[time-nuts] TTimelab question
I doubt that it is something TAPR would do. Building complete systems gets into all sorts of issues (mainly regulatory). But it is easy enough to build. They sell a nice case that the RPI3 and touchscreen mounts in. The PI+touchscreen+case sells for around $110. The TICC(s) connect to it via USB. There are also some Win10 tablets with 1024x600 touch screens that sell for around $60 (apparently Microsoft doesn't charge manufacturers for Win10 on tablets with small/low res screens). I am thinking about laying out a front-end board for the TICC. It would have some switchable (relay?) 50 ohm input terminators, switchable PICDIV dividers for PPS/1MHz/5MHz/10MHz/15MHz (or 2.5 MHz) inputs, footprints for a decent reference oscillator (MV89/8663/DIP/etc), and a 12V to 5V (3A?) power converter for the TICC and PI... most of the better surplus oscillators run off of 12V. Also maybe add a data multiplexer for combining the outputs of two TICC boards into one data stream (but Heather could do that in software). John has some ideas for a similar board. - > Wow! If you can persuade John and TAPR to produce that, I would be there with my chequebook before the ink had dried on the web-page! :-) ___ 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] HP5065A Rubidium questions: some progress
Great news and what a deal a dead 5065 lives. I don't think its that critical and not sure how you would test it. But do get a good stable high temp. As I recall the rn70 series was pretty good. For the moment you can reassemble it and see if the rest works the resistor should hold up for a 30 or so minute run. Don't push it if its a plain old cheapy carbon. Best of luck, though I think you have had plenty so far. Regards Paul WB8TSL On Tue, Feb 21, 2017 at 7:56 PM, David Scott Coburn wrote: > I installed a 10 ohm 1/2 watt carbon resistor and the Rb lamp came right > on! Woo-hoo! > > > I will get a better quality, high temperature resistor to replace this > one. (RN70?) > > > How critical is the resistance value? 10 ohm? 12? Is there a way to > test for an optimum value? > > > Scott > > > On Tue, Feb 21, 2017 at 10:01 AM, paul swed wrote: > > Totally agree with the try a 12 ohm resistor. Nice simple and low risk. >> If thats actually the issue then you do need to obtain a high quality >> resistor that can live in a hot environment. Anything will work for a test >> run. >> Regards >> Paul >> WB8TSL >> >> On Tue, Feb 21, 2017 at 2:22 AM, timeok wrote: >> >> >>>Hi Scott, >>>the emitter resistor have to be in the range 9 to 15 Ohm. Probably the >>> high temperature and current have burned it out. >>>Replace it with a 12 Ohm 1/2 W resistor, It will work. >>>Luciano >>>www.timeok.it >>> >>> >>>From "time-nuts" time-nuts-boun...@febo.com >>>To time-nuts@febo.com >>>Cc >>>Date Mon, 20 Feb 2017 19:25:37 -0500 (EST) >>>Subject [time-nuts] HP5065A Rubidium questions: some progress >>>Hi All, >>> >>> >>>Thank you all for the very helpful suggestions! >>> >>> >>>I will try to reply to you all in this one post. >>> >>> >>>I opened up the A12 assembly and was happy to find that the lamp, >>>windows, and reflector all appear to be in good physical condition. >>> There is some very light corrosion on the aluminum reflector, all of >>>the windows are clear, and the photodiode is very visible at the >>> bottom >>>of the oven. >>> >>> >>>The Rb bulb looks very slightly darkened, maybe like a pair of very >>>lightly polarized sunglasses. >>> >>> >>>I measured the resistance of the 20 VDC supply line to the lamp >>>oscillator and it is 3350 ohms, just as Corby said and as I see it >>>should be from the schematic. >>> >>> >>>I measured the current to the lamp oscillator and it is only about 13 >>>mA. Paul mentioned that if it was about 15 mA it was probably not >>>working. And, Poul-Henning mentioned that it should draw about 3W >>> when >>>working, which at 20 VDC would be 150 mA. >>> >>> >>>I powered up the lamp oscillator with it on the bench and I do not see >>>any light from the bulb. I am assuming that it should be visible, but >>>I'm not sure! What is the spectrum from these lamps like? Visible, >>>UV??? >>> >>> >>>I measured the resistance of the small coil wound around the bulb, it >>> is >>>about 0.3 to 0.4 ohms, which seems reasonable. >>> >>> >>>(It looks like someone has been in this assembly before. There is >>>solder flux on the transistor leads, the 20 VDC connection, and the >>> bulb >>>coil leads.) >>> >>> >>>One odd bit is that the resistor in the transistor emitter leg >>> measures >>>about 350 ohms (this is R3 in my schematic). The schematic says it >>>should be 10 ohms. This resistor is on solder posts, so it looks >>> like a >>>'selected at assembly' item. Corby: it this the 12 ohm resistor you >>>mentioned? >>> >>> >>>The voltage across this resistor when the power is on is about 