Hi Bob, Everything about time & frequency is simply a matter of degree, of decimals points. If all you require is 1 second accuracy then any old WWVB RC clock will work. If you want 0.1 second, or 10 ms, or 1 ms accuracy a PC running NTP should work. As you push closer to the microsecond level you need a correspondingly better internal stable frequency source (e.g., rubidium) or external accurate time source (e.g., GPS). Most of us use GPS one way or another, achieving 100 ns accuracy with no effort and 10 ns with extreme effort. Listening to WWV makes a nice example. Where I am near Seattle, say 1000 miles from NIST, the radio wave delay from Ft Collins (due to speed of light, 1 ns/foot, or 5 us/mile) is about 5 ms. The delay from the WWV radio speaker to my ear (due to the speed of sound, 1 ms/foot, or 5 s/mile) is about 5 ms. /tvb ----- Original Message ----- From: "Bob Albert" <bob91343@yahoo.com> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Saturday, March 01, 2014 6:04 PM Subject: Re: [time-nuts] Another "atomic" clock question All this is very interesting. However, my interest is frequency. In other words, I want to know that my standard oscillators are as close to desired frequency as possible, and how close that turns out to be. Yes, the Internet gives me time of day as close as I care to know. I have an 'atomic' clock from LaCrosse that resets itself nightly, although it's fussy about where in the house I put it. If I put it where I'd like, it won't receive WWVB, so I put it across the room. I called the company inquiring about augmenting the internal antenna but they were of no help. While watching the clock and listening to WWV, it seems the clock is a fraction of a second behind. Even that doesn't matter, but calibrating the counter time base is another kind of thing. I am trying to understand how this is done. Should I ever get a rubidium standard, I'd want to check its calibration, and that's not a trivial exercise. Bob On Saturday, March 1, 2014 4:56 PM, Paul Alfille <paul.alfille@gmail.com> wrote: There are WWVB clocks with serial output. Arcron made one that I added linux ntp support for some years back. http://www.atomictimeclock.com/radsynarcron.htm http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver27.html As I recall, it was under $100, quite nicely styled, and is sitting here on my desk. (Reception on the East Coast can be spotty, so I've switched to standard internet net time source). On Mon, Feb 24, 2014 at 7:44 AM, Bob Camp <lists@rtty.us> wrote: > Hi > > Ok, so 0.1 second at the sync point is indeed a reasonable estimate. If > that's all you need to deal with (you correct out the crystal offset one > way or the other) then: > > At 1 day you have 11.5 ppm accuracy. Roughly a 100 Hz beat note with WWV > at 10 MHz. > > At 10 days you have 1.15 ppm. Roughly a 1 Hz beat note at 10 MHz. > > At 100 days you have 0.115 ppm. That would be about a 10 second period > beat note. > > None of that is to say that a beat note is all there is to getting > accuracy off of WWV or that the two approaches deliver the same net > accuracy. Yes I've done the 10 second beat thing, it can be done with care > and a good stable WWV signal. > > Bob > > On Feb 23, 2014, at 5:21 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: > > >> Now that you have brought up this subject, do you know of any way to > use these LaCrosse clocks to calibrate frequency standards? > > > > I suggest using a direct electric (1.5 VDC high-Z) or indirect magnetic > (high gain) pickup on the coil to get the +/- pulse per second. Compare > this time with your local frequency standard and over several days you > should get accuracy better than 10 ms per day (1e-7). Here's an example of > a raw phase plot: > > http://leapsecond.com/pages/Junghans/ > > > > /tvb

