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] 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] Steve's new QTH...
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. I'm in Silicon Valley. There is a big USGS group here. They used to have a laser setup between Black Mountain and Mt Diablo which are on opposite sides of the fault, roughly 50 miles apart. They used to fly a helicopter along the beam, measuring the temperature so they could get a more accurate answer. Fault motion is ballpark of 1 inch per year, the same as your fingernails grow. So they would want to measure the distance to a (small) fraction of that. I did a quick search, but I didn't find the speed of light as a function of temperature. 50 miles is 3E6 inches so 1 PPM would be a big deal. I think they do it with GPS now. -- 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] Steve's new QTH...
Hal... Maybe they were actually interested in the humidity as a source of phase distortion or attenuation? Maybe they wanted to prove that the temperature did not cause a problem? Or maybe just a government paid-for helicopter ride. Tom Holmes, N8ZM Tipp City, OH EM79 -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray Sent: Tuesday, September 07, 2010 2:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Steve's new QTH... 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. I'm in Silicon Valley. There is a big USGS group here. They used to have a laser setup between Black Mountain and Mt Diablo which are on opposite sides of the fault, roughly 50 miles apart. They used to fly a helicopter along the beam, measuring the temperature so they could get a more accurate answer. Fault motion is ballpark of 1 inch per year, the same as your fingernails grow. So they would want to measure the distance to a (small) fraction of that. I did a quick search, but I didn't find the speed of light as a function of temperature. 50 miles is 3E6 inches so 1 PPM would be a big deal. I think they do it with GPS now. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Steve's new QTH...
Maybe they were actually interested in the humidity as a source of phase distortion or attenuation? Maybe they wanted to prove that the temperature did not cause a problem? Or maybe just a government paid-for helicopter ride. Geologists are interested in plate motions over extended periods of time (years) so there should be lots of opportunities for rides. Are they creeping or jumping? How far? You can measure motion along a fault if you can measure the distance between two places on opposite sides of the fault. In this area, the San Andreas splits into several faults. That pair of mountains straddles most of them. Distance is speed-of-light times time. They can measure the round trip time. The speed of light in air depends upon the density which depends upon temperature. I think I could work out the details with enough time/work, but a quick search didn't find it. Yes, humidity probably is important too. I don't think they are interested in attenuation as long as they have a strong enough signal to get a clean reading on the time. -- 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] 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.
Re: [time-nuts] Steve's new QTH...
time-nuts-boun...@febo.com wrote on 09/07/2010 02:57:07 PM: From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: 09/07/2010 03:15 PM Subject: Re: [time-nuts] Steve's new QTH... Sent by: time-nuts-boun...@febo.com 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. I'm in Silicon Valley. There is a big USGS group here. They used to have a laser setup between Black Mountain and Mt Diablo which are on opposite sides of the fault, roughly 50 miles apart. They used to fly a helicopter along the beam, measuring the temperature so they could get a more accurate answer. Fault motion is ballpark of 1 inch per year, the same as your fingernails grow. So they would want to measure the distance to a (small) fraction of that. I did a quick search, but I didn't find the speed of light as a function of temperature. 50 miles is 3E6 inches so 1 PPM would be a big deal. It is about -0.9 ppm per degree Kelvin at 20 C, for 1310 nm radiation. This comes from the NIST calculator at http://emtoolbox.nist.gov/Wavelength/Abstract.asp, which calculates phase velocity (but not group velocity yet). This is also discussed in Appendix C of ASME B89.4.19-2006 (Performance evaluation of laser-based spherical coordinate measurement systems), which is available gratis on the web. Both phase and group velocity are discussed. Google to find the electrons. Joe Gwinn I think they do it with GPS now. -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Steve's new QTH...
Hal Murray wrote: 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. I'm in Silicon Valley. There is a big USGS group here. They used to have a laser setup between Black Mountain and Mt Diablo which are on opposite sides of the fault, roughly 50 miles apart. They used to fly a helicopter along the beam, measuring the temperature so they could get a more accurate answer. Fault motion is ballpark of 1 inch per year, the same as your fingernails grow. So they would want to measure the distance to a (small) fraction of that. I did a quick search, but I didn't find the speed of light as a function of temperature. 50 miles is 3E6 inches so 1 PPM would be a big deal. it's a big problem.. look for variation in Refractive Index with temperature (and pressure and humidity).. I was working on an 8 GHz antenna design (essentially an interferometer) that in order to be tested needed the source to be at least 27km away to meet the plane wave approximation. Can't do it outdoors (or indoors, even...). CERN has similar problems aligning the beamline with a laser theodolite, and that's in a tunnel underground. I'm thinking they needed mm transverse precision over km distances (i.e. 1 ppm) A 1ppm change in RI is caused by 1degree C 0.4kPa pressure (3mm Hg) 50% RH at 35C It's pronounced enough that you get tropospheric ducting on VHF (e.g. sometimes, repeaters on Mt Wilson above Los Angeles can hear people down in San Diego, below the radio horizon) http://emtoolbox.nist.gov/Wavelength/Documentation.asp go for it... I think they do it with GPS now. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