1.6 V. >>> >>> >>>The base voltage is about 2.2 V (this is across CR1 also) and shows >>>"flat-lined" on my scope with the board powered. >>> >>> >>>So, I'm betting that the collector of the transistor is cooked. (The >>>base-emitter drop of ~0.6 V probably means the base and emitter paths >>>are still OK.) >>> >>> >>>But, it is also possible that the R3=350 ohms is way out of line?? >>> >>> >>>Comments welcomed. >>> >>> >>>Corby: the serial number for the unit is 0968A00302. It has a >>> 105-6012 >>>quartz oscillator, and a mechanical PP clock. The A12 unit is a >>> series >>>1220, and is green in color. (The OCXO and the bands around A12 are >>>blue.) The A12 unit has a warranty expiration of 30 April 1978. It >>> has >>>had its "Mag Filed" and "Thumbwheel" blacked out with marker and new >>>values written in. >>> >>> >>>Cheers, >>> >>> >>>Scott >>>___ >>>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 >>>
Re: [time-nuts] advice
In the confusion, I forgot that we are concerned with gravitational time dilation, not time of flight. The University of Minnesota has a lab about 2500 feet down in the Soudan mine. The following is their brief description: "The Soudan Underground Laboratory is a general-purpose science facility, which provides the deep underground environment required by a variety of sensitive experiments." Here's a link to the Soudan page: https://www.physics.umn.edu/outreach/soudan/tour/ Why is it named Soudan? The original miners found northern Minnesota to be extremely cold at times, so they named the town for someplace warm. Let me know if you are seriously considering this, and I will find a contact for you. Bill Hawkins -Original Message- From: Bill Hawkins [mailto:bill.i...@pobox.com] Sent: Tuesday, February 21, 2017 8:08 PM Neutrinos? Look up the OPERA experiment that measured neutrinos going faster than light. Turned out to be a loose optical fiber connector to a timing instrument. Fermi Lab has/had the MINOS experiment going 500 miles from Chicago to a mine in northern Minnesota. The generated neutrinos go through Wisconsin but are not noticed there, AFAIK. Bill Hawkins (Resident of Minnesota, but not a physicist, just a BSME) -Original Message- From: Bob Stewart Sent: Tuesday, February 21, 2017 1:48 PM Hi, Have you been in touch with Fermi-Lab? They run a neutrino experiment with a receiver somewhere underground in Wisconsin. At least that's what I recall. I used to live next to a Physics professor who has a minor part in the experiment. I'm not even sure what sort of data they collect there; whether it's time or something else. Bob Stewart (Not a physicist) ___ 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] advice
Neutrinos? Look up the OPERA experiment that measured neutrinos going faster than light. Turned out to be a loose optical fiber connector to a timing instrument. Fermi Lab has/had the MINOS experiment going 500 miles from Chicago to a mine in northern Minnesota. The generated neutrinos go through Wisconsin but are not noticed there, AFAIK. Bill Hawkins (Resident of Minnesota, but not a physicist, just a BSME) -Original Message- From: Bob Stewart Sent: Tuesday, February 21, 2017 1:48 PM Hi, Have you been in touch with Fermi-Lab? They run a neutrino experiment with a receiver somewhere underground in Wisconsin. At least that's what I recall. I used to live next to a Physics professor who has a minor part in the experiment. I'm not even sure what sort of data they collect there; whether it's time or something else. Bob Stewart (Not a physicist) ___ 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] ``direct'' RS-232 vs. RS-232 via USB vs. PPSdecoding cards
On Tue, 21 Feb 2017 07:37:34 -0500, BC wrote: > >Some 1588 chip sets have (or had, I havent looked recently) external sync >pins. >This does get into the whole, whats a motherboard / whats a peripheral >debate. Plugging in a 1588 card to get that pin probably no longer counts >as a simple solution. If plugging in a card *does* count then that opens up >a lot of possible options. > >Bob I found while looking at the datasheets for newer Intel server ethernet cards that they have the ability to timestamp GPIO pin transitions, but none of them have their internal timebase synchronized to a counter in the CPU. It looks like they are clocked from a separate XO on the card. Maybe if it was synchronized to the PCIe clock / BCLK they could take advantage of that new Always Running Timer in Skylake processors. I'm surprised that Intel hasn't made a big deal about it. Support for it was added in the Linux e1000e driver early last year. ___ 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] advice
