12 ms·

60 kHz (2022)

250 points by jer0me 2y ago

mehulashah 2y ago
Well said. Simple, solid technology for the benefit of everyone.
anyfoo 2y ago
> I’m not particularly patriotic, but this kind of thing feels particularly American. ??? America has no doubt done some very remarkable things (the moon landing, the first backward compatible color TV standard), but I don't think this is a notable example of that. I think everyone in Europe was familiar with even wristwatches getting the time from "airwaves". At least in Germany, watches were a very common thing since the 80s (I think everyone old enough vividly remembers the many Junghans commercials on TV). The corresponding signal has been broadcast for many decades earlier, as it's no surprise that railroad and airplane networks were in need of a common time: https://en.wikipedia.org/wiki/DCF77 https://en.wikipedia.org/wiki/DCF77 > But we had a problem, and we solved it with technology. And none of that fancy newfangled technology — we solved it using solid technology, the kind that you can touch with your hands and that buzzes in the airwaves. There wasn't much "newfangled technology" around at the time. We essentially solved it using the simplest method there was at the time, at least I find it a bit hard to come up with a simpler one. Also, what would be an example of technology that you can't either "touch with your hands" or that does "buzz in airwaves"?
- aeonik 2y ago
  US seems to be the first to pioneer this according to my very cursory research: https://timeandnavigation.si.edu/multimedia-asset/us-navy-wireless-transmitting-station-arlington-virginia-1913 https://timeandnavigation.si.edu/multimedia-asset/us-navy-wi...
  - anyfoo 2y ago
    I stand corrected, it seems to indeed have been the US Navy that pioneered time signals. France followed up a few years later. I don’t know who had the first system accessible to civilians, but at this point we’d just be arguing details.
    - lloeki 2y ago
      From the link: > Radio time signals for setting chronometers were sent from stations such as NAA in Arlington, Virginia, which began broadcasting in 1913. The time was supplied from a direct communication line with the clocks of the U.S. Naval Observatory in Washington, D.C. In combination with another low-frequency installation mounted on the Eiffel Tower in Paris, the towers had the range to cover the North Atlantic Ocean and the eastern United States. So I looked up the Eiffel tower. > The Eiffel Tower time signal broadcasts began on May 23, 1910 https://tf.nist.gov/general/pdf/2131.pdf https://tf.nist.gov/general/pdf/2131.pdf Also, same source starts with the 1898 proposal of time sync via radio being made by an Irish bloke. > I don’t know who had the first system accessible to civilians, but at this point we’d just be arguing details. Agreed. Even non-civilian, and whoever came first, the timeline of things across various countries, I don't think the core point of TFA holds water: it's not a "particularly American" thing, it just made sense out of engineering requirements: time sync was transmitted over telegraph wires, and telegraph went wireless; the leap is not exactly surprising.
      - aeonik 2y ago
        Nice find! This turns out to be quite an interesting rabbit hole. It's definitely earlier than I would have guessed regardless.
  - deleted 2y ago
    [deleted]
- Dalewyn 2y ago
  >what would be an example of technology that you can't either "touch with your hands" or that does "buzz in airwaves"? Microprocessors and lights/lasers respectively, among I'm certain countless other examples.
  - anyfoo 2y ago
    I can touch microprocessors, and lasers are buzzing in airwaves. It’s the same electromagnetic radiation as what we know as radio, just at much, much higher frequencies. But this was asked in the context of solving this problem, in the 1950s.
    - pavel_lishin 2y ago
      Sure, but trench soldiers used to build their own radios. A soldier today stationed in the middle of a war isn't likely to assemble their own laser emitter.
      - anyfoo 2y ago
        I don’t think anybody at that time could have built a laser emitter, even. Not sure why you would want to, to solve that problem, even today. I feel like the point of my question was lost.
    - Dalewyn 2y ago
      >I can touch microprocessors, No you can't, you're just touching the box they come in. You can touch copper cables and wires, vacuum tubes, resistors, capacitors, breadboards, and (large!) printed circuit boards among other "basic" electronic components. You can't touch microprocessors, it's even stated on the tin they are microscopic in scale; you can't touch that in any meaningful way.
      - anyfoo 2y ago
        We could argue about that, but let me rephrase then: What technology that you can neither touch, nor that buzzes in airwaves, could they have used to solve this problem back then?
- someguydave 2y ago
  Digital communications is America’s gift to the world, look up Claude Shannon
  - sokoloff 2y ago
    I think the Englishman George Boole deserves significant credit as well.
  - spixy 2y ago
    AC motor, steam, diesel, jet engines are european "gifts to the world", yet it would be cringe to write sentence like "I’m not particularly patriotic, but this kind of thing feels particularly European"
- Aloisius 2y ago
  > I think everyone in Europe was familiar with even wristwatches getting the time from "airwaves". At least in Germany, watches were a very common thing since the 80s Not the 80s. The first radio controlled wristwatch came out in 1990 (Junghans Mega 1).
  - anyfoo 2y ago
    Sorry, I mistranslated “clock” (hence why I differentiated “wristwatch” in the sentence before). We owned a Funkuhr-Wecker in the 80s, so, an alarm clock synchronizing to DCF77, in the 80s. The wristwatches came a bit later, yeah (not that I’d have known without looking it up whether that was earlier or later than 1990).
- layman51 2y ago
  I wondered about its American origins too. I vaguely remember a little detail in the novel Cryptonomicon where one of the characters (a Lieutenant in the Imperial Japanese Army during WWII) sets his watch with a radio time signal. So that got me thinking that maybe the idea arose in different places. Also I was wondering about the “forever” wording. I imagine the signal is very robust, but couldn’t American politics just one day decide that it’s not worth it to broadcast the time by radio signal anymore?
2four2 2y ago
There are several of these stations, they are maintained and operated by NIST. Two of them were almost shut down recently due to budget concerns: https://www.radioworld.com/global/why-wwv-and-wwvh-still-matter https://www.radioworld.com/global/why-wwv-and-wwvh-still-mat...