Careful where you step. You may just get sucked into time nuts and it never stops. Get a good crystal, then its an RB, next you know your paying shipping for a 100 Lbs Cesium. Evil stuff. Or you can just skip all the distractions and get a good GPSDO. Not as much fun learning on the way. But depends on your end goal. Regards Paul WB8TSL On Sat, Mar 1, 2014 at 9:04 PM, Bob Albert <bob91343@yahoo.com> wrote: > All this is very interesting. However, my interest is frequency. In > other words, I want to know that my standard oscillators are as close to > desired frequency as possible, and how close that turns out to be. > > > Yes, the Internet gives me time of day as close as I care to know. I have > an 'atomic' clock from LaCrosse that resets itself nightly, although it's > fussy about where in the house I put it. If I put it where I'd like, it > won't receive WWVB, so I put it across the room. I called the company > inquiring about augmenting the internal antenna but they were of no help. > > > While watching the clock and listening to WWV, it seems the clock is a > fraction of a second behind. Even that doesn't matter, but calibrating the > counter time base is another kind of thing. > > I am trying to understand how this is done. Should I ever get a rubidium > standard, I'd want to check its calibration, and that's not a trivial > exercise. > > Bob > > > > > On Saturday, March 1, 2014 4:56 PM, Paul Alfille <paul.alfille@gmail.com> > wrote: > > There are WWVB clocks with serial output. Arcron made one that I added > linux ntp support for some years back. > http://www.atomictimeclock.com/radsynarcron.htm > > http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver27.html > > As I recall, it was under $100, quite nicely styled, and is sitting here on > my desk. (Reception on the East Coast can be spotty, so I've switched to > standard internet net time source). > > > > > > > On Mon, Feb 24, 2014 at 7:44 AM, Bob Camp <lists@rtty.us> wrote: > > > Hi > > > > Ok, so 0.1 second at the sync point is indeed a reasonable estimate. If > > that's all you need to deal with (you correct out the crystal offset one > > way or the other) then: > > > > At 1 day you have 11.5 ppm accuracy. Roughly a 100 Hz beat note with WWV > > at 10 MHz. > > > > At 10 days you have 1.15 ppm. Roughly a 1 Hz beat note at 10 MHz. > > > > At 100 days you have 0.115 ppm. That would be about a 10 second period > > beat note. > > > > None of that is to say that a beat note is all there is to getting > > accuracy off of WWV or that the two approaches deliver the same net > > accuracy. Yes I've done the 10 second beat thing, it can be done with > care > > and a good stable WWV signal. > > > > Bob > > > > On Feb 23, 2014, at 5:21 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: > > > > >> Now that you have brought up this subject, do you know of any way to > > use these LaCrosse clocks to calibrate frequency standards? > > > > > > I suggest using a direct electric (1.5 VDC high-Z) or indirect magnetic > > (high gain) pickup on the coil to get the +/- pulse per second. Compare > > this time with your local frequency standard and over several days you > > should get accuracy better than 10 ms per day (1e-7). Here's an example > of > > a raw phase plot: > > > http://leapsecond.com/pages/Junghans/ > > > > > > /tvb > > > > > > _______________________________________________ > > > 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. >

that WWV has some problem, the propagation path is not very stabile, therefore the arriving signal is phase modulated, if you look it for short time the phase modulation looks like frequency modulation it means the frequency is changing = not stabile, WWVB is a bit better since it ha a more stabile propagation path due to it's much lower frequency, 60kHz but there are al our nice switching mode power supplies which generating lots of concurrence for WWVB, so it is not so simple task to receive it clean 73 KJ6UHN Alex On 3/1/2014 6:31 PM, Tom Van Baak wrote: > Hi Bob, > > Everything about time & frequency is simply a matter of degree, of decimals points. If all you require is 1 second accuracy then any old WWVB RC clock will work. > > If you want 0.1 second, or 10 ms, or 1 ms accuracy a PC running NTP should work. > > As you push closer to the microsecond level you need a correspondingly better internal stable frequency source (e.g., rubidium) or external accurate time source (e.g., GPS). Most of us use GPS one way or another, achieving 100 ns accuracy with no effort and 10 ns with extreme effort. > > Listening to WWV makes a nice example. Where I am near Seattle, say 1000 miles