Re: [time-nuts] Neutrinos not so fast? (defectove connector)
mag...@rubidium.dyndns.org said: I use the rule of thumb that 1 ns is 3 dm in free air and 2 dm in coax and fibre My rule of thumb is that fiber or good coax (foam) slows down by the conversion from km to miles. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
Joe, A possible mechanism occurs to me. High-precision GPS is very vulnerable to multipath errors. A loos connector will have a significant reflection. The reflected energy will propagate backwards, and be reflected off the transmitter output discontinuity, the twice-reflected energy propagating back to the receiver. The original and the triple-transit echo will add coherently (for the modulation, not the photons) in the receiver. This is a perfect multipath scenario. How long must the cable be? Depends on the relative strength of main signal and triple-transit echo. Joe Gwinn Joe, High precision GPS receivers use various correlator schemes that try to minimize multipath. Normal GPS receivers are more vulnerable than geodetic quality receivers. http://webone.novatel.ca/assets/Documents/Papers/PAC.pdf You are of course correct, but timing receivers may not go to such lengths are are needed for geodetic receivers. A lot of the magic of geodetic receivers is in the choke-ring antenna, which ignores signals arriving from too low an angle above the horizon. In the Neutrino case, the multipath is built into the cable between antenna and receiver, so the antenna cannot help. But I will read the article, which looks interesting. Wonder if it would solve such a triple-transit echo problem. Joe I am not discussing antenna multipath attenuation. That is a separate topic. Look at figure 12 in the Novatel paper - noting for the y-axis - that 1 C/A chip length is about 300 meters. Here is an article from the Ashtech/JPS/JNS/Topcon-family. http://tinyurl.com/7w9wl4p Overview results are seen in figure 5. Timing receivers used by time-labs to compare Cs are usually geodetic receivers with the option to lock the internal clock to external 10MHz/1PPS signals coming from the Cs. My point is that good receivers attenuate multipath fairly well. Is it known which GPS receiver type was used in the Neutrino experiment? -- Björn ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
Da: b...@lysator.liu.se Data: 24/02/2012 14.42 A: Discussion of precise time and frequency measurementtime-nuts@febo.com Is it known which GPS receiver type was used in the Neutrino experiment? It was a Septentrio PolaRx2e. See the paper on setup and procedures: http://dl.dropbox.com/u/13409775/cern-cal.pdf Antonio I8IOV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
On Fri, Feb 24, 2012 at 3:41 PM, iov...@inwind.it iov...@inwind.it wrote: Da: b...@lysator.liu.se Data: 24/02/2012 14.42 A: Discussion of precise time and frequency measurementtime-nuts@febo.com Is it known which GPS receiver type was used in the Neutrino experiment? It was a Septentrio PolaRx2e. See the paper on setup and procedures: http://dl.dropbox.com/u/13409775/cern-cal.pdf Here's a more official location with more information: http://www.ohwr.org/projects/cngs-time-transfer/wiki Cheers, Javier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
Da: b...@lysator.liu.se Data: 24/02/2012 14.42 A: Discussion of precise time and frequency measurementtime-nuts@febo.com Is it known which GPS receiver type was used in the Neutrino experiment? It was a Septentrio PolaRx2e. See the paper on setup and procedures: http://dl.dropbox.com/u/13409775/cern-cal.pdf Antonio I8IOV Knowing what you should search for can do wonders... http://www.septentrio.com/sites/default/files/NR_OPERA_final.pdf Here is an 8 year old poster on a slightly different topic. But there is also information about Septentrio's proprietary multipath mitigating correlator solution. ftp://igscb.jpl.nasa.gov/igscb/resource/pubs/04_rtberne/cdrom/Session8/Posters/8_1P_Simsky.pdf -- Björn ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
At 3:24 PM + 2/24/12, time-nuts-requ...@febo.com wrote: Date: Fri, 24 Feb 2012 14:42:36 +0100 From: b...@lysator.liu.se To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defective connector) Bj?rn, [snip] High precision GPS receivers use various correlator schemes that try to minimize multipath. Normal GPS receivers are more vulnerable than geodetic quality receivers. http://webone.novatel.ca/assets/Documents/Papers/PAC.pdf You are of course correct, but timing receivers may not go to such lengths are are needed for geodetic receivers. A lot of the magic of geodetic receivers is in the choke-ring antenna, which ignores signals arriving from too low an angle above the horizon. In the Neutrino case, the multipath is built into the cable between antenna and receiver, so the antenna cannot help. But I will read the article, which looks interesting. Wonder if it would solve such a triple-transit echo problem. Joe I am not discussing antenna multipath attenuation. That is a separate topic. Look at figure 12 in the Novatel paper - noting for the y-axis - that 1 C/A chip length is about 300 meters. Hmm. Isn't 60 nanoseconds (18 meters at C) well within this envelope? Here is an article from the Ashtech/JPS/JNS/Topcon-family. http://tinyurl.com/7w9wl4p Overview results are seen in figure 5. Thanks. I'll read it. Timing receivers used by time-labs to compare Cs are usually geodetic receivers with the option to lock the internal clock to external 10MHz/1PPS signals coming from the Cs. My point is that good receivers attenuate multipath fairly