- dfc 2y ago
  In April one of the two WWVB antennas failed (broke) because of 90mph winds. https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb/wwvb-station-outages https://www.nist.gov/pml/time-and-frequency-division/time-di...
  - Eduard 2y ago
    https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb https://www.nist.gov/pml/time-and-frequency-division/time-di... > Official Notice: Commencing from 0000 Coordinated Universal Time (UTC) on April 7, 2024, the southern antenna of WWVB has been rendered non-operational due to damage sustained from wind gusts exceeding 90 MPH. Please be advised that WWVB continues to function at a diminished overall power, utilizing only its northern antenna. > Update 20 May 2024: The components necessary for the refurbishment of the southern antenna’s triatic are currently being manufactured and shipped. The projected timeline for the completion of these repairs is tentatively set for the latter part of June 2024. We would like to emphasize that this is an estimated timeline and may be subject to alterations based on a variety of factors. We greatly appreciate your understanding and patience during this process. Can someone using WWVB radio clocks describe what the current situation is? Is the second working antenna strong enough to provide signals throughout the US / North America? Are WWVB radio clocks popular at all? Here in Europe, DCF77-based clocks are popular, especially with respect to automatic summer time adaption and (less obvious) leap second HANDLING. It would be very noticeable eventually if the DCF77 signal had severe issues. Also, I'm very surprised about the abysmal historical uptime of Wwvb. It lists thirteen downtimes of more than 5 minutes each in 2023 alone.
    - lxgr 2y ago
tkzed49 2y ago
the bandwidth is just enough to broadcast a single digit of binary every second. I'd be interested in some more context on this. I think it's pretty clear that you can encode more than 1bps in a 60kHz signal, but I'm curious how the encoding was chosen. There's some more detail on it here: https://en.wikipedia.org/wiki/WWVB#Modulation_format https://en.wikipedia.org/wiki/WWVB#Modulation_format The WWVB 60 kHz carrier, which has a normal ERP of 70 kW, is reduced in power at the start of each UTC second by 17 dB (to 1.4 kW ERP). It is restored to full power some time during the second. The duration of the reduced power encodes one of three symbols: If power is reduced for one-fifth of a second (0.2 s), this is a data bit with value zero. If power is reduced for one-half of a second (0.5 s), this is a data bit with value one. If power is reduced for four-fifths of a second (0.8 s), this is a special non-data "mark", used for framing. This is apparently the IRIG H encoding, which dates to the 50s and is probably designed to be easily decoded. By what, I wonder?
- mmastrac 2y ago
  > By what, I wonder? At that length of symbol encoding, by hand. :)
- anyfoo 2y ago
  Relays maybe? EDIT: Not sure why I was downvoted. Relays seem like period-accurate technology (happy to be corrected), and they’re comparably slow.
  - Dylan16807 2y ago
    I can't say why you were downvoted but that's still pretty slow for relays. One bit per second seems more like it's aimed at casual human decoding. Especially because each digit is encoded separately, even for the hours. Also for plain old range purposes, one transmission per minute is about as wide as you can go before things get silly.
- retrac 2y ago
  The signal is not 60 kHz wide. It is at 60 kHz. A pure carrier with no modulation has the inverse of infinite bandwidth. (Assuming perfect transmitters, which can't really exist, of course.) The faster you modulate the signal, the more it spreads out across the spectrum. The frequency-time tradeoff. The time signals run at the low end of longwave. That spans from about 40 to 120 kHz or so. There is about 100 kHz of spectrum down there. Though broadcasting a broadband longwave signal like that would be an imposing task. To cover a large area with AM broadcast (maybe 5 - 10 kHz) uses 1 - 2 megawatt transmitters in Europe. To cover the continent with a 100 kHz broadband digital signal would probably take 10 - 50 megawatts, maybe with 3 transmitter sites. Though I think it could be done. Could fit maybe a megabit a sec in there. Something less ambitious maybe. A few hundred bytes a second? A kilohertz or so of spectrum used. It could work inside elevators, deep underground in parking garages, and so on. Digital alert stream for emergencies, time signal, etc.? Would not be much more complicated than the time signal transmitters, just with a more sophisticated modulation.
khaki54 2y ago
I can picture a room full of engineers in ties, wearing pocket protectors full of implements, chain smoking cigarettes while coming up with this one.
- erikpukinskis 2y ago
  I can picture a black woman at a desk in a nicely pressed dress coming up with this one on pencil and paper.
  - neilv 2y ago
    https://en.wikipedia.org/wiki/Hidden_Figures https://en.wikipedia.org/wiki/Hidden_Figures
- mmastrac 2y ago
  More likely a radio nerd, John Alvin Pierce, that was just really good at radio and obsessed with oscillators (https://ieeexplore.ieee.org/document/60675 https://ieeexplore.ieee.org/document/60675) that inspired a group of distinguished government-employed engineers and scientists. In fairness, there _might_ be a pocket-protector in this picture of them but it's a bit blurry. Actually, yes, there definitely is. No cigarettes, however: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/t... on image to zoom&p=PMC3&id=4487279_jres.119.004f7.jpg [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4487279/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4487279/
  - metaphor 2y ago
    Quick image link fix...spaces in URL broke auto-hyperlinking: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=4487279_jres.119.004f7.jpg https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/t...
    - denton-scratch 2y ago
andrewstuart 2y ago
Pretty sure there’ll be lots of comments on this to do with bandwidth and speed of light.
frankus 2y ago
It's kind of baffling that in 2024 there are appliances that exist for which I have to manually set the time, or at least have to go through some cumbersome IoT set-up process, that most likely is absolute garbage security-wise if it isn't actively acting against my interests (like those fridges that only work with first-party water filters). Maybe I'm under-thinking this, but couldn't my Wi-Fi router just broadcast the current time (and time zone) every minute or so in an unencrypted fashion to all devices within range?
