[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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