Re: [time-nuts] New Zealand, Iceland, Haiti
On 8 September 2010 12:49, jimlux jim...@earthlink.net wrote: Kiwi Geoff wrote: Brooke Clarke wrote: When you look at the time difference between the recent events on a geologic scale you could say they all happened at the same time. Hi Brooke, I'm writing from my home in Christchurch, New Zealand. Local Time of the event is an important variable. Last Saturday we had a 7.1 Richter magnitude event here, which was higher than that of Haiti (where there were 230,000 deaths). We had no loss of life in Christchurch mainly because it happened at 4:35 am local time, and because of our building code, as per: http://www.stuff.co.nz/the-press/news/4096880/Why-we-re-not-Haiti We are still experiencing magnitude 5 aftershocks here as I speak, and for those who like graphs, here is a live feed of the seismograph from Christchurch. http://www.geonet.org.nz/earthquake/drums/mqz-drum.html I now know my home can withstand a magnitude 7.1 earthquake, but it is a test that many houses in Christchurch have failed. What you really want to know is the surface motion *at your house* during the quake. The Northridge earthquake (6.7) was striking because of the radical difference in damage from houses that were close together. Subsurface geology had a big effect. I'm about 15 km from the epicenter, and we had essentially no damage or even permanent effects (although it certainly woke us all up). A friend who also lives 15 km away, but in a different direction, lost all their dishes and glassware when they were launched across the room ( as were he and his girlfriend). The difference was that I had a strong motion of less than 0.1 g and he had 1 g.. peak surface acceleration (1.7g) was some 7km from the epicenter. For the most part, the damage level was continuous (e.g. adjacent houses were damaged about the same amount) but there were some striking anomalies that could not be explained by construction technique, etc. It's theorized that there were reflections and refractions in the subsurface structures that resulted in some places with peaks and nulls. That's aside from things like subsidence and liquefaction, which have big effects on damage. One point to understand is that the original 7.1 quake was just 10km below the surface but we have been experiencing a lot of after-shocks that are up to 5.4 which have been closer the the surface and closer to Christchurch as well. This morning at around 8am was a 5.1 that was just across the other side from the harbour and just 6km deep. These after-shocks seem to be doing more damage than the initial quake as more and more buildings and roads are affected. Believe me, even though it's only a 5.1, when it's that close and shallow, it feels like a massive shake. There have been about 150 after-shocks so far and each days max quake is well over 5. The official estimate of the damage has now doubled to $4bn and it looks like it will take more like years to put everything right here. Certainly the building codes here have saved peoples lives but the fact that we reside on a gravel bed has still rendered a lot of building damage, even to new properties, due to the liquefaction and uneven subsidence. But watch this space as many people fear another big one may occur, as there are new quakes occurring which are not on the same fault line as the initial ones. Anyone got a spare room :) Steve ___ 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What position is measured?
On Wed, Sep 8, 2010 at 02:16, jimlux jim...@earthlink.net wrote: Mark J. Blair wrote: On Sep 7, 2010, at 6:30 AM, jimlux wrote: Yes.. except that the cable's physical and electrical length *do* vary with temperature, so if you're looking at the gnat's eyelash sort of thing, you need to take that into account. Maybe 10 ppm/degree, so a 20 meter run will change a bit less than a millimeter. That's down in the fractional picoseconds time-wise. It's an issue if you're doing things like interferometry at higher frequencies.. Would be possible for the receiver to take into account automatically the delay of the antenna cable, by measuring the delay of an echo of a signal it sends towards the antenna? Do such receivers exists? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What position is measured?