On Tuesday, February 21, 2017 11:13:34 AM Rhoderick Beery wrote: > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure > the gravitational time dilation beneath the surface of the Earth. Boulby > Labs in the UK is 1.1 km down which would generate a time differential from > the surface on the order of 1 part in 10^15 -- not much to work with! > > I've investigated measuring redshift/blueshift from lasers but our > wavemeter technology is no where near accurate enough. I've concluded that > my best solution is to use atomic clocks, of which I know very little > about. I thought a clock-enthusiast mail group would be a fantastic way for > me to learn about the subject as well as possibly spur ideas on the lab > test design itself. > > Thanks in advance!! > --- > Rhoderick Beery > direct: 402-817-9363 > ___ > 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. Rhoderick If you have a dark fiber or 2 between the surface and the lab and a pair of sufficiently stable lasers (one at the surface and one in the underground lab) you could look at the change in beat frequency between the lasers (around 50Hz for a pair of red lasers). Bruce ___ 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] Timelab question
On 21 February 2017 at 23:35, Mark Sims wrote: > ... > I plan to package up my TICC and a couple of TADD-2 Mini dividers with a > RPI-3 and the 7" touchscreen display and an Osciiloquartz 8663 DOXCO to > make a small ADEV analyzer box. > Wow! If you can persuade John and TAPR to produce that, I would be there with my chequebook before the ink had dried on the web-page! :-) Peter ___ 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] HP5065A Rubidium questions: some progress
I installed a 10 ohm 1/2 watt carbon resistor and the Rb lamp came right on! Woo-hoo! I will get a better quality, high temperature resistor to replace this one. (RN70?) How critical is the resistance value? 10 ohm? 12? Is there a way to test for an optimum value? Scott On Tue, Feb 21, 2017 at 10:01 AM, paul swed wrote: Totally agree with the try a 12 ohm resistor. Nice simple and low risk. If thats actually the issue then you do need to obtain a high quality resistor that can live in a hot environment. Anything will work for a test run. Regards Paul WB8TSL On Tue, Feb 21, 2017 at 2:22 AM, timeok wrote: Hi Scott, the emitter resistor have to be in the range 9 to 15 Ohm. Probably the high temperature and current have burned it out. Replace it with a 12 Ohm 1/2 W resistor, It will work. Luciano www.timeok.it From "time-nuts" time-nuts-boun...@febo.com To time-nuts@febo.com Cc Date Mon, 20 Feb 2017 19:25:37 -0500 (EST) Subject [time-nuts] HP5065A Rubidium questions: some progress Hi All, Thank you all for the very helpful suggestions! I will try to reply to you all in this one post. I opened up the A12 assembly and was happy to find that the lamp, windows, and reflector all appear to be in good physical condition. There is some very light corrosion on the aluminum reflector, all of the windows are clear, and the photodiode is very visible at the bottom of the oven. The Rb bulb looks very slightly darkened, maybe like a pair of very lightly polarized sunglasses. I measured the resistance of the 20 VDC supply line to the lamp oscillator and it is 3350 ohms, just as Corby said and as I see it should be from the schematic. I measured the current to the lamp oscillator and it is only about 13 mA. Paul mentioned that if it was about 15 mA it was probably not working. And, Poul-Henning mentioned that it should draw about 3W when working, which at 20 VDC would be 150 mA. I powered up the lamp oscillator with it on the bench and I do not see any light from the bulb. I am assuming that it should be visible, but I'm not sure! What is the spectrum from these lamps like? Visible, UV??? I measured the resistance of the small coil wound around the bulb, it is about 0.3 to 0.4 ohms, which seems reasonable. (It looks like someone has been in this assembly before. There is solder flux on the transistor leads, the 20 VDC connection, and the bulb coil leads.) One odd bit is that the resistor in the transistor emitter leg measures about 350 ohms (this is R3 in my schematic). The schematic says it should be 10 ohms. This resistor is on solder posts, so it looks like a 'selected at assembly' item. Corby: it this the 12 ohm resistor you mentioned? The voltage across this resistor when the power is on is about 1.6 V. The base voltage is about 2.2 V (this is across CR1 also) and shows "flat-lined" on my scope with the board powered. So, I'm betting that the collector of the transistor is cooked. (The base-emitter drop of ~0.6 V probably means the base and emitter paths are still OK.) But, it is also possible that the R3=350 ohms is way out of line?? Comments welcomed. Corby: the serial number for the unit is 0968A00302. It has a 105-6012 quartz oscillator, and a mechanical PP clock. The A12 unit is a series 1220, and is green in color. (The OCXO and the bands around A12 are blue.) The A12 unit has a warranty expiration of 30 April 1978. It has had its "Mag Filed" and "Thumbwheel" blacked out with marker and new values written in. Cheers, Scott ___ 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] Timelab question
