NIST is broadcasting a test signal on minute 8 of the hour on WWV and 48 on WWVH | Hacker News Reader

NIST is broadcasting a test signal on minute 8 of the hour on WWV and 48 on WWVH

wwvarc.org

105 pointsfortran7787 comments

It is worth pointing out that you do not need an amateur radio license to receive signals, and indeed transmitting is not necessary for this experiment.

Any shortwave or "HF" radio will do. A simple receiving antenna for the HF band is simply a length of wire, as long as possible, and as high as possible.

WWV and WWVH transmit on 2.5, 5, 10, 15, and 20 MHz. (Though 2.5MHz is outside the HF band and difficult to receive with most radios.)

If you live on the US west coast it is often possible to receive both, especially at night, which is why their signals are offset in time.

If I'm not mistaken in the UK you actually need a licence to listen to some frequencies. I may be misremembering but it always struck me as rather Sisyphean the moment I bought a cheap SDR.

Ok. Good luck enforcing that.

I don't know how this could even remotely be enforced.

Superheterodyne receivers (https://en.wikipedia.org/wiki/Superheterodyne_receiver) use a local oscillator to downmix the received radio or television signal for processing at a much more sane, lower frequency.

That local oscillator emits its own RF radiation, so it is potentially detectable.

Correct. However, if using an rtl-sdr by itself to listen to HF, you are utilizing direct conversion which doesn't use an intermediate frequency. I believe the IF is still being generated (?), but it's no longer indicative of what you are listening to.

Direct conversion has no IF but still uses a mixer and a LO, and the LO still leaks out of the input port of the mixer. Because you're directly converting the RF to baseband, LO frequency is the tuned frequency. Unlike e.g. a dual or triple conversion receiver (used in e.g. spectrum analyzers), where the first IF is way above the highest tunable frequency.

There is almost definitely something to detect if you brought a van full of RF gear, but it's not like the good old days where it was obvious.

Great link as it mentions Radar Detector Detectors. This is actively enforced in the US state of Virginia.

Which is one of very few places radar detectors are against the law in the US.

I would love to see it challenged all the way up to the Supreme Court if necessary. These laws seem blatantly unconstitutional, and it's kind of amazing that they've held up for so long.

It gets better than that: there were radar-detector-detector-detectors [1] which were consumer radar detectors that could detect the police radar-detector-detector and shut down.

It's tagged as [citation needed] on wikipedia, but the source [2] does mention this as a feature of some radar detectors. I like to hope it's true.

[1]: https://en.wikipedia.org/wiki/Radar_detector_detector

[2]: https://web.archive.org/web/20100620150944/http://radar.757....

The lengths highway patrol go to enforce speed limits manually is insane to me. I've never understood why, if speeding is such an important thing to prevent, why don't they use camera enforcement. If you travel between cameras A and B in less than the minimum time it would take at the speed limit, somewhere along the way you were speeding. There's no way around it. You could speed and then travel slower than the limit to average it out, but there would be no point, and enforcement is already spotty. Just send the ticket in the mail, or dispatch a patrol car if someone is speeding recklessly fast.

It seems like it would calm traffic, because people would travel the speed limit instead of speeding and then abruptly dropping from 90mph to 65 when they see a cop hidden behind a bridge. I've seen demonstrations that traffic waves cause jams even when there is no problem with throughput, just because someone slammed on their brakes. I'm actually not sure what it'd do to ticket revenue. If there was no way around it because your average speed gets measured, I guess people would stop speeding. Maybe the gambling aspect of it is desirable to governments because if there's a small chance of getting a ticket, lots of people will speed and thus get tickets. If tickets are a certainty, no one speeds and revenue dries up.

Do police unions lobby against using this kind of enforcement because it'd mean less cops lurking under bridges for an easy payday?

There are legitimate reasons why someone would go faster than the speed limit (safety) that your simple 2 camera setup would not be able to understand.

Could you elaborate on some of the safety reasons for exceeding the speed limit, to help me understand?

We use average speed cameras in the UK to enforce temporarily reduced speed limits during road repairs on the motorways. It seems to work quite well, it certainly feels like most people adhere to the reduced limits.

Personally, I am aware that if I speed (for whatever internal justification I convince myself of), I just need to reduce my average speed by the time I pass the next camera (they're big and yellow and deliberately conspicuous so drivers know where they are).

Health emergencies or something like that. Though I think it'd be pretty straightforward to say "hey I was going to the hospital, overturn this ticket please" after the fact.

