Re: [time-nuts] Daft idea with the National Grid
On 2/7/21 3:28 PM, Dana Whitlow wrote: Not daft at all, Andy. Closely related would be measurements of phase change between near the switched load and far away, over a stretch of a few system time constants. This would be more challenging, but perhaps doable. Dana K8YUM If you happen to own something like a steel mill running electric furnaces or an aluminum refinery, so you can manipulate the load... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Daft idea with the National Grid
Am 08.02.21 um 00:11 schrieb Philip Gladstone: As an amateur radio guy, I can't help wondering whether I could use this as a *very* low bit rate channel across the country. I have done navigation _for_ tv and phone sats, and the spread navigation signals are just 20 dB under the MPEG data stream via the analog transponder. If you back down another 10 or 20 dB, I'm sure you could disseminate encryption keys or maybe phone without anybody taking note. And everybody has a TV dish in the right direction. Search the right one. Really, I can't imagine that the agencies don't do that already. Gerhard, DK4XP ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Daft idea with the National Grid
Not daft at all, Andy. Closely related would be measurements of phase change between near the switched load and far away, over a stretch of a few system time constants. This would be more challenging, but perhaps doable. Dana K8YUM On Sun, Feb 7, 2021 at 3:44 PM Andy Talbot wrote: > The UK has a standalone frequency locked grid supply, nominal 50Hz, which > typically wanders +/- about 0.15Hz RMS over several minutes , with > occasional short-lived excursions out to 0.2 or 0.3Hz. Average number of > cycles per period generally is normalised to 50Hz after a few days. > The typical loading for the country ranges over ~25GW to 45GW > > Now, I wonder: > I can probably measure the grid frequency to a few micro Hz over a period > of tens of seconds. So I make a continuous recording of this, averaged over > say 10 second periods. > Now take a 7kW load (the maximum reasonably possible on a domestic circuit) > and switch it on and off at intervals of perhaps 10 minutes, precisely > timed so it can be correlated with the frequency log. That 7kW load will > be about 0.2ppm of the average for that for the whole of the UK.By post > processing, and some deep correlation covering days worth of cycles of load > on-off with the frequency, I wonder if it would be possible to see the > loading, the mean frequency changing by a few uHz. > Not sure what the time constant of the grid control is, but for* small > signals* I doubt it can be faster than a few minutes. > > There was a serious outage on 9 August 2019 that caused frequency to drop > below 49.5Hz and initiate automatic load shedding; that happened over a > period of a couple of minutes but was a large scale problem. > > https://www.ofgem.gov.uk/publications-and-updates/investigation-9-august-2019-power-outage > > Andy > www.g4jnt.com > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Daft idea with the National Grid
As an amateur radio guy, I can't help wondering whether I could use this as a *very* low bit rate channel across the country. Philip On Sun, Feb 7, 2021 at 4:44 PM Andy Talbot wrote: > The UK has a standalone frequency locked grid supply, nominal 50Hz, which > typically wanders +/- about 0.15Hz RMS over several minutes , with > occasional short-lived excursions out to 0.2 or 0.3Hz. Average number of > cycles per period generally is normalised to 50Hz after a few days. > The typical loading for the country ranges over ~25GW to 45GW > > Now, I wonder: > I can probably measure the grid frequency to a few micro Hz over a period > of tens of seconds. So I make a continuous recording of this, averaged over > say 10 second periods. > Now take a 7kW load (the maximum reasonably possible on a domestic circuit) > and switch it on and off at intervals of perhaps 10 minutes, precisely > timed so it can be correlated with the frequency log. That 7kW load will > be about 0.2ppm of the average for that for the whole of the UK.By post > processing, and some deep correlation covering days worth of cycles of load > on-off with the frequency, I wonder if it would be possible to see the > loading, the mean frequency changing by a few uHz. > Not sure what the time constant of the grid control is, but for* small > signals* I doubt it can be faster than a few minutes. > > There was a serious outage on 9 August 2019 that caused frequency to drop > below 49.5Hz and initiate automatic load shedding; that happened over a > period of a couple of minutes but was a large scale problem. > > https://www.ofgem.gov.uk/publications-and-updates/investigation-9-august-2019-power-outage > > Andy > www.g4jnt.com > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Daft idea with the National Grid