- joshellington 2y ago
  Yes but then that would require consensus on protocol, encoding/decoding, etc., aka the things large companies are the worst at aligning on.
  - pavel_lishin 2y ago
    Plus you have to defend yourself from the neighborhood kid who thinks that it'd be a laugh riot to randomize everyone's clocks at 5:15 in the morning.
    - joshellington 2y ago
      That would have absolutely been myself, wardriving at 16 (back in the early aughts). Sending nonsensical print jobs and then setting everyone’s clocks to 4:20.
      - MadnessASAP 2y ago
        I'm in my mid 30s and I still regularly tell unattended Google Homes and Alexa's to set an alarm for 4 AM.
        pavel_lishin 2y ago
        I'm not that malicious, I just like picking up friends' unattended phones and snapping a goofy selfie for them to discover later.
FrustratedMonky 2y ago
""I’m not particularly patriotic, but this kind of thing feels particularly American. Perhaps my imagination of American innovation is still set in the era of lunar missions and radio."" Yes. From the first trans continental train, telegraph, up through landing on the moon. It does inspire a lot of patriotism, it was very 'can-do' time. Very innovative, huge public works. The old technology is still amazing.
- wayeq 2y ago
  Not to mention the voyager missions.. still zooming out into interstellar space..
kristofferR 2y ago
This got me thinking of this video: https://www.youtube.com/watch?v=IbUhA6Vt6Sk https://www.youtube.com/watch?v=IbUhA6Vt6Sk "We just lost the most powerful longwave transmitter in Europe, and why that's kind of a big deal" (2023) Slight Technology Connection vibes, really fascinating stuff.
lxgr 2y ago
I remember my dad getting a solar-powered wristwatch that could tune in to the Western European equivalent of WWVB (DCF77, located in Germany) and adjust itself (respecting DST!) when I was a teenager. Not that I'd regularly suffer from empty watch batteries or horribly incorrect time on my quartz watch, but I always found that extremely neat :)
sllabres 2y ago
If I think about time an American nowadays the first thing that comes into my mind is GPS. What WWVB or DCF77 (and JJY) was back then is now GPS timing capabilities. Much higher precision but of course a higher complexity for the receiver. [1] I don't know about WWVB and JJY but the German DFC77 is not only AM modulated but FM too allowing for a better accuracy. [1] https://www.hopf.com/dcf77-gps_en.php#chapter3 https://www.hopf.com/dcf77-gps_en.php#chapter3
rkagerer 2y ago
I looked into getting a wristwatch that uses this.
anonymousiam 2y ago
WWVB data transmission format is described here: https://www.nist.gov/system/files/documents/2017/05/09/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf https://www.nist.gov/system/files/documents/2017/05/09/NIST-...
pcdoodle 2y ago
Can you use this in basically the lower 48 with a long antenna? Free RTC L48?
systemvoltage 2y ago
Slightly tangent: being substantively patriotic is cool. It should be cool. America has done some incredible things like this and I’m sure it’s not just Americans that find it cool.
- nocoiner 2y ago
  Well said. I couldn’t agree more. I think there are a lot of countries that have done some really remarkable things. I’m American, and I’m generally very proud of my country. If I were, say, French, Swedish or Japanese, I’d feel the same way. Obviously none of those countries - or any country - is perfect, and all have some distinctly dark chapters in their past, but there’s something inspiring about a society organizing itself to accomplish generally good things.
  - servus45678981 2y ago
    I honestly think pride only makes sense if the place feels more than home to you; the people always were more important than some man-made borders and identities.
- servus45678981 2y ago
  Blind patriotism isn‘t cool. Most of those inventions were invented by multicultural people, so it has really not so much to do with the country.
vzaliva 2y ago
Decoding these signals should be a fun 1st project for Software Defined Radio. Google search shows several projects which did just that.
- kqbx 2y ago
  Can confirm, it's a great way to get started with radio stuff. Since I live in Europe, I did this with the German DCF77 signal. The frequency is low enough that you can do direct sampling with a 192ksps sound card or with an RP2040. A nice thing about DCF77 is that once you manage to receive the amplitude modulated signal, you can move onto decoding the slightly more advanced spread-spectrum phase modulated signal, which carries (almost) the same data. You can start by buying a time signal receiver module, and once you confirm that the module can receive the signal, cut off the ferrite antenna and use it with your own receiver. Here's a nice article on which I based my own project: https://hal.science/hal-02182845/ https://hal.science/hal-02182845/ Using the same setup (ferrite stick -> discrete transistor amplifier -> RP2040) I also managed to receive the polish AM station at 225kHz.
LeoPanthera 2y ago
Sadly, WWVB is damaged. At midnight on April 7, 2024, WWVB's south antenna was disabled due to damage sustained during high winds. WWVB now broadcasts exclusively from the north antenna, at a reduced power of 30kW. This situation is expected to continue "indefinitely", presumably because of a lack of budget for repairs.
- jimbobimbo 2y ago
  This looks like a great candidate for crowd funding.
  - blt 2y ago
    yes, in this case I'd say a good crowd funding platform is the IRS.
- michaelsshaw 2y ago
  Important to note the update: Update 20 May 2024: The components necessary for the refurbishment of the southern antenna’s triatic are currently being manufactured and shipped. The projected timeline for the completion of these repairs is tentatively set for the latter part of June 2024. We would like to emphasize that this is an estimated timeline and may be subject to alterations based on a variety of factors. We greatly appreciate your understanding and patience during this process.
anArbitraryOne 2y ago
I like the topic very much, but why did this very basic blog post get so many upvotes?
- nicbou 2y ago
  It introduces something new that tickles our curiosity. Not everything needs to be a long read. I do like short posts.
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bb88 2y ago
For those looking to hear what this sounds like without buying any radio gear, there are many public kiwisdr sites that can hear 60khz. It's a matter of choosing AM decoding and tuning to the particular frequency. http://kiwisdr.com/public/ http://kiwisdr.com/public/ Many of these have user limits and time limits as well. Note that you can also hear WWVB on 2.5mhz, 5mhz, 10mhz, and 15mhz.
