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authorMarc Balmer <mbalmer@cvs.openbsd.org>2006-12-09 13:27:06 +0000
committerMarc Balmer <mbalmer@cvs.openbsd.org>2006-12-09 13:27:06 +0000
commit985a324e670fd65c10df3b29fd6b5269e749e929 (patch)
tree5b61dbb594ca8e1d97cdf8fe05d205736206f021 /share
parent4d961f85033dfdba3b00c1c73103b7b5e7feff6b (diff)
Be consistent with writing frequencies, it's n kHz, not nKHz. The DCF77
transmitter uses 77.5 kHz.
Diffstat (limited to 'share')
-rw-r--r--share/man/man4/udcf.412
1 files changed, 6 insertions, 6 deletions
diff --git a/share/man/man4/udcf.4 b/share/man/man4/udcf.4
index 9529d3467da..78fa6f8af92 100644
--- a/share/man/man4/udcf.4
+++ b/share/man/man4/udcf.4
@@ -1,4 +1,4 @@
-.\" $OpenBSD: udcf.4,v 1.16 2006/12/09 13:13:55 jmc Exp $
+.\" $OpenBSD: udcf.4,v 1.17 2006/12/09 13:27:05 mbalmer Exp $
.\"
.\" Copyright (c) 2006 Marc Balmer <mbalmer@openbsd.org>
.\"
@@ -89,13 +89,13 @@ The
driver was written by
.An Marc Balmer Aq mbalmer@openbsd.org .
.Sh CAVEATS
-DCF uses a 77KHz long wave radio signal transmitted from near Frankfurt,
+DCF uses a 77.5 kHz long wave radio signal transmitted from near Frankfurt,
Germany.
-Up to about 900km, the radio signal can travel directly to the receiver,
+Up to about 900 km, the radio signal can travel directly to the receiver,
providing a linearly increasing time offset based on distance.
Due to the curvature of the Earth, beyond this distance the signal must
-bounce off the lower ionosphere (residing at approximately 70km elevation
-during the day, and 90km at night), thus causing a non-linearly increasing
+bounce off the lower ionosphere (residing at approximately 70 km elevation
+during the day, and 90 km at night), thus causing a non-linearly increasing
time offset which can only be roughly calculated using trigonometry.
Since the distance and transmission geometry is not known,
the clock receivers and
@@ -103,6 +103,6 @@ the clock receivers and
driver currently make no effort to calculate this offset.
We simply assume that the offset is small.
.Pp
-In Germany, the train system uses DCF clocks.
+In Germany, the train system uses DCF77 clocks.
As the distance from Frankfurt increases,
trains can be expected to run later.