Print) 4th edition, from 1980. ISBN 0-19-851946-X Or you can try this Biblioquest search http://www.biblioz.com/main.php?action=5u=24b729e881416a4d4feb2da5a9d34 ed3author=Bomfordtitle=Geodesy It is considered one of the primary references for geodetic surveying, albeit somewhat dated. -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] A Simple PIC Divider
Hi Glenn: The PIC uC chips all divide the incoming oscillator signal by 4 to generate a set of 4 internal clock signals so the actual instruction frequency is Fin/4. A 10 MHz input results in a 2.5 Mhz instruction cycle frequency, or 400 ns per instruction. Any code in the PIC that involves a branch and doing something is going to take a few instructions so you end up around a 1 us offset. But for most things you want an offset so that you are not measuring on both sides of zero. It might be possible to change the SYNC function so that instead of trying to make the code as fast as possible instead after the sync pulse is detected to wait for .996 seconds (or some other time TBD) so as to get closer to the 1 PPS edge. Another idea would be to make an external circuit that would be put in series between the 10 Mhz clock and the divider with a button and every press of the button would remove one cycle of the clock giving you a -100 ns step. This idea could be extended to 10 cycles, 100 cycles, etc. Allowing moving the 1 PPS edge. It happens that I've just started looking at how to move the 1 PPS edge in the Precision Clock, see: http://www.pacificsites.com/~brooke/PRC68COM.shtml#PC3 and it looks like the PIC can easily move it in 1 ms steps and I think that may be good enough. Rather than instruction counting, like is used in the tvb divider the clock uses interrupts. This has a big advantage in that the clock keeps running all the time, even while it's being set. That way changing the time will not effect the 1 PPS edge. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Glenn wrote: Does anyone have a good solution for the 1-2 us delay between the divider reset (or start) and the first (and later) pulses? I think this might be a good reason to put a serial port on one of the pins. Then, you could send the divider skip x steps or add x steps. I'm not sure if it would matter if the skipped steps were on the high or low side of the pulse. You could also use this function to compensate for the temperature dependent TTL-RS232 line driver delay used on 1 PPS lines sent to things like NTP servers. cheers, glenn ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Information on the Danjon Astrolab
Hi: After seeing a reference to Splitting the Second by Tony Jones on Tom's web page I read it and found that the Photographic Zenith Telescope was replaced by the Danjon Astrolabe. But Google provides almost no information about it. A patent search has turned up a number of optical systems, mostly for spacecraft, that use star separation for navigation, and if used at a know location on the earth could be used for timing. For these see my Stellar Time Keeping web page: http://www.pacificsites.com/~brooke/StellarTime.shtml Does anyone know how a Danjon Astrolabe works? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Timing or Navigation GPS Receivers (was: Turning off PPS when not enough satellites)
Hi Ulrich: It's interesting that the now in development carrier phase GPS time transfer method that might offer 1,000 times lower uncertanity is based on the Ashtech Z12 surveying receiver, not a timing specific GPS receiver. http://scholar.google.com/scholar?q=Ashtech%20Z12%20carrier%20phase%20GPS%20time%20transferhl=enlr=oi=scholart Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Ulrich Bangert wrote: Poul-Henning did already give the answer. However i am not very happy with the formulation In other words, it has nothing to do with the receiver, it's about what you ask it to do. because a) I never saw a navigation receiver featuring a position hold mode b) I never saw a timing receiver featuring a navigate forever mode. Everything that i had in my hands had a automatic site survey mode after which it would return to position hold. That's why i think the formulation that it depends on the receiver's primary purpose is not that wrong! Regards Ulrich Bangert -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Poul-Henning Kamp Gesendet: Dienstag, 1. August 2006 12:28 An: [EMAIL PROTECTED]; Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Turning off PPS when not enough satellites In message [EMAIL PROTECTED], [EMAIL PROTECTED] writes: On Tue, August 1, 2006 10:56, Ulrich Bangert said: Note that any gps receiver can not be really good for timing and navigation at the same time, so all navigation receivers make bad timing receivers. I am interested in your arguments for the above statement. Please elaborate! The above statement should probably be read as: If you solve for both position and time you get worse time than if you hold the position constant and solve only for time In other words, it has nothing to do with the receiver, it's about what you ask it to do. Not all receivers can do position hold mode of course. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] fts 4050 performance
Hi Chris: If the source of a pulse is 50 Ohms and it's TTL level at open circuit ( 0 to 5 volts) and the load is 50 Ohms, then when you connect a 50 Ohm load the pulse is 0 to 2.5 volts and so setting the trigger to 2.5 volts is just on the edge of not working. It's best to put a T connector and have a look with a scope. If the above is the case then a trigger level of 1.25 might work better. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Christopher Hoover wrote: Attached is what I'm seeing in terms of adev and mdev on my new FTS 4050. The performance is worse than I had expected, as compared to the datasheet. I'm not 100% confident in my test setup, but I'm not seeing any obvious outliers in the data. Test setup is as follows: Counter: HP 53132A Timebase: external, 10MHz from Z3801A Start: 1 PPS from Z3801A, DC, 50Z, 2v5 trigger level Stop: 1 MHz from FTS 4050, AC, 50Z, auto trigger -ch ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] How do I know my GPS stabilized oscillator is working?
Hi Alberto: I don't think so. The crystal oscillator is aging and so the EFC value should match the aging in the long run. See that plots at: http://www.rt66.com/%7Eshera/index_fs.htm To see of a GPSDO is working compare it's 1 PPS output to the GPS 1 PPS. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Alberto di Bene wrote: Didier Juges wrote: --- snip --- The question that comes up is: how do I know my GPSDSO is working and how do I evaluate its stability? --- snip --- Couldn't you plot the EFC value vs time, and check whether it tends asymptotically towards a (pseudo-)stable value ? Knowing the Hz/V parameter of the 10811 should also allow you to guesstimate the quality of the lock obtained. 73 Alberto I2PHD ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Interference effects to GPS timing
Hi Faisal: There have been two articles in GPS World within the last year about this. One case was about Santa Cruz harbor in California being jammed by a malfunctioning active antenna on a boat. The Naval Postgraduate School in Monterey was involved in tracking down the problem. Another case has to do with the radar on military ships burning out GPS receivers on nearby ships, including other military ships. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Phaysal Khan wrote: Hi, Thankyou for your responce. My main prob is not to avoid interference but to see how does a GPS timing rcvr behaves in the interferece environment. I have tried to search for articles/papers on interference effects on GPS timing rcvrs, but was unable to find any good stuff. Although GPS timing is in use for last 16 - 17 years, but it seems that ppl take this thing for-granted. could you locate me any such information? Regards Faisal A. Khan - Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Interference effects to GPS timing
Hi BJörn: Yes, the articles are about GPS in general, but I'm sure that if there's a problem that keeps a general purpose GPS receiver from working a GPS timing receiver will also suffer. Have Fun, Brooke [EMAIL PROTECTED] wrote: On Wed, July 26, 2006 18:23, Brooke Clarke said: Hi Faisal: There have been two articles in GPS World within the last year about this. One case was about Santa Cruz harbor in California being jammed by a malfunctioning active antenna on a boat. The Naval Postgraduate School in Monterey was involved in tracking down the problem. Another case has to do with the radar on military ships burning out GPS receivers on nearby ships, including other military ships. Do not remember any of those to be about the timing receiver aspects of interference/jamming. Interesting about the military ship radar buring out unconnected brand new antennas beeing shipped in with helicopters... The antennas would have needed the tin foil hats! -- BJörn ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Quick Allan deviation measures
Hi Tom: Do you have a plot that goes past 1 day? What happens at 2 days, a week, etc? Have Fun, Brooke Tom Van Baak wrote: See how the GPS diciplined 10811 with extra oven keeps it track above that of a normal 10811 sitting in a unit. Notice also that the Cx1 had been powered only for an hour instead of over 24 hours. Since you're only looking at tau of 0.001 to 1 second things like warm-up time and ovens have little or no effect. Infact, the GPS is worst of all these sources!!! I am quite sure that a 10 s measure would should the GPS even more infavourable. Correct (as it should) and even worse at 100 s and maybe even 1000 s. But beyond an hour of averaging time your Z3801A will start to shine. See typical Z3801A ADEV plot: http://www.leapsecond.com/museum/z3801a/log8286v.gif /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] On Setting Precision Clock
Hi: I've been working on making a LCD based clock where the PIC microcontroller uses a precision frequency source as it's heartbeat. Today I got the LCD navigation and time-date setting to work, but don't like it. The current version stops the clock and then uses the cursor and blink hardware features of the LCD, but the problem is that cursor and blink are global, i.e. they can not be used when the LCD is being updated constantly (like once each second). So I'm thinking of better ways to set the clock and my current idea is to use a couple of characters at the very upper right of the LCD is indicators. They might be HH, MM, SS, YR, MO, DY or others, and can be changed by the Select button. Then pressing the Increment or decrement buttons would change the associated counter. This way you would not loose the 1 PPS edge when changing the time or date. http://www.pacificsites.com/~brooke/PRC68COM.shtml#PC3 - as it is today Any thoughts? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 3325B Function Generator and GPS based frequencycontrol