- misstuned 2y ago
  You can also pick "timecode" from the extensions menu in the KiwiSDR interface and actually decode the time signal live on the receiver.
mikewarot 2y ago
I have a friend with a 300' longwire antenna. A few weeks ago, after we were done repairing an old receiver that included VLF, he tuned in WWVB for me... checking it off my bucket list. It was interesting to hear the beeps of different lengths. It came in surprisingly clear, in our Chicago suburb, especially since this was after the antenna issue on their end.
asix66 2y ago
I wear a Citizen “AT” [1] wristwatch daily. It not only keeps perfect time, because of its daily sync at 2am to WWVB, but it also never needs a battery change since it self charges from light. These two features make it the perfect zero maintenance timepiece IMHO, and it looks stylish too. [1] https://www.citizenwatch.com/us/en/collection/mens-atomic-timekeeping/ https://www.citizenwatch.com/us/en/collection/mens-atomic-ti...
- ansgri 2y ago
  Great watches, I'm a bit sad my Garmin Instinct spoiled more classic wristwatches for me — with GPS and a lot of sensors, and an actually functional flashlight, I cannot imagine giving up that valuable wristspace for a bit of added beauty (fortunately it looks decent with an aftermarket strap).
mlindner 2y ago
This is completely incorrect. Time synchronization across the entire US is done via GPS, not radio signals.
tempodox 2y ago
60 kHz is “long wave”, a frequency so low you could almost still hear. It's just thrice the upper limit of ~20 kHz for the human ear. I love how my wristwatch eats sunlight at day (solar-powered) and drinks radio waves at night. Never has to change a battery and shows time as accurately as any internet-connected device that listens to NTP.
- deleted 2y ago
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squarefoot 2y ago
For the makers here, you can purchase cheap small modules that interface to any microcontroller, including most popular ones like AVR (Arduino), ESP32, etc. so that they can receive and decode time signals from WWVB or the European equivalent DCF77. Just search for "WWVB (or DCF77) module" at the usual online shops.
tanepiper 2y ago
> I’m not particularly patriotic, but this kind of thing feels particularly American. Maybe that tinge of patriotism is why Americans don't even bother to see if something isn't an American invention - https://en.wikipedia.org/wiki/Time_from_NPL_(MSF) https://en.wikipedia.org/wiki/Time_from_NPL_(MSF) - they'll just claim it anyways since they barely read outside their borders. Radio 4 would also like a word: https://en.wikipedia.org/wiki/Greenwich_Time_Signal https://en.wikipedia.org/wiki/Greenwich_Time_Signal
- cjs_ac 2y ago
  The US Bill of Rights is copied almost word-for-word from English legislation: https://en.wikipedia.org/wiki/Bill_of_Rights_1689 https://en.wikipedia.org/wiki/Bill_of_Rights_1689
  - mixmastamyk 2y ago
    A copy of the Magna Carta was in the National Archives for a while, and John Locke was a notable influence on founders such as Jefferson. Nihil novi sub sole.
    - pohl 2y ago
      I saw it there the day before yesterday!
      - mixmastamyk 2y ago
        Cool—I saw it once, and then it was gone a few years later. Maybe being serviced.
      - HocusLocus 2y ago
        Oh dear. Where is it now?
  - CPLX 2y ago
    In fairness, the United States is a breakaway region of Great Britain.
dinoqqq 2y ago
American patriotism set aside, I share the author's enthusiasm for these types of technology! The post's main focus on how we stand on the shoulders of giants is so true! It makes me happy and proud as well. Another fascinating technology that we take for granted, is the possibility to travel with 280km/h in a train and still be able to receive digital bits and bytes. What kind of witchcraft would our grand-grand-grandparents have called that?
barrenko 2y ago
Wonderful post, thank you.
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jgrahamc 2y ago
The WWVB transmitter sometimes has surprisingly long propagation: https://blog.jgc.org/2021/07/receiving-wwvb-time-signal-in-portugal.html https://blog.jgc.org/2021/07/receiving-wwvb-time-signal-in-p... and https://blog.jgc.org/2023/03/wave-ok-wwvb-time-signal-sets-my-clock.html https://blog.jgc.org/2023/03/wave-ok-wwvb-time-signal-sets-m...
belter 2y ago
If you go below 300 Hz, you are probably into some hardcore top secret stuff: https://en.wikipedia.org/wiki/Communication_with_submarines https://en.wikipedia.org/wiki/Communication_with_submarines Assuming salt water, a 1024 Kb message should take around 3 hours to transmit.
evanjrowley 2y ago
Earlier this week I purchased a Casio Waveceptor watch. It features the ability to synchronize with this radio signal. I'm very happy with it. I was also happy with an early-2000s model for several years prior. The older one's receiver seemed to become unreliable after about a decade, possibly due to changes in the wireless spectrum over time. Overall, it was quite a reliable watch and so I have good confidence in this product line.
kwhitefoot 2y ago
1 bps on a 60 kHz carrier? That is certainly not the maximum possible data rate. There are AM stations broadcasting at only two or three times that frequency that broadcast voice and music. Perhaps they meant that it is the most practical for small receivers like watches. BBC R4 Longwave is at 198 kHz (formerly 200 kHz). The transmitter at Droitwich has been broadcasting voice and music since 1934.
esaym 2y ago
I see there are cheap indoor wall clocks that are syncd with WWVB. But can't find anything that use gps instead. I am wondering why? Are the receivers too power hungry or the signals just too weak? I'd think going with a gps time sync would be a more future proof design.
Liftyee 2y ago
Could someone please explain why the low frequency means the bandwidth is limited to 1 bps? Why can't the signal be turned on and off more times per second to transmit at a higher rate?
ProllyInfamous 2y ago
I'm currently reading (1954) The Time Regulation Institute [1], which has as plot element a series of fines for people not having their clocks set correctly. Upon my walls hang two "atomic clocks," identical, which utilize this 60 kHz signal to set each time. For some reason, they are consistantly not set to the same time! In Tanpınar's world, the fines would be laughably immense, updated daily, and intentionally frustrating! In my present realtime world, it is just mildly frustrating. -- Thanks for the background/technical information =D [1]: https://en.wikipedia.org/wiki/The_Time_Regulation_Institute https://en.wikipedia.org/wiki/The_Time_Regulation_Institute