At one time Timelab worked well for me under Wine. It's been years since I tried it. I recently got in a TAPR TICC and am in the process of adding time interval counter support to Lady Heather. It's not even remotely as nifty as Timelab (and never will be), but it does run under Windows / Linux / macOS and FreeBSD. It can calculate and plot ADEV/HDEV/MDEV/TDEV. The code supports up to 4 simultaneous channels of TICC data (but the TICC is currently a 2 channel device). Besides the TICC it should work (single channel) with HP53xxx counters and counters that output time stamps or time intervals in "talk only" mode. There is the possibility of supporting more than one counter device... Heather can now handle up to 10 com devices and TCP/IP links. I plan to package up my TICC and a couple of TADD-2 Mini dividers with a RPI-3 and the 7" touchscreen display and an Osciiloquartz 8663 DOXCO to make a small ADEV analyzer box. -- > Wine is just a mess as far as Timelab is concerned. Most of the time it > doesn't display the plot area. I've pretty much given up on it. ___ 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] advice
Hi Bob and Rhoderick, I believe the experiment you're talking about is MINOS. If there are any specific questions regarding this, I can probe around. I work (indirectly) with a professor and his group that is a collaborator with MINOS and FermiLab. When I have some free time I will ask him about it; seems like something I would be interested in too. Ray Xu (more of an engineer, but a "physicist-in-training") On Tue, Feb 21, 2017 at 1:48 PM, Bob Stewart wrote: > Hi, > Have you been in touch with Fermi-Lab? They run a neutrino experiment > with a receiver somewhere underground in Wisconsin. At least that's what I > recall. I used to live next to a Physics professor who has a minor part in > the experiment. I'm not even sure what sort of data they collect there; > whether it's time or something else. > > Bob Stewart (Not a physicist) > > > From: Rhoderick Beery > To: time-nuts@febo.com > Sent: Tuesday, February 21, 2017 11:13 AM > Subject: [time-nuts] advice > > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure > the gravitational time dilation beneath the surface of the Earth. Boulby > Labs in the UK is 1.1 km down which would generate a time differential from > the surface on the order of 1 part in 10^15 -- not much to work with! > > I've investigated measuring redshift/blueshift from lasers but our > wavemeter technology is no where near accurate enough. I've concluded that > my best solution is to use atomic clocks, of which I know very little > about. I thought a clock-enthusiast mail group would be a fantastic way for > me to learn about the subject as well as possibly spur ideas on the lab > test design itself. > > Thanks in advance!! > --- > Rhoderick Beery > direct: 402-817-9363 > ___ > 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] Timelab question
Thanks, John. That will certainly get it to work as I expect it to. I doubt I'm the only one who's lost a dataset due to being distracted and hitting the enter key to clear the dialog box. Wine is just a mess as far as Timelab is concerned. Most of the time it doesn't display the plot area. I've pretty much given up on it. Bob From: John Miles To: 'Bob Stewart' ; 'Discussion of precise time and frequency measurement' Sent: Tuesday, February 21, 2017 3:56 PM Subject: RE: [time-nuts] Timelab question > John, > I apologize. I was mistaken in my question. Under wine it behaves poorly, > but that's to be expected. Under XP in a Virtual box, it works as you say. > The > same in a real Win 10 box. The problem is actually that I was expecting the > "No" box to be checked, and to require the user to change it to "Yes" if he > really wanted to exit. So, if I press the Enter key to get rid of the dialog > box, > the program exits. I see what you mean. I've got a couple of other minor tweak requests lined up for the next beta, so I'll add MB_DEFBUTTON2 to those prompts to keep that from happening. If Wine is interpreting a second Escape keypress as 'Yes', then that's definitely a bug on their part. Worth reporting to them if it still happens in the current version. -- john 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] Timelab question