Hi John: It's my recollection (and so subject to bad memory) that the 3325's claim to fame is that the amplitude is settable in steps of 0.01 dB. Also the amplitude accuracy is very good. Because of this the 3325 is still called out as part of the required test equipment needed to calibrate other test instruments. The A model uses mechanical attenuators that wear out and the B model uses some more reliable attenuation scheme. Once the A model breaks it's toast. Since they are still needed for doing calibrations the demand for the more reliable B model is driving up the price. http://www.tucker.com/images/images_spec/0015.pdf Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Ackermann N8UR wrote: I've always been curious about the 3325A vs. B -- there is more price spread between those two than just about any other HP A vs. B model. What's the difference between them, and is it worth anything like that much (obviously, Mike doesn't think so :-) ). I've been happy with my A model, though it often fails amplitude calibration on powerup. Waiting a few seconds and then running the cal always works, though. John Mike Feher wrote: Seems like a lot of money to pay for one. I have been using an HP 3325A for about 25 years and like it very much. I bought it brand new from HP for the company I worked, where I was director of engineering. After I resigned, to pursue greener pastures, they eventually closed down their hardware capability and operations and offered me the entire laboratory and inventory which then I purchased personally. I would recommend you getting the A version for about one fifth of the price of that B model, unless, you have an overwhelming desire to get the B for some special reason. Option 001 provides the high accuracy ovenized reference and it does not look like the one on ebay has that option. Normally they would use a TCXO. Regardless, since you will be using an external reference it really does not matter. The A also accepts an external reference and I run my off of a local Rubidium. 73 - Mike ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 3325B Function Generator and GPS based
Hi Xaos: It may have worked fine and just had a rear output modification. But the missing connector on the front is why the price was so low. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com xaos wrote: Well, except for the fact that it had no output it was fine ;) Seriously, though. $100.00 is a bargain for that box. If you got lucky and the bad parts were not some custom jobs you'd have a very nice function generator. Looks like I have to pay a bit more though... -George Here's one that sold for $102 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=31869022 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Some results of PRS10 and Trimble Resolution
Hi Björn: I don't think that's that case. I live in a small town and hired a local surveyor chosen because he's the guy that uses GPS. He was able to use two GPS receivers separated by say 100 feet and connected with a cable to determine an accurate relative bearing between his total station and the remote GPS. I had placed wood stakes at a few locations that were very close to Longitude and Latitude points ending exactly on the seconds, for example 123:09:50.0W by 39:11:24.0N. The idea was for him to locate the exact points and to locate the house GPS antenna. To do this he needed to go back to his office and post process the data. Since the points I wanted to know about were separated by exactly 1 second of Lat and 1 second of Lon he just placed his total station a few feet from the corner one and shot the other stakes. It's my understanding the the military has the crypto key needed to use the L2 channel to full effect and that's not available to surveyors. What surveyors do is record the carrier phase of both the L1 and L2 signals and resolve the ambiguity in post processing. There are a couple of flavors of post processing. In one only the data recorded in the field is used, in the other the filed data is combined with actual data taken at a nearby reference station from the satellites used in the field data. The second method corrects for errors in the ephemeris data broadcast by the satellites. I think what you may be referring to are the differential correction methods, either Low Frequency or satellite broadcasts that improve the position accuracy of GPS receivers. But I don't think these can be used to improve timing accuracy. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com [EMAIL PROTECTED] wrote: . . . . Why are dual freq. receivers not used in timing instruments? Ionospheric errors are almost removed. Surveyors in every small town on earth are routinely getting sub 5cm accuracy in real time. Are not time labs using it to transfer their cesium time to each other? -- Björn ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Linear Interpolator
Hi Brooks: I too got the quote on the GP2 and checked the ExpressPCB software package that does both schematic capture and board layout and it has a template for the QFN32 package. For comparison I placed the ICS525 template right beside the QFN32. The ICS525 has 1/4 pitch (0.025) but the QFN is 0.5 mm (0.02) which is a little finer. I have been able to mount the ICS525 using either solder paste or just an iron. For more on working with SMT parts see my web page: http://www.pacificsites.com/~brooke/SMT.shtml I agree with Randy's comment that the pad on the board needs to be longer to give an iron a place to work. Also solder mask sure is a big help, and that's why it exists. If there's a desired circuit I'm fairly sure I could build it. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Brooks Shera wrote: Inspired by Ulrich's lead regarding the high resolution TDC, I asked the Acam US rep for a quote on the TDC GP2. As Ulrich indicated they are not too expensive: $28 quantity 1, $26 quantity 10. Sounds great. Temperature coefficient isn't quoted but it will be considerable - presumably can be corrected in software. For me the catch seems to be that they are packaged in a QFN-32. The pin spacing is 500 microns and the open space between the solder pads is only 200 microns. Perhaps I am too timid but this sounds like trouble for manual soldering, that's assuming the low cost PCB suppliers could make the appropriate solder mask. Any comments from the experienced? Acam makes a dandy evaluation board, the ATMD-GPX, but for this they want $2298. Oh well. Brooks - Original Message - From: Ulrich Bangert [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com; 'Magnus Danielson' [EMAIL PROTECTED] Sent: Thursday, June 29, 2006 11:41 Subject: Re: [time-nuts] Linear Interpolator Hi Stephan, if you need a ps resolution time interval counter for use in a project of your own, why not simply go out and buy you one? For example here http://www.acam.de/index.php?id=105 They are not that expensive because they are made to be married with cheap sensors. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] The Case for eLoran 9th Pulse Modulation Time Data
Hi Poul: Thanks for that insight on Loran-C in Europe. Have you done any work on the new digital data format for Loran-C? There's a few U.S. stations now transmitting the digital data which includes the time and leap second correction bits. For more info on this technology see: http://www.navcen.uscg.gov/loran/9th-pulse-modulation-ldc.html Too bad Middletown on 9940 is not sending the 9th pulse or I'd give a shot at decoding the time. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Brooke Clarke writes: The British have just published a document about the Enhanced LORAN-C system. It's quite interesting times over here in Europe. Amongst people who know what they are talking about, there seems to be increasing awareness that pretty much all the foundations under Galileo has shifted for the worse. There are no users willing to pay for any of the services. Forcing them to pay by regulation or legislation will take 10-15 years for ships/planes because the regulatory domains extend outside EU political reach. Road-pricing has not (yet) been a killer app anywhere, pretty much all politicians hope that oil-prices will do the job instead so they don't have to put their name behind a very unpopular idea. With the revenue-driven model of Galileo in distress, it is no surprise that the negotiations with private entities about operation has dragged out a couple of years, and decisive developments in the negotiations are not expected until later this year. Pulling countries like China into the Galileo group has many people uneasy, and seen strategically it can only count as a negative in the US/EU friction. If USA didn't have incentives to develop countermeasures for Galileo before, the addition of China certainly provided them. On that account, the initially much trumpted jamming resistance of Galileo seems very much in doubt. Did USA pull a smart one on EU in the modulation negotiations ? Some military personel suspect, strictly off the record, that the new US GPS birds have hardware to specifically jam Galileo, and to them the frequency co-location now seems very much like a major mistake. All in all, galileo looks increasingly like a a negotiation bluff which went horribly wrong and which will end up costing the EU taxpayers a fortune. Because nobody in power would ever be able to admit such a monumental blunder, and because the pure prestige of Europe also having a GNSS system would get a blow, were Galileo to be cancelled, it will not be. Also, the economy of the Arianne rocket would take a severe blow if the planned 7-9 A5 launches does not happen. But more and more politicians are starting to look for a way out, or at least trying to not rush in. In the meantime France in particular, and increasingly also England lobbies for Loran-C extension and expansion as a backup or supplement. The funny thing here is that Loran-C deployment will not happen until the ratification of the European Radio Navigation Plan (which cover much more than just EU). The ERNP drafts warmly advocates Loran-C, citing from memory: 22% of benefit for 7% of money, is currently stalled because the European Commission is too busy, trying to save Galileo... So severe is the mumbling in the corridors that some even say that if we drown just a quarter as much money into Loran-C (or an entirely new VLF system) as is going to be the case for Galileo, we would get much better result. May you live in interesting times indeed... Poul-Henning ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Entry level systems
Hi Keith: A lot depends on what you're trying to do. Do you already have a counter that will make time interval measurements and if so with a lot of averaging what's the smallest time interval you can see? Do you already have frequency standard(s) and just want to use GPS to check on them or discipline them? The features of the TAC may or may not be a good fit to your needs. Can you elaborate on your goals / interests / etc.? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Keith E. Brandt, M.D. wrote: What's a good entry-level time reference system? I'm doing this for the fun/learning/hobby and can't dump $10k into it (without also incurring the attendant lawyer's fee for the divorce settlement :-) I think something along the lines of the TAPR TAC would be perfect if they still made it. Are there other relatively low-cost GPS reference systems out there? Keith LtCol Keith E. Brandt, MD, MPH USAF-NASA Aerospace Medicine Liaison Officer Johnson Space Center, Houston, Texas [EMAIL PROTECTED] Goodbye cruel world that was my home- there's cleaner space out here to roam Put my feet up on the moons of Mars- sit back, relax, and count the stars *This message transmitted with 100% recycled electrons ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Entry level systems HP 5345