60 kHz (2022)

250 points by jer0me 2y ago

Well said. Simple, solid technology for the benefit of everyone.

> I’m not particularly patriotic, but this kind of thing feels particularly American. ??? America has no doubt done some very remarkable things (the moon landing, the first backward compatible color TV standard), but I don't think this is a notable example of that. I think everyone in Europe was familiar with even wristwatches getting the time from "airwaves". At least in Germany, watches were a very common thing since the 80s (I think everyone old enough vividly remembers the many Junghans commercials on TV). The corresponding signal has been broadcast for many decades earlier, as it's no surprise that railroad and airplane networks were in need of a common time: https://en.wikipedia.org/wiki/DCF77 https://en.wikipedia.org/wiki/DCF77 > But we had a problem, and we solved it with technology. And none of that fancy newfangled technology — we solved it using solid technology, the kind that you can touch with your hands and that buzzes in the airwaves. There wasn't much "newfangled technology" around at the time. We essentially solved it using the simplest method there was at the time, at least I find it a bit hard to come up with a simpler one. Also, what would be an example of technology that you can't either "touch with your hands" or that does "buzz in airwaves"?

aeonik 2y ago
US seems to be the first to pioneer this according to my very cursory research: https://timeandnavigation.si.edu/multimedia-asset/us-navy-wireless-transmitting-station-arlington-virginia-1913 https://timeandnavigation.si.edu/multimedia-asset/us-navy-wi...
- anyfoo 2y ago
  I stand corrected, it seems to indeed have been the US Navy that pioneered time signals. France followed up a few years later. I don’t know who had the first system accessible to civilians, but at this point we’d just be arguing details.
  - lloeki 2y ago
    From the link: > Radio time signals for setting chronometers were sent from stations such as NAA in Arlington, Virginia, which began broadcasting in 1913. The time was supplied from a direct communication line with the clocks of the U.S. Naval Observatory in Washington, D.C. In combination with another low-frequency installation mounted on the Eiffel Tower in Paris, the towers had the range to cover the North Atlantic Ocean and the eastern United States. So I looked up the Eiffel tower. > The Eiffel Tower time signal broadcasts began on May 23, 1910 https://tf.nist.gov/general/pdf/2131.pdf https://tf.nist.gov/general/pdf/2131.pdf Also, same source starts with the 1898 proposal of time sync via radio being made by an Irish bloke. > I don’t know who had the first system accessible to civilians, but at this point we’d just be arguing details. Agreed. Even non-civilian, and whoever came first, the timeline of things across various countries, I don't think the core point of TFA holds water: it's not a "particularly American" thing, it just made sense out of engineering requirements: time sync was transmitted over telegraph wires, and telegraph went wireless; the leap is not exactly surprising.
    - aeonik 2y ago
      Nice find! This turns out to be quite an interesting rabbit hole. It's definitely earlier than I would have guessed regardless.
- deleted 2y ago
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Dalewyn 2y ago
>what would be an example of technology that you can't either "touch with your hands" or that does "buzz in airwaves"? Microprocessors and lights/lasers respectively, among I'm certain countless other examples.
- anyfoo 2y ago
  I can touch microprocessors, and lasers are buzzing in airwaves. It’s the same electromagnetic radiation as what we know as radio, just at much, much higher frequencies. But this was asked in the context of solving this problem, in the 1950s.
  - pavel_lishin 2y ago
    Sure, but trench soldiers used to build their own radios. A soldier today stationed in the middle of a war isn't likely to assemble their own laser emitter.
    - anyfoo 2y ago
      I don’t think anybody at that time could have built a laser emitter, even. Not sure why you would want to, to solve that problem, even today. I feel like the point of my question was lost.
  - Dalewyn 2y ago
    >I can touch microprocessors, No you can't, you're just touching the box they come in. You can touch copper cables and wires, vacuum tubes, resistors, capacitors, breadboards, and (large!) printed circuit boards among other "basic" electronic components. You can't touch microprocessors, it's even stated on the tin they are microscopic in scale; you can't touch that in any meaningful way.
    - anyfoo 2y ago
      We could argue about that, but let me rephrase then: What technology that you can neither touch, nor that buzzes in airwaves, could they have used to solve this problem back then?
someguydave 2y ago
Digital communications is America’s gift to the world, look up Claude Shannon
- sokoloff 2y ago
  I think the Englishman George Boole deserves significant credit as well.
- spixy 2y ago
  AC motor, steam, diesel, jet engines are european "gifts to the world", yet it would be cringe to write sentence like "I’m not particularly patriotic, but this kind of thing feels particularly European"
Aloisius 2y ago
> I think everyone in Europe was familiar with even wristwatches getting the time from "airwaves". At least in Germany, watches were a very common thing since the 80s Not the 80s. The first radio controlled wristwatch came out in 1990 (Junghans Mega 1).
- anyfoo 2y ago
  Sorry, I mistranslated “clock” (hence why I differentiated “wristwatch” in the sentence before). We owned a Funkuhr-Wecker in the 80s, so, an alarm clock synchronizing to DCF77, in the 80s. The wristwatches came a bit later, yeah (not that I’d have known without looking it up whether that was earlier or later than 1990).
layman51 2y ago
I wondered about its American origins too. I vaguely remember a little detail in the novel Cryptonomicon where one of the characters (a Lieutenant in the Imperial Japanese Army during WWII) sets his watch with a radio time signal. So that got me thinking that maybe the idea arose in different places. Also I was wondering about the “forever” wording. I imagine the signal is very robust, but couldn’t American politics just one day decide that it’s not worth it to broadcast the time by radio signal anymore?