well. If it's old, it may well have none of these improvements. The timing receivers I have used usually say that they are within 100 nanoseconds; I assume this to be the three sigma range. I do know that in stationary receivers, the Allan Deviation of a given such receiver is quite good, implying that the error is a slowly drifting offset. A cable multipath could well cause a bias error. Is it known which GPS receiver type was used in the Neutrino experiment? Another poster (Antonio I8IOV) answered this: It was a Septentrio PolaRx2e. See the paper on setup and procedures: http://dl.dropbox.com/u/13409775/cern-cal.pdf I don't know anything about that make and model. But someone will. I wonder when this unit was made. And if it has a Rubidium local oscillator. Actually, I bet there are multiple Time Nuts with more than one GPS timing receiver. It is a simple experiment to feed a pair from a single antenna plus splitter, and put an impedance bump or two in one feed line, and compare the 1PPS outputs. (I don't have the equipment.) Or, split, delay one path, recombine, using a variable attenuatior in the delay path to adjust the overall multipath effect with which to challenge one of the two receivers receiver. Joe ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On Wed, Feb 22, 2012 at 11:26 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. PHK come on, you can do much better than this :) I am sorry guys. I really owe this list a lot of knowledge and I try to give back every time I have an opportunity, but I will not be able to react to all suppositions in real-time. Also I am not even a completely reliable source of information myself because these things have been found in OPERA, and I only know of them indirectly. I only have two points: - Delays in fiber connections can be modified because of changes in input power (due to improper screwing), which turn into delay changes via the input capacitance of the photo-diode. This only has an effect on the final result if the calibration was conducted with the proper screwing (sure) and the experiment with improper screwing (not sure). - OPERA and CERN have followed the scientific method in an exemplary way all throughout the process. The published information is the result of a leak and has two problems: a) it's incomplete and b) it's too soon to publish anything meaningful, it would have been much better to study the effects of the two issues found, quantify them and then go public. Maybe there is virtually no effect on the final result, who knows. So please stay tuned for proper information. That's all I can say for now. Cheers, Javier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Hi Javier, On 02/23/2012 09:42 AM, Javier Serrano wrote: So please stay tuned for proper information. That's all I can say for now. Which is more or less all you should say. I agree fully with you. From a scientific point of view, all we have heard is indications, but it needs to be verified. Best Regards, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
I have found the official CERN director's words: (from Marco URLs) Ecco l’annuncio del Direttore del CERN: The OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino’s time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time of flight of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May”. On Thu, Feb 23, 2012 at 11:15 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi Javier, On 02/23/2012 09:42 AM, Javier Serrano wrote: So please stay tuned for proper information. That's all I can say for now. Which is more or less all you should say. I agree fully with you. From a scientific point of view, all we have heard is indications, but it needs to be verified. Best Regards, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Just for completeliness I was pointed to this information: http://www.nature.com/news/flaws-found-in-faster-than-light-neutrino-measurement-1.10099 Arnold Am 23.02.2012 12:21, schrieb Azelio Boriani: I have found the official CERN director's words: (from Marco URLs) Ecco l’annuncio del Direttore del CERN: The OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino’s time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time of flight of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May”. On Thu, Feb 23, 2012 at 11:15 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi Javier, On 02/23/2012 09:42 AM, Javier Serrano wrote: So please stay tuned for proper information. That's all I can say for now. Which is more or less all you should say. I agree fully with you. From a scientific point of view, all we have heard is indications, but it needs to be verified. Best Regards, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Yes, this doesn't mean the results are necessarily wrong but only questionable. Too bad we have to wait until May to know the damage extension on the observed results. Here in Italy, unfortunately and as usual, the announcement was distorted by our media today: now Einstein is the winner as much as he was a looser in September. As usual they are very fast in hanging or rising someone instead of shading the correct light on science information. And don't forget that nothing comes early here in Italy :) On Thu, Feb 23, 2012 at 2:47 PM, Arnold Tibus arnold.ti...