Hi Setups like that do exist and are fairly common. I have never seen the technique integrated into a GPS receiver. It's normally done with a secondary setup. My observation is that something like 99% of the GPSDO's out there never get their antenna delay set to the proper number. It's commonly done for surveying work, but not so much for timing. The cell phone guys can get away without that fine an adjustment, so they ignore it. Bob -- From: Pierpaolo Bernardi olopie...@gmail.com Sent: Wednesday, September 08, 2010 6:35 AM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] What position is measured? On Wed, Sep 8, 2010 at 02:16, jimlux jim...@earthlink.net wrote: Mark J. Blair wrote: On Sep 7, 2010, at 6:30 AM, jimlux wrote: Yes.. except that the cable's physical and electrical length *do* vary with temperature, so if you're looking at the gnat's eyelash sort of thing, you need to take that into account. Maybe 10 ppm/degree, so a 20 meter run will change a bit less than a millimeter. That's down in the fractional picoseconds time-wise. It's an issue if you're doing things like interferometry at higher frequencies.. Would be possible for the receiver to take into account automatically the delay of the antenna cable, by measuring the delay of an echo of a signal it sends towards the antenna? Do such receivers exists? ___ 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] Steve's new QTH...
Got this post 5 times - you still getting aftershocks?? :-) Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Steve Rooke Sent: 07 September 2010 11:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Steve's new QTH... Burt, On 8 September 2010 01:45, Burt I. Weiner b...@att.net wrote: Steve, Depending on the type of antenna used for your GPS, you might want to check the Zenith or vertical angle, and if possible, compare that to pre-quake positioning. Your antenna may now be seeing a change in multipath from some nearby environmental change (no pun intended under the circumstances) that could cause a difference in reflected signals arriving at the antenna. With that in mind I've just changed the default 10 deg elevation mask angle to 30 deg and will see what effects that has. Looking closely at the antenna mounting I cannot see any change in it's angle or position but there may have been some movement of this area as we are on an artificial bank abutting the wetland wildfowl park. What I really need is a real GPS survey system to determine my correct location. Many years ago I ran into a combined group on Mt. Wilson, our local broadcast farm in the mountains, from Cal Tech and MIT that was measuring the movement between Southern California mountains using lazers. While this was scientifically fascinating, it gave me the willies. Yes, it really brings it home that we live on just the skin of a rice pudding. This sort of thing must be a nightmare for the ground stations in control of the GPS system. What happens if the 0 deg meridian (used to be the Greenwich meridian) physically moves, do they account for this I wonder. Considering that the American continent and Europe/Africa are constantly moving apart, and Asia and the Americas are moving closer, this must mean that the position of basically most places on the Earth are constantly changing anyway. Makes you feel like saying, where am I today. 73, Steve ZL3TUV Burt, K6OQK Date: Tue, 7 Sep 2010 18:08:31 +1200 From: Steve Rooke sar10...@gmail.com Subject: Re: [time-nuts] Freestanding mast Well, Steve has been experiencing a LOT of after-shocks, some of which are still big enough to move things around and I found I had to grab hold of my cup of tea to stop it shaking onto the floor last night. In fact these after-shocks are still opening up new cracks in roads and causing buildings to fall. As for my height position, I have run a few surveys but I'm getting varying readings and I wonder if the after-shocks are messing up the survey results. The latest one which was during a fairly stable period was 6.8 MSL. The mast could have sunk a bit or even this whole area could have done as I live on reclaimed marsh-land. My Mothers 3 year old house looks like it has sunk a bit at one and and risen at the other, ie. it looks like it has tipped slightly as her house is built on a concrete pontoon. It wouldn't surprise me if they adjust the height of MSL but I would have thought they would have moved it the other way in an attempt to forestall fears of the effects of Global Warming. Regards from Quake City, Steve Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What position is measured?
It's usually a manual setting of antenna delay on receivers I've used, and based on assumed delay in the particular cable connectors. You can tweak things closer if you have a good 1PPS to compare with. Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Pierpaolo Bernardi Sent: 08 September 2010 11:36 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] What position is measured? On Wed, Sep 8, 2010 at 02:16, jimlux jim...@earthlink.net wrote: Mark J. Blair wrote: On Sep 7, 2010, at 6:30 AM, jimlux wrote: Yes.. except that the cable's physical and electrical length *do* vary with temperature, so if you're looking at the gnat's eyelash sort of thing, you need to take that into account. Maybe 10 ppm/degree, so a 20 meter run will change a bit less than a millimeter. That's down in the fractional picoseconds time-wise. It's an issue if you're doing things like interferometry at higher frequencies.. Would be possible for the receiver to take into account automatically the delay of the antenna cable, by measuring the delay of an echo of a signal it sends towards the antenna? Do such receivers exists? ___ 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] Gaia Satellites time challenge
GAIA is the successor satellite to the improbably successfull Hipparcos satellite which gave us the most precise star-catelog we have ever had. The most recent newsletter from the data processing consortium has a short overview of their time-keeping challenge: Put a Rb at L2, synchronize (relativistically) to 1microsecond. http://www.rssd.esa.int/SA/GAIA/docs/DPAC/web/DPAC_NL_009.pdf Poul-Henning PS: Amongst many other interesting features, GAIA will sport a focal plane covered with a half sqaremeter of CCDs, and the entire optical bench, including mirors, is built out of SiC for thermal performance: http://www.rssd.esa.int/index.php?project=GAIApage=picture_of_the_weekpow=119 -- 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] What position is measured?