> John, > I apologize. I was mistaken in my question. Under wine it behaves poorly, > but that's to be expected. Under XP in a Virtual box, it works as you say. > The > same in a real Win 10 box. The problem is actually that I was expecting the > "No" box to be checked, and to require the user to change it to "Yes" if he > really wanted to exit. So, if I press the Enter key to get rid of the dialog > box, > the program exits. I see what you mean. I've got a couple of other minor tweak requests lined up for the next beta, so I'll add MB_DEFBUTTON2 to those prompts to keep that from happening. If Wine is interpreting a second Escape keypress as 'Yes', then that's definitely a bug on their part. Worth reporting to them if it still happens in the current version. -- john 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] advice
Hi, Have you been in touch with Fermi-Lab? They run a neutrino experiment with a receiver somewhere underground in Wisconsin. At least that's what I recall. I used to live next to a Physics professor who has a minor part in the experiment. I'm not even sure what sort of data they collect there; whether it's time or something else. Bob Stewart (Not a physicist) From: Rhoderick Beery To: time-nuts@febo.com Sent: Tuesday, February 21, 2017 11:13 AM Subject: [time-nuts] advice Greetings Time-Nuts! I'm a physics theorist interested in performing an experiment to measure the gravitational time dilation beneath the surface of the Earth. Boulby Labs in the UK is 1.1 km down which would generate a time differential from the surface on the order of 1 part in 10^15 -- not much to work with! I've investigated measuring redshift/blueshift from lasers but our wavemeter technology is no where near accurate enough. I've concluded that my best solution is to use atomic clocks, of which I know very little about. I thought a clock-enthusiast mail group would be a fantastic way for me to learn about the subject as well as possibly spur ideas on the lab test design itself. Thanks in advance!! --- Rhoderick Beery direct: 402-817-9363 ___ 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] advice
Hi! Take a look at http://www.leapsecond.com/great2005/ and http://www.leapsecond.com/great2016a/ Edésio On Tue, Feb 21, 2017 at 11:13:34AM -0600, Rhoderick Beery wrote: > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure > the gravitational time dilation beneath the surface of the Earth. Boulby > Labs in the UK is 1.1 km down which would generate a time differential from > the surface on the order of 1 part in 10^15 -- not much to work with! > > I've investigated measuring redshift/blueshift from lasers but our > wavemeter technology is no where near accurate enough. I've concluded that > my best solution is to use atomic clocks, of which I know very little > about. I thought a clock-enthusiast mail group would be a fantastic way for > me to learn about the subject as well as possibly spur ideas on the lab > test design itself. > > Thanks in advance!! > --- > Rhoderick Beery > direct: 402-817-9363 > ___ > 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] advice
Hi Rhoderick, Check your estimates -- for 1 km the redshift should be 1e-13, not 1e-15. The experiment is certainly possible. It's been done many times -- going up, and going down -- though usually above MSL. Doing it below MSL is on my TODO list; using either mine shaft (land) or bathysphere (sea). The logistics are a bit more complicated than driving clocks up a mountain. You can contact me directly for more info. To get an idea of how these experiments are done, see: http://leapsecond.com/great2016a/ http://leapsecond.com/great2005/ http://leapsecond.com/ptti2006/ /tvb - Original Message - From: "Rhoderick Beery" To: Sent: Tuesday, February 21, 2017 9:13 AM Subject: [time-nuts] advice > Greetings Time-Nuts! > > I'm a physics theorist interested in performing an experiment to measure > the gravitational time dilation beneath the surface of the Earth. Boulby > Labs in the UK is 1.1 km down which would generate a time differential from > the surface on the order of 1 part in 10^15 -- not much to work with! > > I've investigated measuring redshift/blueshift from lasers but our > wavemeter technology is no where near accurate enough. I've concluded that > my best solution is to use atomic clocks, of which I know very little > about. I thought a clock-enthusiast mail group would be a fantastic way for > me to learn about the subject as well as possibly spur ideas on the lab > test design itself. > > Thanks in advance!! > --- > Rhoderick Beery > direct: 402-817-9363 > ___ > 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] advice
Greetings Time-Nuts! I'm a physics theorist interested in performing an experiment to measure the gravitational time dilation beneath the surface of the Earth. Boulby Labs in the UK is 1.1 km down which would generate a time differential from the surface on the order of 1 part in 10^15 -- not much to work with! I've investigated measuring redshift/blueshift from lasers but our wavemeter technology is no where near accurate enough. I've concluded that my best solution is to use atomic clocks, of which I know very little about. I thought a clock-enthusiast mail group would be a fantastic way for me to learn about the subject as well as possibly spur ideas on the lab test design itself. Thanks in advance!! --- Rhoderick Beery direct: 402-817-9363 ___ 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] Timelab question
