[time-nuts] RFDO - Experience and questions

[Anders Wallin]

FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days
ago. The signals look like this from our site:
http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg
http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg
http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg

I guess the +/- 40 Hz side-bands on TDF are by design?

I have an SDR set up also, so the gnu-radio demodulators could run in
parallel on each of these, and the sdr sampling clock could come from a
local clock. One more project on the to-do list...

Anders


On Mon, Mar 6, 2017 at 12:42 AM, Iain Young <iain at g7iii.net> wrote:

> On 05/03/17 20:23, paul swed wrote:
>
> Gilles what signal is that at 162KHz. A European station? Nice thats its C
>> controlled.
>>
>
> That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> the AM Station France Inter as well, but that went when France turned
> off all LW, MW, and LORAN stations at the end of 2016.
>
> The Time Signal is Phase Modulated (I have a gnuradio decoder which
> works very well if anyone is interested)
>
> See https://en.wikipedia.org/wiki/TDF_time_signal and
> https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
>
> With no AM modulation, there are obvious benefits with regards to using
> it as a frequency reference. Average phase and frequency deviation is
> zero over 200msec (see link above for details)
>
>
> Iain
>
> PS, The signal is used by the French railways SNCF, the electricity
> distributor ENEDIS, airports, hospitals according to the Allouis link
> above
>
>
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