@gmx.de wrote: Just for completeliness I was pointed to this information: http://www.nature.com/news/flaws-found-in-faster-than-light-neutrino-measurement-1.10099 Arnold Am 23.02.2012 12:21, schrieb Azelio Boriani: I have found the official CERN director's words: (from Marco URLs) Ecco l’annuncio del Direttore del CERN: The OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino’s time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time of flight of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May”. On Thu, Feb 23, 2012 at 11:15 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi Javier, On 02/23/2012 09:42 AM, Javier Serrano wrote: So please stay tuned for proper information. That's all I can say for now. Which is more or less all you should say. I agree fully with you. From a scientific point of view, all we have heard is indications, but it needs to be verified. Best Regards, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Thanks Azelio, so let's wait for domani ;-) , Arnold Am 23.02.2012 15:12, schrieb Azelio Boriani: Yes, this doesn't mean the results are necessarily wrong but only questionable. Too bad we have to wait until May to know the damage extension on the observed results. Here in Italy, unfortunately and as usual, the announcement was distorted by our media today: now Einstein is the winner as much as he was a looser in September. As usual they are very fast in hanging or rising someone instead of shading the correct light on science information. And don't forget that nothing comes early here in Italy :) On Thu, Feb 23, 2012 at 2:47 PM, Arnold Tibusarnold.ti...@gmx.de wrote: Just for completeliness I was pointed to this information: http://www.nature.com/news/flaws-found-in-faster-than-light-neutrino-measurement-1.10099 Arnold Am 23.02.2012 12:21, schrieb Azelio Boriani: I have found the official CERN director's words: (from Marco URLs) Ecco l’annuncio del Direttore del CERN: The OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino’s time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time of flight of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May”. On Thu, Feb 23, 2012 at 11:15 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi Javier, On 02/23/2012 09:42 AM, Javier Serrano wrote: So please stay tuned for proper information. That's all I can say for now. Which is more or less all you should say. I agree fully with you. From a scientific point of view, all we have heard is indications, but it needs to be verified. Best Regards, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On 2/23/12 6:24 AM, Alberto di Bene wrote: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Am 23.02.2012 15:24, schrieb Alberto di Bene: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD What I do not understand after all, is it not possible to run an overall test for the measurement loop by sending eg. a timestamp controlled signal including all the lines and connections etc. ? Final end to end tests were for me always the most important procedures. regards, Arnold ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
I recommend the differential pair: here the trigger have to sense the crossing of the two signals and this crossing is well definite. On Thu, Feb 23, 2012 at 3:36 PM, Jim Lux jim...@earthlink.net wrote: On 2/23/12 6:24 AM, Alberto di Bene wrote: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On 02/23/2012 03:36 PM, Jim Lux wrote: On 2/23/12 6:24 AM, Alberto di Bene wrote: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) I think that there is a little bit different approach to all this. It raises the issue of fault detection, and over in the telecom world we spend quite a bit of time just approving the signal and monitoring it. It starts of with signal presence, and the Loss Of Signal defect. Then other qualities of the signal is monitored, different defects is correlated into a fault cause which then has a second level of persistance filtering before hitting alarms and logs. The side effect of this is that you not only build monitoring support but also actively think about what is a good signal anyway, how can one handle variations of signal and where to you put your cut-off. In this case, the measurement noise should have been significantly higher in the error state. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
And by using a differential pair is like halving the rise time: when one arm rises the other falls, effectively doubling the speed of the crossing and the sharpening of the trigger event. Sort of auto_ schmitt_trigger... On Thu, Feb 23, 2012 at 3:45 PM, Azelio Boriani azelio.bori...@screen.itwrote: I recommend the differential pair: here the trigger have to sense the crossing of the two signals and this crossing is well definite. On Thu, Feb 23, 2012 at 3:36 PM, Jim Lux jim...@earthlink.net wrote: On 2/23/12 6:24 AM, Alberto di Bene wrote: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
To square a sine 10MHz you can use a 4:1 transformer with the center tap: connect the tap to GND and use a differential line receiver (ADM485, MAX485) connected to the differential signal that comes out from the transformer. The input of the transformer receives the single ended sine 10MHz. On Thu, Feb 23, 2012 at 3:51 PM, Azelio Boriani azelio.bori...@screen.itwrote: And by using a differential pair is like halving the rise time: when one arm rises the other falls, effectively doubling the speed of the crossing and the sharpening of the trigger event. Sort of auto_ schmitt_trigger... On Thu, Feb 23, 2012 at 3:45 PM, Azelio Boriani azelio.bori...@screen.itwrote: I recommend the differential pair: here the trigger have to sense the crossing of the two signals and this crossing is well definite. On Thu, Feb 23, 2012 at 3:36 PM, Jim Lux jim...@earthlink.net wrote: On 2/23/12 6:24 AM, Alberto di Bene wrote: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