John, I apologize. I was mistaken in my question. Under wine it behaves poorly, but that's to be expected. Under XP in a Virtual box, it works as you say. The same in a real Win 10 box. The problem is actually that I was expecting the "No" box to be checked, and to require the user to change it to "Yes" if he really wanted to exit. So, if I press the Enter key to get rid of the dialog box, the program exits. Bob From: John Miles To: 'Discussion of precise time and frequency measurement' Sent: Tuesday, February 21, 2017 12:39 AM Subject: Re: [time-nuts] Timelab question > Is there a way to change the escape key in Timelab so that it doesn't default > to "yes"? I love Timelab, but this is driving me nuts. I hit the escape key > and > it asks me if I really want to exit. No, I don't! So, I hit the escape key > and > yes, it does exit. > Bob Hmm. I can't repro this on Win7 x64 -- what version of Windows are you running? If I hit Escape followed by Enter, it does exit, since 'Yes' is the default choice. But hitting Escape twice doesn't do anything (and shouldn't). -- john 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. ___ 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] HP5065A Rubidium questions: some progress
Totally agree with the try a 12 ohm resistor. Nice simple and low risk. If thats actually the issue then you do need to obtain a high quality resistor that can live in a hot environment. Anything will work for a test run. Regards Paul WB8TSL On Tue, Feb 21, 2017 at 2:22 AM, timeok wrote: > >Hi Scott, >the emitter resistor have to be in the range 9 to 15 Ohm. Probably the > high temperature and current have burned it out. >Replace it with a 12 Ohm 1/2 W resistor, It will work. >Luciano >www.timeok.it > > >From "time-nuts" time-nuts-boun...@febo.com >To time-nuts@febo.com >Cc >Date Mon, 20 Feb 2017 19:25:37 -0500 (EST) >Subject [time-nuts] HP5065A Rubidium questions: some progress >Hi All, > > >Thank you all for the very helpful suggestions! > > >I will try to reply to you all in this one post. > > >I opened up the A12 assembly and was happy to find that the lamp, >windows, and reflector all appear to be in good physical condition. > There is some very light corrosion on the aluminum reflector, all of >the windows are clear, and the photodiode is very visible at the bottom >of the oven. > > >The Rb bulb looks very slightly darkened, maybe like a pair of very >lightly polarized sunglasses. > > >I measured the resistance of the 20 VDC supply line to the lamp >oscillator and it is 3350 ohms, just as Corby said and as I see it >should be from the schematic. > > >I measured the current to the lamp oscillator and it is only about 13 >mA. Paul mentioned that if it was about 15 mA it was probably not >working. And, Poul-Henning mentioned that it should draw about 3W when >working, which at 20 VDC would be 150 mA. > > >I powered up the lamp oscillator with it on the bench and I do not see >any light from the bulb. I am assuming that it should be visible, but >I'm not sure! What is the spectrum from these lamps like? Visible, >UV??? > > >I measured the resistance of the small coil wound around the bulb, it is >about 0.3 to 0.4 ohms, which seems reasonable. > > >(It looks like someone has been in this assembly before. There is >solder flux on the transistor leads, the 20 VDC connection, and the bulb >coil leads.) > > >One odd bit is that the resistor in the transistor emitter leg measures >about 350 ohms (this is R3 in my schematic). The schematic says it >should be 10 ohms. This resistor is on solder posts, so it looks like a >'selected at assembly' item. Corby: it this the 12 ohm resistor you >mentioned? > > >The voltage across this resistor when the power is on is about 1.6 V. > > >The base voltage is about 2.2 V (this is across CR1 also) and shows >"flat-lined" on my scope with the board powered. > > >So, I'm betting that the collector of the transistor is cooked. (The >base-emitter drop of ~0.6 V probably means the base and emitter paths >are still OK.) > > >But, it is also possible that the R3=350 ohms is way out of line?? > > >Comments welcomed. > > >Corby: the serial number for the unit is 0968A00302. It has a 105-6012 >quartz oscillator, and a mechanical PP clock. The A12 unit is a series >1220, and is green in color. (The OCXO and the bands around A12 are >blue.) The A12 unit has a warranty expiration of 30 April 1978. It has >had its "Mag Filed" and "Thumbwheel" blacked out with marker and new >values written in. > > >Cheers, > > >Scott >___ >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] WWV off-air for 2 days...
