[time-nuts] NS3kview Software for CW25 receiver
Hello, I’m using the NavSyncview software with the FTS125 GPS module. Is it possible to set the time readout on the NavSync software to a local time? I actually need UTC plus 8 hours. It’s at UTC and I cannot see any way of changing it. Best Regards Garry ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
Hi, I usually don't use drift removal as I want to see the effects of drift! The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. Cheers, Corby ___ time-nuts mailing 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 tide gauge uses GPS signals to measure sea level change
On 28 May 2014 14:06, Tom Holmes thol...@woh.rr.com wrote: Which begs the question: just where the heck, exactly, is the center of the Earth given that it is in the 'middle' of a molten and dynamic core. I always thought that the centre was molten. There was something on the TV in the UK a couple of weeks ago which seemed to indicate that the centre is actually solid, although around that it is molten. I did not see it all and was only watching bits of it, but it would appear some female researcher had proven this. The proof appeared to be based on the time of travel of shock wases from earthquakes and the different speed they travel through solid and liquid. Dave. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] New tide gauge uses GPS signals to measure sea level change
On 5/30/14, 2:41 AM, Dr. David Kirkby wrote: On 28 May 2014 14:06, Tom Holmes thol...@woh.rr.com wrote: Which begs the question: just where the heck, exactly, is the center of the Earth given that it is in the 'middle' of a molten and dynamic core. I always thought that the centre was molten. There was something on the TV in the UK a couple of weeks ago which seemed to indicate that the centre is actually solid, although around that it is molten. Molten, but it's a composite material under a lot of pressure, so the transition between liquid and solid isn't like between ice and water. Think cold peanut butter. I did not see it all and was only watching bits of it, but it would appear some female researcher had proven this. The proof appeared to be based on the time of travel of shock wases from earthquakes and the different speed they travel through solid and liquid. Seismic evidence is how they knew it was liquid in the first place. As you get better at doing the models, and getting better time measurements of the seismic propagation with higher performance seismometers, you can get a better model. Combine that with precise orbit determination (using accurate measurements of time and frequency from orbits) which allows accurate gravity models (e.g. GRACE and GRACE-Follow-On) Dave. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
What did NIST do with its Rubidium ensemble before they got the cesium fountain? Did they break one of the rubidiums off the ensemble, maybe in a different room with different HVAC, and look at the one vs many? Would that be useful for OCXO's, measuring one OCXO against an ensemble? Tim N3QE On 5/30/14, cdel...@juno.com cdel...@juno.com wrote: Hi, I usually don't use drift removal as I want to see the effects of drift! The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. Cheers, Corby ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
Hi Rubidium ensemble? That would have been quite a while back. They have been running on long tube Cs standards for quite a while. Bob On May 30, 2014, at 2:03 PM, Tim Shoppa tsho...@gmail.com wrote: What did NIST do with its Rubidium ensemble before they got the cesium fountain? Did they break one of the rubidiums off the ensemble, maybe in a different room with different HVAC, and look at the one vs many? Would that be useful for OCXO's, measuring one OCXO against an ensemble? Tim N3QE On 5/30/14, cdel...@juno.com cdel...@juno.com wrote: Hi, I usually don't use drift removal as I want to see the effects of drift! The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. Cheers, Corby ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
I usually don't use drift removal as I want to see the effects of drift! The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Well, it will reflect the true stability if they're not exposed to the same drift stimuli, right? Neglecting shared long-term aging trends, they should both end up in random-walk territory over the long run. Otherwise, if you run the two oscillators in open air in the same room or even the same building, then they will respond similarly to HVAC cycles, diurnal cycles, and whatever other environmental changes are common to both. That will make their ADEV look better than reality when you measure them against each other. It doesn't mean the long-term ADEV is necessarily invalid as a statistic, just that you probably haven't eliminated all of the common-mode influences. To the extent the two oscillators drift independently, the ADEV measurement is valid. For that matter, the isolation amps in your DMTD are also exposed to the same environment. Their residual phase tempco should be much better than any quartz oscillator, but if they're worse for some reason, they may dominate the long-term measurement. And of course, if you don't have enough isolation, you could be injection-locking the OCXOs in a really low bandwidth (days, perhaps). Shared power supply leads can also induce entrainment -- or even separate power supplies, if you run the leads right next to each other. Some of the Wenzel ULNs seem to be susceptible to this if you don't add bypassing at their power terminals. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. True, because they aren't as sensitive to environmental effects. But if you benchmark two nearby 5065As or masers carefully enough, their long-term ADEV will also look better than it really is, and for the same reasons. (Some people have even reported similar behavior with cesium standards, although I don't see how that could happen. There aren't supposed to be any first-order temperature effects in a CBT, and I'd think that any lower-order effects would be way beneath the tube's flicker floor...) -- john, KE5FX Miles Design LLC ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