A transformer or differential signaling would also have the virtue of allowing easy galvanic isolation to prevent ground loops. Fiber optic and line receivers often set their switching threshold using a positive and negative peak detector. The same design works very well for analog peak to peak automatic triggering in oscilloscopes. AN47-59, 50 MHz Adaptive Threshold Trigger Circuit: http://www.linear.com/docs/4138 AN61-15, High Speed Adaptive Trigger Circuit: http://www.linear.com/docs/4150 On Thu, 23 Feb 2012 16:01:55 +0100, Azelio Boriani azelio.bori...@screen.it wrote: To square a sine 10MHz you can use a 4:1 transformer with the center tap: connect the tap to GND and use a differential line receiver (ADM485, MAX485) connected to the differential signal that comes out from the transformer. The input of the transformer receives the single ended sine 10MHz. On Thu, Feb 23, 2012 at 3:51 PM, Azelio Boriani azelio.bori...@screen.itwrote: And by using a differential pair is like halving the rise time: when one arm rises the other falls, effectively doubling the speed of the crossing and the sharpening of the trigger event. Sort of auto_ schmitt_trigger... On Thu, Feb 23, 2012 at 3:45 PM, Azelio Boriani azelio.bori...@screen.itwrote: I recommend the differential pair: here the trigger have to sense the crossing of the two signals and this crossing is well definite. Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector) - new approach
Hi Back in the long ago, processing was expensive. Much of what we do goes back to that era and paradigm. A bidirectional loop with smarts on both ends would make a lot of sense today. Spend $5 on each end and you can be sure of what's going on. Yell to higher authority if something didn't look right. If it's your connection (as it is for most simple timing links) send lots of data and average to improve the SNR. The added cost is nearly zero... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Lux Sent: Thursday, February 23, 2012 9:37 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) On 2/23/12 6:24 AM, Alberto di Bene wrote: On 2/23/2012 1:04 AM, Poul-Henning Kamp wrote: I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. I spoke with a physicist of Cern, friend of the leader of the team that performed the Opera experiment. He told me that the badly seated connector caused the amplitude of the signal to be lower, and for this reason the trigger point, which was set at a specific level, was reached 60ns later. 73 Alberto I2PHD Darn those finite rise timesgrin I've been bitten more than once by this very phenomenon (which I admit doesn't say a lot for me.. being bitten once is ok, but since I've had multiple bites...) But this brings up an interesting time-nut problem for the hive mind.. If you had to design some scheme for interconnecting boxes and wanted to transmit an accurate time sync, what should it look like, so that you're insensitive to things like rise time. (maybe this harkens back to the discussion about 10 MHz, why sine vs square wave distribution) It has to be a single signal (maybe a differential pair), because otherwise, don't you have potential for skew between the multiple signals. Zerocrossing sort of works, if you take only one direction, but does asymmetry of the waveform screw you up? (e.g. what's zero.. is it half way between peak values + and -?) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
A possible mechanism occurs to me. High-precision GPS is very vulnerable to multipath errors. A loos connector will have a significant reflection. The reflected energy will propagate backwards, and be reflected off the transmitter output discontinuity, the twice-reflected energy propagating back to the receiver. The original and the triple-transit echo will add coherently (for the modulation, not the photons) in the receiver. This is a perfect multipath scenario. How long must the cable be? Depends on the relative strength of main signal and triple-transit echo. Joe Gwinn time-nuts-boun...@febo.com wrote on 02/22/2012 06:31:54 PM: From: Jim Palfreyman jim77...@gmail.com To: rich...@karlquist.com, Discussion of precise time and frequency measurement time-nuts@febo.com Date: 02/22/2012 06:32 PM Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) Sent by: time-nuts-boun...@febo.com Maybe the loose connector meant the clock at one end *never* synced with the GPS and just happened to be 60ns fast. Tighten the connecter, clock resyncs, problem solved. Jim On 23 February 2012 09:57, Rick Karlquist rich...@karlquist.com wrote: Maybe they checked the connector by replacing the whole fiber optic cable with a new one, and while doing that had the oh sh.. moment of realizing the length of the old one was 20 meters different than it was supposed to be. I think this sort of thing has happened to all of us with significant experience. Or maybe the cable was marked with an incorrect length (not due to error by the experimenters) and they forgot trust but verify. We've probably all gotten bit by that one as well. Rick Poul-Henning Kamp wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
