[ntp:questions] Re: Using a Radio for setting a PC clock.

David L. Mills mills at udel.edu
Sat Jun 4 23:57:30 UTC 2005


Not to speak to your other comments, but the WWV/H driver has been 
carefully maintained by me and worked just fine the last time I looked. 
In the northeast here, Canadian radio CHU is somewhat more reliable and 
there is a driver for that, too. While I still have a WWVB receiver 
working at home, I've given up on campus. Too much radio-frequency 
interference from uninterruptable power systems in the near vicinity. 
Apparently, at least some of them operate at 60 kHz and overwhelm the 
WWVB signal.


Richard B. Gilbert wrote:
> arupkgeorge at coolgoose.com wrote:
>> Is there any way in which an ordinary radio can be used for
>> synchronising the clock of a PC? I have read in a Japaneese site that
>> by connecting the audio out of a radio to the mic in of a sound card,
>> some sort of timing information can be extracted and it can be used for
>> setting a PC's Clock. If some one knows about this please clarify.
>> Please provide some links, if there is any?
>> Thanks
> There are a couple of ways to do this!   The so called "Atomic'" 
> wristwatches and clocks use a 60KHz signal broadcast by WWVB in  Fort 
> Collins, Colorado.   The modulation can be decoded by some very simple 
> circuitry  that plugs into a serial port and a small program (radioclkd) 
> by Jonathan Buzzard.
> ntpd includes a driver for decoding the HF signal broadcast by WWV (also 
> in Fort Collins).  This requires a short-wave receiver capable of 
> receiving one or more of the frequencies: 2.5MHz, 5MHZ, 10MHz, 15MHz or 
> 20MHz.  You plug the receiver audio output into the audio input on your 
> computer.  I recall reading a message from Professor Mills that this 
> driver was no longer maintainable; using wording from which I infer that 
> it has been hacked too often by too many people to the point where it is 
> impossible to fix a bug without introducing at least one more bug!
> It might work for your particular combination of hardware, O/S, and 
> software or, it might not.  If it doesn't, don't expect a fix any time 
> soon unless you do it yourself.
> Frankly, I don't think it's worth the effort unless you have no other 
> means of getting the time.  HF radio propagation is such that there are 
> places in the US where reception is poor to non-existent for many hours 
> of the day.  VLF radio propagation isn't so great either;  the "atomic" 
> clocks and wrist watches that use it typically synch up once per day, 
> late at night, and free run the rest of the time.  If you are close 
> enough to Fort Collins, this may not be a problem for you.   If you live 
> in New Jersey I can practically guarantee that you will have problems.

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