[time-nuts] Thunderbolt GPSDO

[Didier Juges]

Well, some of us who have been on this list much longer than me can tell 
you that when you only have one clock, it's pretty hard to tell if it's 
working right, or how accurate it is. If you have two clocks, they 
probably won't agree perfectly, and you have no way to tell which is 
right, if any, so you are not much better off.

So, if you have three clocks (more being better of course), you can 
compare them 2 by 2 and draw some conclusions, with any luck, about 
which one is the best, and how bad are the others. This will still not 
tell you how good the best one is, but you are getting closer.

You compare clocks using a statistical tool called Allan Deviation. I 
have documented what I know about it (which is not much, but it's a lot 
more than I knew six months ago...) there:

http://www.ko4bb.com/Timing/index.html

These pages have a number of links to pages written by people who 
actually know what they are talking about...

Good reading and good luck.

Didier KO4BB



Steve wrote:
>    Two other what? Thunderbolts? I'm new at this . . . would you be so
>    kind as to elaborate?
>    Thanks.
>    Steve K8JQ
>