MSF Clock Decoder for Linux

A simple public domain utility which enables a machine running a Linux operating system to decode and act on radio time signals received from MSF Rugby by a 'Galleon' Atomic Radio Controlled Computer Clock (ARC) receiver.

It should be noted that any software offered is simple in nature, in alpha test, and is offered without any warranty, and at the users own risk. Neither is the utility the last word in femto-second precision, but it should at least keep your machine accurate to within second or so of MSF.

Galleon Receiver

Pic of receiver

Pic filched from Maplin catalog

This is the cheapest in the range (or the "entry level model"), which Maplin flog for Seventy quid, and there are also some other models made by Galleon to choose from if you have deeper pockets than I.

This particular beast has no display of its own, and feeds data to your com port via a fitted lead and 9 pin 'D' type connector. It requires 2x AAA cells to operate (batteries not included).

Features of the Linux utility

Ability to stay locked to GMT through the summer months
Hours 'offset' facility for our european friends
Low battery warning
Signal strength utility

Known shortcomings of the utility

Exact marking of the beginning of the second is not implemented, neither is very precise updating of the computer clock although the result on the development machine seems to be close enough for all but the fussiest of applications. I'm searching for a cure.

The package consists of source code, a little documentation, and a compiled binary that the faint of heart may find useful.

Download msfclock-0.15.tgz (February 2004)
This is the version to use with most modern linux distributions. Robert Savage had problems compiling version 0.13 and was getting error messages, and this has some very small tweaks in the code to cope with newer libraries.

Download msfclock-0.14.tgz (November 2000)
A user (R. Mankin) found that there could be a problem with buffer over-run and string terminators in certain circumstances. Because my own clock hardware is employed on vital duties elsewhere, I have not been able to test the small rectifications to the code used to make this version just yet.

Download msfclock-0.13.tar.gz(July 99)
Please only make use of this old version if you find that version 0.15 or 0.14 is messing up the time on your system - and tell me.

Please let me know how you get on !

msfclock is based on substantial code written by Lyndon David

Links

Serious UNIX and NTP merchants might like to check out Damon's page at www2.exnet.com

MSF's "home page" at the UK's National Physical Laboratory web site includes outage information as well as documents describing the MSF data stream.

Visit this planet's 'Time Lords' down at the U.S. Naval Observatory Time Service Department