[time-nuts] Alternative to GPS?
jimlux at earthlink.net
Wed Oct 6 14:21:32 UTC 2010
Henry Hallam wrote:
> On Tue, Oct 5, 2010 at 9:04 PM, Neville Michie <namichie at gmail.com> wrote:
>> How far could you get passing time around from amateur station to station
>> with a two way handshake system that establishes the instantaneous delay
>> on the two way path and assumes a delay of half that value? A time relay.
>> The stations would need their own short term clocks so they could keep
>> their own time between contacts, and somewhere you would need heros
>> with primary standards to synch the whole system.
>> You would not be able to find a good position, because you would not know
>> propagation mode.
> A lot of work has been put into NTP which does a fine job of this and
> considers a lot of subtleties. In practice it has precision limits.
yes, but the filter in NTP is somewhat optimized for a kind of
propagation paths (e.g. internet) which have properties that aren't very
much like HF.
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