Fellow time-nuts, Just for fun I have been looking at the mains as a time-reference. I've used an OSA 8600 as reference and divided down to PPS by a TADD-2. While not absolute time reference, it is way quieter than the mains so I think it is good enough to have some fun at least. Just to illustrate the issue. I use a HP5335A to measure the time from PPS to rising edge of 50 Hz as being accessible through a transformer. The ADEV has a peak at 30 s measuring 2,3E-4 and another at 6000 s measuring 4,3E-4. The phase changes over -0.11923 to +10,979 so a time difference peak-to-peak of 11,098 seconds. While I could refine my measurements to ensure trigger jitter is not causing any major issues, the ADEV slope from 1 s is rising rather than lowering, so it rather seems like source behaviour dominates. While this attempt is a hack, I hope it inspires people to fiddle around a little. :) Cheers, Magnus

Magnus, See fellow mains measurement men: http://www.xs4all.nl/~rjoris/gridfrequency.html http://www.vf.utwente.nl/~ptdeboer/misc/mains.html http://www.leapsecond.com/pages/mains/ /tvb ----- Original Message ----- From: "Magnus Danielson" <magnus@rubidium.dyndns.org> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Wednesday, December 29, 2010 10:45 AM Subject: [time-nuts] Mains as time-reference > Fellow time-nuts, > > Just for fun I have been looking at the mains as a time-reference. > > I've used an OSA 8600 as reference and divided down to PPS by a TADD-2. > While not absolute time reference, it is way quieter than the mains so I > think it is good enough to have some fun at least. Just to illustrate > the issue. > > I use a HP5335A to measure the time from PPS to rising edge of 50 Hz as > being accessible through a transformer. > > The ADEV has a peak at 30 s measuring 2,3E-4 and another at 6000 s > measuring 4,3E-4. > > The phase changes over -0.11923 to +10,979 so a time difference > peak-to-peak of 11,098 seconds. > > While I could refine my measurements to ensure trigger jitter is not > causing any major issues, the ADEV slope from 1 s is rising rather than > lowering, so it rather seems like source behaviour dominates. > > While this attempt is a hack, I hope it inspires people to fiddle around > a little. :) > > Cheers, > Magnus

One of your references links to a nice real time graph for UK :) http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm I've looked to see if Red Eléctrica de España, the equivalent organisation here, provides same data... but nothing interesting to time-nuts, only electrical production and demand graphs (and a very politically correct graph of corresponding estimates of CO2 emissions). Regards, Javier El 29/12/2010 20:01, Tom Van Baak escribió: > Magnus, > > See fellow mains measurement men: > > http://www.xs4all.nl/~rjoris/gridfrequency.html > http://www.vf.utwente.nl/~ptdeboer/misc/mains.html > http://www.leapsecond.com/pages/mains/ > > /tvb > > ----- Original Message ----- From: "Magnus Danielson" > <magnus@rubidium.dyndns.org> > To: "Discussion of precise time and frequency measurement" > <time-nuts@febo.com> > Sent: Wednesday, December 29, 2010 10:45 AM > Subject: [time-nuts] Mains as time-reference > > >> Fellow time-nuts, >> >> Just for fun I have been looking at the mains as a time-reference. >> >> I've used an OSA 8600 as reference and divided down to PPS by a >> TADD-2. While not absolute time reference, it is way quieter than the >> mains so I think it is good enough to have some fun at least. Just to >> illustrate the issue. >> >> I use a HP5335A to measure the time from PPS to rising edge of 50 Hz >> as being accessible through a transformer. >> >> The ADEV has a peak at 30 s measuring 2,3E-4 and another at 6000 s >> measuring 4,3E-4. >> >> The phase changes over -0.11923 to +10,979 so a time difference >> peak-to-peak of 11,098 seconds. >> >> While I could refine my measurements to ensure trigger jitter is not >> causing any major issues, the ADEV slope from 1 s is rising rather >> than lowering, so it rather seems like source behaviour dominates. >> >> While this attempt is a hack, I hope it inspires people to fiddle >> around a little. :) >> >> 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. > >

Page 2 of this document gives some insight as to the changes of the mains frequency that may be seen in the USA. http://www.nerc.com/docs/docs/oc/oc_16-17Mar05_highlights.pdf This presentation also contains some related info. http://www.nerc.com/fileUploads/File/Training/Webinar-Generator-Frequency-Response.050509.pdf --- On Wed, 12/29/10, Javier Herrero <jherrero@hvsistemas.es> wrote: > From: Javier Herrero <jherrero@hvsistemas.es> > Subject: Re: [time-nuts] Mains as time-reference > To: time-nuts@febo.com > Received: Wednesday, December 29, 2010, 8:17 PM > One of your references links to a > nice real time graph for UK :) > > http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm > > I've looked to see if Red Eléctrica de España, the > equivalent organisation here, provides same data... but > nothing interesting to time-nuts, only electrical production > and demand graphs (and a very politically correct graph of > corresponding estimates of CO2 emissions). > > Regards, > > Javier > > El 29/12/2010 20:01, Tom Van Baak escribió: > > Magnus, > > > > See fellow mains measurement men: > > > > http://www.xs4all.nl/~rjoris/gridfrequency.html > > http://www.vf.utwente.nl/~ptdeboer/misc/mains.html > > http://www.leapsecond.com/pages/mains/ > > > > /tvb > > > > ----- Original Message ----- From: "Magnus Danielson" > <magnus@rubidium.dyndns.org> > > To: "Discussion of precise time and frequency > measurement" <time-nuts@febo.com> > > Sent: Wednesday, December 29, 2010 10:45 AM > > Subject: [time-nuts] Mains as time-reference > > > > > >> Fellow time-nuts, > >> > >> Just for fun I have been looking at the mains as a > time-reference. > >> > >> I've used an OSA 8600 as reference and divided > down to PPS by a TADD-2. While not absolute time reference, > it is way quieter than the mains so I think it is good > enough to have some fun at least. Just to illustrate the > issue. > >> > >> I use a HP5335A to measure the time from PPS to > rising edge of 50 Hz as being accessible through a > transformer. > >> > >> The ADEV has a peak at 30 s measuring 2,3E-4 and > another at 6000 s measuring 4,3E-4. > >> > >> The phase changes over -0.11923 to +10,979 so a > time difference peak-to-peak of 11,098 seconds. > >> > >> While I could refine my measurements to ensure > trigger jitter is not causing any major issues, the ADEV > slope from 1 s is rising rather than lowering, so it rather > seems like source behaviour dominates. > >> > >> While this attempt is a hack, I hope it inspires > people to fiddle around a little. :) > >> > >> Cheers, > >> Magnus > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > _______________________________________________ > time-nuts 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. >