Hi John: I'm using the HP 5345A opt 11 now and really like it. When in the Time Interval mode (cesium s/n 1227 1 MHz on start and cesium s/n 1013 1 MHz on stop) you can turn the Gate Time knob up from MIN to say 1 SEC. What this does is to accumulate the gate times for as many receptive measurements as it takes to get to a total of 1 second, so the number of measurements depends on the actual TI being measured. For example with 1 SEC gate time and a TI of about 574 ns it takes about 3 seconds of clock time per measurement. The display is like 574.419,441 nano seconds. That's 574 nano seconds and 419 pico seconds and 441 femto seconds. If you set the gate time longer you get more digits. So at 10 SEC you get 0.1 femto seconds resolution after a 30 second wait. Simply fantastic! It counts to 500 MHz without any plugins unlike the HP 5245 that needs a plugin to get to 500 MHz. But a drawback to the early models is that the air filter is buried behind the FRONT panel and needs servicing something like twice a year. This required taking the counter apart. In later versions they removed the air filter. Although I can read HP-IB data in talk only mode, I haven't figured out the secret of two way communication. But the SR620 is still hands down my favorite TI counter. 16 digits with a fixed weight on the positions is a really good layout. Have Fun, Brooke Clarke John Day wrote: At 06:31 PM 5/24/2006, John Ackermann N8UR wrote: Keith E. Brandt, M.D. said the following on 05/24/2006 06:06 PM: What's a good entry-level time reference system? I'm doing this for the fun/learning/hobby and can't dump $10k into it (without also incurring the attendant lawyer's fee for the divorce settlement :-) I think something along the lines of the TAPR TAC would be perfect if they still made it. Are there other relatively low-cost GPS reference systems out there? Interesting question! Assuming you mainly want to have a test-bed for learning and experimentation, I'd say you want three things: 1) a local frequency standard, 2) a frequency/time interval counter, and 3) a GPS or other radio reference. For the frequency standard, one of the surplus HP 10811A or 10544A oven crystal oscillators (OCXO) which can be had on eBay for $50 - $150 would be good, or one of the surplus Efratom Rubidium standards that go for the $250 range -- each has its own advantages; the crystal will have better short term stability and less phase noise, but the Rb will have better long term stability and will need to be recalibrated far less often. You will often find that it is cheaper to buy a counter with the high-stab oven option than to buy the oven separately. For the frequency counter/time interval counter, I am very partial to the HP 5334A or B. They are quite cheap on eBay (usually less than $150 and have 2ns time interval resolution. As a bonus, many of them have the high-stability option (001) that includes an HP 10811A oscillator, and if you find one with the channel C option you will be able to read frequency to 1.3GHz. The 5335A is also sold from about $100 up and has the oven option as opt010, 1.3GHz is opt030 and opt040 - expanded HPIB control is worth having if you plan to remote the counter at all. A little heavier is the 5345A which can be equipped for operation all the way to 40GHz or so at not a huge expense. It is one of my all time favourites. It has 2ns resolution and counts direct to 500MHz. They came as standard with the high stab oven, opt001 removes the oven. Opt010 is very basic HPIB talk only, opt011 HPIB with remote programming, opt012 is HPIB like 011 but has control of slope and trigger level as well. You can pay from $80 or so for basic counter with HPIB. Just get the seller to confirm it is not Opt 001! The 5345 is heavy, and a bit noisier than the newer 5334A/B or 5335A. To my m ind if you are interested in frequerncy measurement, this counter can give you flexibility well beyond anything else that mere mortals can afford when coupled with various plug-ins and convertor heads. 73's, John (ex VK3ZJF) Finally for the GPS. We're in a state of flux right now because Motorola sold their line of GPS receivers and the one everyone would have recommended last year is no longer available. Nonetheless, you may be able to find an M12+T receiver which is the best unit they had available, or the slightly older UT+. You'll need an antenna, but you don't necessarily need the TAC-2 -- all it really does is provide power supply and I/O buffering. You can do that on a piece of perfboard if you want. There are lots of other neat toys, but with those three you'll have a good frequency standard and a way to calibrate it. Hope this helps. 73, John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Sign of Time Interval SR620 Hint 2
Hi: Not knowing which direction to move the C-field, I tried 000 where 500 is probably more like correct. The result on s/n 1013 is no change, in the TI when compared to s/n 1227 that's probably near 1E-13. The difference between the two cesium standards is 9.9E-12 and changing the C-field on s/n 1013 has no effect. s/n 1013 is the one the shipper did not put in the Jiffy-box, and instead metal banded to the pallet. I think there is a problem with the C-field circuitry. Maybe that's why the green Lock LED is on but it can't be set. This is very easy to see when using a good cesium as a reference. --SR620 Hint #2 -- The External reference can be either 5 or 10 MHz, but not 1 MHz. If you connect a 1 MHz source to the ext ref input it confuses the counter, i.e. may change in internal reference frequency value. To fix that you need to go into the CAL menu and set the frequency to 1000. Also after moving the jumper on the PCB to enable cal constants (I'm leaving it there since I'm the only person using this counter) you can use the front panel keys to view and change internal calibration constant #4 which can be between 0 and 4095. This is the control voltage to the internal 10.0 MHz oscillator. Mine was slow 17 Hz and changing the cal constant from 02038 to 01957 brought it back to within 0.01 Hz. This might make it easier for locking to the external reference. Have Fun, Brooke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] FTS4060 Saga
Hi: I've been comparing s/n 1227 aginst GPS for a couple of weeks and am within a tick or two of getting the c field optimized. I think the current actual offset is less than +2.2E-13, but R^2 is only at 0.2 so am not really sure yet. A problem that shows up every now and then is that the standard deviation on a 500 second average is above 10 ns (typical is 9 ns). For example here is some data all this morning (17 May 06): Time Interval (ps) time sigma 975803 04:49:20 9 969817 04:57:4098 919359 05:06:00 240 838596 05:14:20 349 957634 05:22:40 150 979542 05:31:00 9 917433 05:39:20 244 903613 05:47:40 267 913995 05:56:00 251 936876 06:04:20 206 976696 06:12:40 9 973410 06:21:0062 959098 06:29:20 144 976590 06:37:40 9 I have a couple of ideas of what might be causing this. One is that there were no satellites to track and the crystal in the M12+T drifted, but think this is almost impossible since the elevation mask now is at 20 degrees. The other is multipath. Is there any information on how multipath effects the M12+T? I would think that in 0-D mode and tracking only one satellite then multipath would be a factor, but if tracking a bunch of satellites then multipath on one of them would not be a factor. Since I'm logging the sigma when I see this I just toss the data. Notice that for the 3 points where sigma is 9 ns the TI looks like: 975803 979542 976696 976590 Where the spread is under 5 ns which is good. I would like to know what's causing this. Any thoughts? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] FTS4060 Saga
Hi: The prior data was logged while I was not at the computer. But while writing the last email there was another high sigma data point: 978618 11:12:40 45 TAC32 is reporting that the M12+T is tracking 8 SV #s: 22 15 14 3 18 21 7 and 19 yet there's a bad data point. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Interesting Patent
Hi: I came across a 1946 patent for a vacuum tube based counter circuit that will divide 60 Hz down to 1 Hz. It's interesting in that there's a discussion about the advantage of using binary instead of base 10 and also about using feedback to change the scale of the counter from 64 to 60 (or 50). See: 2410156 http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=2410156 Electronic Timing Device, Oct. 29, 1946, 368/58 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2Sect2=HITOFFp=1u=%2Fnetahtml%2Fsearch-bool.htmlr=0f=Sl=50TERM1=368%2F58FIELD1=ORCLco1=ANDTERM2=FIELD2=d=pall; 327/118 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2Sect2=HITOFFp=1u=%2Fnetahtml%2Fsearch-bool.htmlr=0f=Sl=50TERM1=327%2F118FIELD1=ORCLco1=ANDTERM2=FIELD2=d=pall; 340/332 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2Sect2=HITOFFp=1u=%2Fnetahtml%2Fsearch-bool.htmlr=0f=Sl=50TERM1=340%2F332FIELD1=ORCLco1=ANDTERM2=FIELD2=d=pall; 968/564 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2Sect2=HITOFFp=1u=%2Fnetahtml%2Fsearch-bool.htmlr=0f=Sl=50TERM1=968%2F564FIELD1=ORCLco1=ANDTERM2=FIELD2=d=pall; 968/946 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2Sect2=HITOFFp=1u=%2Fnetahtml%2Fsearch-bool.htmlr=0f=Sl=50TERM1=968%2F946FIELD1=ORCLco1=ANDTERM2=FIELD2=d=pall; 968/DIG.1 http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO2Sect2=HITOFFp=1u=%2Fnetahtml%2Fsearch-bool.htmlr=0f=Sl=50TERM1=968%2FDIG.1FIELD1=ORCLco1=ANDTERM2=FIELD2=d=pall- There's reference to using gas discharge tubes as indicators on one of the tubes in each trigger circuit (flip-flop) which means a neon tube. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] ICS525 synthesizer performance
Hi John: I can see that your product is very different from mine and would like to link to your web page if that's OK. Thanks for posting the phase noise plots. I've started a web page for my Battery Top Signal Generator ICS525, see: http://www.pacificsites.com/~brooke/BTSG.shtml I'm still in the process of Pushing the Limits in terms of the frequencies you can get out of the 525-02 but so far I've seen outputs between 360 kHz and 525 Mhz. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Ackermann N8UR wrote: I got my prototype ICS525 Clock-Block built this weekend, and had a chance to use my friend's HP3048A phase noise system to measure it. I've put the results, plus some other info, at http://www.febo.com/time-freq/hardware/ICS525/index.html . The bottom line is that the phase noise isn't great, and is quite variable depending on the divider ratios used, but isn't as horrible as I thought it might be. It's not going to make a good LO for your receiver, but for some other applications it could be perfectly acceptable, particularly if you can follow it with some filtering to knock down the wide band noise. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] FTS4060 Auxillary Power Connector ID?
Hi: Inside the FTS4060 there's a white plastic Molex like connector that has a male body and female sockets. Probably for use with the optional internal battery charger. The male mating part of the body is 0.248 x 0.824. The holes for the contacts are 0.161 ID and the female contacts are 0.084 ID. This looks similar to the Molex 03-09-1042 except that instead of a point on one end this connector has a couple of the corners chamfered sort of like and IEC line cord connector. A drawing and link to data sheet of the Molex connector is at: http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1storeId=10001catalogId=10001productId=224160 Molex and Amp (Tyco) don't seem to carry anything like it. The three active contacts are: Black = Ground Red = 30 volts from the brick power supply (nice place to connect an external Austron 1290A backup supply) Orange = +5 Volts from chassis voltage regulator (nice place to get power for a TVB divider). Does anyone know what this and it's mating connector are? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FTS4060 Auxillary Power Connector ID?