The UK has a standalone frequency locked grid supply, nominal 50Hz, which typically wanders +/- about 0.15Hz RMS over several minutes , with occasional short-lived excursions out to 0.2 or 0.3Hz. Average number of cycles per period generally is normalised to 50Hz after a few days. The typical loading for the country ranges over ~25GW to 45GW Now, I wonder: I can probably measure the grid frequency to a few micro Hz over a period of tens of seconds. So I make a continuous recording of this, averaged over say 10 second periods. Now take a 7kW load (the maximum reasonably possible on a domestic circuit) and switch it on and off at intervals of perhaps 10 minutes, precisely timed so it can be correlated with the frequency log. That 7kW load will be about 0.2ppm of the average for that for the whole of the UK.By post processing, and some deep correlation covering days worth of cycles of load on-off with the frequency, I wonder if it would be possible to see the loading, the mean frequency changing by a few uHz. Not sure what the time constant of the grid control is, but for* small signals* I doubt it can be faster than a few minutes. There was a serious outage on 9 August 2019 that caused frequency to drop below 49.5Hz and initiate automatic load shedding; that happened over a period of a couple of minutes but was a large scale problem. https://www.ofgem.gov.uk/publications-and-updates/investigation-9-august-2019-power-outage Andy www.g4jnt.com ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] History of HP Mercury Clocks Digest, Vol 199, Issue 6
Richard’s description is close. They were shipped to the USNO in the mid-80s, and they didn’t work well. I was the only physicist there at the time, and was asked to take time off from VLBI and Earth rotation to work on it. That’s how I entered the timekeeping world. My contribution was to discover that frequencies would go bananas in coincidence with vacuum and heater events. That was published as "Eight Years of Experience with Mercury Stored-Ion Devices", D.N. Matsakis, A. Kubik, J. De Young, R.P. Giffard, and L. Cutler, Proceedings of IEEE Frequency Control Symposium, 86 (1995). I may have a copy of it somewhere. The shipping disaster was before my time, but I certainly heard about it. It had come upside down. I was told the insurance covered it, but I don’t know if some special branch of HP served as the self-insurer. I remember Len Cutler telling me that they had to pay HP for any HP equipment involved, even though everybody worked for HP. Later, at a pulsar meeting, I heard a talk by Lute Maleki about the JPL device, and we ordered one of those from them. Thereafter JPL made a steady stream of improvements, including hiring one of my employees - Eric Burt. And the rest is history. Or will be once the Deep Space Atomic Clock data are published. > > On Wed, 10 Jul 2019 10:55:07 -0700 > "Richard (Rick) Karlquist" wrote: > >> FWIW, about 20 years ago, Len Cutler and Robin Giffard of 5071A fame >> built several Hg ion clocks to be shipped to some govt customer I >> don't remember. One of the clocks was dropped by the shipping company >> UPS or FedEX) and destroyed. Only then did Len learn that HP was >> self insured, probably as part of a package deal to get a low >> corporate shipping rate. HP products were packed extremely well, so >> the only real risk was the unit getting stolen. I vaguely remember >> Len saying they were out $10K, which was probably just the cost of >> parts. Nevertheless, it didn't seem like building an Hg clock was >> all that big of a project. Way simpler than the 5071A. >> Now a days, the electronics would be considerably easier and cheaper. >> The mechanical parts would all be CNC'ed by an online machine shop. > > Magnus just send me out to chase an (unrelated) paper and I stumbled > over [1] which describes the Hg standard that Cutler & Co built. > Remembering this discussion I thought