In message 013401cf7c46$31ac3cc0$9504b640$@miles.io, John Miles writes: (Some people have even reported similar behavior with cesium standards, although I don't see how that could happen. There aren't supposed to be any first-order temperature effects in a CBT, and I'd think that any lower-order effects would be way beneath the tube's flicker floor...) One important trick in this area: Always locate your DUTs physically orthogonal to each other. Almost none of our DUTs have 3 axis of symmetry, and therefore most environmental effects are not symmetric with respect to orientation. I noticed this by accident comparing three identical OCXO's because I had put one of them in a different orientation than the other two: The environmental noise were much larger between that one and the two other, than between the two co-aligned DUTs. I'm not entirely sure this is relevant for Rb/Cs/H, their environmentals should be attenuated enough for it to not matter. -- 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] New tide gauge uses GPS signals to measure sea level change
[Structure of Earth's core] jim...@earthlink.net said: Molten, but it's a composite material under a lot of pressure, so the transition between liquid and solid isn't like between ice and water. Think cold peanut butter. Seismic evidence is how they knew it was liquid in the first place. As you get better at doing the models, and getting better time measurements of the seismic propagation with higher performance seismometers, you can get a better model. There was an article in Scientific American back in the early 1970s discussing the structure of the Earth and all the tricks the seismologists used to figure things out. I remember a diagram of the cross section of the Earth with a blizzard of seismic paths, bending and bouncing at each boundary. In that time frame, there was a lot of money for seismic research. It was a key part of the test ban treaties. What did seismologists use for timing back then? -- These are my opinions. 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] New tide gauge uses GPS signals to measure sea level change
On 5/30/14, 3:00 PM, Hal Murray wrote: [Structure of Earth's core] jim...@earthlink.net said: Molten, but it's a composite material under a lot of pressure, so the transition between liquid and solid isn't like between ice and water. Think cold peanut butter. Seismic evidence is how they knew it was liquid in the first place. As you get better at doing the models, and getting better time measurements of the seismic propagation with higher performance seismometers, you can get a better model. There was an article in Scientific American back in the early 1970s discussing the structure of the Earth and all the tricks the seismologists used to figure things out. I remember a diagram of the cross section of the Earth with a blizzard of seismic paths, bending and bouncing at each boundary. In that time frame, there was a lot of money for seismic research. It was a key part of the test ban treaties. What did seismologists use for timing back then? A good wristwatch? Most of the work was done with conventional ink on graph paper drum recorders, and the sync was probably done with some sort of conventional derived from national time reference source: WWV or similar in the US. It's not like you need nanosecond precision when you're looking at propagation times of minutes. P wave propagates at about 5 km/sec S wave propagates at about 3 km/sec That's enough difference that you can tell how far the epicenter is from you in a local earthquake. If it's close (within 10km), you feel the earthquake as a single event, because the P wave arrives in a couple seconds and the S wave is a second later, while the shaking is still going on (unless it's a very small quake). If it's farther away (say 50km), then you feel two separate events (50 sec vs 80 sec). I would say that most people who live in Southern California for a while and are somewhat aware of it can tell the rough distance and magnitude of an earthquake because of this, even if they don't know why. Duration of shaking correlates well with magnitude. The short thump is probably a 2 or 3 (was that an earthquake or a sonic boom or someone dropping a truck load of something), a 4 will maybe be a rumble or a couple sways, a 5 is we're definitely having an earthquake because it lasts distinctly long enough for you to realize that something's going on that's not a short event, and a 6 is in the seems to last forever category. So if you get a crack, thump, rattle followed a few seconds later by the lamps or cupboard door swinging a bit, you say hey, a 3.5 10 miles away The P wave has a distinct crack and feels short to me, and the S (shear, transverse to propagation direction) wave is more the rolling and swaying (depending on the direction of motion). It's kind of like counting seconds between lightning flash and thunder (short duration event, delay, long duration event) In any case, to propagate the 10,000-15,000 km across the earth takes the better part of an hour. ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
Hi Corby, On 05/30/2014 07:26 PM, cdel...@juno.com wrote: Hi, I usually don't use drift removal as I want to see the effects of drift! Yes, but the drift effect is not best represented in the ADEV, but phase or frequency plots however. The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! Good to hear. My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. Would you care to give example plots to illustrate what difference you mean? 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] Caveats on Allan Deviation with ultra stable oscillators