Hi Dave, Rex Hal: Yes, it sure looks like FTS used the same wire end connector that is commonly used for hard drive DC power. Thanks very much for pointing this out. Have Fun, Brooke Clarke Dave Brown wrote: Sounds like its similar to a standard HDD power connector? DaveB, NZ - Original Message - From: Brooke Clarke [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, May 14, 2006 4:33 AM Subject: [time-nuts] FTS4060 Auxillary Power Connector ID? Hi: Inside the FTS4060 there's a white plastic Molex like connector that has a male body and female sockets. Probably for use with the optional internal battery charger. The male mating part of the body is 0.248 x 0.824. The holes for the contacts are 0.161 ID and the female contacts are 0.084 ID. This looks similar to the Molex 03-09-1042 except that instead of a point on one end this connector has a couple of the corners chamfered sort of like and IEC line cord connector. A drawing and link to data sheet of the Molex connector is at: http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1storeId=10001catalogId=10001productId=224160 Molex and Amp (Tyco) don't seem to carry anything like it. The three active contacts are: Black = Ground Red = 30 volts from the brick power supply (nice place to connect an external Austron 1290A backup supply) Orange = +5 Volts from chassis voltage regulator (nice place to get power for a TVB divider). Does anyone know what this and it's mating connector are? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.392 / Virus Database: 268.5.6/338 - Release Date: 12/05/2006 -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] [FA] ICS525 Battery Top Singnal Generator
Hi: To get some feel for what these will sell for I'm auctioning a prototype unit as eBay item number 7616994287. Have Fun, Brooke Clarke, N6GCe Brooke Clarke wrote: Hi: Awhile ago there was some discussion about the ICS525 and I finally got a quote on their demo board it was $57 and 10 weeks. Well it's been less than 10 weeks and I've made my own, with more features than the stock version. There's been some delay getting all the stuff to do fine pitch Surface Mount Parts, see: http://www.pacificsites.com/~brooke/SMT.shtml Version 1.0 has the ICS525-02 (160 MHz max out) a couple of 10 position SIP switches, a power supply including snaps for a 9 volt battery and a 14 pin socket that will hold either a full or half size DIP oscillator. There's also a BNC input connector that can supply the chip instead of the DIP oscillator. BNC output connector. See more at: http://www.pacificsites.com/~brooke/PRC68COM.shtml#BTSG http://www.icst.com/icscs/PartSummary.aspx?id=cf3d07a6-2cb4-4faf-8ad6-f4749fb2c1a8name=ICS525-02mode=short Data Sheet for ICS525: http://www.icst.com/datasheets/ics5250102.pdf When using the calculator be sure to scroll down to the results for the high speed -02 version, see: http://www.icst.com/calculators/ics525inputForm.html For now I'm calling it the Battery Top Signal Generator, but it might have numerous uses. Is there any interest in my making more of these to sell? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] ICS525 Battery Top Singnal Generator - Frequency Synthesizer-Translator, Test Transmitter, (Crystal Replacement?)
Hi: Awhile ago there was some discussion about the ICS525 and I finally got a quote on their demo board it was $57 and 10 weeks. Well it's been less than 10 weeks and I've made my own, with more features than the stock version. There's been some delay getting all the stuff to do fine pitch Surface Mount Parts, see: http://www.pacificsites.com/~brooke/SMT.shtml Version 1.0 has the ICS525-02 (160 MHz max out) a couple of 10 position SIP switches, a power supply including snaps for a 9 volt battery and a 14 pin socket that will hold either a full or half size DIP oscillator. There's also a BNC input connector that can supply the chip instead of the DIP oscillator. BNC output connector. See more at: http://www.pacificsites.com/~brooke/PRC68COM.shtml#BTSG http://www.icst.com/icscs/PartSummary.aspx?id=cf3d07a6-2cb4-4faf-8ad6-f4749fb2c1a8name=ICS525-02mode=short Data Sheet for ICS525: http://www.icst.com/datasheets/ics5250102.pdf When using the calculator be sure to scroll down to the results for the high speed -02 version, see: http://www.icst.com/calculators/ics525inputForm.html For now I'm calling it the Battery Top Signal Generator, but it might have numerous uses. Is there any interest in my making more of these to sell? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Motorola Oncore Basic Command @@Bk Help
Hi George: My 8 channel manual lists it: Position/Status/Data Extension Message @@BkmCCRLF m - mode (0 = respone once when polled, 1.. 255 # per second) C = checksum @@BkggpphhvvttmmnneeuuaarrCCRLF gg- Current GDOP pp - Current PDOP hh- Current HDOP vv - Current VDOP tt - Current TDOP Velocity : nn- North ee- East uu- Up Age of differential correction data aa - seconds REceiver position in ECEF (X,Y,Z) cm - - - URA for each of 6 channels r - (0 to 15, 63 not decoded yet) least squares A-1 matrix ii- receiver clock bias cc - meters osc offset oo- m/sec C - Checksum Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.co xaos wrote: Hello Everybody, Does anyone here know what the Motorola Oncore @@Bk command does? It is from a Basic 6 channel Model. More importantly does anyone have the docs for it? Many hanks in advance, -George, N2FGX ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] u-blox LEA-4T Timing GPS receiver?
Hi: Does anyone know about the new u-blox LEA-4T Timing GPS receiver and time stamp? http://www.u-blox.com/products/lea_4t.html Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Spectracom 8140T distribution amps
Hi John: eBay auction 7605840019 says up to 25 boxes on the master coax. But I suspect it's a function of the power supply in the main box. 73, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Ackermann N8UR wrote: Does anyone on the list have any specs or manuals for the Spectracom 8140 distribution amplifiers? While I'd like schematics, I'm particularly interested in how many of them you can put in a single chain. For those who aren't familiar, these are part of a frequency distribution system where there is a master coax line that carries 10MHz on top of 12VDC. You attach multiple 8140T boxes along this line (with BNC tees) and each one provides a single output, usually a sinewave but there were versions that did frequency conversion, output a square wave, etc. There was also a multiple version (8140M I think) that provides three square wave outputs and can be externally powered. These make a nice way to route signals around the lab. They were designed to work with a box (just plain 8140, I think) that took a single input and could drive up to 4 strings of amps. Also, my 8164 WWVB-disciplined oscillator has an option installed that put 12 volts on its outputs. Right now, I'm driving it from my slightly modified HP 5065A Rb standard; I tapped the signal off before the divide-by-2 (later model 5061As and 5065As used a 10811A oscillator followed by a divider to maintain a 5MHz output) and used a mini-version of the TADD-1 amplifier with an injector circuit to put 12 volts on the output. The original 5MHz is still available and doesn't seem to be affected. Anyway, I'm just wondering how many of these amps I can string together; right now I have 8 and it seems to work OK but I'm not sure if I'm stretching things. Thanks, John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran - any good for timekeeping?
Hi Poul: What is a Frame rate cyclic averaging buffer? Is this where you use a GRI generator to trigger sampling the incoming signal? I've found that the quality of LORAN-C for timing depends on how close you are to the transmitter. When in the 100 mile range the quality is equal to better than GPS, but when it's many hundreds of miles there's a lot of variation. I'm attaching a gif of the spectrum here from 0 to 200 kHz that goes with the web page: http://www.pacificsites.com/~brooke/Spec_0002.shtml Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Poul-Henning Kamp wrote: In message robkimberley1$86.140.134.222$.!!AAAYAOYAZyOzV8ERq+ LmT45ypI7CgAAAEHZ+5J10IM9Kj/[EMAIL PROTECTED], Rob Kimber ley writes: Long time since I played with a LORAN-C timing receiver, but the Austron units were good to a microsecond. Interesting to know what the newer technology can manage. For anyone wanting to play: the way forward is software defined radio: http://phk.freebsd.dk/loran-c Poul-Henning ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran - any good for timekeeping?
Hi John: Setting the 2100T is really a two step process. After you have done all the setup possible and then connect you house 1 PPS and put in a phony TOC that's say 10 seconds ahead, then at the TOC the 2100T will sync it's 1 PPS output (you will get a red error light). You need to do this to get the seconds ticking with UTC. Then you can set the time so it ticks over on the UTC second edge. Then do a real TOC sync. More at: http://www.pacificsites.com/~brooke/A2100F.shtml#2100T Have Fun, Brooke John Ackermann N8UR wrote: M. Warner Losh wrote: Can't you recover the time by tracking multiple chains and using the relationship between them to come up with at least small number of possible seconds? Hasn't the US started broadcasting data that can be used to know which second you are at? I don't think that the US has started broadcasting a timecode, though I think those plans are in the works. I have to look at the Austron 2100T manual to get the exact sequence of events, but basically you set the clock, feed an external PPS signal that is roughly accurate (within some tens of milliseconds, I think), and then enter the next time of coincidence (TOC) which you obtain from the USNO (http://tycho.usno.navy.mil/lortoc.html). The TOC is when the Loran pulse coincides with the UTC second. When the TOC rolls around (which occurs a couple of times per day, the receiver locks to that and you can remove the external PPS. From that point on, the PPS output should track with the stability of the Loran signal unless/until it loses lock. Not sure about the idea of tracking multiple chains; it seems like that should work, but that's not how the Austron receiver, at least, does it. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran - any good for timekeeping?
Hi Tom: If you're in the U.S. here's a list of stations: http://www.pacificsites.com/~brooke/Loran-c.shtml I'm not sure how to find the others. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com tom wrote: where can I find a list of the stations to locate one that is near me rather than look up a number tom [EMAIL PROTECTED] ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran - any good for timekeeping?