I’ve never had an officer understand my legitimate reason either, and even if they had, the time spent checking my ID and running insurance would far exceed whatever time I gained by speeding.

In a state I lived in, these kinds of camera-based enforcement of vehicle laws were ruled unconstitutional (state constitution). The argument was that traffic laws apply to the person driving the car, not the car, and it's too difficult to tell from videos who is driving the car. There were probably other arguments against them but basically the state supreme court decided there was no way a camera could establish evidence at the level of certainty needed.

It's odd now that I think of it because traffic cameras used for other reasons have been used in felony investigations (eg, murder). My guess is in those cases they have to establish that the person being charged was likely in the car?

I think it's the automatic charging aspect of it.

In Croatia, the owner of the vehicle is responsible to identify the person driving. Otherwise, he pays a fixed fine.

That seems reasonable to me.

> I've never understood why, if speeding is such an important thing to prevent, why don't they use camera enforcement. If you travel between cameras A and B in less than the minimum time it would take at the speed limit, somewhere along the way you were speeding.

I don't know about the US, and I suppose it varies between states anyway, but in the UK that's exactly how it works on our motorways and some larger dual carriageways.

> The lengths highway patrol go to enforce speed limits manually is insane to me.

Enforcing speed limits is not among the things that I think police try at all to do. I rarely see anyone pulled over while driving, and of those, I reason, not all are for speeding; meanwhile cars fly by me constantly at 20 or more beyond the posted limit. I live in Pennsylvania and drive through the Commonwealth and near by states with some regularity.

Although I do think more should be done to both enforce speed limits and make posted speed limits more sensible/natural.

Traffic enforcement is just a state/municipality funded jobs program. On the interstate they seem to solely target speeders, while ignoring the packs of cars following <1s behind each other-- which should be easy enough to spot while stationary in the median. They also seem to selectively enforce, when they should probably be taking into consideration that a 3.5 ton lifted pickup truck with mud terrain tires going 10 over and tailgating is much more dangerous than a Toyota Camry going 10 over by itself, but you never see the pickups pulled over. In most cases, they're not making the highway safer by giving someone a ticket for going 80 in a 70 when the roads are sparsely populated. If they were actually there to promote safety, limits would be set at the 85th percentile[1] and then enforcement would be on actually dangerous driving behaviors such as tailgating, aggressive lane changes and excessively different speed vs flow of traffic.

There are places in the US with "hidden" speed cameras on interstates-- I think Sioux City, IA has them. They're marked on Google Maps & locals know to slow down near the signs that hide them, then immediately speed back up. Strangely enough, traffic doesn't accordion as much such as when an unexpected braking event happens otherwise.

[1]https://www.strongtowns.org/journal/2020/7/24/understanding-...

Magic. Got it.

In the UK you need a license to receive the BBC[1]. And they drive around in vans[2] looking for evidence of unlicensed receivers.

[1] https://en.wikipedia.org/wiki/Television_licensing_in_the_Un...

[2] https://en.wikipedia.org/wiki/TV_detector_van

I'd be willing to wager that the detection techniques said to be used in the vans are a product of mendacious fantasy (some might say that is par for the course with the BBC), and the actual method used is to simply correlate homes that do not have licences with those that previously had them, and to simply look towards the roof and see if an aerial is present.

Ockham's razor and all that.

Analogue CRT television sets emitted some distinctive signals, I think, like the horizontal scan rate of about 15 kHz: https://en.wikipedia.org/wiki/Horizontal_scan_rate

That's hardly relevant today, of course.

True, but it's low power signal and it's not an easy job to triangulate on that in say a 12-storey building, 8 apartments per floor, and where everyone has TVs emitting on the same frequency. It makes very questionable the legality of entering someone home based just on that.

They're not legally allowed to enter your home without your consent, anyway.

Legally that may be the case but it seems - if the videos on the Crimebodge channel[1] are anything to go by - that they are forcing their way in, often with the help of the police.

[1] https://www.youtube.com/channel/UCUSL8poMxM_uXWzWExJaY-w

Edit: It appears that large chunks of Crimebodge's channel is private now because Youtube were threatening to delete his channel (or something, I'm not clear as to what's happened since the last time I looked) but those BBC licence fee vids don't seem to be up. I hope he gets things sorted, sorry to have wasted anyone's time with that link.

