On 06/27/2012 04:04 PM, Tony Finch wrote: > Are there any basic steps I should take to improve the reception quality > of a radio clock? I have a cheap and cheerful DCF77 receiver for > connecting to some GPIO pins, but its PPS output is basically noise with > maybe a one-second period. Perhaps it's just cheap and nasty. >
Be careful what you connect the ground of the receiver to. When I did my DCF77 receiver, my first source of interference was the common noise on the output of the supply I was powering it off of. I went to a linear power supply, and things were good for a few years. Then they installed remote-reading power meters in the neighbourhood, and DCF77 was completely jammed. The meters talk back on 75kHz with ~6kHz bandwidth. Halfway by accident I found out that if I earth the receiver well enough, thereby shunting off some of the 75kHz common mode signal, I get mostly reliable reception all day. I would suggest, at least for development, a battery and an optocoupler to isolate the receiver section from conducted interference. Hmm, I do have a Pi. And when you have trouble decoding the signal at around 04 in the morning, you too will have rediscovered sferics, and the need for a filter that handles that. /Kasper Pedersen _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
