> It looks like you still have some missing pulses, probably due to local
> interference.   This is a problem here as well, as you saw from my logfile
> posting. 

This thread is pretty old, so just for the record:

Note that there's a relatively easy way to judge the quality of DCF77 
reception: using your ears :-) The regular pulses are extremely easy to 
distinguish from any kind of "noise", which presents itself as random 
"warbling". If all you can hear is the "alien scanner tapping", you've found a 
nice spot for your antenna.

To get your alien scanner going, just plug or "wiretap" the output pulse train 
of your DCF77 receiver into a speaker. The output itself is too "soft" to drive 
a passive speaker or earphones, but if you use a powered computer speaker 
(anything you find lying around), that will have a high-Z line input and will 
work. Or, you can plug the DCF77 pulse train into the line input of a computer 
sound card. Note: line in, not microphone in - the signal is too strong for a 
mic in. I've used this not only for immediate playback, but also for recording. 
This way I was able to discover ionospheric interferential outages in my 
reception. Obviously you don't want to sit there listening to hours of DCF77 
tapping, but you can use software such as the Spectrum Lab to create an FFT 
waterfall, which will fit the spectrum of the "audio" for the period of a day 
onto a single screen of the waterfall diagram.

Example spectrum waterfall:
http://support.fccps.cz/download/Meinberg/prehled/2012_06_29__around_23-00_UTC_spectrum.png

Using some additional circuitry, I was also able to measure the RSSI signal 
from a Meinberg analog receiver:
http://support.fccps.cz/download/Meinberg/prehled/RSSI_UL.png

DCF77 is analog HAM fun, especially if you live further away from Frankfurt (a 
couple hundred km). YMMV.

Frank

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