[time-nuts] WWVB BPSK Receiver Project? (fwd)
marek at duch.cz
Sat Mar 17 15:24:53 UTC 2012
> I don't know where you are in CZ. I'm on the boarder in DE near PL and CZ.
my former measurement (the one at YouTube, fairly good reception, winter)
has been done under Erzgebirge, Teplice, CZ. Now I moved near Sumava
(Boehmischer Wald), so tests may follow, if I will return to the topic.
> The distance to DCF77 is about 450km and if I check the amplitude across 24h
> I see considerable very deep fading effects! I think it is useless as a
> phase-coupled time receiver. At least in specific positions. It will loose
> phase at least for twice the day for approx. 2h ! That was the report for a
> ferrite rod.
> The other way would be a high-impedance FET-preamp vertical-wire antenna. I
> think this will resist much more fading effects. But it is unchecked at the
> moment. You're welcome to do it.
> The benefit of a resonated ferrite rod is the good bandpass filtering for
> local interferers like TV. The FET vertical wire will need heavily filtering
> thereafter. All in the whole dynamice range, of course.
This was almost the only reason for ferrite rod -- simplicity and
attenuation of TVs, some LCDs, 50Hz etc.
> Ferrites can be temperature controlled. They have big spreads in parameters
> anyway! The production procedure is explained in the classical book about
> Ferrites: Snelling "Soft Ferrites".
Thank you for your pointer.
Your idea of ferrite ovenization is cool.
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