[time-nuts] live 50 Hz measurements

[Will Matney]

Pieter-Tjerk,

Now that is exactly what I had pictured in my head yesterday, and the day
before. The chart will give a comparison, over a long time period, of any
deviation. We do the same with calibrations, when we're looking for the
deviation on voltage and resistance, over a month to a year. It's really
similar to the old paper chart recorders on the OCXO and Rubidium WWVB
standards. This is a job well done!

If you don't want to mess with the full line voltage, use a step-down type
isolation transformer, and drive a LED to phottransistor IC, or just use a
1:1 isolation xformer, and use a neon like here. I think Chris mentioned
using the fluorescent lights in his shop as the drive. For accuracy sake,
I'd still compare the line freq. to a standard, but that's just me.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 7/1/2011 at 7:58 PM Pieter-Tjerk de Boer wrote:

>Hello 50 & 60 Hz nuts,
>
>The recent discussions here on measuring the mains frequency and
>phase prompted me to revive an experiment I set up some 3 years ago.
>Live data about the phase and frequency of the 50 Hz mains here in
>the Netherlands can now be viewed at:
>  http://websdr.ewi.utwente.nl:8901/lichtnet/
>
>The system consists of a simple circuit to feed the mains signal
>safely into an RS232 port (using a neon bulb and a phototransistor;
>the schematic is on the web page), and some cobbled-together
>software running under Linux.
>
>Regards,
>  Pieter-Tjerk
>
>
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