[ntp:questions] Only Garbage from Raw DCF

Rob nomail at example.com
Fri Jan 30 21:01:43 UTC 2015


Andreas Mattheiss <please.post at publicly.invalid> wrote:
> Hello,
>
> Am Fri, 30 Jan 2015 19:24:05 +0000 schrieb Rob:
>
>> 
>> No, it is the wrong way around.  Your signal should be < -3 most of the
>> time, and pulse to > +3 during the 100/200ms pulses.
>
> aaah - thanks for this. I'll see if i have a transistor lying around
> somewhere that  i can press into service as an inverter. I'll report.
>
> Regards
> Andreas

Note than an RS232 port usually works fine with just the 0 and +3..5v levels
so you can directly connect the output to the RS232 line without MAX232.

Those drivers are a good idea when you have a long wire, but are not really
required when it is short.

Also note that the DCF77 signal is very sensitive to noise from power
supplies, CRT monitors, and sometimes TL lamps.  Keep the receiver in
a clean location.   It is quite usual to have errors in the logfile:

30 Jan 21:37:00 ntpd[3410]: parse: convert_rawdcf: INCOMPLETE DATA - time code only has 13 bits
30 Jan 21:37:53 ntpd[3410]: parse: convert_rawdcf: parity check FAILED for "---#-##--#---#-R----s-2--1--p-2-81-P1-----------811-48----P_?"
30 Jan 21:38:14 ntpd[3410]: parse: convert_rawdcf: INCOMPLETE DATA - time code only has 13 bits
30 Jan 21:39:00 ntpd[3410]: parse: convert_rawdcf: INCOMPLETE DATA - time code only has 45 bits
30 Jan 21:46:15 ntpd[3410]: parse: convert_rawdcf: INCOMPLETE DATA - time code only has 28 bits
30 Jan 21:46:28 ntpd[3410]: parse: convert_rawdcf: INCOMPLETE DATA - time code only has 13 bits
30 Jan 22:00:34 ntpd[3410]: parse: convert_rawdcf: INCOMPLETE DATA - time code only has 34 bits



More information about the questions mailing list