Tom Holmes wrote: One other delay contributor would appear to be processing delay in the receiver, which thus begs the question of how the PPS signal is actually synchronized to the GPS system. The GPS nav messages is synchronized to the seconds, so it's a matter of making sure the output pulse is synced to the appropriate time in the GPS signal. The delay in the receiver is (reasonably) constant, so the mfr essentially calibrates it out. It's not done precisely like this, but conceptually, you have a 1pps on the spacecraft driven by a Cs clock, you receive the signal in your receiver (some time later than the actual change of second) and subtract out the light time delay from satellite to you. (or, more accurately, delay the signal from the receiver to the next second). It's controlling for that light time delay that's the tricky part, since it varies depending on the degree of ionization of the ionosphere. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What position is measured?
Pierpaolo Bernardi wrote: On Wed, Sep 8, 2010 at 02:16, jimlux jim...@earthlink.net wrote: Mark J. Blair wrote: On Sep 7, 2010, at 6:30 AM, jimlux wrote: Yes.. except that the cable's physical and electrical length *do* vary with temperature, so if you're looking at the gnat's eyelash sort of thing, you need to take that into account. Maybe 10 ppm/degree, so a 20 meter run will change a bit less than a millimeter. That's down in the fractional picoseconds time-wise. It's an issue if you're doing things like interferometry at higher frequencies.. Would be possible for the receiver to take into account automatically the delay of the antenna cable, by measuring the delay of an echo of a signal it sends towards the antenna? Do such receivers exists? Not for GPS, to my knowledge, but in other time distribution systems, certainly. It's also used in antenna ranges when you need phase information (as in a near field range). It's also been done over the air in radio telescope arrays (e.g. VLA). At JPL, we navigate spacecraft in deep space by very accurately measuring the time delay of a round trip to the spacecraft from earth and back. These days, position uncertainties are in the cm range and velocity in the mm/s, implying measurements of picoseconds in a round trip time of 10,000 seconds. All of this implies that the entire measurement chain (including the cables carrying the maser reference signal) are carefully characterized and controlled. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What position is measured?
Thanks, Jim. I assume that neither the satellite nor the receiver knows what the variation in the light time delay is, so it must be small enough to allow the claimed nanosecond accuracy of the PPS edge. Although one sat is sufficient for time work, would using more improve the PPS accuracy? Seems like having more inputs would help with the light delay and other corrections, but it probably is no different than having multiple Rb's in the lab (the guy with two is never quite sure and all that). Mostly just curious, as my Z3801 is quite good enough for my needs. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jimlux Sent: Wednesday, September 08, 2010 9:42 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] What position is measured? Tom Holmes wrote: One other delay contributor would appear to be processing delay in the receiver, which thus begs the question of how the PPS signal is actually synchronized to the GPS system. The GPS nav messages is synchronized to the seconds, so it's a matter of making sure the output pulse is synced to the appropriate time in the GPS signal. The delay in the receiver is (reasonably) constant, so the mfr essentially calibrates it out. It's not done precisely like this, but conceptually, you have a 1pps on the spacecraft driven by a Cs clock, you receive the signal in your receiver (some time later than the actual change of second) and subtract out the light time delay from satellite to you. (or, more accurately, delay the signal from the receiver to the next second). It's controlling for that light time delay that's the tricky part, since it varies depending on the degree of ionization of the ionosphere. ___ 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] watch innards video
Hi all!! If you don't know a mainspring from an escapement, watch this video. I was wondering about the physics of the hairspring, jewel pin and escapement/pallete arm. Cool stuff. Norm n3ykf ___ 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] watch innards video
Norm, the link was stripped out of your message. Please send it to me directly. Thanks, Dave W6TE Date: Wed, 8 Sep 2010 10:32:52 -0400 From: normn3...@stny.rr.com To: time-nuts@febo.com Subject: [time-nuts] watch innards video Hi all!! If you don't know a mainspring from an escapement, watch this video. I was wondering about the physics of the hairspring, jewel pin and escapement/pallete arm. Cool stuff. Norm n3ykf ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] What position is measured?