In reality it was mostly just a stunt to scare people into paying the fees. In 90s a number of countries in Europe had tried the similar actions, I remember in Serbia the national tv station RTS was advertising continuously how their technicians are walking the city with "Swedish detectors", which were some mysterious boxes, probably some kind of EM detectors, that supposedly could detect TV devices inside the homes - but of course the whole thing was a load of crap as it's a way too much work to make it profitable, so it was mainly used just to scare the senior population into paying them.

Later they simply changed the laws to make it mandatory for every household to pay the TV tax, as their detectors obviously didn't work.

Approximately every house has an aerial, its presence is not a good indicator of if there’s a TV hooked up to it. I think most likely they just look through your window.

It's the reason that there are no live streams of ATC transmissions online for UK airports. Doing that would trigger some "enforcement".

"No live streams" is a little broad. LiveATC specifically was targeted by Ofcom. GlobalTuners and dozens of other sites have UK ATC broadcasts, they just can't advertise them publicly.

> Under Section 5(1)(b) of the WT Act 1949 it is an offence if a person "otherwise than under the authority of a designated person, either:(i) uses any wireless telegraphy apparatus with intent to obtain information as to the contents, sender or addressee of any message whether sent by means of wireless telegraphy or not, of which neither the person using the apparatus nor a person on whose behalf he is acting is an intended recipient;

So yes, use of radio receivers to listen to anything in the UK, other than general broadcast or frequencies you're specifically licenced to listen to is an offence without express permission. I believe it's the main reason you can't stream Air Traffic Control frequencies in the UK, where as their available for other countries.

More information available here: http://www.monitoringtimes.com/html/mtlaws_may04.html

You don't necessarily need a radio at all to tune into WWV/WWVH -- you can listen on a telephone. (Nevermind that most telephones today use radio waves.)

(303) 499-7111 for WWV (Colorado)

(808) 335-4363 for WWVH (Hawaii)

https://www.nist.gov/time-distribution/radio-station-wwv/tel...

This would, however, void the entire purpose of this experiment.

Also it greatly reduces the value of the time signal. Over the PSTN it's usually a couple hundred milliseconds off.

> It is worth pointing out that you do not need an amateur radio license to receive signals, and indeed transmitting is not necessary for this experiment.

I don't think that's true everywhere. There is a reason that at least in the 80s/90s, scanners were exclusively sold as "export equipment" in Germany, meaning you were not allowed to buy them for use within Germany. (Don't know if that's still the case.)

They still were advertised next to all the other non-export equipment in consumer electronic store catalogues, just with a warning. I would be shocked, shocked, if there ever were any customers who bought such a scanner without the explicit intent to export it to another country.[1]

[1] I didn't, like actually didn't. Not only was I too young to have that kind of money, at that age I actually thought using one might get me into serious trouble (I have no idea how).

A scanner and a shortwave receiver are not the same thing.

I don't know if listening to this particular signal is legal or not in Germany or anywhere else, I'm just pointing out that for the general case (as I read OP's sentence) it may well depend on the jurisdiction.

The only countries as far as I know that banned shortwave reception were the former eastern block countries and other similar regimes.

Reception of the entire HF band is legal globally, as defined by the ITU. You don't need a scanner to receive shortwave radio, and in fact most scanners can't receive shortwave radio.

ITU doesn't get to decide what's legal in countries. If Cuba wants to tell you it's illegal to listen to Voice of America on HF, they can.

ITU just helps countries agree on uses for spectrum and conventions for its use.

The ITU defines what the bands are, but of course not the legality of using them.

OP said you don't need a license to "receive signals". As far as I know that's not correct. Maybe OP meant specifically these signals, but that's not how I read it, and it's worth pointing out anyway.

> at that age I actually thought using one might get me into serious trouble (I have no idea how).

Aber es war streng verboten!

So, my advice is: if is not legal to receive SW signals in your country: Build your own receiver if needed, but make a point of DO receiving SW signals and try to help as much people as possible while you make sure the State knows people are making it without letting know WHO is doing it.

>as long as possible, and as high as possible.

Caveat about 'long as possible' (for general shortwave listening): Once the antenna is over a half wavelength long at the operating frequency (10MHz, one wavelength is ~~ 100 feet, 30 meters), it becomes increasingly more directional along its axis. (Longer still, even more directional.) This may dampen the signal amplitude for signals coming in 'off the side' (compared to a dipole at least).

WWV also transmits on 25 MHz. This is an experimental transmitter that's not mentioned in the broadcast at minute 0.

WWVH does not transmit on 20 MHz.

