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Do radio controlled watches work in Hong Kong?

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  1. #1

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    Do radio controlled watches work in Hong Kong?

    Do radio controlled wrist watches work in Hong Kong?

    There is a transmitter in Shangqiu, Henan, 1355Km away according to google. The signal has a reach of 1500Km. So it's near end of reach.

    Anybody here knows?


  2. #2

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    Mine has no trouble

    flameproof likes this.

  3. #3

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    Thanks. Good to know, saw that Seiko Rolex Explorer lookalike but wasn't sure it works here.


  4. #4

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    Quote Originally Posted by flameproof:
    Do radio controlled wrist watches work in Hong Kong?

    There is a transmitter in Shangqiu, Henan, 1355Km away according to google. The signal has a reach of 1500Km. So it's near end of reach.

    Anybody here knows?
    Wouldn't Taiwan be closer?

  5. #5

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    Quote Originally Posted by qhank:
    Wouldn't Taiwan be closer?
    Whatever works will be fine. Does it need to be setup for a specific transmitter? I thought it does that automatically?

  6. #6

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    Quote Originally Posted by qhank:
    Wouldn't Taiwan be closer?
    Taiwan IS closer. However Seiko tunes only to a few transmitters, and (at least for the ones I got) Taiwan isn't included.

    I got two, one has the 7B52 caliber - which is Japan only. So outside Japan it works like a normal quartz watch.

    The other has a 7B72 caliber and can tune to a few transmitters, including the one the Henan. So far I don't know if it really does.

    Thinking about it, GPS watches get the time signal from satellites and should be similar accurate - and work everywhere. They might be a better option for ultra-high-accuracy watches.

    The China transmitter, BPC, transmits at 68.5KHz, worst case might be possible to build something with a RasPi.

  7. #7

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    Don't mobile networks and ntp servers also provide accurate time data?


  8. #8

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    Quote Originally Posted by shri:
    Don't mobile networks and ntp servers also provide accurate time data?
    Yes. There are aps that can mimic various protocols with your phone time. And phone times comes typically from a very accurate source. So that's totally fine. But you need to gat the accurate time to your watch.

    Latest: The 7B72 caliber (many Seiko SBTM model I presume) gets the China signal (BPC 68.5KHz) fine. I left it last night near a window and this morning it signaled "success".

    For the older 7B52 caliber watch I got an android signal emulator. You simply set the watch to manual receive and put it next to the phone speaker (watch antenna is at 09:00). After a few Minutes it synced fine. Room should be quit and no EMF noise (router etc) too close. Watch must be set to Japan time zone too to set the local time correctly.

    There are a few apps, this one is free:

    https://play.google.com/store/apps/d...yo.jjyemulator

  9. #9

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    Quote Originally Posted by shri:
    Don't mobile networks and ntp servers also provide accurate time data?
    I looked into radio-synchronised clocks for home use for a while, very expensive.

    Then realised that a cheap Android tablet hooked up to wifi to run clock app did exactly the same thing, plus other stuff like weather forecast and air quality displays.