Tom Holmes wrote: Thanks, Jim. I assume that neither the satellite nor the receiver knows what the variation in the light time delay is, so it must be small enough to allow the claimed nanosecond accuracy of the PPS edge. Well.. that's the difference between a L1 only and a L1/L2 receiver. If you measure the same signal at two different frequencies, you can use that to estimate the total electron content (TEC) of the path, which in turn can be turned into a delay correction. The uncertainties are on the order of meters/few ns, so keeping the 1pps to within 10ns is doable with a L1 receiver. Although one sat is sufficient for time work, would using more improve the PPS accuracy? Seems like having more inputs would help with the light delay and other corrections, but it probably is no different than having multiple Rb's in the lab (the guy with two is never quite sure and all that). One sat works *if* you know where it and you are. In practice, though, you look at multiple satellites and solve for position and time offset simultaneously. The secret sauce in GPS receivers that distinguishes one from another is: 1) acquisition (how long does it take to find the signal and start tracking) 2) how do you best form the estimate of position and clock offset. Typically it's done with some form of Extended Kalman Filter (EKF) so you also wind up with estimates of the covariance matrix. Whether or not that gets shoved out to the user is another matter. the timing receivers separate the where am I and the what time is it questions.. you do a survey mode to get a precise position, then lock that down, and go to timing only mode, essentially averaging the time info from multiple satellites (not true averaging, almost always a weighted average) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New Zealand, Iceland, Haiti
Hi Steve: The Ricter scale was developed based on pendulum seismometers and that the P wave arrives first then the S. The time delay between the P and S wave gives the distance to the epicenter (time nuts connection). The magnitude of the S wave (adjusted for the distance) gives a Ricter magnitude. But this system does not relate to the energy contained in the quake. http://www.prc68.com/I/Seismometer.shtml At the time of the Loma Prieta quake I was standing in front of the company where I worked and watched the windows oil can with the magnitude of the in-out motion increasing with each cycle. If the quake had lasted a few seconds longer they would have exploded, either sending glass into or out of the building. We were all starting to lay flat on the ground in case the glass was coming out. Then the quake ended. The subject locations are all on or adjacent to the Pacific plate as is California. Have Fun, Brooke Clarke http://www.PRC68.com Steve Rooke wrote: On 8 September 2010 12:49, jimluxjim...@earthlink.net wrote: Kiwi Geoff wrote: Brooke Clarke wrote: When you look at the time difference between the recent events on a geologic scale you could say they all happened at the same time. Hi Brooke, I'm writing from my home in Christchurch, New Zealand. Local Time of the event is an important variable. Last Saturday we had a 7.1 Richter magnitude event here, which was higher than that of Haiti (where there were 230,000 deaths). We had no loss of life in Christchurch mainly because it happened at 4:35 am local time, and because of our building code, as per: http://www.stuff.co.nz/the-press/news/4096880/Why-we-re-not-Haiti We are still experiencing magnitude 5 aftershocks here as I speak, and for those who like graphs, here is a live feed of the seismograph from Christchurch. http://www.geonet.org.nz/earthquake/drums/mqz-drum.html I now know my home can withstand a magnitude 7.1 earthquake, but it is a test that many houses in Christchurch have failed. What you really want to know is the surface motion *at your house* during the quake. The Northridge earthquake (6.7) was striking because of the radical difference in damage from houses that were close together. Subsurface geology had a big effect. I'm about 15 km from the epicenter, and we had essentially no damage or even permanent effects (although it certainly woke us all up). A friend who also lives 15 km away, but in a different direction, lost all their dishes and glassware when they were launched across the room ( as were he and his girlfriend). The difference was that I had a strong motion of less than 0.1 g and he had1 g.. peak surface acceleration (1.7g) was some 7km from the epicenter. For the most part, the damage level was continuous (e.g. adjacent houses were damaged about the same amount) but there were some striking anomalies that could not be explained by construction technique, etc. It's theorized that there were reflections and refractions in the subsurface structures that resulted in some places with peaks and nulls. That's aside from things like subsidence and liquefaction, which have big effects on damage. One point to understand is that the original 7.1 quake was just 10km below the surface but we have been experiencing a lot of after-shocks