Since no one bothered to explain what WWV and WWVH are:

https://en.wikipedia.org/wiki/WWV_(radio_station)

https://en.wikipedia.org/wiki/WWVH

The signal sounds just like a banger DJ intro.

[MAN] at the tone. 22 hours. 8 minutes. coordinated universal time.

[TONE]

[WOMAN] follows is a scientific modulation test. for more information visit DJ NIST

Yeah, I got Aphex Twin vibes from it: https://www.youtube.com/watch?v=ip2w2mNFTAc

Or Baby's tape recorded remix https://youtu.be/Dtb_8Y5bHww

You’re in for a treat - https://youtu.be/qN8tm5RulFU

That signal almost sounds like you could make a clock from it. Like you manually set it and it syncs to beat in the video.

That's the whole point: https://en.wikipedia.org/wiki/WWV_(radio_station)#Broadcast_...

The "clicks" are second markers, and the low-frequency hum that follows each click encodes a single bit of a binary datastream conveying the current time. If you've ever had an automatic clock in the US, it sets the time by tuning in to WWV and decoding this signal.

I think most automatic clocks are setting themselves based on WWVB, not WWV.

It broadcasts on longwave rather than shortwave and uses a different modulation.

https://www.nist.gov/pml/time-and-frequency-division/time-di...

You don't even need to manually set it, the date and time is encoded in the tones.

Is that Russian station still sending signals? I watched a YouTube thing about it. I think nobody cracked the code as to what it’s doing.

Number stations and some either weird shit is still going on.

https://priyom.org/number-stations

There are a few still transmitting, if you mean number stations.

If you mean UVB-76 then I'm pretty sure it's just them parking the frequency for when the American imperialists set the sky ablaze. (You can apparently hear the operators listening to music or watching memes every now and again so it's obviously not a hugely important broadcast)

wow that website is a treasure trove of encoding details

My only exposure to number stations is the podcast "99% Invisible", an entertaining account sprinkled with audio clips of various stations: https://99percentinvisible.org/episode/numbers-stations/

Got a link to the youtube video?

UVB-76 is the mysterious station. forgot the exact video.

Two theories I like wrt number stations.

1. Most of the time you don't have a message to send, so you send random numbers. Maybe you have an agreed upon header to signal to your spy that the following bytes are significant

2. Maybe you don't have any spies, and just want your adversary to think you have spies, so you blast your numbers station into their territory just to make them nervous. Who knows, someday maybe you'll have spies, and you wouldn't want to announce this change by suddenly having a numbers station.

Related to #2, the US puts out bogus patents, press releases, etc so that adversaries will spend resources investigating whether they're real or not. Other countries do it, too. That's how the US got Project Stargate[1] in response to word that Soviets had psychic spies.

Some number stations could be a low-cost effort to keep other nations busy.

[1] https://en.wikipedia.org/wiki/Stargate_Project

Note that the description above doesn't match the Wikipedia article: it wasn't "bogus patents", it was a full fledged research program.

It reads like it's the outcome of the Soviets doing this successfully. The US spent resources on a bunch of BS (a full-fledged research program) because the Soviets got the US to believe they were taking it seriously and had achieved results.

Right, the Soviets successfully caused the US to spend time and resources on a full fledged research program based on rumors about Soviet psychic spies.

The US regularly does this as well. Coded messages in the form of seemingly random letters and numbers are broadcast over HF and VLF in the clear all over the world. One use is for Emergency Action Messages (nuke orders). [1]

NIST also makes broadcasts for things like timekeeping. You can listen to 5k or 10k Hz and it’ll tell you what time it is. Handy for checking that your gear works.

1. https://en.m.wikipedia.org/wiki/Emergency_Action_Message

I think you meant megahertz, not kilohertz.

The human-readable broadcasts are at 2.5, 5, 10, 15, and 20 MHz.

https://www.nist.gov/pml/time-and-frequency-division/time-di...

Yes, MHz, my mistake

I’ll mention that the abilities of cheap shortwave radios have never been better. The new Countycomm GP-7 SSB https://countycomm.com/collections/radio/products/countycomm... is under $100 and fits in your hand. It supports SSB modulation, so you can listen to utility and ham radio transmissions as well as AM used by broadcasters. It's one of the neatest shortwave receivers out there. (I don't own it, but I do own the predecessor, along with several other HF receivers.)

Been meaning to get my tech license. Hope to get to it eventually in 2022!