Bob, The long tube Cs standard (NIST 7) is parked in the entrance. Too noisy to contribute much value. They have a bunch of 5071As and hydrogen masers. They live in individually temperature stabilized compartments. One typically is selected as the reference and then you measures differences. With these differences they then run the ensemble program on a pair of redundant PCs every 12 min. Cheers, Magnus On 05/30/2014 09:24 PM, Bob Camp wrote: Hi Rubidium ensemble? That would have been quite a while back. They have been running on long tube Cs standards for quite a while. Bob On May 30, 2014, at 2:03 PM, Tim Shoppa tsho...@gmail.com wrote: What did NIST do with its Rubidium ensemble before they got the cesium fountain? Did they break one of the rubidiums off the ensemble, maybe in a different room with different HVAC, and look at the one vs many? Would that be useful for OCXO's, measuring one OCXO against an ensemble? Tim N3QE On 5/30/14, cdel...@juno.com cdel...@juno.com wrote: Hi, I usually don't use drift removal as I want to see the effects of drift! The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. Cheers, Corby ___ time-nuts mailing 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] Caveats on Allan Deviation with ultra stable oscillators
Hi The question was “Rb ensemble” …. AFIK you would have to go back quite a way to find NIST running one…. Bob On May 30, 2014, at 7:52 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Bob, The long tube Cs standard (NIST 7) is parked in the entrance. Too noisy to contribute much value. They have a bunch of 5071As and hydrogen masers. They live in individually temperature stabilized compartments. One typically is selected as the reference and then you measures differences. With these differences they then run the ensemble program on a pair of redundant PCs every 12 min. Cheers, Magnus On 05/30/2014 09:24 PM, Bob Camp wrote: Hi Rubidium ensemble? That would have been quite a while back. They have been running on long tube Cs standards for quite a while. Bob On May 30, 2014, at 2:03 PM, Tim Shoppa tsho...@gmail.com wrote: What did NIST do with its Rubidium ensemble before they got the cesium fountain? Did they break one of the rubidiums off the ensemble, maybe in a different room with different HVAC, and look at the one vs many? Would that be useful for OCXO's, measuring one OCXO against an ensemble? Tim N3QE On 5/30/14, cdel...@juno.com cdel...@juno.com wrote: Hi, I usually don't use drift removal as I want to see the effects of drift! The effects of oscillators locking together are very apparent on both the phase and AD plots when using a DMTD system. There was no indications of such locking! My point was that if you are measuring ultrastable Quartz oscillators against each other the AD at the higher Tau will not reflect the true stability of the oscillators. Only a Maser or high performance Rubidium (HP5065A) will reveal the true behavior. Cheers, Corby ___ time-nuts mailing 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.
[time-nuts] cheap GPS receiver (NavSpark) with timestamp feature
It seems there is some interest in an inexpensive GPS receiver with a timestamp feature. As far as I know, the recently released NavSpark ( http://navspark.mybigcommerce.com/ ) may be the least expensive such device available. It was a crowd-funded effort from an established small GNSS design house in Taiwan (Skytraq). Recently I received some of the first of these items. It is programmable using a modified Arduino type development environment, and uses a 32-bit CPU (LEON3 Sparc-V8) for baseband processing with a 3rd party L1 receiver section (Skyworks SE4150L). The 1PPS output signal has a granularity of 10 ns, but the input signal timestamp feature is ~60 ns (GPS model with 16.368MHz clock) or ~40 ns (GPS + GLONASS model with 24.552MHz clock). I only just tested the demo timestamp code on a GPS model this morning, and it works mostly as expected, generating timestamps (text output on one of two UARTS) based on 1PPS input from a not-calibrated OCXO I had lying around. At least the millisecond output has jumps of ~ 60 ns size. The GPS time-of-day conversion seems to have a roundoff problem at the microsecond level. The NavSpark contains a TCXO of unknown performance, but with the entire unit costing $22 at retail, it's not gold- plated. 484282681.511417 ms, week #1794 since 1980; 2014-05-30 @ 02:31:06(+0.68151140) PM 484283681.511432 ms, week #1794 since 1980; 2014-05-30 @ 02:31:07(+0.68151140) PM 484284681.511452 ms, week #1794 since 1980; 2014-05-30 @ 02:31:08(+0.68151093) PM 484285681.511488 ms, week #1794 since 1980; 2014-05-30 @ 02:31:09(+0.68151093) PM 484286681.511498 ms, week #1794 since 1980; 2014-05-30 @ 02:31:10(+0.68151093) PM 484287681.511514 ms, week #1794 since 1980; 2014-05-30 @ 02:31:11(+0.68151093) PM 484288681.511524 ms, week #1794 since 1980; 2014-05-30 @ 02:31:12(+0.68151188) PM 484289681.511536 ms, week #1794 since 1980; 2014-05-30 @ 02:31:13(+0.68151188) PM 484290681.511541 ms, week #1794 since 1980; 2014-05-30 @ 02:31:14(+0.68151188) PM 484291681.511554 ms, week #1794 since 1980; 2014-05-30 @ 02:31:15(+0.68151188) PM 484292681.511570 ms, week #1794 since 1980; 2014-05-30 @ 02:31:16(+0.68151093) PM 484293681.511578 ms, week #1794 since 1980; 2014-05-30 @ 02:31:17(+0.68151093) PM 484294681.511538 ms, week #1794 since 1980; 2014-05-30 @ 02:31:18(+0.68151093) PM 484295681.511564 ms, week #1794 since 1980; 2014-05-30 @ 02:31:19(+0.68151093) PM 484296681.511588 ms, week #1794 since 1980; 2014-05-30 @ 02:31:20(+0.68151093) PM --- John Beale www.bealecorner.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.
