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Could someone provide quick background on WWVB, or at least say if the Wikipedia page is accurate? I clicked the link to the NIST page,[0] which helped a little

Could someone provide quick background on WWVB, or at least say if the Wikipedia page is accurate? I clicked the link to the NIST page,[0] which helped a little but was written for someone already familiar with it - it's both too detailed and leaves fundamental questions unanswered; for example: * Is WWVB the norm for consumer clocks that synchronize to an outside source? If I see a clock with that feature, should I assume it uses WWVB? Is it one of several options? * Why not use GPS? Because of poor signal indoors? * How far does this signal from Colorado propagate? [0] https://www.nist.gov/pml/time-and-frequency-division/radio-stations/wwvb https://www.nist.gov/pml/time-and-frequency-division/radio-s...

zitterbewegung 10y ago
To answer your points 1. WWWVB is the norm. When they say 'Atomic Clock' they are using WWVB to synchronise time. 2. Putting GPS on a consumer electronic would be WAY more expensive. 3. WWVB covers Continental US and Southern Canada. https://en.wikipedia.org/wiki/WWVB#Propagation https://en.wikipedia.org/wiki/WWVB#Propagation
tjohns 10y ago
1. In the US, yes. In other parts of the world, you'll see clocks that instead use a closer station (like DCF77 in Germany). 2. Indoor operation is part of it. Also, GPS receivers are more expensive and power hungry. 3. Depends on time of day, but it generally covers most of North America. There's coverage maps here: http://tf.nist.gov/stations/wwvbcoverage.htm http://tf.nist.gov/stations/wwvbcoverage.htm
anishathalye 10y ago
EDIT: apparently a couple other people have already answered your questions, but I didn't see the other answers because I was typing my response. I'll leave my answer here cause it contains some information not in the other responses. The Wikipedia page seems to be pretty accurate. To answer your questions: > Is WWVB the norm for consumer clocks that synchronize to an outside source? If I see a clock with that feature, should I assume it uses WWVB? Is it one of several options? In the United States, yes. Clocks labeled "atomic clock" or "radio clock" are set up to sync with WWVB. Nowadays, many clocks are multi-band, which means that they are designed so that they can receive from multiple radio stations (there are a bunch of these; see https://en.wikipedia.org/wiki/Radio_clock#List_of_radio_time_signal_stations https://en.wikipedia.org/wiki/Radio_clock#List_of_radio_time...). Usually, the clock decides which station to try to sync to based on which time zone they are in (which is part of the configuration). For example, my wristwatch, a Casio AWGM100B, can receive from DCF77 (Germany, 77.5 kHz), MSF (UK, 60 kHz), WWVB (United States, 60 kHz), JJY (Japan, 40 kHz / 60 kHz), and BPC (China, 68.5 kHz). > Why not use GPS? Because of poor signal indoors? I think the main reason is that GPS is a lot more complicated, so it requires more sophisticated hardware and software (and more power) to get time via GPS. There are some higher-end watches that do use GPS - for example, the Casio GPW1000-1A. > How far does this signal from Colorado propagate? Depends on weather conditions and time of day. NIST has coverage maps that show where you can get > 100µV/m for different times of the day: http://tf.nist.gov/stations/wwvbcoverage.htm http://tf.nist.gov/stations/wwvbcoverage.htm
- hackuser 10y ago
  Thank you (and thanks to everyone else who responded) for such a detailed response. I'm not sure how I got this far without knowing about WWVB, but it's now my favorite radio station.
- dom0 10y ago
  > DCF77 (Germany, 77.5 kHz) Actually DCF77 can be received all over Europe :) I believe reception is even possible in Russia and along the northern African coast.
  - mynameisvlad 10y ago
    I don't think OP ever claimed it couldn't be, just that that's where the signal propagates from.
- stordoff 10y ago
  There was a radio controlled clock in the Computer Lab at Cambridge, but it seems the actual clock mechanism ran fast (gain a couple of minutes over the course of a day). More often than not, if I happened to be walking past at around 1600, the clock would be mid-way through a fast twelve-hour cycle to get back to the right time.
jlgaddis 10y ago
This doesn't answer your questions (others already have), but if this interests you, you might also find WWVB's "sister" stations interesting: WWV (at the same site) and WWVH (in Hawaii). Those transmit a voice signal (but no carrier/time code) on 2.5, 5, 10, 15, and 20 MHz. If you have an SDR that will tune that low (or a shortwave receiver), you should be able to receive at least one of them on at least frequency at any given time of the day. See also "The Current Readability of the WWVB Time Code": http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi As a teenager with the newly issued amateur radio call sign N9WWV, I used to set my wristwatch to WWV as I would constantly get asked, "What time is it?" anytime someone heard my call sign. It sounds like this: https://en.wikipedia.org/wiki/File:WWV_time_signal_-_20090904.ogg https://en.wikipedia.org/wiki/File:WWV_time_signal_-_2009090... (.ogg, via Wikipedia). When I started reading the article, I assumed the author would be using the PPS signal from the GPS for synchronization. You can do this w/ cheap GPS receivers and a small embedded computer (i.e. Raspberry Pi, BeagleBone Black, etc.) and synchronize your computer to it for extremely accurate time.
- jrockway 10y ago
  I can pretty much always receive WWV in New York on one frequency. Problem with WWV is that the propagation delay depends on how many hops the signal takes (it's skywave, unlike WWVB at night which is groundwave). GPS time is much better, because you know exactly how far away you are from each satellite, so can subtract out the transit time reliably. WWV varies from day to day (and frequency to frequency).
dragontamer 10y ago
> Is WWVB the norm for consumer clocks that synchronize to an outside source? If I see a clock with that feature, should I assume it uses WWVB? Is it one of several options? Yes. WWVB is the NIST Atomic clock radio station. In fact, any cheap clock that auto-synchronizes is going to be WWVB. Its the cheapest option for mass electronics that I'm aware of. WWVB however has one major fault: and its the speed of light. The speed of light can make the signal off by a few dozen miliseconds as it travels across the country. So extreme accuracy is not really possible. But for anything that can take a few miliseconds of delay (ie: most consumer clocks), this isn't a problem. > Why not use GPS? Because of poor signal indoors? GPS is far more expensive. A WWVB receiver is only $5 for an antenna, $3 for amplifying components, and $1 for a very low-end microcontroller. The 60-bits to determine a timestamp are sent at 1Hz (yes, one-bit per second). And indeed, the 1Hz signal is sent exactly on the second, on every second. As the signal is so low-baud, it is trivial to find a microcontroller that is fast enough to process it. As a very very low frequency, the WWVB signal penetrates through most walls. It also reflects off the ionosphere, giving a very long-distance range... far longer than the horizon. The WWVB signal is also the atomic time standard of the USA. The radio station is owned by NIST and the signal is basically the current American definition of time. > How far does this signal from Colorado propagate? At night, when there's the least amount of interference from the sun, the signal propagates all the way to the Pacific Ocean and Atlantic Ocean, covering the entirety of the continental USA, and a good chunk of Canada as well.