that are up to 5.4 which have been closer the the surface and closer to Christchurch as well. This morning at around 8am was a 5.1 that was just across the other side from the harbour and just 6km deep. These after-shocks seem to be doing more damage than the initial quake as more and more buildings and roads are affected. Believe me, even though it's only a 5.1, when it's that close and shallow, it feels like a massive shake. There have been about 150 after-shocks so far and each days max quake is well over 5. The official estimate of the damage has now doubled to $4bn and it looks like it will take more like years to put everything right here. Certainly the building codes here have saved peoples lives but the fact that we reside on a gravel bed has still rendered a lot of building damage, even to new properties, due to the liquefaction and uneven subsidence. But watch this space as many people fear another big one may occur, as there are new quakes occurring which are not on the same fault line as the initial ones. Anyone got a spare room :) Steve ___ 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. -- Have Fun, Brooke Clarke http://www.PRC68.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] What position is measured?
Hi Actually they do know a bit about the light delay. They include that data in the information the stat's broadcast. The data is fairly coarse grained. I posted some links a week or so back that go into all the grubby details. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Holmes Sent: Wednesday, September 08, 2010 10:19 AM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] What position is measured? Thanks, Jim. I assume that neither the satellite nor the receiver knows what the variation in the light time delay is, so it must be small enough to allow the claimed nanosecond accuracy of the PPS edge. Although one sat is sufficient for time work, would using more improve the PPS accuracy? Seems like having more inputs would help with the light delay and other corrections, but it probably is no different than having multiple Rb's in the lab (the guy with two is never quite sure and all that). Mostly just curious, as my Z3801 is quite good enough for my needs. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jimlux Sent: Wednesday, September 08, 2010 9:42 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] What position is measured? Tom Holmes wrote: One other delay contributor would appear to be processing delay in the receiver, which thus begs the question of how the PPS signal is actually synchronized to the GPS system. The GPS nav messages is synchronized to the seconds, so it's a matter of making sure the output pulse is synced to the appropriate time in the GPS signal. The delay in the receiver is (reasonably) constant, so the mfr essentially calibrates it out. It's not done precisely like this, but conceptually, you have a 1pps on the spacecraft driven by a Cs clock, you receive the signal in your receiver (some time later than the actual change of second) and subtract out the light time delay from satellite to you. (or, more accurately, delay the signal from the receiver to the next second). It's controlling for that light time delay that's the tricky part, since it varies depending on the degree of ionization of the ionosphere. ___ 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] watch innards video
http://www.youtube.com/watch?v=OiCPu0SjEW4 OHH!!! If I didn't find electronics so fascinating, I'd be going to school for an ME degree rather than an EE.. David Smith w...@msn.com wrote: Norm, the link was stripped out of your message. Please send it to me directly. Thanks, Dave W6TE Date: Wed, 8 Sep 2010 10:32:52 -0400 From: normn3...@stny.rr.com To: time-nuts@febo.com Subject: [time-nuts] watch innards video Hi all!! If you don't know a mainspring from an escapement, watch this video. I was wondering about the physics of the hairspring, jewel pin and escapement/pallete arm. Cool stuff. Norm n3ykf ___ 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] Possibly OT: Maintenance manual for Racal 1998 and 1999 now available for download
I just received an email from EADS (used to be Racal Instruments): Dear David, The 1998/9 Maintenance Manual has now been scanned and is available for download from our web-site. Please use the link below to access the downloads page. http://www.eads-ts.com/index.php?url=Customer%20Support/Reference%20Library/index.php Many thanks are due from all of us to the folks at EADS who made this happen. They know who they are! Regards, David Partridge ___ 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] Possibly OT: Maintenance manual for Racal 1998 and 1999 now available for download
