[ntp:questions] Tobit LAN!Time DCF77 receiver not working

David Lord snews at lordynet.org
Wed Jan 6 17:41:19 UTC 2010


John Hasler wrote:
> David Lord writes:
>> I'm about 1000km away and propagation effects give me a complete loss
>> of signal twice a day on most days depending on weather conditions etc
>> so even ms accuracy is difficult to maintain.
> 
> What sort of antenna do you have?  That's the most important component
> of a VLF receiver.

ferrite rod

I assume to get the phase info you need to pll to the signal,
demodulate the phase encoding and align your own encoded pll
to that either by some analogue method I can't work out, or
use a digital pll with correction. An analogue pll match might
work ok but I don't know the maths.

I doubt it would be worth any effort at my 1000km due to
variation in propagation delay but if within close range you
are locked to the transmitted signal and just correct for the
delay.

David




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