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Time Station Emulator

github.com

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Re: Time Station Emulator

#21

Post by fragmede »

mikestew wrote: post #4

“One of the higher-frequency harmonics inevitably created by any real-world DAC during playback will then be the original fundamental, which should leak to the environment as a short-range radio transmission via the ad-hoc antenna formed by the physical wires and circuit traces in the audio output path.” Sometimes I think I’m a smart guy…and then I read of people doing shit like this.

Van Eck Phreaking dates back to 1982, which used CRTs, and if you're aware of that, it's not an insurmountably huge logical leap to realize that modern hardware can be exploited the same way (thanks to greater sensitivity in receiving devices).

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

Re: Time Station Emulator

#22

Post by wildzzz »

sublinear wrote: post #17

I can't tell if I'm fooling myself or if this actually (partially) worked. Is it possible for only the hour and seconds to sync if the signal isn't perfectly received? How long is it supposed to take to sync the time? Is it possible that this can confuse clocks that get a strong enough real signal while the phone is running this nearby? I just tried it on a clock that has only ever successfully synced once many years…

It takes a whole minute for the entire data frame to be transmitted. While 1 bps is great for propagation, WWVB (and it's kin) is a really weak signal to pickup using the tiny antennas these kinds of clocks have. There's a relationship between received power, modulation type, data rate, error correction, and error rate so changing one will change others. Thus it can sometimes take at least several minutes for all of the timing data to be gathered as there is no error correction included in the data frame. Also the HF spectrum is incredibly noisy as switch-mode power supplies (pretty much in everything these days) produce a ton of interference so taking a battery powered clock outside can help greatly.

WWVB clocks are great but aren't so good these days. NTP is pretty much as good as anyone will ever need in their home but this has the downside of usually requiring internet access. GPS clocks have been the standard for 30+ years for anyone needing precision timing.

Re: Time Station Emulator

#23

Post by pimlottc »

This certainly looks impressive but it’s a bit misleading to say it works on “almost any phone” when it doesn’t work on iPhone (which only allows mobile Safari)

Re: Time Station Emulator

#24

Post by McGlockenshire »

labcomputer wrote: post #12
McGlockenshire wrote: post #8

This is pretty darn cool, but I have to say I was somewhat let down by the WWVB signal. I was expecting the entire audible range instead of simply the extracted data. That being said, that's also really darn cool. I find the WWV/WWVB droning soothing somehow.

Err… WWVB has no audio range. The carrier frequency is only 60 kHz. It’s effectively a CW signal since the amplitude is only modulated once per second.

> WWVB has no audio range

I got my WWVB and WWVH confused!

There's a reasonable emulator here: https://wwv.mcodes.org/

Unfortunately it doesn't let you play both at the same time, which is what you need for the full experience.

Re: Time Station Emulator

#25

Post by bityard »

brilliang wrote: post #14

Whenever I see things like this, my first thought is that somebody is going to write something to mess up nearby atomic clocks, just because they can, then I think- why, why did you do this? Then someone will respond: you’re just catatrophising- anyone could’ve done this years before now, and I’ll say no, because it wasn’t up on frontpage HN there with code so that anyone would think of it. Then they’ll say, well why…

Are you sure the beer didn't come first?

Re: Time Station Emulator

#26

Post by NegativeK »

cvoss wrote: post #5

I once programmed my TI-84 calculator to do exactly this! The only missing thing was a circuit to convert the audio jack output voltage into the needed form for an antenna. I had the CS know-how but no EE know-how, so I never got it to work. It was fun to dream about confusing my high school's clocks though. (Sadly, the other obstacle was that the clocks only listened for the signal overnight, which improved their ch…

I didn't know that about the overnight; that's neat. I'm often in my garage before work, and I always assumed the 5am reset time was just because only weirdos are noticing a clock whir its arms around then.

Re: Time Station Emulator

#27

Post by xattt »

jofzar wrote: post #18
mikestew wrote: post #4

“One of the higher-frequency harmonics inevitably created by any real-world DAC during playback will then be the original fundamental, which should leak to the environment as a short-range radio transmission via the ad-hoc antenna formed by the physical wires and circuit traces in the audio output path.” Sometimes I think I’m a smart guy…and then I read of people doing shit like this.

Came here to say this, I literally can't believe this works. It's like a couple of years ago where someone showed a proof of concept of turning a HDD into a microphone

… and I thought the Scanjet 5p “Ode to Joy” easter egg was incredible.

Re: Time Station Emulator

#28

Post by xattt »

NegativeK wrote: post #26
cvoss wrote: post #5

I once programmed my TI-84 calculator to do exactly this! The only missing thing was a circuit to convert the audio jack output voltage into the needed form for an antenna. I had the CS know-how but no EE know-how, so I never got it to work. It was fun to dream about confusing my high school's clocks though. (Sadly, the other obstacle was that the clocks only listened for the signal overnight, which improved their ch…

I didn't know that about the overnight; that's neat. I'm often in my garage before work, and I always assumed the 5am reset time was just because only weirdos are noticing a clock whir its arms around then.

I live just beyond the fringe zone for reception of WWVB on my Casio Waveceptor. Depending on solar conditions, and how I leave the watch overnight (south-east facing window with space to a metal window frame for a coupling effect), I can get it to sync once in a while.

Re: Time Station Emulator

#29

Post by com2kid »

I remember years ago I bought a clock that advertised it set itself using the atomic clock broadcast.

Which it did. The very first time it was plugged in, and then never again after. The clock also kept horrible time, it lost a couple minutes every month. Truly an astonishing piece of wtf engineering.

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