Here Here, I also hope that any other company lurkers realise that availability of support old equipment for us hobbyists can impact their current business. When looking at new equipment for the day job the availabilty of support for older products does have an effect on supplier choice. This ranges from the good who actively provide data and manuals through those who don't care down to the worst who actively suppress distribution of manuals. Well Done EADS (and David) Robert G8RPI. --- On Wed, 8/9/10, David C. Partridge david.partri...@perdrix.co.uk wrote: From: David C. Partridge david.partri...@perdrix.co.uk Subject: [time-nuts] Possibly OT: Maintenance manual for Racal 1998 and 1999 now available for download To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com, teksco...@yahoogroups.com, tekscop...@yahoogroups.com, hp_agilent_equipm...@yahoogroups.com, manual_excha...@yahoogroups.com Date: Wednesday, 8 September, 2010, 16:57 I just received an email from EADS (used to be Racal Instruments): Dear David, The 1998/9 Maintenance Manual has now been scanned and is available for download from our web-site. Please use the link below to access the downloads page. http://www.eads-ts.com/index.php?url=Customer%20Support/Reference%20Library/index.php Many thanks are due from all of us to the folks at EADS who made this happen. They know who they are! Regards, David Partridge ___ 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] New Zealand, Iceland, Haiti
Brooke Clarke wrote: Hi Steve: The Ricter scale was developed based on pendulum seismometers and that the P wave arrives first then the S. The time delay between the P and S wave gives the distance to the epicenter (time nuts connection). The magnitude of the S wave (adjusted for the distance) gives a Ricter magnitude. But this system does not relate to the energy contained in the quake. That's why they use moment magnitude these days, rather than straight Richter (which after all is the log of the deflection reported on a particular kind of seismograph). http://www.prc68.com/I/Seismometer.shtml At the time of the Loma Prieta quake I was standing in front of the company where I worked and watched the windows oil can with the magnitude of the in-out motion increasing with each cycle. If the quake had lasted a few seconds longer they would have exploded, either sending glass into or out of the building. We were all starting to lay flat on the ground in case the glass was coming out. Then the quake ended. The subject locations are all on or adjacent to the Pacific plate as is California. Most of California is on the North American Plate. The San Andreas fault is roughly the dividing line. Los Angeles is on the Pacific Plate. Half of San Francisco is on each side(!).. Berkeley, Oakland, etc, are all on the NA plate. ___ 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] Steve's new QTH...
On 9 September 2010 00:51, Rob Kimberley r...@timing-consultants.com wrote: Got this post 5 times - you still getting aftershocks?? That must be level 5 on the posting scale:) Don't know why you got 5 copies of it as I had no problem sending it but my apologies to all if you've received multiple copies of this. And yes, we are still receiving after-shocks but they seem to have quietened down in the last 24 hours. Steve :-) Rob K -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Steve Rooke Sent: 07 September 2010 11:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Steve's new QTH... Burt, On 8 September 2010 01:45, Burt I. Weiner b...@att.net wrote: Steve, Depending on the type of antenna used for your GPS, you might want to check the Zenith or vertical angle, and if possible, compare that to pre-quake positioning. Your antenna may now be seeing a change in multipath from some nearby environmental change (no pun intended under the circumstances) that could cause a difference in reflected signals arriving at the antenna. With that in mind I've just changed the default 10 deg elevation mask angle to 30 deg and will see what effects that has. Looking closely at the antenna mounting I cannot see any change in it's angle or position but there may have been some movement of this area as we are on an artificial bank abutting the wetland wildfowl park. What I really need is a real GPS survey system to determine my correct location. Many years ago I ran into a combined group on Mt. Wilson, our local broadcast farm in the mountains, from Cal Tech and MIT that was measuring the movement between Southern California mountains using lazers. While this was scientifically fascinating, it gave me the willies. Yes, it really brings it home that we live on just the skin of a rice pudding. This sort of thing must be a nightmare for the ground stations in control of the GPS system. What happens if the 0 deg meridian (used to be the Greenwich meridian) physically moves, do they account for this I wonder. Considering that the American continent and Europe/Africa are constantly moving apart, and Asia and the Americas are moving closer, this must mean that the position of basically most places on the Earth are constantly changing anyway. Makes you feel like saying, where am I today. 73, Steve ZL3TUV Burt, K6OQK Date: Tue, 7 Sep 2010 18:08:31 +1200 From: Steve Rooke sar10...