I can’t recommend HamStudy[0] more highly for getting licensed. I put the app on my phone last spring and used it to run through questions whenever I had some downtime. I was able to get my tech within a few days, and I used HS to upgrade to Extra. It makes the process painless and easy, especially for tech where the goal really is just to get your license so you can get on the air.

You can also use the HS website to find online exam sessions, which makes the testing process even easier.

[0] https://hamstudy.org/

It couldn't be easier now. It's a 35 question test and it's given by volunteers and amazingly everyone seems to pass.

I failed first try. (Some obscure antenna question) Paid another $10, retook it immediately and passed.

I was at a conference where some volunteers offered it, and about half the people passed -- not a surprise given that many people had only studied for 15-30 minutes.

I've studied radio astronomy, so it wasn't so hard for me -- YMMV.

It's pretty easy to prep for, and pass, the technician test. The test pool is published online (with answers) for everyone to see. And the actual test is just 35 questions drawn randomly from the overall pool. So really, if you wanted to, you could just memorize the answers to enough of the question and have a chance of passing ranging anywhere from "ok" to "pretty much 100%". Now I don't recommend just memorizing answers without actually trying to understand the material, but I do recommend doing repeated practice exams in conjunction with your studies, that are based on the actual test pool, which will pretty much tell you when you're ready for the real test.

There are a number of sites that will generate a mock exam for you, drawn from the test pool, give you your score, and then let you generate another random test. Some sites keep track of your progress and let you do useful things like generating a test drawn only from questions you've previously missed. So yeah, again, if blind memorization is your thing, getting ready to pass this test is not hard at all. But I really do recommend making some effort to really understand what's going on and not just memorizing stuff blindly. But ultimately it's up to you.

> I really do recommend making some effort to really understand what's going on and not just memorizing stuff blindly.

I definitely second this. When I was “studying,” I just memorized the answers and got from Tech to Extra. I can access all the amateur bands now, but my understanding of the hobby is still minimal as a result. But I know how not to land a fine from the FCC, so there is that!

There are plenty of good resources on YT. The ARRL also has a number of excellent publications: the study guides are great for learning the materials on the tests, and the Handbook covers pretty much everything else you’d want to know in extensive detail.

I've been intrigued for a while, but I feel like I should be learning the theory and not doing a SAT-style cram course. Is there a recommended resource for that? I've got three weeks of vacation time coming up and very little else better to do.

That's a good question. A portion of the exam is just FCC rules & regs and operating procedures. That stuff is, IMO, fine to "just memorize" because there isn't much theory to begin with. The main part where there is some theory (at the Technician level) is some basic knowledge of electronics and just a hint of some stuff that would probably be covered in a Physics 101 course (electromagnetic radiation, frequency spectrum, etc.). I don't know of one consolidated course that covers that from a ham radio perspective specifically.

In my case, I'd been dabbling with hobby electronics for nigh on 40 years when I took my test, and was always a little bit of a physics geek, so I mostly just had to learn the FCC rules and procedures bit. The downside is, since my knowledge was cobbled together from many sources over many decades, that I can't give you a good reference to a nice, consolidated, comprehensive course on this stuff.

That said, here are a couple of books that might be useful for picking up some of the theory, without going overly deep. Also note that "going deep" isn't a Bad Thing, especially if you want to progress beyond the Technician level license, as the subsequent exams do require deeper knowledge on some of the electronics/physics theory stuff. You don't have to be an EE or a physicist to do any of this of course, but just be aware that the theory component does increase a bit as you progress.

https://www.amazon.com/Understanding-Basic-Electronics-Softc...

https://www.amazon.com/Radio-Theory-Handbook-Beginner-Advanc...

https://www.amazon.com/How-Radio-Signals-Work-Sinclair/dp/00...

https://www.amazon.com/Basic-Communications-Electronics-Jack...

The Ham Radio Village folks from DEFCON[0] and other conferences provide online testing once a month. Keep an eye on their twitter account if you want to do something online, but, if you look on ARRL's website, it's possible that you can find close to you.

It's usually under $20 to take the test, but, there are many times where you can test for free if you're willing to wait a few weeks.

[0]: I have volunteered as an examiner for Ham Radio Village for a few years now.

If you want to listen, go to http://kiwisdr.com/public/, find an SDR operating in North America, and tune it to 2500, 5000, 10000, 15000 or 20000.

Some have better reception than others. I've had the best luck with 10000 (10Mhz)

You can also listen via telephone.

Dial (303) 499-7111 for WWV Dial (808) 335-4363 for WWVH

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