[time-nuts] Test WWV timecube against Cesium, Rubidium, MASER or other precision time (UT-1) metrology
Martin Burnicki
martin.burnicki at burnicki.net
Fri Dec 8 03:31:27 EST 2017
Hal Murray wrote:
>
> kb8tq at n1k.org said:
>> To get the accuracy into the 1 ms range on WWV, you would need a pretty good
>> idea of the path length between you and WWV.
>
> Dave Mills has a program to compute delays.
>
> * By default it prints out a summer (F2 average virtual height 350 km) and
> * winter (F2 average virtual height 250 km) number. The results will be
> * quite approximate but are about as good as you can do with HF time anyway.
> * You might pick a number between the values to use, or use the summer
> * value in the summer and switch to the winter value when the static
> * above 10 MHz starts to drop off in the fall. You can also use the
> * -h switch if you want to specify your own virtual height.
>
> What's the height difference between night and day?
>
> This was google's first response.
> https://opensource.apple.com/source/ntp/ntp-136/clockstuff/propdelay.c
Hm, this file is part of the standard NTP source code package available
here:
http://support.ntp.org/bin/view/Main/SoftwareDownloads
Martin
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