@gmail.com Subject: Re: [time-nuts] Freestanding mast Well, Steve has been experiencing a LOT of after-shocks, some of which are still big enough to move things around and I found I had to grab hold of my cup of tea to stop it shaking onto the floor last night. In fact these after-shocks are still opening up new cracks in roads and causing buildings to fall. As for my height position, I have run a few surveys but I'm getting varying readings and I wonder if the after-shocks are messing up the survey results. The latest one which was during a fairly stable period was 6.8 MSL. The mast could have sunk a bit or even this whole area could have done as I live on reclaimed marsh-land. My Mothers 3 year old house looks like it has sunk a bit at one and and risen at the other, ie. it looks like it has tipped slightly as her house is built on a concrete pontoon. It wouldn't surprise me if they adjust the height of MSL but I would have thought they would have moved it the other way in an attempt to forestall fears of the effects of Global Warming. Regards from Quake City, Steve Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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. -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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] watch innards video
normn3...@stny.rr.com wrote: http://www.youtube.com/watch?v=OiCPu0SjEW4 OHH!!! If I didn't find electronics so fascinating, I'd be going to school for an ME degree rather than an EE.. Even cooler is building the large models. At my former work, we used to do a bit of this for museum displays and the like. ___ 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] Small DMTD project parts
I not able to organize a parts order but did notice a break in price on the transformers at mini-circuits at quantity 10, went from $9.95 to $2.29 this maybe a mistake, as this is the only part that had such a break. Stanley ___ 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] watch innards video
When I was a kid, I loved to watch the pendulum swing back and forth and listen to the tick-tock of my grandparents old wall clock. When I was about five, I completely disassembled my parent's mantle clock. It wasn't until many years later that I learned to put them back together and learn about what makes them work. For an interesting document about clock and watch escapements, check this out: http://www.angelfire.com/ut/horology/EscMechanics.pdf For endless hours of entertainment, watch the animated drawings on this website: http://www.angelfire.com/ut/horology/escapement.html -- FL --- Den ons 8/9/10 skrev normn3...@stny.rr.com normn3...@stny.rr.com: Fra: normn3...@stny.rr.com normn3...@stny.rr.com Emne: Re: [time-nuts] watch innards video Til: Discussion of precise time and frequency measurement time-nuts@febo.com Dato: onsdag 8. september 2010 08.45 http://www.youtube.com/watch?v=OiCPu0SjEW4 OHH!!! If I didn't find electronics so fascinating, I'd be going to school for an ME degree rather than an EE.. David Smith w...@msn.com wrote: Norm, the link was stripped out of your message. Please send it to me directly. Thanks, Dave W6TE Date: Wed, 8 Sep 2010 10:32:52 -0400 From: normn3...@stny.rr.com To: time-nuts@febo.com Subject: [time-nuts] watch innards video Hi all!! If you don't know a mainspring from an escapement, watch this video. I was wondering about the physics of the hairspring, jewel pin and escapement/pallete arm. Cool stuff. Norm n3ykf ___ 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] Possibly OT: Maintenance manual for Racal 1998 and 1999 now available for download
Boy do I agree with your comments. I know it effects my thinking and spending On Wed, Sep 8, 2010 at 4:36 PM, Robert Atkinson robert8...@yahoo.co.ukwrote: Here Here, I also hope that any other company lurkers realise that availability of support old equipment for us hobbyists can impact their current business. When looking at new equipment for the day job the availabilty of support for older products does have an effect on supplier choice. This ranges from the good who actively provide data and manuals through those who don't care down to the worst who actively suppress distribution of manuals. Well Done EADS (and David) Robert G8RPI. --- On Wed, 8/9/10, David C. Partridge david.partri...@perdrix.co.uk wrote: From: David C. Partridge david.partri...@perdrix.co.uk Subject: [time-nuts] Possibly OT: Maintenance manual for Racal 1998 and 1999 now available for download To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com, teksco...@yahoogroups.com, tekscop...@yahoogroups.com, hp_agilent_equipm...@yahoogroups.com, manual_excha...@yahoogroups.com Date: Wednesday, 8 September, 2010, 16:57 I just received an email from EADS (used to be Racal Instruments): Dear David, The 1998/9 Maintenance Manual has now been scanned and is available for download from our web-site. Please use the link below to access the downloads page. http://www.eads-ts.com/index.php?url=Customer%20Support/Reference%20Library/index.php Many thanks are due from all of us to the folks at EADS who made this happen. They know who they are! Regards, David Partridge ___ 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] What position is measured?