it might be interesting to > some. > > > Attila Kinali > "Trapped Mercury 199 Ion Frequency Standard", Cutler, > Giffard, McGuire, PTTI, 1981 > http://time.kinali.ch/ptti/1981papers/Vol%2013_30.pdf > > -- > The driving force behind research is the question: "Why?" > There are things we don't understand and things we always > wonder about. And that's why we do research. > -- Kobayashi Makoto > > > > -- > > Message: 2 > Date: Sat, 6 Feb 2021 14:29:35 -0500 > From: Bob kb8tq > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Used Hydrogen Maser > Message-ID: > Content-Type: text/plain; charset=us-ascii > > Cool !!! > >> On Feb 6, 2021, at 1:05 PM, Attila Kinali wrote: >> >> Moin, >> >> On Wed, 10 Jul 2019 10:55:07 -0700 >> "Richard (Rick) Karlquist" wrote: >> >>> FWIW, about 20 years ago, Len Cutler and Robin Giffard of 5071A fame >>> built several Hg ion clocks to be shipped to some govt customer I >>> don't remember. One of the clocks was dropped by the shipping company >>> UPS or FedEX) and destroyed. Only then did Len learn that HP was >>> self insured, probably as part of a package deal to get a low >>> corporate shipping rate. HP products were packed extremely well, so >>> the only real risk was the unit getting stolen. I vaguely remember >>> Len saying they were out $10K, which was probably just the cost of >>> parts. Nevertheless, it didn't seem like building an Hg clock was >>> all that big of a project. Way simpler than the 5071A. >>> Now a days, the electronics would be considerably easier and cheaper. >>> The mechanical parts would all be CNC'ed by an online machine shop. >> >> Magnus just send me out to chase an (unrelated) paper and I stumbled >> over [1] which describes the Hg standard that Cutler & Co built. >> Remembering this discussion I thought it might be interesting to >> some. >> >> >> Attila Kinali >> "Trapped Mercury 199 Ion Frequency Standard", Cutler, >> Giffard, McGuire, PTTI, 1981 >> http://time.kinali.ch/ptti/1981papers/Vol%2013_30.pdf >> >> -- >> The driving force behind research is the question: "Why?" >> There are things we don't understand and things we always >> wonder about. And that's why we do research. >> -- Kobayashi Makoto >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the
Re: [time-nuts] Some old Time & Frequency stuff for sale, eastern Ontario, Canada
Well that was fun looking up the radios and those are very fine prices. I agree with Bob that the heavier tube receivers will be a fair shipping charge. But as Martin wisely says come pick it up. Good luck to some lucky person. Regards Paul. WB8TSL On Sun, Feb 7, 2021 at 9:50 AM Bob kb8tq wrote: > Hi > > There’s six pretty big gizmos there. My local UPS store would charge > me $20 to $30 a box to pack each of them (and barely do an adequate job). > Looking up shipping rates from here to there, each of the 6 packages > would run about $70 to ship. Net would likely be in the $400 to $600 > range. > > Yes, there’s a lot of guesswork in those numbers. They probably would go > a bit cheaper via the post office. > > Bob > > > > On Feb 7, 2021, at 8:57 AM, John Franke wrote: > > > > I would pay $250, via PayPal, including shipping, if you would ship the > pile. If not, I would understand. I figured I had to at least give it a > shot. > > > > John Franke WA4WDL > > 4500 Ibis Ct > > Portsmouth, VA 23703 > > > > > >> On February 6, 2021 at 10:34 PM Martin VE3OAT wrote: > >> > >> > >> > >> Trying to down-size a bit and these must go, as I will probably never > >> use them again. All units are rack-mountable. Heavy stuff, only > >> local pick-up (in Greely, just south of Ottawa) or can meet within an > >> hour's drive of Ottawa. Value $160, take it all home for $100! > >> > >> 1. and 2. Two General Radio 1123-A digital synchronometers (clocks). > >> Displays time HH:MM:SS. Requires input of 1 MHz or 100 kHz, sine or > >> square wave. Can be synced by local clock pulse, with provision for > >> propagation delay. One (black panel) was working fine when taken out > >> of service. The other one (white panel) worked but did not reset at > >> 23:59 (the old missing reset pulse problem). I never found time to > >> fix it while the first one was working fine. These units are typical > >> GR construction and work reliably, except that the display modules > >> are a bit of a pain to keep working due to recurring contact problems > >> (annual maintenance recommended). With