DCF77 signal change
I happened to notice this morning that my old "Conrad" DCF77 wall
clock had not changed to summertime and indicated "no lock" even
though the pulses looked good to my eye.
After about I minute I noticed that the first 14 pulses were no longer
uniform '0' bits, and a bit of googleing turned up the interesting news
that there is now weather information embedded in the first 14 bits.
http://www.meteotime.com/web/de/System/Default.aspx
0 1 2 3 4 5
012345678901234567890123456789012345678901234567890123456789
-#--#---#--####--#--#--#--#--#--##-#---#-###-##---###-----#
--#----#--####---#--##-#--#-##--##-#---#-###-##---###-----#
-##--#-#-##-#----#--#-##--#-##--##-#---#-###-##---###-----#
--###-##-##-#----#--####--#--#--##-#---#-###-##---###-----#
---#-----#-#-#---#--#---#-#--#--##-#---#-###-##---###-----#
-#------#--#-##--#--##--#-#-##--##-#---#-###-##---###-----#
-#-----#--##-#---#--#----##--#--##-#---#-###-##---###-----#
--#--#----#####--#--##---##-##--##-#---#-###-##---###-----#
^^^^^^^^^^^^^^
Obviously, my clock is so old that it was writte for the older "if
you see any of these bits, the transmitter has problems" signal spec.
Anyone know the encoding of the weather info ? I wonder if they
use the minute bits to designate regions to save bits ?
Poul-Henning
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Hi Poul-Henning,
Anyone know the encoding of the weather info ? I wonder if they
use the minute bits to designate regions to save bits ?
http://www.ptb.de/en/org/4/44/442/dcf77_kode_e.htm :
"In addition weather data are transmitted, which are supplied by the
Swiss firm Meteo Time GmbH. The same data are transmitted also by the
Swiss standard frequency and time signal service HBG (75 kHz)."
HBG claims to be quite DCF77 compatible with their modulation, so hope
is that it's actually the same encoding. I did not find any info about
how they encode the information, though :-(
Chris
Hi Everyone,
Poul-Henning wrote:
Anyone know the encoding of the weather info ? I wonder if they
use the minute bits to designate regions to save bits ?
This PDF is written in german, it contains the following Paragraph:
(http://www.hkw-elektronik.de/pdf/DB%20W-Protokoll-V%201.pdf)
"""Die übertragenen Daten können nur mit der über den Lizenzvertrag
beschaffbaren Dechiffriervarianten geprüft und für die Auswertung bzw.
Anzeige nutzbar gemacht werden"""
--> The transmitted data can only be used using the deciphering-methods
availabe via license...
Their homepage also states further that to decipher the data one has to
be a licensee of Meteotime.
With greetings from Germany,
Chris
Pou,
the German electronics magazine ELV does already sell small "weather
stations" that beneath measuring local parameters are said to "receive
weather information from satellite". I have been asking myself which
satellite could be used for such a purpose but your notice makes of
course everything understandable!
Best regards
Ulrich Bangert
-----Ursprüngliche Nachricht-----
Von: time-nuts-bounces@febo.com
[mailto:time-nuts-bounces@febo.com] Im Auftrag von Poul-Henning Kamp
Gesendet: Mittwoch, 28. März 2007 19:36
An: time-nuts@febo.com
Betreff: [time-nuts] DCF77 signal change
I happened to notice this morning that my old "Conrad" DCF77
wall clock had not changed to summertime and indicated "no
lock" even though the pulses looked good to my eye.
After about I minute I noticed that the first 14 pulses were
no longer uniform '0' bits, and a bit of googleing turned up
the interesting news that there is now weather information
embedded in the first 14 bits.
http://www.meteotime.com/web/de/System/Default.aspx
0 1 2 3 4 5
012345678901234567890123456789012345678901234567890123456789
-#--#---#--####--#--#--#--#--#--##-#---#-###-##---###-----#
--#----#--####---#--##-#--#-##--##-#---#-###-##---###-----#
-##--#-#-##-#----#--#-##--#-##--##-#---#-###-##---###-----#
--###-##-##-#----#--####--#--#--##-#---#-###-##---###-----#
---#-----#-#-#---#--#---#-#--#--##-#---#-###-##---###-----#
-#------#--#-##--#--##--#-#-##--##-#---#-###-##---###-----#
-#-----#--##-#---#--#----##--#--##-#---#-###-##---###-----#
--#--#----#####--#--##---##-##--##-#---#-###-##---###-----#
^^^^^^^^^^^^^^
Obviously, my clock is so old that it was writte for the older "if you
see any of these bits, the transmitter has problems" signal spec.
Anyone know the encoding of the weather info ? I wonder if they use the
minute bits to designate regions to save bits ?
Poul-Henning
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by
incompetence.
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