"Geoffrey S. Mendelson" wrote:

Michael A. Terrell wrote:
?
? "Geoffrey S. Mendelson" wrote:
?? It's because the US is trying to get rid of those broadcasts. With GPS they
?? are obsolete.
?
?
? Then why did they replace the WWVB towers ? transmitters a couple
? years ago? They built a better antenna array, and raised the
? transmitter power so that it can be received in Florida on a $20 'Atomic
? clock'.

They are playing "cheap catch up". The original plans were to build an
east coast station, but they were unable to get any government installation
to "host" it, (NIMBY) and lost the funding.


So, they gave up and started the upgrade in the late '90s?


? Not only are they not looking to discontinue the service, but they
? are looking at a new modulation method to improve noise immunity. This
? web page from NIST says that there are about 50,000,000 radio controlled
? clocks using WWVB in the United States:

The are using the improved modulation to keep relevant. In most large cities,
the noise from computer and home electronic equipment, BPL (still very much
in use but not for internet to customers), aDSL, etc has made it next
to impossible to receive a signal.


BPL isn't used around here. Progress Energy drives down the street
and pings the transponders in their meters. The SW bands are fairly
dead, these days. The SMPS in traffic lihts cause more noise than
anything else, and appear to operate on the low end of the AM BCB,


They exist today because people are willing to accept the poor service they
get as it is the only game in town at that price tag. Most users never
pay attention to how often they get sync, if ever.


I am near Orlando, Florida and have no problem with my WWVB clocks.
The one in this room is about ten feet from several computers &
monitors, yet it matches the internet time on the screen.


If they have to pay $100-$150 for a BPSK decoding clock, GPS or Wifi NTP clocks
will seem a lot better deal.


Who says they will cost that much? Custom ICs will make it into a
single or two chip design. FQPSK would require a lot more processing,
and the only place I used it was in the Microdyne DR2000 & RCB2000
telemetry recievers. Some people don't want to screw with wi-fi crap.
There are times when every availible channel is full of noise



I'd love to know how they came up with the number of clocks in use. Anyone
have an idea?

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379
In 1969 the US could put a man on the moon, now teenagers just howl at it. :-(


--
You can't have a sense of humor, if you have no sense.