photocopy of the manual and > >> fold-out schematics in a binder. And a box of spare bulbs for the > >> display modules. Needs GR-type power cord. $40 for the pair. > >> > >> 3. Fluke 207-13 VLF Receiver/Phase Comparator. > >> * See Note. Phase comparison receiver, tunes 8.0-31.9 and 60.0 > >> kHz. Local standard comparison input 100 kHz or 1 MHz. Modified > >> antenna input circuit. Was working fine when taken out of service, > >> and checked OK in recent "lash-up" test. With bound photocopy of > >> manual with fold-out circuit diagrams, and a box of untested spare > >> circuit cards from a cannibalized Fluke 207. $30. > >> > >> 4. Spectracom 8164 NBS Receiver/Disciplined Oscillator. > >> * See Note. A 60 kHz phase comparison receiver. Local standard > >> input 0.1, 1.0, 5.0, or 10.0 MHz. Modified to add 10 MHz, 100 kHz > >> and 1 Hz TTL outputs, and to remove 12VDC from 10 MHz sine wave > >> outputs (distribution amplifier) to remote sites. Was working fine > >> when taken out of service when WWVB changed to phase modulation. > >> With original manual and diagrams. $30. > >> > >> 5. Kinemetrics/TrueTime 60-TF LF Receiver/Frequency Comparator. > >> * See Note. Phase comparison receiver for 60 kHz, compact > >> construction (1.75-inch rack panel). Local standard comparison input > >> 1 MHz but might work with others. Was working fine when taken out > >> of service, and checked OK in recent "lash-up" test. Digital phase > >> display and strip chart recorder on front, analog voltage output on > >> rear. Unfortunately, no manual or other documentation. $20. > >> > >> 6. Beckman Instruments 905 WWV Receiver. > >> HF AM receiver, all vacuum tubes, selectable channels 2.5, 5, 10, 15, > >> 20, or 25 MHz, with fine tuning, audio filters, internal speaker, > >> S-meter, modified for AGC voltage output on the rear (BNC). With > >> photocopy of the manual and schematic. Working fine but power cord > >> should be replaced. $20. > >> > >> 7. Lavoie LA-800D WWV Frequency Comparator. > >> Compares local standard frequency (50 kHz to 10 MHz) with WWV on 5 or > >> 15 MHz. Vacuum tubes. Scope trace is good but screen has small burn > >> mark (does not affect operation). Tested with 1 and 10 MHz local > >> standards and seems to be working fine, except there is no derived 400 > >> kHz standard output (not needed). Probably needs alignment. When fed > >> with a good local standard, it is fun to watch the phase changes on > >> WWV signal caused by propagation. Big and heavy. With 19" cabinet > >> and photocopy of operation and service manual. $20. > >> > >> * NOTE -- The VLF receivers do not work by themselves with the new > >> WWVB signal format. You must first de-phase-modulate the raw 60 kHz > >> WWVB signal to remove the PSK time code modulation before passing the > >> signal to the receiver's antenna input. See the
Re: [time-nuts] Some old Time & Frequency stuff for sale, eastern Ontario, Canada
Hi There’s six pretty big gizmos there. My local UPS store would charge me $20 to $30 a box to pack each of them (and barely do an adequate job). Looking up shipping rates from here to there, each of the 6 packages would run about $70 to ship. Net would likely be in the $400 to $600 range. Yes, there’s a lot of guesswork in those numbers. They probably would go a bit cheaper via the post office. Bob > On Feb 7, 2021, at 8:57 AM, John Franke wrote: > > I would pay $250, via PayPal, including shipping, if you would ship the pile. > If not, I would understand. I figured I had to at least give it a shot. > > John Franke WA4WDL > 4500 Ibis Ct > Portsmouth, VA 23703 > > >> On February 6, 2021 at 10:34 PM Martin VE3OAT wrote: >> >> >> >> Trying to down-size a bit and these must go, as I will probably never >> use them again. All units are rack-mountable. Heavy stuff, only >> local pick-up (in Greely, just south of Ottawa) or can meet within an >> hour's drive of Ottawa. Value $160, take it all home for $100! >> >> 1. and 2. Two General Radio 1123-A digital synchronometers (clocks). >> Displays time HH:MM:SS. Requires input of 1 MHz or 100 kHz, sine or >> square wave. Can be synced by local clock pulse, with provision for >> propagation delay. One (black panel) was working fine when taken out >> of service. The other one (white panel) worked but did not reset at >> 23:59 (the old missing reset pulse problem). I never found time to >> fix it while the first one was