2four2 2y ago

There are several of these stations, they are maintained and operated by NIST. Two of them were almost shut down recently due to budget concerns: https://www.radioworld.com/global/why-wwv-and-wwvh-still-matter https://www.radioworld.com/global/why-wwv-and-wwvh-still-mat...

dfc 2y ago
In April one of the two WWVB antennas failed (broke) because of 90mph winds. https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb/wwvb-station-outages https://www.nist.gov/pml/time-and-frequency-division/time-di...
- Eduard 2y ago
  https://www.nist.gov/pml/time-and-frequency-division/time-distribution/radio-station-wwvb https://www.nist.gov/pml/time-and-frequency-division/time-di... > Official Notice: Commencing from 0000 Coordinated Universal Time (UTC) on April 7, 2024, the southern antenna of WWVB has been rendered non-operational due to damage sustained from wind gusts exceeding 90 MPH. Please be advised that WWVB continues to function at a diminished overall power, utilizing only its northern antenna. > Update 20 May 2024: The components necessary for the refurbishment of the southern antenna’s triatic are currently being manufactured and shipped. The projected timeline for the completion of these repairs is tentatively set for the latter part of June 2024. We would like to emphasize that this is an estimated timeline and may be subject to alterations based on a variety of factors. We greatly appreciate your understanding and patience during this process. Can someone using WWVB radio clocks describe what the current situation is? Is the second working antenna strong enough to provide signals throughout the US / North America? Are WWVB radio clocks popular at all? Here in Europe, DCF77-based clocks are popular, especially with respect to automatic summer time adaption and (less obvious) leap second HANDLING. It would be very noticeable eventually if the DCF77 signal had severe issues. Also, I'm very surprised about the abysmal historical uptime of Wwvb. It lists thirteen downtimes of more than 5 minutes each in 2023 alone.
  - lxgr 2y ago

tkzed49 2y ago

the bandwidth is just enough to broadcast a single digit of binary every second. I'd be interested in some more context on this. I think it's pretty clear that you can encode more than 1bps in a 60kHz signal, but I'm curious how the encoding was chosen. There's some more detail on it here: https://en.wikipedia.org/wiki/WWVB#Modulation_format https://en.wikipedia.org/wiki/WWVB#Modulation_format The WWVB 60 kHz carrier, which has a normal ERP of 70 kW, is reduced in power at the start of each UTC second by 17 dB (to 1.4 kW ERP). It is restored to full power some time during the second. The duration of the reduced power encodes one of three symbols: If power is reduced for one-fifth of a second (0.2 s), this is a data bit with value zero. If power is reduced for one-half of a second (0.5 s), this is a data bit with value one. If power is reduced for four-fifths of a second (0.8 s), this is a special non-data "mark", used for framing. This is apparently the IRIG H encoding, which dates to the 50s and is probably designed to be easily decoded. By what, I wonder?

mmastrac 2y ago
> By what, I wonder? At that length of symbol encoding, by hand. :)
anyfoo 2y ago
Relays maybe? EDIT: Not sure why I was downvoted. Relays seem like period-accurate technology (happy to be corrected), and they’re comparably slow.
- Dylan16807 2y ago
  I can't say why you were downvoted but that's still pretty slow for relays. One bit per second seems more like it's aimed at casual human decoding. Especially because each digit is encoded separately, even for the hours. Also for plain old range purposes, one transmission per minute is about as wide as you can go before things get silly.
retrac 2y ago
The signal is not 60 kHz wide. It is at 60 kHz. A pure carrier with no modulation has the inverse of infinite bandwidth. (Assuming perfect transmitters, which can't really exist, of course.) The faster you modulate the signal, the more it spreads out across the spectrum. The frequency-time tradeoff. The time signals run at the low end of longwave. That spans from about 40 to 120 kHz or so. There is about 100 kHz of spectrum down there. Though broadcasting a broadband longwave signal like that would be an imposing task. To cover a large area with AM broadcast (maybe 5 - 10 kHz) uses 1 - 2 megawatt transmitters in Europe. To cover the continent with a 100 kHz broadband digital signal would probably take 10 - 50 megawatts, maybe with 3 transmitter sites. Though I think it could be done. Could fit maybe a megabit a sec in there. Something less ambitious maybe. A few hundred bytes a second? A kilohertz or so of spectrum used. It could work inside elevators, deep underground in parking garages, and so on. Digital alert stream for emergencies, time signal, etc.? Would not be much more complicated than the time signal transmitters, just with a more sophisticated modulation.

khaki54 2y ago

I can picture a room full of engineers in ties, wearing pocket protectors full of implements, chain smoking cigarettes while coming up with this one.

erikpukinskis 2y ago
I can picture a black woman at a desk in a nicely pressed dress coming up with this one on pencil and paper.
- neilv 2y ago
  https://en.wikipedia.org/wiki/Hidden_Figures https://en.wikipedia.org/wiki/Hidden_Figures
mmastrac 2y ago
More likely a radio nerd, John Alvin Pierce, that was just really good at radio and obsessed with oscillators (https://ieeexplore.ieee.org/document/60675 https://ieeexplore.ieee.org/document/60675) that inspired a group of distinguished government-employed engineers and scientists. In fairness, there _might_ be a pocket-protector in this picture of them but it's a bit blurry. Actually, yes, there definitely is. No cigarettes, however: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/t... on image to zoom&p=PMC3&id=4487279_jres.119.004f7.jpg [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4487279/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4487279/
- metaphor 2y ago
  Quick image link fix...spaces in URL broke auto-hyperlinking: https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=4487279_jres.119.004f7.jpg https://www.ncbi.nlm.nih.gov/core/lw/2.0/html/tileshop_pmc/t...
  - denton-scratch 2y ago

andrewstuart 2y ago

Pretty sure there’ll be lots of comments on this to do with bandwidth and speed of light.

frankus 2y ago

It's kind of baffling that in 2024 there are appliances that exist for which I have to manually set the time, or at least have to go through some cumbersome IoT set-up process, that most likely is absolute garbage security-wise if it isn't actively acting against my interests (like those fridges that only work with first-party water filters). Maybe I'm under-thinking this, but couldn't my Wi-Fi router just broadcast the current time (and time zone) every minute or so in an unencrypted fashion to all devices within range?

joshellington 2y ago
Yes but then that would require consensus on protocol, encoding/decoding, etc., aka the things large companies are the worst at aligning on.
- pavel_lishin 2y ago
  Plus you have to defend yourself from the neighborhood kid who thinks that it'd be a laugh riot to randomize everyone's clocks at 5:15 in the morning.
  - joshellington 2y ago
    That would have absolutely been myself, wardriving at 16 (back in the early aughts). Sending nonsensical print jobs and then setting everyone’s clocks to 4:20.
    - MadnessASAP 2y ago
      I'm in my mid 30s and I still regularly tell unattended Google Homes and Alexa's to set an alarm for 4 AM.
      - pavel_lishin 2y ago
        I'm not that malicious, I just like picking up friends' unattended phones and snapping a goofy selfie for them to discover later.

