[time-nuts] BPSK decoder for WWVB

Majdi S. Abbas msa at latt.net
Wed Jul 3 23:06:01 UTC 2013


On Wed, Jul 03, 2013 at 05:03:40PM -0400, Tim Shoppa wrote:
> I have heard MSF on 60kHz in our early evening on some winter nights but
> never would describe it as jamming :-)

	I have an MSF receiver, if only I could get rid of the
semi-local (1000 km) interference from WWVB.  :)

> I have also heard YVTO on 5MHz underneath both WWV and WWVH, strangely
> off-kilter by half a second or so.

	Satellite bounce, maybe?

> All that said, BPSK sounds like it could be substantially more robust than
> on/mostly-off keying. I'm surprised given how enthusiastic WWVB was to drop
> continuous-phase transmissions, that nobody's bought into it yet.

	Because we can't.  They converted to a new modulation for which,
the only legal (non-patent encumbered) receiver chipset...is not yet 
shipping.  Xtendwave is promising samples "real soon now," but
commercial quantities aren't supposed to be available until later this
year, and who knows when we'll see a product.

	It's unclear to me why NIST was in such a hurry to go to full
time BPSK without a single receiver in an end-users hand.  Seems like
they could have alternated both modulations for a longer period of 
time without any harm.

	--msa



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