https://www.nist.gov/pml/time-and-frequency-division/time-services/wwv-broadcast-outages -Brian, WA1ZMS iPhone ___ 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] ``direct'' RS-232 vs. RS-232 via USB vs. PPSdecoding cards
Hi > On Feb 20, 2017, at 9:26 PM, Trevor N. wrote: > > SA6CID wrote: >> >> So, I thought actually of the jitter added on the way between our >> accurate source (GPS rx), until we can capture our timer. How much can >> this be? As far as I see we don't have a capture mode for the HPET. But, >> if we have to do it in software, we get more than 100 ns jitter. I just >> measured 60-80 ns for a instruction cache miss, with Intels mlc software. >> Overall I would guess > 500 ns, are there measurements on this? > >> This then defines some lower bound of what can be archived for >> synchronizing the clock off the OS. Also hardware time stamping on a >> dedicated PPS card (or PTP ethernet card) does not help unless the clock >> on the card is synchronized to the clock used by the OS. >> > > On Intel processors newer than the core2 it appears that there are no > input pins that can be polled or used as an interrupt source. Current > AMD processors still have LINT0 and LINT1 pins that can be polled > through the XAPIC interface, but using them would require modifying > the motherboard to temporarily disconnect them from their usual > sources. It seems likely that a transition on those pins could be > timestamped within a few tens of ns. > > An option for Linux kernel 4.6 or newer on Skylake processors when > using PTP on the chipset ethernet would be to use the > PTP_SYS_OFFSET_PRECISE ioctl to eliminate the problem you mentioned in > the quoted text. See > https://patchwork.kernel.org/patch/8497611/ > https://patchwork.kernel.org/patch/8497621/ > https://lwn.net/Articles/670081/ > It looks like the chipset and CPU share an "Always Running Timer" > which the chipset can sample in sync with the ethernet PTP, USB[2] and > audio timing registers, and it has a defined relationship to the CPU > TSC. I didn't spot a way to timestamp a GPIO pin transition in the > chipset datasheet, so this sort of kicks the can down the road when > using PTP. It might be possible to use this to improve PPS over USB. > > Skylake chipsets have three 16550-compatible UARTS, so depending on > how they are connected internally (might be on the LPC bus) the line > status signals may have very low read latency. It looks like they are > supported in Linux 4.3 and newer; has anyone tested them? > > For now I've focused on using parallel port cards for PPS capture. The > machine I'm using has a Q67 chipset and i5-2500 processor (the Q67 is > one of the last chipsets with native parallel PCI). There is no option > in the BIOS to disable clock spread-spectrum so it's probably active. > The system XO was replaced with an IDT525 so I can use 10MHz sources. > I added a polling mode and PPS echo to the Linux 4.1 pps_parport > driver. > > Using a Lava parallel PCI card, port reads and writes take an average > of 962ns when done in a calibration loop with the processor TSC. For > measurements I'm using a TIC hooked to the PPS input and echo output, > and Miroslav Lichavar's ppsallan program[3]. The counter I'm using > only has GPIB and I don't yet have an interface card, so I can only do > short tests with it at the moment since I have to watch it. I've > listed some results below with a test time of 1 minute. The system > oscillator and PPS source is an Endrun Technologies Praecis Cf, so all > the data below should be showing only the PPS capture error. Some 1588 chip sets have (or had, I haven’t looked recently) external sync pins. This does get into the whole, what’s a motherboard / what’s a peripheral debate. Plugging in a 1588 card to get that pin probably no longer counts as a simple solution. If plugging in a card *does* count then that opens up a lot of possible options. Bob > > --Driver in polling mode with no system load: > The minimum observed interval between the PPS input and echo was > 1.3us, maximum interval was 2.3us, eyeball-average 1.9us, and the 1t > adev was 513ns. attachment: > adev-praecis-lavanew-poll-noload-1min-04.plog > > --Driver in polling mode with high system load: > min 1.3us, max 2.4us, avg 1.9us, 1t adev 549ns > adev-praecis-lavanew-poll-load-1min-01.plog > > --Driver in interrupt mode with