[time-nuts] Reference oscillator accuracy

[Kasper Pedersen]

On 11/13/2009 07:15 PM, Don Latham wrote:
> The ground wave path of WWVB varies due to a very small changes in the
> index of refraction (temperature and absolute humidity) over the path. It
> is not much, but is measurable.
> Don
>

My own nuttiness started with that, and the innocent question "How much? 
What does it take to measure it? What do I need to build?"

http://n1.taur.dk/dcf/  (raw data and plots, time is UTC+1)

I am no more than 6-700 km north of DCF77, and get ~5us p-p. Now that is 
quite large, when I started out that number seemed a lot smaller.

/Kasper Pedersen