working fine. These units are typical >> GR construction and work reliably, except that the display modules >> are a bit of a pain to keep working due to recurring contact problems >> (annual maintenance recommended). With photocopy of the manual and >> fold-out schematics in a binder. And a box of spare bulbs for the >> display modules. Needs GR-type power cord. $40 for the pair. >> >> 3. Fluke 207-13 VLF Receiver/Phase Comparator. >> * See Note. Phase comparison receiver, tunes 8.0-31.9 and 60.0 >> kHz. Local standard comparison input 100 kHz or 1 MHz. Modified >> antenna input circuit. Was working fine when taken out of service, >> and checked OK in recent "lash-up" test. With bound photocopy of >> manual with fold-out circuit diagrams, and a box of untested spare >> circuit cards from a cannibalized Fluke 207. $30. >> >> 4. Spectracom 8164 NBS Receiver/Disciplined Oscillator. >> * See Note. A 60 kHz phase comparison receiver. Local standard >> input 0.1, 1.0, 5.0, or 10.0 MHz. Modified to add 10 MHz, 100 kHz >> and 1 Hz TTL outputs, and to remove 12VDC from 10 MHz sine wave >> outputs (distribution amplifier) to remote sites. Was working fine >> when taken out of service when WWVB changed to phase modulation. >> With original manual and diagrams. $30. >> >> 5. Kinemetrics/TrueTime 60-TF LF Receiver/Frequency Comparator. >> * See Note. Phase comparison receiver for 60 kHz, compact >> construction (1.75-inch rack panel). Local standard comparison input >> 1 MHz but might work with others. Was working fine when taken out >> of service, and checked OK in recent "lash-up" test. Digital phase >> display and strip chart recorder on front, analog voltage output on >> rear. Unfortunately, no manual or other documentation. $20. >> >> 6. Beckman Instruments 905 WWV Receiver. >> HF AM receiver, all vacuum tubes, selectable channels 2.5, 5, 10, 15, >> 20, or 25 MHz, with fine tuning, audio filters, internal speaker, >> S-meter, modified for AGC voltage output on the rear (BNC). With >> photocopy of the manual and schematic. Working fine but power cord >> should be replaced. $20. >> >> 7. Lavoie LA-800D WWV Frequency Comparator. >> Compares local standard frequency (50 kHz to 10 MHz) with WWV on 5 or >> 15 MHz. Vacuum tubes. Scope trace is good but screen has small burn >> mark (does not affect operation). Tested with 1 and 10 MHz local >> standards and seems to be working fine, except there is no derived 400 >> kHz standard output (not needed). Probably needs alignment. When fed >> with a good local standard, it is fun to watch the phase changes on >> WWV signal caused by propagation. Big and heavy. With 19" cabinet >> and photocopy of operation and service manual. $20. >> >> * NOTE -- The VLF receivers do not work by themselves with the new >> WWVB signal format. You must first de-phase-modulate the raw 60 kHz >> WWVB signal to remove the PSK time code modulation before passing the >> signal to the receiver's antenna input. See the article at : >> http://maxmcarter.com/rubidium/2012_mod/index.html for one solution. >> >> >> Take all seven units for $100 cash. >> >> 73, >> ... Martin Potter VE3OAT >> >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > >
Re: [time-nuts] Some old Time & Frequency stuff for sale, eastern Ontario, Canada
I would pay $250, via PayPal, including shipping, if you would ship the pile. If not, I would understand. I figured I had to at least give it a shot. John Franke WA4WDL 4500 Ibis Ct Portsmouth, VA 23703 > On February 6, 2021 at 10:34 PM Martin VE3OAT wrote: > > > > Trying to down-size a bit and these must go, as I will probably never > use them again. All units are rack-mountable. Heavy stuff, only > local pick-up (in Greely, just south of Ottawa) or can meet within an > hour's drive of Ottawa. Value $160, take it all home for $100! > > 1. and 2. Two General Radio 1123-A digital synchronometers (clocks). > Displays time HH:MM:SS. Requires input of 1 MHz or 100 kHz, sine or > square wave. Can be synced by local clock pulse, with provision for > propagation delay. One (black panel) was working fine when taken out > of service. The other one (white panel) worked but did not reset at > 23:59 (the old missing reset pulse problem). I never found time to > fix it while the first one was working fine. These units are typical > GR construction and work reliably, except that the display modules > are a bit of a pain to keep