With regards to using WWV as a frequency source you need to watch out for the doppler shift of sky wave signals which can be a few hz or so.
This doccument has some more info re this. http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA284610&Location=U2&doc=GetTRDoc.pdf ----- Original Message ---- From: Bill Hawkins <[email protected]> To: Discussion of precise time and frequency measurement <[email protected]> Sent: Sun, November 22, 2009 5:32:56 PM Subject: Re: [time-nuts] Alternate frequency sources - second opinions IIRC, NTP turns a computer clock into a DO with millisecond accuracy. Accuracy is stratified, with a number of Stratum 1 sources available. Don't know if anyone has designed a collection of differentiated silicon and stored programs that hooks to the internet and delivers a disciplined 10 MHz at 50 ohms. Probably not, since even crystal oscillators do better than NTP. Beat one against WWV and you were good to 10-7 or so. Mills was working on microsecond accuracy five years ago. Where does NTP stand now? Bill Hawkins _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __________________________________________________________________ Yahoo! Canada Toolbar: Search from anywhere on the web, and bookmark your favourite sites. Download it now http://ca.toolbar.yahoo.com. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