zitterbewegung 10y ago

To answer your points 1. WWWVB is the norm. When they say 'Atomic Clock' they are using WWVB to synchronise time. 2. Putting GPS on a consumer electronic would be WAY more expensive. 3. WWVB covers Continental US and Southern Canada. https://en.wikipedia.org/wiki/WWVB#Propagation https://en.wikipedia.org/wiki/WWVB#Propagation

tjohns 10y ago

1. In the US, yes. In other parts of the world, you'll see clocks that instead use a closer station (like DCF77 in Germany). 2. Indoor operation is part of it. Also, GPS receivers are more expensive and power hungry. 3. Depends on time of day, but it generally covers most of North America. There's coverage maps here: http://tf.nist.gov/stations/wwvbcoverage.htm http://tf.nist.gov/stations/wwvbcoverage.htm

anishathalye 10y ago

EDIT: apparently a couple other people have already answered your questions, but I didn't see the other answers because I was typing my response. I'll leave my answer here cause it contains some information not in the other responses. The Wikipedia page seems to be pretty accurate. To answer your questions: > Is WWVB the norm for consumer clocks that synchronize to an outside source? If I see a clock with that feature, should I assume it uses WWVB? Is it one of several options? In the United States, yes. Clocks labeled "atomic clock" or "radio clock" are set up to sync with WWVB. Nowadays, many clocks are multi-band, which means that they are designed so that they can receive from multiple radio stations (there are a bunch of these; see https://en.wikipedia.org/wiki/Radio_clock#List_of_radio_time_signal_stations https://en.wikipedia.org/wiki/Radio_clock#List_of_radio_time...). Usually, the clock decides which station to try to sync to based on which time zone they are in (which is part of the configuration). For example, my wristwatch, a Casio AWGM100B, can receive from DCF77 (Germany, 77.5 kHz), MSF (UK, 60 kHz), WWVB (United States, 60 kHz), JJY (Japan, 40 kHz / 60 kHz), and BPC (China, 68.5 kHz). > Why not use GPS? Because of poor signal indoors? I think the main reason is that GPS is a lot more complicated, so it requires more sophisticated hardware and software (and more power) to get time via GPS. There are some higher-end watches that do use GPS - for example, the Casio GPW1000-1A. > How far does this signal from Colorado propagate? Depends on weather conditions and time of day. NIST has coverage maps that show where you can get > 100µV/m for different times of the day: http://tf.nist.gov/stations/wwvbcoverage.htm http://tf.nist.gov/stations/wwvbcoverage.htm