Hi: Just added links on many of the names to sattelite photos of the LORAN-C stations. The scale is different for different locations. In some places it gets down to 1 meter. So far the most photogenic one is Dana, IN. http://www.google.com/maps?f=qhl=enq=39%C2%B0+51%27+07.658%22+N+87%C2%B0+29%27+11.586%22+Wll=39.852681,-87.486556spn=0.003179,0.010697t=hom=0 You can almost see how to decode the URL. Have Fun, Brooke Brooke Clarke wrote: Hi Tom: If you're in the U.S. here's a list of stations: http://www.pacificsites.com/~brooke/Loran-c.shtml I'm not sure how to find the others. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran-C Austron
Hi Rob: What happened to Austron? Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Rob Kimberley wrote: No, LORAN is most definitely not dead. Good news, as I used to sell LORAN-C timing from Austron back in the 80's. Worked well then, and works well now. Rob K -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Day Sent: 20 April 2006 20:21 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] time-nuts Digest, Vol 21, Issue 22 So Loran isn't really dead yet! John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Antenna (50ohm) and Satelite Splitters and Amps(75ohm)
Hi Don: I'm using both Radio Shack parts for my house GPS antenna system. http://www.pacificsites.com/~brooke/4GPS.shtml But be very careful about which 4-way divider ports are DC connected to the antenna. 73, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Don Mimlitch wrote: I want to split my best 5 Volt GPS Antenna among several Time Standards Systems (some 5VDC and some 12VDC). I can get inexpensive Satelite Splitters (2GHz) from Radio Shack or Monster makes a 4GHz Splitter. These splitters are 75 Ohm but my Antenna and Receivers are 50 Ohm. My question is how much of a problem is this? Should I use 75 Ohm Coax on either side? Is there a circuit to correct any problems? I can also get a Radio Shack InLine Satelite Amplifier. Again 75 Ohm. Any other problems here? Thanks for any Help or Advice, Don Mimlitch [EMAIL PROTECTED] ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] GPS Satellite Elevation Observation
Hi: I'm seeing distortion in the time interval between GPS and the FTS4060 standard. The time interval jumps about 60 ns for about 4 hours and I think it's because the satellite signal(s) have multipath. I would expect multipath if the satellite was being tracked at or very near the horizon. In TAC32 you can plot the horizon by setting the mask angle to zero and letting the program run for a number of days. But, when you increase the elevation mask angle I think the horizon plot is just moved up. I think this may be a bug in version 2.7.2. Because of the orbit inclination there's a region to the north where there never will be a satellite. So for a given latitude there's some elevation mask which would never let any satellite be near the horizon. But that is wasting the good fixes that can be obtained when satellites are to the West, South or East at lower elevation angles. It would be better if TAC32 would allow the elevation mask to be different for different azimuth angles. I think this would improve the quality of time interval measurements or to say it another way it would be useful in getting rid of bad time intervals. I'm sensitive to this because I'm in a canyon and need a mask angle of about 60 degrees. The above problem may have been caused by setting the mask angle to 50 degrees. I'm now replotting the horizon in TAC32 with the mask set for 60 degrees and expect to see a solid circle, not the noisy horizon plot that was there (which was moved up from the zero degree plot). After about 4 weeks my FTS4060 plot shows -7 ns/day but with an R^2 value of only 0.54. Part of the reason for such a low correlation may be the above mask angle allowing skimming passes? Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] IC for 1 PPS Output
Hi Rex: Yup. It's really hard to get 50 of those 2 Ohm cables. Brooke Rex wrote: On Thu, 06 Apr 2006 21:14:29 -0700, Brooke Clarke [EMAIL PROTECTED] wrote: to drive 50 a couple of Ohm cables he he. Interesting typo. I assume you really meant 2 50-ohm cables, rather than 50 2-ohm cables. I'll defer to others with more knowledge for a real answer to your question. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] IC for 1 PPS Output
Hi: I've got the TVB 1 PPS PIC circuit working and would like to add an output IC to drive 50 a couple of Ohm cables. Need two outputs, the normal 1 PPS and also the 10 kHz output since I think it would work with the SRS app note for making 1,000 TI measurements in one second to better see small offsets. I seem to remember that there may be an internal resistance already in some chips so putting a 47 or 50 Ohm resistor in series may result in an impedance above 50 Ohms. Any thoughts? Thanks, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] ...Your thoughts on the Trimble Resolution T?
Hi: I'm not sure if Trimble does it on the Resolution T, but on the Trimpack GPS receivers, http://www.pacificsites.com/~brooke/Trimpack.shtml#BUB have a Lithium battery soldered to one of the PCBs and a Dallas chip that turns all the RAM into non volatile memory (just like core memory in operation). This means that when powered up it not only has the almanac and ephemeris data for all the satellites it also has the fix information so the warm start time is very short. They say if the receiver is moved more than 100 km TTFT will be longer. My Trimpacks which were built in the 1990 (Gulf war) time period all have good batteries, so the current needed to do this must be very small. The sawtooth correction can be used with hardware to move the 1 PPS edge or it can be used in software where a computer does the math on the measured time interval. Have Fun, Brooke Clarke, N6GCE [EMAIL PROTECTED] wrote: . . . Also, the Motorola parts have one drawback: they need a Lithium battery (or similar) to keep the most recent Almanac. I have found that the TTFF (first fix) can take quite long if the battery is weak (2V) and the RTC stops due to this, or if there is no Almanac in Memory. Don't know how the Trimble unit behaves. . . . . ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Austron Manuals
Hi: I've suffered a hard drive failure (a drive recovery service may be able to get some data out of it) and would like to borrow back a copy of the CD-ROM that I was selling with the Austron Manuals. In particular the one that includes the 1250 and 1250B. Thanks, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Telecom Solutions DCD Cesium
Hi Magnus: If what you have is an FTS clone I might be able to help. Can you email to me a top or bottom hi resolution photo of your unit with the covers removed? Thanks, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Magnus Danielson wrote: Hi! This morning a Telecom Solutions DCD Cesium landed on my lab-bench at home. There is something wrong with it, but there should still be some time left on the tube according to the source. Anyway, I am looking for info (the manuals *should* be on the way, but I will not hold my breath) and especially anything giving away usefull info on the serial port as well as service info. Any hints and tips is welcome. In the meanwhile I am figuring out how to solve the 48V problem, but I have a cludge available. Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] retro encabulator
Hi: Here's a Rockwell Automation Products commercial you just can't miss. http://video.google.com/videoplay?docid=5125780462773187994q=retro+encabulator Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FTS4060 Continuing Saga
Hi: Problem solved. The Ultra Stable Oscillator coarse tuning pot needed adjustment. Once it was adjusted to put the strong center peak into the center of the control voltage range s/n 1013 locked right up. This procedure is described in appendix A of the manual. But the procedure for the S/24 is much easier since the coarse tuning pot is on top of the USO, not on the inaccessible front like on earlier 4060 models that require removing the USO to get access to the pot. Now back to the regularly scheduled data logging. Having Fun, Brooke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FTS4060 Continuing Saga
Hi Gar: OK. It's time to pull the plug and leave it out for awhile. I tried pulling the plug for 10 seconds, but that may not have been long enough to get the oven cooled down. More later, Brooke NE8S wrote: Brooke, One of my FTS4060's behaved the same way during a power interrupt. It was the only one that was not on a UPS. After many attempts to reset the logic while powered up, I finally brought the clock down and 24 hours later, powered it back up again. As a result, it performed its normal power-up sequence and the control logic seemed to have reset itself properly. It this point, it was back to normal. It has been fine ever since. First time it has happened to me. I am mainly an HP man and very much prefer the HP clocks and their digital logic structure and methods. Hope this helps a little. Kind regards, Gar Ko NE8S CsUTC Observatory Bio-Nucleonics Laboratory - Original Message - From: Brooke Clarke [EMAIL PROTECTED] To: Tom Van Baak [EMAIL PROTECTED]; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 06, 2006 10:58 AM Subject: Re: [time-nuts] FTS4060 Continuing Saga, GPS rain Hi Tom: I think the problem is related to the FTS4060. During the brown out my computer and the SR620 counter reset, but the two green LEDs on the 4060 stayed on, at the time my thought was cool. But the yellow Align light behind the door has turned on and so far I have not been able to get it to turn off. But after trying a bunch of stuff the jitter value is now back in the 9 ns area. I have not been able to find anything in the manual about operation with the Align light on and with the Lock and AC Pwr LEDs on. Does anyone have any ideas about it? On the rain thing. I think the key parameter of water that matters is the dielectric constant which is about 80. The propagation constant is proportional to 1 / SQRT( e ) or about 11% of what it is in air. If it's 1 ns per foot in air then it's 8.9 ns per foot in water I haven't figured out how to calculate the total volume of water in the column between the satellites and the receiving antenna. I did find a web page that shows the terminal velocity of rain and it varies from 0.02 MPH for small drops to 20 MPH for big drops. But this would need to be coupled with the rate of rain fall (inches/hour) to determine how much water was in the column. Assuming big drops (20 MPH = 352 IPS) and 0.1 IPS rain rate says that the rain takes up 1 part in 3520. If the height of the rain is 20,000 feet then there's 5.6 feet of rain for a delay of 50.5 ns??? Have Fun, Brooke Tom Van Baak wrote: Rain should have an effect on the timing of the signal, since the propagation speed of radio waves through water is different from that through air. It will also attenuate the signal, causing worse S/N ratio which would cause the lower-elevation satellites to not be seen. David, Maybe we can figure this out. First, the refractive index of water is about 1.3. So I think this means the propagation speed of radio waves in water is down to about 0.75 c, right? Then, how much water are the GPS signals traveling through? Let's assume the typical amount of rain in a heavy storm is a couple of inches. All that water is either puddles already on the ground, drops on their way down, or moisture still in the clouds waiting to come down. The total amount of water in a cross section column of the atmosphere that the GPS signals travel though is thus a couple of inches total, max. Let's assume a worst case -- 6 inches. So, those GPS signals go through 20,000 km of empty space and atmosphere containing a total of 6 inches of water; in which it slows down by 30%. At a ns/foot, this comes to 25 ps per inch of water content in the air; a total of 150 ps in my worst-case example above. My conclusion is that rain or snow, light or heavy, has no effect, even at the ns level. Can someone who really knows double check this back of the envelope calculation? Thanks, /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FTS4060 Continuing Saga
