[ntp:questions] Arcron DCF77 ref clock driver: problem with timezone and UTC

Eric Voisard evoisard at MAPS.ON.ieee.org
Mon Mar 21 11:28:45 UTC 2005

Hi all,

I have managed to make a small HKW DC77 receiver (same as Arcron) working on
a Solaris 9 box here.

I installed release 4.2.0 of ntpd and chose the Arcron MSF reference clock
driver (type 27) which I set to mode 2 (DCF77).


Well, it works, serial connection with the device is established and ntpd
apparently gets the time which I can see on the small LCD display of the
receiver, however after a while ntpd complains about too large an offset and

What I can see is that this offset is around 3600 seconds, what corresponds
to GMT+1, the local shift in my country...

However, the computer is set to work in GMT time. The /etc/TIMEZONE file is
set accordingly and the "date" and "date -u" commands give same time, so
it's ok.

The receiver's LCD display indeed shows the local time (GMT+1), but its
specs say that a driver can query the time in UTC. On its side, the type 27
refclock driver says that by default it queries the time in UTC (as it
should do anyway since ntpd only works with UTC times). And in addition it
provides the fudge parameter "flag1" to toggle between UTC and local time.

I tried to play with this "flag1" parameter, but it makes no difference:
ntpd keeps complaining about this 1 hour offset. The type 27 driver seems
mistaking the local time for the UTC one...

Is this a bug in the type 27 Arcron driver, or am I forgetting something

# my Arcron setting in ntp.conf
server mode 2
fudge stratum 0
fudge flag1 0

Any help is welcome, thanks in advance

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