[time-nuts] Advice on good reception for radio clocks

[Azelio Boriani]

Good idea... do you think to use batteries or along the differential line
run a power line? Power... only a few mA would be enough.

On Wed, Jun 27, 2012 at 6:20 PM, Chris Albertson
<albertson.chris at gmail.com>wrote:

> One trick that works, place the entire receiver. on a pole (black ABS pipe)
> fixed to the back yard fence.  This places it as far from any house or
> power line.  I don't think the pole needs to be tall.  8 feet get should be
> enough.    Of course now you need a long wire and a pair of RS422 driver
> chips and so on.
>
> My next experiment with this will be to use a loop antenna.
>
>
>
> On Wed, Jun 27, 2012 at 8:59 AM, Kasper Pedersen <time-nuts at kasperkp.dk
> >wrote:
>
> > 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
> >
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>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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