working due to recurring contact problems > (annual maintenance recommended). With photocopy of the manual and > fold-out schematics in a binder. And a box of spare bulbs for the > display modules. Needs GR-type power cord. $40 for the pair. > > 3. Fluke 207-13 VLF Receiver/Phase Comparator. > * See Note. Phase comparison receiver, tunes 8.0-31.9 and 60.0 > kHz. Local standard comparison input 100 kHz or 1 MHz. Modified > antenna input circuit. Was working fine when taken out of service, > and checked OK in recent "lash-up" test. With bound photocopy of > manual with fold-out circuit diagrams, and a box of untested spare > circuit cards from a cannibalized Fluke 207. $30. > > 4. Spectracom 8164 NBS Receiver/Disciplined Oscillator. > * See Note. A 60 kHz phase comparison receiver. Local standard > input 0.1, 1.0, 5.0, or 10.0 MHz. Modified to add 10 MHz, 100 kHz > and 1 Hz TTL outputs, and to remove 12VDC from 10 MHz sine wave > outputs (distribution amplifier) to remote sites. Was working fine > when taken out of service when WWVB changed to phase modulation. > With original manual and diagrams. $30. > > 5. Kinemetrics/TrueTime 60-TF LF Receiver/Frequency Comparator. > * See Note. Phase comparison receiver for 60 kHz, compact > construction (1.75-inch rack panel). Local standard comparison input > 1 MHz but might work with others. Was working fine when taken out > of service, and checked OK in recent "lash-up" test. Digital phase > display and strip chart recorder on front, analog voltage output on > rear. Unfortunately, no manual or other documentation. $20. > > 6. Beckman Instruments 905 WWV Receiver. > HF AM receiver, all vacuum tubes, selectable channels 2.5, 5, 10, 15, > 20, or 25 MHz, with fine tuning, audio filters, internal speaker, > S-meter, modified for AGC voltage output on the rear (BNC). With > photocopy of the manual and schematic. Working fine but power cord > should be replaced. $20. > > 7. Lavoie LA-800D WWV Frequency Comparator. > Compares local standard frequency (50 kHz to 10 MHz) with WWV on 5 or > 15 MHz. Vacuum tubes. Scope trace is good but screen has small burn > mark (does not affect operation). Tested with 1 and 10 MHz local > standards and seems to be working fine, except there is no derived 400 > kHz standard output (not needed). Probably needs alignment. When fed > with a good local standard, it is fun to watch the phase changes on > WWV signal caused by propagation. Big and heavy. With 19" cabinet > and photocopy of operation and service manual. $20. > > * NOTE -- The VLF receivers do not work by themselves with the new > WWVB signal format. You must first de-phase-modulate the raw 60 kHz > WWVB signal to remove the PSK time code modulation before passing the > signal to the receiver's antenna input. See the article at : > http://maxmcarter.com/rubidium/2012_mod/index.html for one solution. > > > Take all seven units for $100 cash. > > 73, > ... Martin Potter VE3OAT > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Anybody plotted the ADEV of a V8 idle speed?
Idle speed is simply controlled to an rpm value, which thus makes it tied, loosely, to the CPU clock. The phase noise is quite awful, by anyone's standards, mainly because the parameters measured to control fuel and spark timing, are noisy. Tom Holmes, N8ZM -Original Message- From: time-nuts On Behalf Of Hal Murray Sent: Saturday, February 06, 2021 9:48 PM To: Discussion of precise time and frequency measurement Cc: hmur...@megapathdsl.net Subject: [time-nuts] Anybody plotted the ADEV of a V8 idle speed? w...@triconet.org said: > Although Mr. Wineland's IQ must be at least 50 points higher than mine, we do > have something in common. I too owned a '36 Ford in my youth, about the same > time as he did, although mine was a Cabriolet not a coupe, and I fitted it > with an OHV Studebaker V8, a smaller displacement clone of a Cadillac V8. Speaking of V8s... Just a simple graph of idle speed vs time for the first few minutes after a cold start might be a fun high school science project. Is the idle speed of a modern warm engine locked to the CPU's crystal or is there a feedback loop setting some pollution or mileage parameter? In the old days (pre computer), there was some thermal input to the idle speed. I assume it was a bimetalic element. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_l ists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