hackuser 10y ago
Thank you (and thanks to everyone else who responded) for such a detailed response. I'm not sure how I got this far without knowing about WWVB, but it's now my favorite radio station.
dom0 10y ago
> DCF77 (Germany, 77.5 kHz) Actually DCF77 can be received all over Europe :) I believe reception is even possible in Russia and along the northern African coast.
- mynameisvlad 10y ago
  I don't think OP ever claimed it couldn't be, just that that's where the signal propagates from.
stordoff 10y ago
There was a radio controlled clock in the Computer Lab at Cambridge, but it seems the actual clock mechanism ran fast (gain a couple of minutes over the course of a day). More often than not, if I happened to be walking past at around 1600, the clock would be mid-way through a fast twelve-hour cycle to get back to the right time.

jlgaddis 10y ago

This doesn't answer your questions (others already have), but if this interests you, you might also find WWVB's "sister" stations interesting: WWV (at the same site) and WWVH (in Hawaii). Those transmit a voice signal (but no carrier/time code) on 2.5, 5, 10, 15, and 20 MHz. If you have an SDR that will tune that low (or a shortwave receiver), you should be able to receive at least one of them on at least frequency at any given time of the day. See also "The Current Readability of the WWVB Time Code": http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi http://tf.nist.gov/tf-cgi/wwvbmonitor_e.cgi As a teenager with the newly issued amateur radio call sign N9WWV, I used to set my wristwatch to WWV as I would constantly get asked, "What time is it?" anytime someone heard my call sign. It sounds like this: https://en.wikipedia.org/wiki/File:WWV_time_signal_-_20090904.ogg https://en.wikipedia.org/wiki/File:WWV_time_signal_-_2009090... (.ogg, via Wikipedia). When I started reading the article, I assumed the author would be using the PPS signal from the GPS for synchronization. You can do this w/ cheap GPS receivers and a small embedded computer (i.e. Raspberry Pi, BeagleBone Black, etc.) and synchronize your computer to it for extremely accurate time.

jrockway 10y ago
I can pretty much always receive WWV in New York on one frequency. Problem with WWV is that the propagation delay depends on how many hops the signal takes (it's skywave, unlike WWVB at night which is groundwave). GPS time is much better, because you know exactly how far away you are from each satellite, so can subtract out the transit time reliably. WWV varies from day to day (and frequency to frequency).

dragontamer 10y ago

> Is WWVB the norm for consumer clocks that synchronize to an outside source? If I see a clock with that feature, should I assume it uses WWVB? Is it one of several options? Yes. WWVB is the NIST Atomic clock radio station. In fact, any cheap clock that auto-synchronizes is going to be WWVB. Its the cheapest option for mass electronics that I'm aware of. WWVB however has one major fault: and its the speed of light. The speed of light can make the signal off by a few dozen miliseconds as it travels across the country. So extreme accuracy is not really possible. But for anything that can take a few miliseconds of delay (ie: most consumer clocks), this isn't a problem. > Why not use GPS? Because of poor signal indoors? GPS is far more expensive. A WWVB receiver is only $5 for an antenna, $3 for amplifying components, and $1 for a very low-end microcontroller. The 60-bits to determine a timestamp are sent at 1Hz (yes, one-bit per second). And indeed, the 1Hz signal is sent exactly on the second, on every second. As the signal is so low-baud, it is trivial to find a microcontroller that is fast enough to process it. As a very very low frequency, the WWVB signal penetrates through most walls. It also reflects off the ionosphere, giving a very long-distance range... far longer than the horizon. The WWVB signal is also the atomic time standard of the USA. The radio station is owned by NIST and the signal is basically the current American definition of time. > How far does this signal from Colorado propagate? At night, when there's the least amount of interference from the sun, the signal propagates all the way to the Pacific Ocean and Atlantic Ocean, covering the entirety of the continental USA, and a good chunk of Canada as well.