Date: Sat, 04 May 1996 14:44:12 +0000 From: Poul-Henning Kamp <phk@critter.tfs.com> To: hackers@freebsd.org Cc: thorinn@diku.dk Subject: DCF77 + xntpd + freebsd = WOW! Message-ID: <5649.831221052@critter.tfs.com>
next in thread | raw e-mail | index | archive | help
(thorinn: please forward to any interested parties in the NTP club) DCF77 is a 77.5 Khz radio-xmitter close to Frankfurt in Germany, which is probably a little over a thousand kilometers from where I live. I have a receiver for this station hooked up via a serial port to my P5/133 box running FreeBSD-current, I use the "siointrts" interrupt entry for this port to provide the precise timestamp xntpd needs. I have saved the peerstats and loopstats files since some time last november, and now I finally got around to run some stats on them. Here is the result: Clock-offset less than +/- 5ms: 97.8623 % Clock-offset less than +/- 2ms: 94.5631 % Clock-offset less than +/- 1ms: 80.0504 % Clock-offset less than +/- 500us: 65.6242 % The histogram of these offsets is a near-perfect bell-curve... Here then is the punchline: That receiver cost me something like 40 DMK via mail-order from "Konrad Electronic". Who said precise time-keeping had to be expensive ? :-) Poul-Henning Kamp
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?5649.831221052>