from NIST, the radio wave delay from Ft Collins (due to speed of light, 1 ns/foot, or 5 us/mile) is about 5 ms. The delay from the WWV radio speaker to my ear (due to the speed of sound, 1 ms/foot, or 5 s/mile) is about 5 ms. > > /tvb > > ----- Original Message ----- > From: "Bob Albert" <bob91343@yahoo.com> > To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> > Sent: Saturday, March 01, 2014 6:04 PM > Subject: Re: [time-nuts] Another "atomic" clock question > > > All this is very interesting. However, my interest is frequency. In other words, I want to know that my standard oscillators are as close to desired frequency as possible, and how close that turns out to be. > > > Yes, the Internet gives me time of day as close as I care to know. I have an 'atomic' clock from LaCrosse that resets itself nightly, although it's fussy about where in the house I put it. If I put it where I'd like, it won't receive WWVB, so I put it across the room. I called the company inquiring about augmenting the internal antenna but they were of no help. > > > While watching the clock and listening to WWV, it seems the clock is a fraction of a second behind. Even that doesn't matter, but calibrating the counter time base is another kind of thing. > > I am trying to understand how this is done. Should I ever get a rubidium standard, I'd want to check its calibration, and that's not a trivial exercise. > > Bob > > > > > On Saturday, March 1, 2014 4:56 PM, Paul Alfille <paul.alfille@gmail.com> wrote: > > There are WWVB clocks with serial output. Arcron made one that I added > linux ntp support for some years back. > http://www.atomictimeclock.com/radsynarcron.htm > > http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver27.html > > As I recall, it was under $100, quite nicely styled, and is sitting here on > my desk. (Reception on the East Coast can be spotty, so I've switched to > standard internet net time source). > > > > > > > On Mon, Feb 24, 2014 at 7:44 AM, Bob Camp <lists@rtty.us> wrote: > >> Hi >> >> Ok, so 0.1 second at the sync point is indeed a reasonable estimate. If >> that's all you need to deal with (you correct out the crystal offset one >> way or the other) then: >> >> At 1 day you have 11.5 ppm accuracy. Roughly a 100 Hz beat note with WWV >> at 10 MHz. >> >> At 10 days you have 1.15 ppm. Roughly a 1 Hz beat note at 10 MHz. >> >> At 100 days you have 0.115 ppm. That would be about a 10 second period >> beat note. >> >> None of that is to say that a beat note is all there is to getting >> accuracy off of WWV or that the two approaches deliver the same net >> accuracy. Yes I've done the 10 second beat thing, it can be done with care >> and a good stable WWV signal. >> >> Bob >> >> On Feb 23, 2014, at 5:21 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: >> >>>> Now that you have brought up this subject, do you know of any way to >> use these LaCrosse clocks to calibrate frequency standards? >>> I suggest using a direct electric (1.5 VDC high-Z) or indirect magnetic >> (high gain) pickup on the coil to get the +/- pulse per second. Compare >> this time with your local frequency standard and over several days you >> should get accuracy better than 10 ms per day (1e-7). Here's an example of >> a raw phase plot: >>> http://leapsecond.com/pages/Junghans/ >>> >>> /tvb > > _______________________________________________ > 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.

Hi With WWV you need to do it at the right time and the right frequency. There may not be a right combination every day. You want to do it when you have a stable path between you and them. That can (and does) happen, just not all the time. Bob On Mar 1, 2014, at 9:55 PM, Alex Pummer <alex@pcscons.com> wrote: > that WWV has some problem, the propagation path is not very stabile, therefore the arriving signal is phase modulated, if you look it for short time the phase modulation looks like frequency modulation it means the frequency is changing = not stabile, WWVB is a bit better since it ha a more stabile propagation path due to it's much lower frequency, 60kHz but there are al our nice switching mode power supplies which generating lots of concurrence for WWVB, so it is not so simple task