Why does the "Conrad parallel port radio clock"driver has a standard offset of 0.1725s? - NTP

This is a discussion on Why does the "Conrad parallel port radio clock"driver has a standard offset of 0.1725s? - NTP ; Hi, While going through the documentation we found that the "Conrad parallel port radio clock" driver has a default offset calibration factor of 0.1725s. Why is that specific factor chosen? This is especially interesting as my GPS has an offset ...

+ Reply to Thread
Results 1 to 2 of 2

Thread: Why does the "Conrad parallel port radio clock"driver has a standard offset of 0.1725s?

  1. Why does the "Conrad parallel port radio clock"driver has a standard offset of 0.1725s?

    Hi,

    While going through the documentation we found that the "Conrad parallel
    port radio clock" driver has a default offset calibration factor of
    0.1725s.
    Why is that specific factor chosen?

    This is especially interesting as my GPS has an offset of -0.173s! Is
    that a coincidence?


    Folkert van Heusden

    --
    Looking for a cheap but fast webhoster with an excellent helpdesk?
    http://keetweej.vanheusden.com/redir.php?id=1001
    ----------------------------------------------------------------------
    Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com

  2. Re: Why does the "Conrad parallel port radio clock" driver has a standard offset of 0.1725s?

    Hi,

    Folkert van Heusden wrote:
    > While going through the documentation we found that the "Conrad parallel
    > port radio clock" driver has a default offset calibration factor of
    > 0.1725s.
    > Why is that specific factor chosen?


    I bet this has been determined by a measurement. The DCF77 amplitude is
    lowered at the beginning of a new second. Most cheap receivers detect the
    second change when the amplitude has dropped below a certain limit. The
    delay of this depends strongly on the bandwith of the transmitting and
    reeiving antenna and circuit.

    > This is especially interesting as my GPS has an offset of -0.173s! Is
    > that a coincidence?


    I'm sure it does. You might try to "fudge time1" for that particular device,
    if the driver supports that.


    Martin
    --
    Martin Burnicki

    Meinberg Funkuhren
    Bad Pyrmont
    Germany

+ Reply to Thread