FrustratedMonky 2y ago

""I’m not particularly patriotic, but this kind of thing feels particularly American. Perhaps my imagination of American innovation is still set in the era of lunar missions and radio."" Yes. From the first trans continental train, telegraph, up through landing on the moon. It does inspire a lot of patriotism, it was very 'can-do' time. Very innovative, huge public works. The old technology is still amazing.

wayeq 2y ago
Not to mention the voyager missions.. still zooming out into interstellar space..

kristofferR 2y ago

This got me thinking of this video: https://www.youtube.com/watch?v=IbUhA6Vt6Sk https://www.youtube.com/watch?v=IbUhA6Vt6Sk "We just lost the most powerful longwave transmitter in Europe, and why that's kind of a big deal" (2023) Slight Technology Connection vibes, really fascinating stuff.

lxgr 2y ago

I remember my dad getting a solar-powered wristwatch that could tune in to the Western European equivalent of WWVB (DCF77, located in Germany) and adjust itself (respecting DST!) when I was a teenager. Not that I'd regularly suffer from empty watch batteries or horribly incorrect time on my quartz watch, but I always found that extremely neat :)

sllabres 2y ago

If I think about time an American nowadays the first thing that comes into my mind is GPS. What WWVB or DCF77 (and JJY) was back then is now GPS timing capabilities. Much higher precision but of course a higher complexity for the receiver. [1] I don't know about WWVB and JJY but the German DFC77 is not only AM modulated but FM too allowing for a better accuracy. [1] https://www.hopf.com/dcf77-gps_en.php#chapter3 https://www.hopf.com/dcf77-gps_en.php#chapter3

rkagerer 2y ago

I looked into getting a wristwatch that uses this.

anonymousiam 2y ago

WWVB data transmission format is described here: https://www.nist.gov/system/files/documents/2017/05/09/NIST-Enhanced-WWVB-Broadcast-Format-1_01-2013-11-06.pdf https://www.nist.gov/system/files/documents/2017/05/09/NIST-...

pcdoodle 2y ago

Can you use this in basically the lower 48 with a long antenna? Free RTC L48?

systemvoltage 2y ago

Slightly tangent: being substantively patriotic is cool. It should be cool. America has done some incredible things like this and I’m sure it’s not just Americans that find it cool.

nocoiner 2y ago
Well said. I couldn’t agree more. I think there are a lot of countries that have done some really remarkable things. I’m American, and I’m generally very proud of my country. If I were, say, French, Swedish or Japanese, I’d feel the same way. Obviously none of those countries - or any country - is perfect, and all have some distinctly dark chapters in their past, but there’s something inspiring about a society organizing itself to accomplish generally good things.
- servus45678981 2y ago
  I honestly think pride only makes sense if the place feels more than home to you; the people always were more important than some man-made borders and identities.
servus45678981 2y ago
Blind patriotism isn‘t cool. Most of those inventions were invented by multicultural people, so it has really not so much to do with the country.

vzaliva 2y ago

Decoding these signals should be a fun 1st project for Software Defined Radio. Google search shows several projects which did just that.

kqbx 2y ago
Can confirm, it's a great way to get started with radio stuff. Since I live in Europe, I did this with the German DCF77 signal. The frequency is low enough that you can do direct sampling with a 192ksps sound card or with an RP2040. A nice thing about DCF77 is that once you manage to receive the amplitude modulated signal, you can move onto decoding the slightly more advanced spread-spectrum phase modulated signal, which carries (almost) the same data. You can start by buying a time signal receiver module, and once you confirm that the module can receive the signal, cut off the ferrite antenna and use it with your own receiver. Here's a nice article on which I based my own project: https://hal.science/hal-02182845/ https://hal.science/hal-02182845/ Using the same setup (ferrite stick -> discrete transistor amplifier -> RP2040) I also managed to receive the polish AM station at 225kHz.

LeoPanthera 2y ago

Sadly, WWVB is damaged. At midnight on April 7, 2024, WWVB's south antenna was disabled due to damage sustained during high winds. WWVB now broadcasts exclusively from the north antenna, at a reduced power of 30kW. This situation is expected to continue "indefinitely", presumably because of a lack of budget for repairs.

jimbobimbo 2y ago
This looks like a great candidate for crowd funding.
- blt 2y ago
  yes, in this case I'd say a good crowd funding platform is the IRS.
michaelsshaw 2y ago
Important to note the update: Update 20 May 2024: The components necessary for the refurbishment of the southern antenna’s triatic are currently being manufactured and shipped. The projected timeline for the completion of these repairs is tentatively set for the latter part of June 2024. We would like to emphasize that this is an estimated timeline and may be subject to alterations based on a variety of factors. We greatly appreciate your understanding and patience during this process.

anArbitraryOne 2y ago

I like the topic very much, but why did this very basic blog post get so many upvotes?

nicbou 2y ago
It introduces something new that tickles our curiosity. Not everything needs to be a long read. I do like short posts.