Hi Gar: Interesting. I just tried a 30 minute power down, and again the ALIGN light in on. So I guess it's an overnight power down to get it reset. More tomorrow, Brooke NE8S wrote: Brooke, Now that you mention it, I did power down at first for 45 minutes. After this initial power-up sequence, the same prevailed. I then decided on the 24 hour down period for the oscillator and cesium ovens to fully recycle. Gar - Original Message - From: Brooke Clarke [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 06, 2006 11:54 AM Subject: Re: [time-nuts] FTS4060 Continuing Saga Hi Gar: OK. It's time to pull the plug and leave it out for awhile. I tried pulling the plug for 10 seconds, but that may not have been long enough to get the oven cooled down. More later, Brooke NE8S wrote: Brooke, One of my FTS4060's behaved the same way during a power interrupt. It was the only one that was not on a UPS. After many attempts to reset the logic while powered up, I finally brought the clock down and 24 hours later, powered it back up again. As a result, it performed its normal power-up sequence and the control logic seemed to have reset itself properly. It this point, it was back to normal. It has been fine ever since. First time it has happened to me. I am mainly an HP man and very much prefer the HP clocks and their digital logic structure and methods. Hope this helps a little. Kind regards, Gar Ko NE8S CsUTC Observatory Bio-Nucleonics Laboratory - Original Message - From: Brooke Clarke [EMAIL PROTECTED] To: Tom Van Baak [EMAIL PROTECTED]; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 06, 2006 10:58 AM Subject: Re: [time-nuts] FTS4060 Continuing Saga, GPS rain Hi Tom: I think the problem is related to the FTS4060. During the brown out my computer and the SR620 counter reset, but the two green LEDs on the 4060 stayed on, at the time my thought was cool. But the yellow Align light behind the door has turned on and so far I have not been able to get it to turn off. But after trying a bunch of stuff the jitter value is now back in the 9 ns area. I have not been able to find anything in the manual about operation with the Align light on and with the Lock and AC Pwr LEDs on. Does anyone have any ideas about it? On the rain thing. I think the key parameter of water that matters is the dielectric constant which is about 80. The propagation constant is proportional to 1 / SQRT( e ) or about 11% of what it is in air. If it's 1 ns per foot in air then it's 8.9 ns per foot in water I haven't figured out how to calculate the total volume of water in the column between the satellites and the receiving antenna. I did find a web page that shows the terminal velocity of rain and it varies from 0.02 MPH for small drops to 20 MPH for big drops. But this would need to be coupled with the rate of rain fall (inches/hour) to determine how much water was in the column. Assuming big drops (20 MPH = 352 IPS) and 0.1 IPS rain rate says that the rain takes up 1 part in 3520. If the height of the rain is 20,000 feet then there's 5.6 feet of rain for a delay of 50.5 ns??? Have Fun, Brooke Tom Van Baak wrote: Rain should have an effect on the timing of the signal, since the propagation speed of radio waves through water is different from that through air. It will also attenuate the signal, causing worse S/N ratio which would cause the lower-elevation satellites to not be seen. David, Maybe we can figure this out. First, the refractive index of water is about 1.3. So I think this means the propagation speed of radio waves in water is down to about 0.75 c, right? Then, how much water are the GPS signals traveling through? Let's assume the typical amount of rain in a heavy storm is a couple of inches. All that water is either puddles already on the ground, drops on their way down, or moisture still in the clouds waiting to come down. The total amount of water in a cross section column of the atmosphere that the GPS signals travel though is thus a couple of inches total, max. Let's assume a worst case -- 6 inches. So, those GPS signals go through 20,000 km of empty space and atmosphere containing a total of 6 inches of water; in which it slows down by 30%. At a ns/foot, this comes to 25 ps per inch of water content in the air; a total of 150 ps in my worst-case example above. My conclusion is that rain or snow, light or heavy, has no effect, even at the ns level. Can someone who really knows double check this back of the envelope calculation? Thanks, /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http
Re: [time-nuts] FTS4060 Continuing Saga
Hi: The antenna is on a mast about 6 feet above a chimney top. There are a number of surrounding 100 foot trees and this caused a lot of jitter last year due to multipath. I fixed that by changing the elevation mast to 50 degrees and that's where it is now. Changing the elevation mask to 70 degrees still shows 400 ns of jitter for a 10 second average. I doubt that any trees are in that cone. I'm in the zero-degree timing mode and have a surveyed antenna location and so don't see Lat-Lon-Alt type outputs. For some averages of 10 seconds the jitter is in the 9 ns range but for others are in the 300 ns area. Turning Tropo Corrections off seems to lower the jitter. Thanks, Brooke Clarke Rob Kimberley wrote: Brooke, GPS is affected by heavy rain. Signal will be attenuated, and some at low elevations may be blocked. Snow is even a worse culprit especially if it settles on the antenna. Do you have antenna mounted in the clear or do you have any partial obscuration from buildings or trees (especially wet ones!)? Best Rob Kimberley -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Brooke Clarke Sent: 05 March 2006 20:03 To: Discussion of precise time and frequency measurement Subject: [time-nuts] FTS4060 Continuing Saga Hi: After Tom helped me a month ago to get the trigger level correct for 50 Ohm loaded TTL (1.25 volts), I've been seeing no aging on the FTS4060 s/n 1013 and have been tweaking the C field and all was going well, but today (heavy rain) the jitter on each 500 second average has jumped up from about 9 ns to more like 300 ns which means you can not believe the readings. It's snowing on the nearby mountains and heavy rain here. Note that on prior days the daily spread in the Time Interval has been around 10 ns peak to peak. So does GPS suffer with heavy rain? I checked TAC32 and the receiver settings are correct. Interesting sidelight: A couple of days ago there was a brown out the caused the SR620 counter and the computer to reset, but the FTS4060/S24 (no backup battery) did not reset (Lock and AC ON green LEDs) and the data shows that there was a recovery that lasted about 1,500 seconds. Not sure what was moving. Have Fun, Brooke Clake -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] FTS4060 Continuing Saga
Hi Tom: It very well may be a wet connector (but they all are filled with Lube Gel silicon grease). Yes the DC coupled setting was lost when the SR620 browned out, but the trigger levels are set by knobs and are not lost. For a day or two after the brown out all appeared to be working fine. The Time Interval numbers are all over the place, but consistent with the jitter (sigma) value. If the integration time is shortened to say 10 seconds then there will be a number of averages that have a jitter of about 9 ns, but when the number of averages is raised to 100 the jitter is in the hundreds. When the power cord is pulled for 10 seconds on the SR620 it seems to remember it's settings except the clock source changes to int from rear. It also may be that that the receiver looses lock on all sats and is free running. But this may be because at the time of my last posting I increased the elevation mask to 70 degrees, which may be too high. Just now changed it back to 50 degrees which is where it's been for the last year or so. At 70 degrees there were no sats. I can't use time raim and the high elevation angle at the same time since it takes redundant sats for raim to work and a low elevation mask causes high jitter, making raim worthless. But after changing to 50 deg El mask and locking to sat PRNs 1 and 25 (with Eb/No in the 25 range) the jitter is still in the three hundreds. Have Fun, Brooke Tom Van Baak wrote: Brooke, Check for a wet connector or cable at the GPS antenna. Check your SR620 settings. They are lost when you power cycle, yes? The jitter sounds more like an input trigger issue than GPS signal rain issue. We get rain here all the time... It certainly doesn't cause the magnitude of what you're seeing. Did just the jitter change, or are you seeing a new phase offset and/or a new frequency offset than before? Did you have to re-load the zero-D coords into your GPS receiver? Make a lat/lon typo perhaps? /tvb - Original Message - From: Brooke Clarke [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, March 05, 2006 12:02 Subject: [time-nuts] FTS4060 Continuing Saga Hi: After Tom helped me a month ago to get the trigger level correct for 50 Ohm loaded TTL (1.25 volts), I've been seeing no aging on the FTS4060 s/n 1013 and have been tweaking the C field and all was going well, but today (heavy rain) the jitter on each 500 second average has jumped up from about 9 ns to more like 300 ns which means you can not believe the readings. It's snowing on the nearby mountains and heavy rain here. Note that on prior days the daily spread in the Time Interval has been around 10 ns peak to peak. So does GPS suffer with heavy rain? I checked TAC32 and the receiver settings are correct. Interesting sidelight: A couple of days ago there was a brown out the caused the SR620 counter and the computer to reset, but the FTS4060/S24 (no backup battery) did not reset (Lock and AC ON green LEDs) and the data shows that there was a recovery that lasted about 1,500 seconds. Not sure what was moving. Have Fun, Brooke Clake ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] source for ICS525 demo board ...
Hi Hal: I Googled ICS525 and found that there are a few ham projects using the chip. Mostly as a one chip 2 meter transmitter although with a single crystal there's a limited number of channels you can hit. I thought that the PCI slots were for I/O cards on the back panel. What's a front panel bracket? Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Hal Murray wrote: I keep hoping that the TAPR people will issue a board with it... I've also been thinking of building something along that line... My straw man is to use a PCI front panel bracket for mounting. I was thinking of getting power from a disk connector rather than the PCI slot because the low cost PCB fab places don't include gold fingers. Anybody know an inexpensive place that does handle PCI cards? The ICS525 is the best chip I've seen for this sort of work, but I haven't looked all that hard. All it takes is one chip and a bunch of jumpers to be able to select a wide range of output frequencies. Plan B is your favorite PLL and a CPLD. Looks like ICS has been Borged by IDT. Avnet carries IDT, but I don't know if they sell to hackers/hobbyists and/or if they carry the ICS parts yet. What sort of frequency range is interesting? (I'll summarize if people respond directly to me.) If you were building something like this, what else would you put on the board? I was thinking of an option for a TCXO or OCXO. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] source for ICS525 demo board ...
Hi Hal: In that case something like the Jameco 141372 Prototype board might work. Doing this implies that you want a tight connection between the ICS525 and the PC, which might be the case for an NTP type application. http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1storeId=10001catalogId=10001productId=141372 In the ham radio uses they typically have a common PIC, like the 16F84, that sends the divider codes to the ICS525 and has some sort of selector switches to choose the channel number. 73, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Hal Murray wrote: I thought that the PCI slots were for I/O cards on the back panel. What's a front panel bracket? Same difference. I was just looking/thinking at the other end of the box. I was thinking of a PC. I'm not sure about the Soekris box. Something like a PCI bracket would be a good place for a BNC connector to get the signal into the PC as well as a place to mount a small PCB with the PLL. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Second FTS4060 shows Drift, is it me? Good Links
Hi Tom: The plot with red and blue is the old data on s/n 1227 where the red points are from LORAN-C and the blue points from GPS. s/n 1227 = http://www.pacificsites.com/~brooke/pdf/Cs_Drift0429.pdf from April 29, 2005. This might be a clue to the problem I'm now having with s/n 1013. http://www.pacificsites.com/~brooke/pdf/sn1013_850_Drift2.pdf s/n 1013 from yesterday. It's my understanding the a properly working Cs standard probably has it's frequency slightly off from perfect, but does NOT have any drift in frequency. So a Time Interval plot, like those in the links above, should be just a straight line, i.e. it should not have a parabolic shape. The slope of the TI plot is the first derivative of the equation of the points and should have included two terms. The second derivative gives the aging rate which should be zero for a Cs standard. When I recompute based on the Excell equation coefficients the answer is off, so I think that Excell is giving rough values. But in any case the second derivative is just a single number whose units would be ns/day/day. Don't have plots of s/n 1013 vs. s/n 1227. I just have one SR620 counter. Is there a common way to check the TI counter, maybe based on a coax cable? Thanks, Brooke Tom Van Baak wrote: Brooke, For the last couple of weeks it has shown a parabolic plot like s/n 1227, although this time the polarity is opposite that of s/n 1227 which also showed drift, but that may be a setup difference. A plot of s/n 1227 is at: file:///C:/Webdocs/pdf/Cs_Drift0429.pdf This plot has both blue and red dots; which is which? The red dots look like you should draw a line though them, not a parabola. The linear slope is approximately +700ns/21days = +4e-13, a perfectly reasonable value of the frequency error in a Cs standard. I see nothing wrong with the 3 weeks red dot data. Let it go another month or two and see if it shows parabolic behavior (frequency drift) rather than just linear (frequency offset). The equation for s/n 1013 is: y = 2.7943x2 - 302.64x + 8969.4 and the quality of fit is R2 = 0.9088. The x-axis is in days and the y-axis is in ns. The first derivative of the equation has a first term of 2 * 2.7943 * x ns/day or +5.3E-14 seconds/seconds drift rate. Today's plot is at: file:///C:/Webdocs/pdf/sn1013_850_Drift2.pdf I'm not sure I follow your math here; and frequency drift rates don't have units of seconds/seconds. My eye tells me your frequency error (phase slope) the first few days is about -25ns/day (-3e-13). The last few days it is +25ns/day (+3e-13). The net change in frequency is 6e-13 over a 10 day span so your frequency drift is about 6e-14/day. This is odd. It's way too low to be free-running quartz (say 1e-9 to 1e-12 per day); it's even too low for Rb (about 1e-10 to 1e-11 per month). Yet it seems too high to be a correctly working Cs. Do you have simultaneous M12+ plots of both S/N 1227 and 1013? /tvb http://www.LeapSecond.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Second FTS4060 shows Drift, is it me?