On 09/08/2010 04:51 PM, jimlux wrote: Tom Holmes wrote: Thanks, Jim. I assume that neither the satellite nor the receiver knows what the variation in the light time delay is, so it must be small enough to allow the claimed nanosecond accuracy of the PPS edge. Well.. that's the difference between a L1 only and a L1/L2 receiver. If you measure the same signal at two different frequencies, you can use that to estimate the total electron content (TEC) of the path, which in turn can be turned into a delay correction. The uncertainties are on the order of meters/few ns, so keeping the 1pps to within 10ns is doable with a L1 receiver. Although one sat is sufficient for time work, would using more improve the PPS accuracy? Seems like having more inputs would help with the light delay and other corrections, but it probably is no different than having multiple Rb's in the lab (the guy with two is never quite sure and all that). One sat works *if* you know where it and you are. In practice, though, you look at multiple satellites and solve for position and time offset simultaneously. The secret sauce in GPS receivers that distinguishes one from another is: 1) acquisition (how long does it take to find the signal and start tracking) 2) how do you best form the estimate of position and clock offset. Typically it's done with some form of Extended Kalman Filter (EKF) so you also wind up with estimates of the covariance matrix. Whether or not that gets shoved out to the user is another matter. the timing receivers separate the where am I and the what time is it questions.. you do a survey mode to get a precise position, then lock that down, and go to timing only mode, essentially averaging the time info from multiple satellites (not true averaging, almost always a weighted average) Missing is the RAIM and in timing context the T-RAIM. RAIM helps to drop false-tickers from the solution and this process is done dynamically for every solution. It is fairly straightforward. The remaining sources forms an average after the RAIM. 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] What position is measured?
On 09/08/2010 05:34 PM, Bob Camp wrote: Hi Actually they do know a bit about the light delay. They include that data in the information the stat's broadcast. The data is fairly coarse grained. I posted some links a week or so back that go into all the grubby details. Coarse grain is certainly a good way of saying it. The ionosphere corrections are based on a simplification and then fitting data to the model curve. The way to improve on this is to use DGPS sources such as WAAS/EGNOS, which should be good enough for most timing purposes of the hobbyist. Estimating ionospheric delay using dual frequency beats that. Still leaves tropospheric delays thought. Reference network helps for that. 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] OT: Christchurch NZ Quake Map
Sorry this is a bit OT but various people have shown interest in what is happening over here so you might like to look at this animated map showing the progress of the quakes in chronological order. This was designed and produced by Paul Nicholls of the University of Canterbury, Christchurch, New Zealand. http://www.christchurchquakemap.co.nz/ Steve -- Steve Rooke - ZL3TUV G8KVD The only reason for time is so that everything doesn't happen at once. - Einstein ___ 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] Possibly OT: Maintenance manual for Racal 1998 and 1999 now available for download
David, Thank you very much for your efforts. And BTW, any PTS 040 manual around? Best regards Ignacio, EB4APL David C. Partridge wrote: I just received an email from EADS (used to be Racal Instruments): Dear David, The 1998/9 Maintenance Manual has now been scanned and is available for download from our web-site. Please use the link below to access the downloads page. http://www.eads-ts.com/index.php?url=Customer%20Support/Reference%20Library/index.php Many thanks are due from all of us to the folks at EADS who made this happen. They know who they are! Regards, David Partridge ___ 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.