It is hard to believe that they would go public with such earth shaking results based on a single GPS timebase, but I have found it is easy to focus on the test head and neglect the back end of an experiment. I must also admit it is even worse science for someone sitting in Boulder Co like myself to second guess these brilliant researchers without all the facts. In any case I am really look forward to the cause of this mystery. I hope public will judge CERN on their successes and understand that in science there is really no such thing as a mistake if we learn from it. Thomas Knox To: time-nuts@febo.com From: gw...@raytheon.com Date: Thu, 23 Feb 2012 13:57:11 -0500 CC: time-nuts-boun...@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) A possible mechanism occurs to me. High-precision GPS is very vulnerable to multipath errors. A loos connector will have a significant reflection. The reflected energy will propagate backwards, and be reflected off the transmitter output discontinuity, the twice-reflected energy propagating back to the receiver. The original and the triple-transit echo will add coherently (for the modulation, not the photons) in the receiver. This is a perfect multipath scenario. How long must the cable be? Depends on the relative strength of main signal and triple-transit echo. Joe Gwinn time-nuts-boun...@febo.com wrote on 02/22/2012 06:31:54 PM: From: Jim Palfreyman jim77...@gmail.com To: rich...@karlquist.com, Discussion of precise time and frequency measurement time-nuts@febo.com Date: 02/22/2012 06:32 PM Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) Sent by: time-nuts-boun...@febo.com Maybe the loose connector meant the clock at one end *never* synced with the GPS and just happened to be 60ns fast. Tighten the connecter, clock resyncs, problem solved. Jim On 23 February 2012 09:57, Rick Karlquist rich...@karlquist.com wrote: Maybe they checked the connector by replacing the whole fiber optic cable with a new one, and while doing that had the oh sh.. moment of realizing the length of the old one was 20 meters different than it was supposed to be. I think this sort of thing has happened to all of us with significant experience. Or maybe the cable was marked with an incorrect length (not due to error by the experimenters) and they forgot trust but verify. We've probably all gotten bit by that one as well. Rick Poul-Henning Kamp wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
I'm sure are all aware that in the general perceptions of the world, there are great scientific achievements and disastrous engineering failures. Never the other way around. Yeah, I'm an engineer. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Knox Sent: Thursday, February 23, 2012 2:47 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) It is hard to believe that they would go public with such earth shaking results based on a single GPS timebase, but I have found it is easy to focus on the test head and neglect the back end of an experiment. I must also admit it is even worse science for someone sitting in Boulder Co like myself to second guess these brilliant researchers without all the facts. In any case I am really look forward to the cause of this mystery. I hope public will judge CERN on their successes and understand that in science there is really no such thing as a mistake if we learn from it. Thomas Knox To: time-nuts@febo.com From: gw...@raytheon.com Date: Thu, 23 Feb 2012 13:57:11 -0500 CC: time-nuts-boun...@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) A possible mechanism occurs to me. High-precision GPS is very vulnerable to multipath errors. A loos connector will have a significant reflection. The reflected energy will propagate backwards, and be reflected off the transmitter output discontinuity, the twice-reflected energy propagating back to the receiver. The original and the triple-transit echo will add coherently (for the modulation, not the photons) in the receiver. This is a perfect multipath scenario. How long must the cable be? Depends on the relative strength of main signal and triple-transit echo. Joe Gwinn time-nuts-boun...@febo.com wrote on 02/22/2012 06:31:54 PM: From: Jim Palfreyman jim77...@gmail.com To: rich...@karlquist.com, Discussion of precise time and frequency measurement time-nuts@febo.com Date: 02/22/2012 06:32 PM Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) Sent by: time-nuts-boun...@febo.com Maybe the loose connector meant the clock at one end *never* synced with the GPS and just happened to be 60ns fast. Tighten the connecter, clock resyncs, problem solved. Jim On 23 February 2012 09:57, Rick Karlquist rich...@karlquist.com wrote: Maybe they checked the connector by replacing the whole fiber optic cable with a new one, and while doing that had the oh sh.. moment of realizing the length of the old one was 20 meters different than it was supposed to be. I think this sort of thing has happened to all of us with significant experience. Or maybe the cable was marked with an incorrect length (not due to error by the experimenters) and they forgot trust but verify. We've probably all gotten bit by that one as well. Rick Poul-Henning Kamp wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
A possible mechanism occurs to me. High-precision GPS is very vulnerable to multipath errors. A loos connector will have a significant reflection. The reflected energy will propagate backwards, and be reflected off the transmitter output discontinuity, the twice-reflected energy propagating back to the receiver. The original and the triple-transit echo will add coherently (for the modulation, not the photons) in the receiver. This is a perfect multipath scenario. How long must the cable be? Depends on the relative strength of main signal and triple-transit echo. Joe Gwinn Joe, High precision GPS receivers use various correlator schemes that try to minimize multipath. Normal GPS receivers are more vulnerable than geodetic quality receivers. http://webone.novatel.ca/assets/Documents/Papers/PAC.pdf -- Björn ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
