[ntp:questions] Re: What is a good, cheap, Linux-supported hardware clock for a NTP-server? Any recommendations?

Helmut Wollmersdorfer helmut at wollmersdorfer.at
Fri Oct 22 14:50:48 UTC 2004

Evert Meulie wrote:

> My (public) NTP server current 'leeches' its time from other servers 
> higher up the tree. I'd like to get my own hardware unit now.

How accurate do you need the time?

> The 2 (affordable) options are DCF77 & GPS, right? Who can recommend 
> something?

Depends on your distance to DCF/Frankfurt, and if you can receive a good 
signal from DCF77. Her in Vienna, 600km apart from Frankfurt, in my 
office the quality is good (no signal loss). 10 minutes walking away in 
another building there is absolutely no signal. If one of the cheap 
radioclocks (wall mounted or tabletop) synchronize within some minutes, 
you should aspect a good signal for a DCF77 receiver.

Oslo is 1100 km apart from Frankfurt. Thus maybe you a good antenna.

If you are not afraid to solder a little bit, then 
http://www.buzzard.org.uk/jonathan/radioclock.html is a good solution. I 
tried other circuits, but jonathans is the simplest and stablest.
Accuracy will be below 20 milliseconds.

With GPS you will not have the antenna problem. But you need free sight 
to the sky.

> It doesn't really matter to me whether it's a serial or USB unit...

Serial is better.

Helmut Wollmersdorfer

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