no system load: > min 2.4us, max 3.1us, avg 2.7us, 1t adev 467ns > adev-praecis-lavanew-int-noload-1min-01.plog > > --Driver in interrupt mode with high system load: > min 2.4us, max 4.1us avg 2.8us, 1t adev 533ns > adev-praecis-lavanew-int-load-1min-01.plog > > After subtracting the echo's port write time, polling mode can go > below 400ns delay. This is below the 962ns read time, but is probably > valid since the PPS edge could occur between when the card has decoded > the read command and when it samples the port pins to place on the > bus. 962ns latency seems very high for parallel PCI -- it should be > able to achieve below 300ns. The lava card may be using wait cycles to > throttle down to standard LPT speeds. The card uses an FPGA so it > might be possible to improve its performance. It's also
Re: [time-nuts] HP5065A Rubidium questions: some progress
Hi Scott, the emitter resistor have to be in the range 9 to 15 Ohm. Probably the high temperature and current have burned it out. Replace it with a 12 Ohm 1/2 W resistor, It will work. Luciano www.timeok.it From "time-nuts" time-nuts-boun...@febo.com To time-nuts@febo.com Cc Date Mon, 20 Feb 2017 19:25:37 -0500 (EST) Subject [time-nuts] HP5065A Rubidium questions: some progress Hi All, Thank you all for the very helpful suggestions! I will try to reply to you all in this one post. I opened up the A12 assembly and was happy to find that the lamp, windows, and reflector all appear to be in good physical condition. There is some very light corrosion on the aluminum reflector, all of the windows are clear, and the photodiode is very visible at the bottom of the oven. The Rb bulb looks very slightly darkened, maybe like a pair of very lightly polarized sunglasses. I measured the resistance of the 20 VDC supply line to the lamp oscillator and it is 3350 ohms, just as Corby said and as I see it should be from the schematic. I measured the current to the lamp oscillator and it is only about 13 mA. Paul mentioned that if it was about 15 mA it was probably not working. And, Poul-Henning mentioned that it should draw about 3W when working, which at 20 VDC would be 150 mA. I powered up the lamp oscillator with it on the bench and I do not see any light from the bulb. I am assuming that it should be visible, but I'm not sure! What is the spectrum from these lamps like? Visible, UV??? I measured the resistance of the small coil wound around the bulb, it is about 0.3 to 0.4 ohms, which seems reasonable. (It looks like someone has been in this assembly before. There is solder flux on the transistor leads, the 20 VDC connection, and the bulb coil leads.) One odd bit is that the resistor in the transistor emitter leg measures about 350 ohms (this is R3 in my schematic). The schematic says it should be 10 ohms. This resistor is on solder posts, so it looks like a 'selected at assembly' item. Corby: it this the 12 ohm resistor you mentioned? The voltage across this resistor when the power is on is about 1.6 V. The base voltage is about 2.2 V (this is across CR1 also) and shows "flat-lined" on my scope with the board powered. So, I'm betting that the collector of the transistor is cooked. (The base-emitter drop of ~0.6 V probably means the base and emitter paths are still OK.) But, it is also possible that the R3=350 ohms is way out of line?? Comments welcomed. Corby: the serial number for the unit is 0968A00302. It has a 105-6012 quartz oscillator, and a mechanical PP clock. The A12 unit is a series 1220, and is green in color. (The OCXO and the bands around A12 are blue.) The A12 unit has a warranty expiration of 30 April 1978. It has had its "Mag Filed" and "Thumbwheel" blacked out with marker and new values written in. Cheers, Scott ___ 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] Timelab question
> Is there a way to change the escape key in Timelab so that it doesn't default > to "yes"? I love Timelab, but this is driving me nuts. I hit the escape key > and > it asks me if I really want to exit. No, I don't! So, I hit the escape key > and > yes, it does exit. > Bob Hmm. I can't repro this on Win7 x64 -- what version of Windows are you running? If I hit Escape followed by Enter, it does exit, since 'Yes' is the default choice. But hitting Escape twice doesn't do anything (and shouldn't). -- john 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.