Björn, time-nuts-boun...@febo.com wrote on 02/23/2012 04:53:06 PM: From: b...@lysator.liu.se To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: 02/23/2012 04:53 PM Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) Sent by: time-nuts-boun...@febo.com A possible mechanism occurs to me. High-precision GPS is very vulnerable to multipath errors. A loos connector will have a significant reflection. The reflected energy will propagate backwards, and be reflected off the transmitter output discontinuity, the twice-reflected energy propagating back to the receiver. The original and the triple-transit echo will add coherently (for the modulation, not the photons) in the receiver. This is a perfect multipath scenario. How long must the cable be? Depends on the relative strength of main signal and triple-transit echo. Joe Gwinn Joe, High precision GPS receivers use various correlator schemes that try to minimize multipath. Normal GPS receivers are more vulnerable than geodetic quality receivers. http://webone.novatel.ca/assets/Documents/Papers/PAC.pdf You are of course correct, but timing receivers may not go to such lengths are are needed for geodetic receivers. A lot of the magic of geodetic receivers is in the choke-ring antenna, which ignores signals arriving from too low an angle above the horizon. In the Neutrino case, the multipath is built into the cable between antenna and receiver, so the antenna cannot help. But I will read the article, which looks interesting. Wonder if it would solve such a triple-transit echo problem. Joe ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Neutrinos not so fast? (defectove connector)
From http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html?ref=hp : BREAKING NEWS: Error Undoes Faster-Than-Light Neutrino Results ... It appears that the faster-than-light neutrino results, announced last September by the OPERA collaboration in Italy, was due to a mistake after all. A bad connection between a GPS unit and a computer may be to blame. Physicists had detected neutrinos travelling from the CERN laboratory in Geneva to the Gran Sasso laboratory near L'Aquila that appeared to make the trip in about 60 nanoseconds less than light speed. Many other physicists suspected that the result was due to some kind of error, given that it seems at odds with Einstein's special theory of relativity, which says nothing can travel faster than the speed of light. That theory has been vindicated by many experiments over the decades. According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos' flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis. Well, timenuts friends, how may a fiberoptic bad connection explain 60 ns? Hmm. Marco IK1ODO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
It depends on the meaning of bad connection... was it not correctly seated in the connector and so distant from the optical receiver? We don't know... hope someone can tell or the experiment be repeated. On Wed, Feb 22, 2012 at 9:41 PM, Marco IK1ODO ik1...@spin-it.com wrote: From http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html?ref=hp: BREAKING NEWS: Error Undoes Faster-Than-Light Neutrino Results ... It appears that the faster-than-light neutrino results, announced last September by the OPERA collaboration in Italy, was due to a mistake after all. A bad connection between a GPS unit and a computer may be to blame. Physicists had detected neutrinos travelling from the CERN laboratory in Geneva to the Gran Sasso laboratory near L'Aquila that appeared to make the trip in about 60 nanoseconds less than light speed. Many other physicists suspected that the result was due to some kind of error, given that it seems at odds with Einstein's special theory of relativity, which says nothing can travel faster than the speed of light. That theory has been vindicated by many experiments over the decades. According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos' flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis. Well, timenuts friends, how may a fiberoptic bad connection explain 60 ns? Hmm. Marco IK1ODO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. /tvb (iPhone4) On Feb 22, 2012, at 12:41 PM, Marco IK1ODO ik1...@spin-it.com wrote: Well, timenuts friends, how may a fiberoptic bad connection explain 60 ns? Hmm. Marco IK1ODO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Yes, so it can help knowing what kind of adapter is being used. On Wed, Feb 22, 2012 at 10:32 PM, Tom Van Baak (lab) t...@leapsecond.comwrote: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. /tvb (iPhone4) On Feb 22, 2012, at 12:41 PM, Marco IK1ODO ik1...@spin-it.com wrote: Well, timenuts friends, how may a fiberoptic bad connection explain 60 ns? Hmm. Marco IK1ODO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Maybe they checked the connector by replacing the whole fiber optic cable with a new one, and while doing that had the oh sh.. moment of realizing the length of the old one was 20 meters different than it was supposed to be. I think this sort of thing has happened to all of us with significant experience. Or maybe the cable was marked with an incorrect length (not due to error by the experimenters) and they forgot trust but verify. We've probably all gotten bit by that one as well. Rick Poul-Henning Kamp wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Neutrinos not so fast?