Hi: A year ago I took apart the FTS4060 that was DOA (s/n 1013) because of rough shipping and used it to figure out most of the interconnect wiring. A few months ago I put it back together with the thought of selling it as a parts unit. But first powered it up and found that it now locked and seemed to be working so tried to set the C-field. For the last couple of weeks it has shown a parabolic plot like s/n 1227, although this time the polarity is opposite that of s/n 1227 which also showed drift, but that may be a setup difference. A plot of s/n 1227 is at: file:///C:/Webdocs/pdf/Cs_Drift0429.pdf The equation for s/n 1013 is: y = 2.7943x2 - 302.64x + 8969.4 and the quality of fit is R2 = 0.9088. The x-axis is in days and the y-axis is in ns. The first derivative of the equation has a first term of 2 * 2.7943 * x ns/day or +5.3E-14 seconds/seconds drift rate. Today's plot is at: file:///C:/Webdocs/pdf/sn1013_850_Drift2.pdf The current setup is: SR620 time interval counter doing 500 averages (500 seconds = 8 1/3 minutes). Start from Motorola M12+T (9 ns jitter). Stop from FTS4060 1 MHz output. Manually enter into spreadsheet date and time of reading (usually not on the 8 1/3 minute change, just a random time) and counter value. For most of the test the SR620 was using it's internal oscillator and just recently I changed it to the PRS10 external standard but that does not seem to have made any difference. Is there something I'm doing wrong that would cause apparent drift? Thanks for any thoughts, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Second FTS4060 shows Drift, is it me? Good Links
Hi: Sorry for the bad links, here are good ones: Today's plot = http://www.pacificsites.com/~brooke/pdf/sn1013_850_Drift2.pdf s/n 1227 29 Apr 2005 plot = http://www.pacificsites.com/~brooke/pdf/Cs_Drift0429.pdf Brooke Brooke Clarke wrote: Hi: A year ago I took apart the FTS4060 that was DOA (s/n 1013) because of rough shipping and used it to figure out most of the interconnect wiring. A few months ago I put it back together with the thought of selling it as a parts unit. But first powered it up and found that it now locked and seemed to be working so tried to set the C-field. For the last couple of weeks it has shown a parabolic plot like s/n 1227, although this time the polarity is opposite that of s/n 1227 which also showed drift, but that may be a setup difference. A plot of s/n 1227 is at: file:///C:/Webdocs/pdf/Cs_Drift0429.pdf The equation for s/n 1013 is: y = 2.7943x2 - 302.64x + 8969.4 and the quality of fit is R2 = 0.9088. The x-axis is in days and the y-axis is in ns. The first derivative of the equation has a first term of 2 * 2.7943 * x ns/day or +5.3E-14 seconds/seconds drift rate. Today's plot is at: file:///C:/Webdocs/pdf/sn1013_850_Drift2.pdf The current setup is: SR620 time interval counter doing 500 averages (500 seconds = 8 1/3 minutes). Start from Motorola M12+T (9 ns jitter). Stop from FTS4060 1 MHz output. Manually enter into spreadsheet date and time of reading (usually not on the 8 1/3 minute change, just a random time) and counter value. For most of the test the SR620 was using it's internal oscillator and just recently I changed it to the PRS10 external standard but that does not seem to have made any difference. Is there something I'm doing wrong that would cause apparent drift? Thanks for any thoughts, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Battery Top Power Supply
Hi: For my own use I have made prototype quantities of a power supply that uses TO-92 packaged linear voltage regulator chips. The small printed circuit board has battery snaps to go on top of a 9 volt battery, on top of a 10 AA battery holder or gets power from a wall wart with a 9 volt battery snap connection. More info at: http://www.pacificsites.com/~brooke/BTPS.shtml Both fixed voltage and variable voltage versions are available. If interested let me know. Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS timing receivers
Hi Michelangelo: The LORAN-C Timing receivers (Austron 2100T) have a 1 PPS input becasue the LORAN-C system can not be used to set a clock so the 1 PPS input is used to mark the top of a second. Which GPS receiver has a 1 PPS input? Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com TwoSpades wrote: Hi everybody, Two questions about GPS timing receivers: 1) Why most timing receivers have a 1pps input? For what they use that input signal? 2) Are there some connections between timing receivers and geodetic receivers? I'm looking forward an expert on Timing Receivers with whom to exchange ideas. Thanks, Michelangelo. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] RE: phase locking Rb to GPS
Hi Richard: It's my understanding that this optimization can be done by changing the oscillator power level at the crystal. In the case of the 32768 Hz watch crystal, it must be run a very low power and it has a very low aging rate when compared to higher frequency crystals that are typically run at higher power levels. I think this is related to the crystal throwing off atoms, so more power means more acceleration and more atoms thrown off. Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Richard H McCorkle wrote: . . . snip . . Since both units are the same model, but with different P/N and both meet the OCXO134-10 spec but have different characteristics I believe they were each optimized for a different characteristic when originally ordered, one for low aging, and one for high stability. -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] HP 5110A A1A4 Schematic Wanted
Hi: I'm looking for a schematic parts layout drawing for the HP 5110A Harmonic Generator PCB A1A4. A complete hard copy manual would also be great. http://www.pacificsites.com/~brooke/HP5100.shtml Thanks, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Timing receivers
Hi Tom: When I was learning about the Trimble 1990 vintage Trimpack family of receivers I bought a number of antennas and learned that the Trimpacks need an antenna with about 40 dB of gain, which is a lot different from a passive antenna or an active antenna with the more common 20 dB of gain. http://www.pacificsites.com/~brooke/Trimpack.shtml#Ant A passive antenna is good for use as a re-radiating antenna for indoor GPS. I'm using a Motorola Timing antenna on a TV mast to get it above the chimney closest to my radio room. But in order to get rid of the multipath I've had to move the elevation mask up to the 50 or 60 degree level. At lower elevation levels the standard deviation on TI measurements gets much higher. I think that if a choke ring type antenna was in the same position I could lower the elevation mask and receive more satellites, thus enabling TRAIM, or getting better 1 PPS signals. But the choke ring antennas are larger than the Timing antenna and are not easily mounted to a TV antenna type mast (they want to see pipe threads). Have Fun, Brooke Tom Van Baak wrote: Tom, John A and I had a short antenna email earlier today, mostly about the fact that both of the GPS antennas we were using died. I asked a question about certain commercial antennas which included the Timing 2000, HP 58532A and the Datum 2640NW/DE, as to wether there were any opinions as to which is the better timing antenna. Neither of us has much of an idea, do you have any thoughts? Had I've heard that many modern telecom GPS timing antennas are heavily filtered since they are usually placed in high RFI locations. This may be good for them but I think it has negative side effects for the kind of precise timing we do, so I'm told. I'm going to ask Dr Clark to handle this one as he understands GPS antennas very well. TAC -- what I'd like to know is if patch is better than helix, if filtered is better than unfiltered, how much amplification is too much, vintage 1990's era antennas vs. 2005 antennas, real splitters vs. Radio Shack splitters, antenna or preamp tempco issues, cable loss and impedance issues, etc. At what ns level does a groundplane start to matter. I guess what we need is some kind of Time Nuts guide to surplus GPS antennas. If it's not possible to give a black and white answer to what kind of antenna is best for a Z3801A-style GPSDO, then at least, what are the factors that make one better than another. And is any of this simple to determine with experimentation? Maybe we can all chip in and test a dozen antenna types to find the answer or to confirm a prediction. /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Antenna for 8163
Hi Joe: The Dymec DA100 active whip works well as does the (modified) AMRAD active whip, see: http://www.pacificsites.com/~brooke/LF-Ant.shtml http://www.pacificsites.com/~brooke/DR33.shtml#DA100 Do you have any nearby RTTY stations near 60 kHz? If so the loop may have the advantage of being able to null it out. Welcome and Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Joe Lippencott wrote: Hi, New member to the group. Thank you for letting me participate. I have a question. Just received a Spectracom 8163, but can't find an 8206 antenna anywhere, reasonably priced. Has anyone on the East coast (I am in NJ) had any results with the shielded loop antenna shown on the febo website with an 8163 ? I wonder if I should go thru the trouble to build the antenna, or just wait until I can find another that will work. Also, any alternate suggestions would be appreciated. Thanks much Joe Lippencott ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Off the wall: anyone with experience programmingHP3456A?