to receive it clean > 73 > KJ6UHN > Alex > > On 3/1/2014 6:31 PM, Tom Van Baak wrote: >> Hi Bob, >> >> Everything about time & frequency is simply a matter of degree, of decimals points. If all you require is 1 second accuracy then any old WWVB RC clock will work. >> >> If you want 0.1 second, or 10 ms, or 1 ms accuracy a PC running NTP should work. >> >> As you push closer to the microsecond level you need a correspondingly better internal stable frequency source (e.g., rubidium) or external accurate time source (e.g., GPS). Most of us use GPS one way or another, achieving 100 ns accuracy with no effort and 10 ns with extreme effort. >> >> Listening to WWV makes a nice example. Where I am near Seattle, say 1000 miles from NIST, the radio wave delay from Ft Collins (due to speed of light, 1 ns/foot, or 5 us/mile) is about 5 ms. The delay from the WWV radio speaker to my ear (due to the speed of sound, 1 ms/foot, or 5 s/mile) is about 5 ms. >> >> /tvb >> >> ----- Original Message ----- >> From: "Bob Albert" <bob91343@yahoo.com> >> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> >> Sent: Saturday, March 01, 2014 6:04 PM >> Subject: Re: [time-nuts] Another "atomic" clock question >> >> >> All this is very interesting. However, my interest is frequency. In other words, I want to know that my standard oscillators are as close to desired frequency as possible, and how close that turns out to be. >> >> >> Yes, the Internet gives me time of day as close as I care to know. I have an 'atomic' clock from LaCrosse that resets itself nightly, although it's fussy about where in the house I put it. If I put it where I'd like, it won't receive WWVB, so I put it across the room. I called the company inquiring about augmenting the internal antenna but they were of no help. >> >> >> While watching the clock and listening to WWV, it seems the clock is a fraction of a second behind. Even that doesn't matter, but calibrating the counter time base is another kind of thing. >> >> I am trying to understand how this is done. Should I ever get a rubidium standard, I'd want to check its calibration, and that's not a trivial exercise. >> >> Bob >> >> >> >> >> On Saturday, March 1, 2014 4:56 PM, Paul Alfille <paul.alfille@gmail.com> wrote: >> There are WWVB clocks with serial output. Arcron made one that I added >> linux ntp support for some years back. >> http://www.atomictimeclock.com/radsynarcron.htm >> >> http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver27.html >> >> As I recall, it was under $100, quite nicely styled, and is sitting here on >> my desk. (Reception on the East Coast can be spotty, so I've switched to >> standard internet net time source). >> >> >> >> >> >> >> On Mon, Feb 24, 2014 at 7:44 AM, Bob Camp <lists@rtty.us> wrote: >> >>> Hi >>> >>> Ok, so 0.1 second at the sync point is indeed a reasonable estimate. If >>> that's all you need to deal with (you correct out the crystal offset one >>> way or the other) then: >>> >>> At 1 day you have 11.5 ppm accuracy. Roughly a 100 Hz beat note with WWV >>> at 10 MHz. >>> >>> At 10 days you have 1.15 ppm. Roughly a 1 Hz beat note at 10 MHz. >>> >>> At 100 days you have 0.115 ppm. That would be about a 10 second period >>> beat note. >>> >>> None of that is to say that a beat note is all there is to getting >>> accuracy off of WWV or that the two approaches deliver the same net >>> accuracy. Yes I've done the 10 second beat thing, it can be done with care >>> and a good stable WWV signal. >>> >>> Bob >>> >>> On Feb 23, 2014, at 5:21 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: >>> >>>>> Now that you have brought up this subject, do you know of any way to >>> use these LaCrosse clocks to calibrate frequency standards? >>>> I suggest using a direct electric (1.5 VDC high-Z) or indirect magnetic >>> (high gain) pickup on the coil to get the +/- pulse per second. Compare >>> this time with your local frequency standard and over several days you >>> should get accuracy better than 10 ms per day (1e-7). Here's an example of >>> a raw phase plot: >>>> http://leapsecond.com/pages/Junghans/ >>>> >>>> /tvb >> >> _______________________________________________ >> 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.