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bb88 2y ago

For those looking to hear what this sounds like without buying any radio gear, there are many public kiwisdr sites that can hear 60khz. It's a matter of choosing AM decoding and tuning to the particular frequency. http://kiwisdr.com/public/ http://kiwisdr.com/public/ Many of these have user limits and time limits as well. Note that you can also hear WWVB on 2.5mhz, 5mhz, 10mhz, and 15mhz.

misstuned 2y ago
You can also pick "timecode" from the extensions menu in the KiwiSDR interface and actually decode the time signal live on the receiver.

mikewarot 2y ago

I have a friend with a 300' longwire antenna. A few weeks ago, after we were done repairing an old receiver that included VLF, he tuned in WWVB for me... checking it off my bucket list. It was interesting to hear the beeps of different lengths. It came in surprisingly clear, in our Chicago suburb, especially since this was after the antenna issue on their end.

asix66 2y ago

I wear a Citizen “AT” [1] wristwatch daily. It not only keeps perfect time, because of its daily sync at 2am to WWVB, but it also never needs a battery change since it self charges from light. These two features make it the perfect zero maintenance timepiece IMHO, and it looks stylish too. [1] https://www.citizenwatch.com/us/en/collection/mens-atomic-timekeeping/ https://www.citizenwatch.com/us/en/collection/mens-atomic-ti...

ansgri 2y ago
Great watches, I'm a bit sad my Garmin Instinct spoiled more classic wristwatches for me — with GPS and a lot of sensors, and an actually functional flashlight, I cannot imagine giving up that valuable wristspace for a bit of added beauty (fortunately it looks decent with an aftermarket strap).

mlindner 2y ago

This is completely incorrect. Time synchronization across the entire US is done via GPS, not radio signals.

tempodox 2y ago

60 kHz is “long wave”, a frequency so low you could almost still hear. It's just thrice the upper limit of ~20 kHz for the human ear. I love how my wristwatch eats sunlight at day (solar-powered) and drinks radio waves at night. Never has to change a battery and shows time as accurately as any internet-connected device that listens to NTP.

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squarefoot 2y ago

For the makers here, you can purchase cheap small modules that interface to any microcontroller, including most popular ones like AVR (Arduino), ESP32, etc. so that they can receive and decode time signals from WWVB or the European equivalent DCF77. Just search for "WWVB (or DCF77) module" at the usual online shops.

tanepiper 2y ago

> I’m not particularly patriotic, but this kind of thing feels particularly American. Maybe that tinge of patriotism is why Americans don't even bother to see if something isn't an American invention - https://en.wikipedia.org/wiki/Time_from_NPL_(MSF) https://en.wikipedia.org/wiki/Time_from_NPL_(MSF) - they'll just claim it anyways since they barely read outside their borders. Radio 4 would also like a word: https://en.wikipedia.org/wiki/Greenwich_Time_Signal https://en.wikipedia.org/wiki/Greenwich_Time_Signal

cjs_ac 2y ago
The US Bill of Rights is copied almost word-for-word from English legislation: https://en.wikipedia.org/wiki/Bill_of_Rights_1689 https://en.wikipedia.org/wiki/Bill_of_Rights_1689
- mixmastamyk 2y ago
  A copy of the Magna Carta was in the National Archives for a while, and John Locke was a notable influence on founders such as Jefferson. Nihil novi sub sole.
  - pohl 2y ago
    I saw it there the day before yesterday!
    - mixmastamyk 2y ago
      Cool—I saw it once, and then it was gone a few years later. Maybe being serviced.
    - HocusLocus 2y ago
      Oh dear. Where is it now?
- CPLX 2y ago
  In fairness, the United States is a breakaway region of Great Britain.

dinoqqq 2y ago

American patriotism set aside, I share the author's enthusiasm for these types of technology! The post's main focus on how we stand on the shoulders of giants is so true! It makes me happy and proud as well. Another fascinating technology that we take for granted, is the possibility to travel with 280km/h in a train and still be able to receive digital bits and bytes. What kind of witchcraft would our grand-grand-grandparents have called that?

barrenko 2y ago

Wonderful post, thank you.

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jgrahamc 2y ago

The WWVB transmitter sometimes has surprisingly long propagation: https://blog.jgc.org/2021/07/receiving-wwvb-time-signal-in-portugal.html https://blog.jgc.org/2021/07/receiving-wwvb-time-signal-in-p... and https://blog.jgc.org/2023/03/wave-ok-wwvb-time-signal-sets-my-clock.html https://blog.jgc.org/2023/03/wave-ok-wwvb-time-signal-sets-m...

belter 2y ago

If you go below 300 Hz, you are probably into some hardcore top secret stuff: https://en.wikipedia.org/wiki/Communication_with_submarines https://en.wikipedia.org/wiki/Communication_with_submarines Assuming salt water, a 1024 Kb message should take around 3 hours to transmit.

evanjrowley 2y ago

Earlier this week I purchased a Casio Waveceptor watch. It features the ability to synchronize with this radio signal. I'm very happy with it. I was also happy with an early-2000s model for several years prior. The older one's receiver seemed to become unreliable after about a decade, possibly due to changes in the wireless spectrum over time. Overall, it was quite a reliable watch and so I have good confidence in this product line.

kwhitefoot 2y ago

1 bps on a 60 kHz carrier? That is certainly not the maximum possible data rate. There are AM stations broadcasting at only two or three times that frequency that broadcast voice and music. Perhaps they meant that it is the most practical for small receivers like watches. BBC R4 Longwave is at 198 kHz (formerly 200 kHz). The transmitter at Droitwich has been broadcasting voice and music since 1934.

esaym 2y ago

I see there are cheap indoor wall clocks that are syncd with WWVB. But can't find anything that use gps instead. I am wondering why? Are the receivers too power hungry or the signals just too weak? I'd think going with a gps time sync would be a more future proof design.

Liftyee 2y ago

Could someone please explain why the low frequency means the bandwidth is limited to 1 bps? Why can't the signal be turned on and off more times per second to transmit at a higher rate?

ProllyInfamous 2y ago

I'm currently reading (1954) The Time Regulation Institute [1], which has as plot element a series of fines for people not having their clocks set correctly. Upon my walls hang two "atomic clocks," identical, which utilize this 60 kHz signal to set each time. For some reason, they are consistantly not set to the same time! In Tanpınar's world, the fines would be laughably immense, updated daily, and intentionally frustrating! In my present realtime world, it is just mildly frustrating. -- Thanks for the background/technical information =D [1]: https://en.wikipedia.org/wiki/The_Time_Regulation_Institute https://en.wikipedia.org/wiki/The_Time_Regulation_Institute