Hi John: The problem is caused by modern computers being much faster than the ones available in the late 1970s. With the older computers, after sending a command the instrument had plenty of time to make a measurement and format the response. With today's fast computers if you send a command then immediately ask for a response, the instrument has just started to make the measurement and this can cause problems. The newer instruments that support SCPI commands have nice ways to handle this, but the R2D2 instruments need a little wait time prior to any data request. Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Miles wrote: . . . One other thing we've found, particularly with the older HP instruments, is that you often need to insert a sleep of anything from 500uS to 5ms after issuing a command before sending another command. Interesting; I hadn't run across that. The examples in the manuals commonly show multiple commands in a single string; maybe the old-school BASIC controllers were smart enough to pause briefly after transmitting semicolons or string terminators...? -- john, KE5FX ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Off the wall: anyone with experience programming HP 3456A?
Hi John: It may be that there are other register bits that need to be enabled in order to let the SRQ out. Is there a status register diagram in the manual? Have Fun, Brooke John Ackermann N8UR wrote: By any chance, has anyone here done any GPIB programming of the HP 3456A DMM? I am having great trouble getting it to output SRQ at the end of a reading; it appears as though it simply doesn't recognize the SM command that the manual says should be used to set the SRQ mask. Setting the mask with, e.g., SM004 which according to the manual should cause SRQ to be asserted at the completion of a reading, results in the 004 being briefly displayed on the LED during setup, but no sign of SRQ actually being asserted. I've tried numerous values of the octal code representing the status byte, but all act the same. I realize it's a long shot, but wonder if anyone here has wrestled with this? Thanks, John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Oscillator and Synthesizer Specs
Hi John: I'd like to see the Dataum 1000B Ultra-Stable 10 MHz oscillator as used in the FTS4060 included. Brooke John Ackermann N8UR wrote: For a while, I've had two web pages with specs on various frequency standards and synthesizers of interest to our community. I've combined the two pages and added some additional info. The new page is at: http://www.febo.com/time-freq/hardware/specs.html. If you have info on additional devices, please feel free to send it to me for addition. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Oscillator and Synthesizer (and Analyzer) Specs
Hi John: How about the HP 4395A. Although limited to 500 Mhz the performance is fantastic. http://www.pacificsites.com/~brooke/4395A.shtml 73, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Miles wrote: Cool stuff. I have been trying to gather some similar figures for various spectrum analyzers, in the form of baseline plots that show the analyzers' response to sources that are much cleaner than their own LO subsystems. I have been including noise plot files for all of the analyzers that have been tested to date in my homebrew noise-measurement software package ( http://www.speakeasy.org/~jmiles1/ke5fx/pn.htm ). These baseline plots are useful because they illustrate which analyzer models are capable of direct noise measurement at various quality levels and carrier offsets. I'd like to hear from anyone on the list who has access to an HP 8560A-series analyzer with a National Instruments GPIB interface and a Windows PC; that's the most conspicuous blank spot in my collection so far. -- john, KE5FX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of John Ackermann N8UR Sent: Saturday, September 03, 2005 12:00 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Oscillator and Synthesizer Specs For a while, I've had two web pages with specs on various frequency standards and synthesizers of interest to our community. I've combined the two pages and added some additional info. The new page is at: http://www.febo.com/time-freq/hardware/specs.html. If you have info on additional devices, please feel free to send it to me for addition. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] DC Voltage Ramp?
Hi Tom: The plot at http://www.thinksrs.com/products/PRS10.htm showing GPS and Rb indicates that GPS for times less than say 500 seconds has more noise than the Rb source. So a voltage ramped 1000B should be very clean below 500 seconds. Have Fun, Brooke Tom Van Baak wrote: I was thinking of using a Datum 1000B Ultra Stable Oscillator (the one used in the FTS 4060 Cesium standard). The data sheet says that after a few years the aging rate gets down to parts in E-12/day. I would think that the Allan plot would be cleaner if the control voltage was well behaved than if it was derived from a noisy process like GPS or maybe Cesium. The 1000B makes a good standalone standard. What tau range of the Allan plot were you thinking of making cleaner? Note that frequency standards like the HP 105B use a very clean control voltage: a 10k pot. /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Tracor Omega VLF Synthesizer
Hi Bob: Mike Murphy is selling an Omega Station, see: http://www.murphyjunk.bizland.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=560linkpath=http://murphyjunk.bizland.com/sitebuildercontent/sitebuilderpictures/5458A.JPGtarget=_selftitle=OMEGA%20VLF%20STATION:%20CLEAN%20COND.%20%20$349%20EA. 73, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Bob Voelker wrote: Does anyone have any information on the Tracor Omega VLF Synthesizer? It seems to be some kind of a precision frequency and time interval reference for the Omega navigation system. Although the Omega navigation system and thus the Tracor synthesizer are no longer used, it would still be fascinating to get a better understanding of this piece of cold-war electronics history. Here are more details to help identify the Tracor Omega VLF Synthesizer: -There is no model number on the unit, only the part number 142801-0001. -The serial number is blank. -It was made around 1985. -The synthesizer and its power supply each are 3-1/2 high, 19 wide white rack panels mounted in one blue carrying case. The depth of the synthesizer and power supply is about 19. -Eight toggle switches select Omega Format Segment: A, B, C, ..., H. -Four toggle switches are for Freq Sel (kHz): 10.2, 13.6, 11-1/3, 11.05. -The power supply, labeled Power Interface, has a round mil-style 15-contact connector labeled Signal Output. -There is an Austron 1100 ovenized 5.304 MHz crystal oscillator inside. (Does anyone know the specs for the Austron 1100?) I've seen Tracor frequency references and comparators before, but nothing like this unit. Any information would be appreciated. Thanks, Bob ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Low cost synchronization
Hi Mike: It may not be possible to get what you are asking for as a stand alone time keeper but I think could be done by periodically resetting. Using a radio signal for resetting has problems with the coverage area and/or power consumption. Maybe the resetting signal could be an audio time code optimized for this application. The user could call an 800 phone number and a microphone in the device would hear the code and reset. Or at a public meeting the audio code could be put on the P.A. system so all present would be synchronized. If the microphone can hear the beeper of another unit there might be a way to use a button on a unit to cause it to send it's audio time sync signal so other nearby units would sync to it. The device could learn it's aging rate at each reset and so change the divisor number to match the current aging rate. After sync the device might emit beeps or Morse code telling the user how far off it was allowing the user to gauge how often they need to resync. A TCXO should work for this. Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Mike Ciholas wrote: Hi, I have a challenging research project to build thousands, perhaps millions, of devices that maintain mutual synchronization. The devices need to be low cost (under $20 retail, $8 manufacturing), small in size (key chain fob), and low power (operate at least 18 months on a battery). Synchronization ideally needs to be within a second or two over a year but there is some leeway to trade cost for performance here up to perhaps 10 seconds of variation per year. Ideally, the device works anywhere in the world but we may have to limit it to North America. 1. Crystal Modeling First idea was to get stable 32.768KHz watch crystals, perform a factory initial calibration, and use a temperature sensor to correct for the crystal temp curve. This idea is the cheapest, simplest, works everywhere, and uses the lowest power. Initial tolerance on the crystals is +/- 20 ppm (I've not found better in commodity parts), which equates to +/- 10 minutes a year, clearly unacceptable. I suspect that if I did an initial factory calibration and tracked temperature, I might improve this to +/- 2 ppm much like Maxim did with this part: http://pdfserv.maxim-ic.com/en/ds/DS32kHz.pdf But even so, +/- 1 minute per year is not really good enough. I suspect getting to a few seconds (+/- 0.1ppm) is unrealistic with any algorithm one can come up with. The base physics is simply not that predictable. 2. WWVB Receiver A second idea is to provide some external reference and the most logical choice is WWVB as used in several wrist watches. A little more cost but manageable. We've dissected several wrist watches and found they use a small ferrite antenna. The reception performance is spotty, however. I was unable to lock at work (lots of equipment) but did well at home (electrically quiet). If we go to the NE tip of Maine, that's twice as far from WWVB as we are here, so I wonder if the watch will ever pick up the signal. The saving grace is that the device needs to get the signal only sporadically, once a week or even once a month would do it since we can feed that back into correcting the local crystal. The negatives are that such a device is limited to the US and nearby, and it may have poor performance in many locales due to weak signals, local interference, and the small antenna rod we are limited to due to size (less than 1 inch). It does cost more, maybe $1-2 more in production quantity. Right now, this seems like the best option available to us. There are similar time broadcasting stations in Europe and China. We could build a unit that works in those regions, either as different models, or as a unit with multiple receivers. Still not global, but perhaps covering 50% of the world's population? 3. GPS Receiver A more precise external reference, use a GPS receiver. This gets us global coverage and is very precise. Uses a lot of power, so we would only activate it very briefly and not very often (once a week perhaps) to save battery. Major issue here is cost. Best I can do for an OEM module is around $25 in qty which busts the budget severely. It also has similar problems of being used in a place with no sky visibility. Size can be a problem in the cheaper modules. Some modules are quite small: http://www.u-blox.com/products/lea_la.html Cute, huh? 4. GPS Time Receiver This is fantasy land. I don't need the 100ns time reference, all I need is something good to one second or so. In this case, it seems possible to receive only 1 satellite, decode the digital data, and extract the time. It would be off by the variation in pseudo range which can't be corrected for. But I don't care about that level of accuracy. The question is, if you
Re: [time-nuts] Jupiter T question
Hi Rich: Although I have a manual there's no receiver here and so I don't have any experience. Brooke Richard and Marcia Putz wrote: Hi All, The otherday I asked about the Jupoiter T receivers and Brooke mentioned the results of his experience with it, I was curious what he meant when he spoke of the clock zero-beat times (TvB calls them hanging bridges) .Brooke, can you or Tom direct me to somewhere where I might get a better understanding of this? Thanks; Rich ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] My Austron 2100T Loran-C Timing Receiver w/IEEE-488 on eBay
Hi: I'm in the process of selling stuff and have just put on eBay an Austron 2100T Loarn-C timing receiver in excellent condition. It has the very hard to find IEEE-488 interface card. See: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=7537337811 This receiver will add 1 PPS and a UTC clock to a 1, 5 or 10 MHz frequency standard. This is an End Use Certificate item and can not be sold outside the U.S. Have Fun, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