Here's a little anecdote that tells how far we have come in the last 50 years. I had the privilege of visiting a NASA lab in 64 I think it was. They showed us, I was with a student group, a setup with a scope a WWV receiver and a rotating transformer that would change the time on a clock one millisecond for every turn of a crank. The seconds output from the divider chain triggered a scope sweep and the vertical displayed the audio from WWV. The guy could turn the crank and position the start of the time tick on the left of the screen. Then he turned the crank to correct for light time delay. I think WWV was still in Maryland at that time. I don't remember exactly when they moved it to Colorado. Anyway, this was the master clock for tracking and telemetry for the manned space flights of that time. Regards. Max. K 4 O DS. Email: max@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscribe@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscribe@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscribe@yahoogroups.com ----- Original Message ----- From: "paul swed" <paulswedb@gmail.com> To: "Bob Albert" <bob91343@yahoo.com>; "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Saturday, March 01, 2014 8:33 PM Subject: Re: [time-nuts] Another "atomic" clock question > Careful where you step. You may just get sucked into time nuts and it > never > stops. > Get a good crystal, then its an RB, next you know your paying shipping for > a 100 Lbs Cesium. Evil stuff. > Or you can just skip all the distractions and get a good GPSDO. > Not as much fun learning on the way. But depends on your end goal. > Regards > Paul > WB8TSL > > > On Sat, Mar 1, 2014 at 9:04 PM, Bob Albert <bob91343@yahoo.com> wrote: > >> All this is very interesting. However, my interest is frequency. In >> other words, I want to know that my standard oscillators are as close to >> desired frequency as possible, and how close that turns out to be. >> >> >> Yes, the Internet gives me time of day as close as I care to know. I >> have >> an 'atomic' clock from LaCrosse that resets itself nightly, although it's >> fussy about where in the house I put it. If I put it where I'd like, it >> won't receive WWVB, so I put it across the room. I called the company >> inquiring about augmenting the internal antenna but they were of no help. >> >> >> While watching the clock and listening to WWV, it seems the clock is a >> fraction of a second behind. Even that doesn't matter, but calibrating >> the >> counter time base is another kind of thing. >> >> I am trying to understand how this is done. Should I ever get a rubidium >> standard, I'd want to check its calibration, and that's not a trivial >> exercise. >> >> Bob >> >> >> >> >> On Saturday, March 1, 2014 4:56 PM, Paul Alfille <paul.alfille@gmail.com> >> wrote: >> >> There are WWVB clocks with serial output. Arcron made one that I added >> linux ntp support for some years back. >> http://www.atomictimeclock.com/radsynarcron.htm >> >> http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver27.html >> >> As I recall, it was under $100, quite nicely styled, and is sitting here >> on >> my desk. (Reception on the East Coast can be spotty, so I've switched to >> standard internet net time source). >> >> >> >> >> >> >> On Mon, Feb 24, 2014 at 7:44 AM, Bob Camp <lists@rtty.us> wrote: >> >> > Hi >> > >> > Ok, so 0.1 second at the sync point is indeed a reasonable estimate. If >> > that's all you need to deal with (you correct out the crystal offset >> > one >> > way or the other) then: >> > >> > At 1 day you have 11.5 ppm accuracy. Roughly a 100 Hz beat note with >> > WWV >> > at 10 MHz. >> > >> > At 10 days you have 1.15 ppm. Roughly a 1 Hz beat note at 10 MHz. >> > >> > At 100 days you have 0.115 ppm. That would be about a 10 second period >> > beat note. >> > >> > None of that is to say that a beat note is all there is to getting >> > accuracy off of WWV or that the two approaches deliver the same net >> > accuracy. Yes I've done the 10 second beat thing, it can be done with >> care >> > and a good stable WWV signal. >> > >> > Bob >> > >> > On Feb 23, 2014, at 5:21 PM, Tom Van Baak <tvb@LeapSecond.com> wrote: >> > >> > >> Now that you have brought up this subject, do you know of any way to >> > use these LaCrosse clocks to calibrate frequency standards? >> > > >> > > I suggest using a direct electric (1.5 VDC high-Z) or indirect >> > > magnetic >> > (high gain) pickup on the coil to get the +/- pulse per second. Compare >> > this time with your local frequency standard and over several days you >> > should get accuracy better than 10 ms per day (1e-7). Here's an example >> of >> > a raw phase plot: >> > > http://leapsecond.com/pages/Junghans/ >> > > >> > > /tvb >> > > >> > > _______________________________________________ >> > > 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. --- This email is free from viruses and malware because avast! 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