Re: Future version 1.27 of the "World Map" #future


jdow
 

On 20220511 23:56:07, Alan G4ZFQ wrote:
On 12/05/2022 05:15, Radioman ZeroZero wrote:
not sure what amateur radio part of the hobby requires a super accurate time.

Steve,

Super accurate, not many. http://www.dxatlas.com/faros/ is one that measures propagation delay, it actually contains it's own NTP clock.
The Kiwi radio network uses GPS PPS to use TOA station location.

Meinberg as mentioned is one that sets PC time and maintains it  to within miliseconds.

73 Alan G4ZFQ

I've run across a reference of an ntp server that maintains time by fiddling with the counter settings. If you have a 3.57954545454 MHz timer oscillator (5e6/88*63) then it fiddles the time keeping divider up and down from 3579 to account for the fractional part and apply further correction so that long term timing is in the microsecond range if you can supply it with an accurate time tick. The pro radio astronomers use an even fancier setup to make precision time using motherboards that reference time to 100 MHz or higher oscillators in the PCs. (I wonder how many replace the timer oscillator with a TCVCXO and lock the loop. I bet the VLB array uses this sort of technique.)

PCs have a lot more potential than most people realize, especially for a hardware hacker.

{^_^}

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