[time-nuts] WWVB phase plots
Bill Fuqua
wlfuqu00 at uky.edu
Tue Mar 20 14:16:59 UTC 2012
>Yes---it's too bad that the proposed WWVB changes don't increase the
>number of transitions at all. Could they not do the
>low-modulation-index DCF77-like signal on top of the BPSK? That is,
>put some small, fast phase wiggles on top of the slow 180-degree
>transitions (or 120-degree transitions if NIST can be convinced to
>change to that)?
The problem is that if you superimpose a wider bandwidth modulation over
the narrow one you have distributed the available sideband power over the
broader bandwidth. You have less power transmitted over the narrow bandwidth
than before. This reduces the range of the station for narrow and wide
bandwidth
users. I changed the batteries in our cheap clock here at home and it took
several
days for it to finally get a signal strong enough to set the time. The
signals are weak for
many everyday users since their clocks have relative small antennas and
they have
lots of local interference from compact florescent bulbs and switching
power supplies
in computers and TV sets.
73
Bill wa4lav
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