The Great American Philosopher George Wallace (racist former governor of Alabama) supposedly said, If those university professors are so smart why can't they park their bicycles in a straight line? Those OPERA Collaboration scientists should hire my ex-wife. She could help them out a lot. Her grandmother who died over fifty years ago frequently visits her and sneaks around the house. If she can smell her grandmother's perfume surely she could have found that loose connector. Best regards, Brad Dye Editor, CMA Wireless Messaging News P.O. Box 266 Fairfield, IL 62837 USA Telephone: 618-599-7869 Skype: braddye http://www.braddye.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Maybe the loose connector meant the clock at one end *never* synced with the GPS and just happened to be 60ns fast. Tighten the connecter, clock resyncs, problem solved. Jim On 23 February 2012 09:57, Rick Karlquist rich...@karlquist.com wrote: Maybe they checked the connector by replacing the whole fiber optic cable with a new one, and while doing that had the oh sh.. moment of realizing the length of the old one was 20 meters different than it was supposed to be. I think this sort of thing has happened to all of us with significant experience. Or maybe the cable was marked with an incorrect length (not due to error by the experimenters) and they forgot trust but verify. We've probably all gotten bit by that one as well. Rick Poul-Henning Kamp wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
The explanation is that the connector was loose, by 20 meters. Hard to believe the signal can jump a 20 meter air gap but apparently so. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Examples of GPSDO, rise time, impedance and trigger level: http://www.leapsecond.com/pages/gpsdo-rise/ /tvb (iPhone4) On Feb 22, 2012, at 2:26 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
In message b81e52be-e1b5-430e-bdb0-5e54d9728...@leapsecond.com, Tom Van Baak (lab) writes: Examples of GPSDO, rise time, impedance and trigger level: ... But no examples of *fiber* connector being involved. I simply don't buy the story that tightening the connector makes a consistent 60 nanoseconds difference on a signal. It can add a signal where one was missing before, but it does not change the timing of a signal that already made it through by a consistent 60 nanoseconds. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
I think we are thinking to much. In the real world any press is good press, and careers have been made on less, nearly everyone has heard of Cold Fusion, I bet you could still find investors. Thomas Knox (and his weak sense of humor) From: t...@leapsecond.com Date: Wed, 22 Feb 2012 15:48:45 -0800 To: time-nuts@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) Examples of GPSDO, rise time, impedance and trigger level: http://www.leapsecond.com/pages/gpsdo-rise/ /tvb (iPhone4) On Feb 22, 2012, at 2:26 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. 20m of extra fiber sounds *much* more plausible. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
I read that the news came from sources familiar with the experiment. Is there any official press release? Or only rumors? Antonio I8IOV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Indeed cold fusion is here again... in Italy... google Rossi-Focardi, if interested. Yes, I'm actually struggling finding something about this news flash... On Thu, Feb 23, 2012 at 1:35 AM, iov...@inwind.it iov...@inwind.it wrote: I read that the news came from sources familiar with the experiment. Is there any official press release? Or only rumors? Antonio I8IOV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On 02/22/2012 11:26 PM, Poul-Henning Kamp wrote: In message9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. OTDR works just as normal TDR. If the fibre is not connected you get a reflection and not enough transmission. This is what you use OTDRs for. I agree it needs more details to be believable. 20m of extra fiber sounds *much* more plausible. 60 ns is more like 12 m of fibre. SMF-28 has a refraction index of about 1.45 depending on the wavelength of the laser. I use the rule of thumb that 1 ns is 3 dm in free air and 2 dm in coax and fibre, it's usually good enough for reality check calculations. Oh, and it's about 40 feet. Anyway, I would like to see much more detailed description to see that it indeed was due to this error. Also I'd love to see it repeated such that one can see the time error go on and off. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. This is science, making a spectacular error and then explain it in painstakingly detail can teach a lot more than a otherwise uneventful day at the lab, doing about the same measurement. Learning something means better prepared to avoid it next time. Experience is being built. Still don't know what really happened here, rumours at the best. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Try this: http://www.nature.com/news/flaws-found-in-faster-than-light-neutrino-measurement-1.10099 On Thu, Feb 23, 2012 at 2:10 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 02/22/2012 11:26 PM, Poul-Henning Kamp wrote: In message9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. OTDR works just as normal TDR. If the fibre is not connected you get a reflection and not enough transmission. This is what you use OTDRs for. I agree it needs more details to be believable. 20m of extra fiber sounds *much* more plausible. 60 ns is more like 12 m of fibre. SMF-28 has a refraction index of about 1.45 depending on the wavelength of the laser. I use the rule of thumb that 1 ns is 3 dm in free air and 2 dm in coax and fibre, it's usually good enough for reality check calculations. Oh, and it's about 40 feet. Anyway, I would like to see much more detailed description to see that it indeed was due to this error. Also I'd love to see it repeated such that one can see the time error go on and off. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. This is science, making a spectacular error and then explain it in painstakingly detail can teach a lot more than a otherwise uneventful day at the lab, doing about the same measurement. Learning something means better prepared to avoid it next time. Experience is being built. Still don't know what really happened here, rumours at the best. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On 02/23/2012 02:14 AM, Azelio Boriani wrote: Try this: http://www.nature.com/news/flaws-found-in-faster-than-light-neutrino-measurement-1.10099 Still unverified rumours level. Best article so far thought. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Italy has rewritten the laws of Physics many time throughout history. And I am sure as our understanding increases the Laws will be rewritten many times in the future. But sadly I do not believe this is one of those times. I googled Rossi-Focardi and at least their device looks to have some shielding, unlike the USA version, so in the unlikely event they did create fusion everyone in the room would not die from the radiation. Thomas Knox Date: Thu, 23 Feb 2012 01:42:43 +0100 From: azelio.bori...@screen.it To: iov...@inwind.it; time-nuts@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) Indeed cold fusion is here again... in Italy... google Rossi-Focardi, if interested. Yes, I'm actually struggling finding something about this news flash... On Thu, Feb 23, 2012 at 1:35 AM, iov...@inwind.it iov...@inwind.it wrote: I read that the news came from sources familiar with the experiment. Is there any official press release? Or only rumors? Antonio I8IOV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defective connector)
Well said regarding the willingness to discuss the science in public, Magnus. Too often we get the media wanting to hang someone for a mistake rather than help the process of understanding. The folks at OPERA should be commended for being open about what is going on, even if no one is ever publicly crucified for the connector problem. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Magnus Danielson Sent: Wednesday, February 22, 2012 8:10 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Neutrinos not so fast? (defectove connector) On 02/22/2012 11:26 PM, Poul-Henning Kamp wrote: In message9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. OTDR works just as normal TDR. If the fibre is not connected you get a reflection and not enough transmission. This is what you use OTDRs for. I agree it needs more details to be believable. 20m of extra fiber sounds *much* more plausible. 60 ns is more like 12 m of fibre. SMF-28 has a refraction index of about 1.45 depending on the wavelength of the laser. I use the rule of thumb that 1 ns is 3 dm in free air and 2 dm in coax and fibre, it's usually good enough for reality check calculations. Oh, and it's about 40 feet. Anyway, I would like to see much more detailed description to see that it indeed was due to this error. Also I'd love to see it repeated such that one can see the time error go on and off. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. This is science, making a spectacular error and then explain it in painstakingly detail can teach a lot more than a otherwise uneventful day at the lab, doing about the same measurement. Learning something means better prepared to avoid it next time. Experience is being built. Still don't know what really happened here, rumours at the best. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Tightening up a connector may make a few pSec difference, in terms of absolute delay length, but it could have a very large effect if it caused enough reflection - then the entire time-length of the cable, or some multiple of it, would come into play. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
On 2/22/12 2:26 PM, Poul-Henning Kamp wrote: In message9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. A 10 meter cable with a good reflection/air gap where it should be flush butt joint? 20m of extra fiber sounds *much* more plausible. Oops, I thought it was cable number A321241Z, not cable number A321242Z. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. Lends new meaning to the term defense, I should think. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
Why would this (60ns error, and connector issue) have not shown up in the time transfers and validations done by the labs cited? Brent On Wed, Feb 22, 2012 at 11:03 PM, Jim Lux jim...@earthlink.net wrote: On 2/22/12 2:26 PM, Poul-Henning Kamp wrote: In message9a458dba-3875-43b2-8383-5ca2f86be...@leapsecond.com, Tom Van Baak (lab) writes: Could be on the electrical side of the adapter, not the optical side. It's not impossible to get 60 ns of phase or trigger error with RF connectors. I don't buy that explanation. It's very hard to get 60 ns *consistent* phase or trigger error, with any kind of connector, almost no matter how you go about it. A 10 meter cable with a good reflection/air gap where it should be flush butt joint? 20m of extra fiber sounds *much* more plausible. Oops, I thought it was cable number A321241Z, not cable number A321242Z. Inventing an excuse about a loose connector to cover up the mistake sounds even more plausible. You really don't want to defend your phd dissertation, being known as the idiot who made a fool of both CERN and SanGrasso in one go. Lends new meaning to the term defense, I should think. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
At 01:35 23-02-12, you wrote: I read that the news came from sources familiar with the experiment. Is there any official press release? Or only rumors? Antonio I8IOV Antonio, vedi Battiston su Le Scienze http://www.lescienze.it/news/2012/02/22/news/neutrini_pi_veloci_della_luce_era_un_problema_strumentale-868358/ e http://battiston-lescienze.blogautore.espresso.repubblica.it/2012/02/22/riecco-i-neutrini-probabilmente-piu-lenti/ Dovrebbero dire qualcosa di ufficiale oggi. Comunque l'errore di trigger dovuto allo slope del segnale purtroppo mi sembra credibile. Marco IK1ODO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Neutrinos not so fast? (defectove connector)
sorry for previous message in Italian, had to be a personal one :-) Marco IK1ODO ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
