[ntp:questions] wwvb "east" at 40KHz
David L. Mills
mills at udel.edu
Mon Apr 28 18:09:14 UTC 2008
Twenty-five years ago the best source of time available was WWVB. Over
the years I have had five good WWVB receivers, one of which is still in
However, in recent years accuracy, at least on the right (east) coast,
accuracy has deteriorated very seriously. This is not the fault of the
WWVB signal or propagation loss, but the enormously increased
radio-frequency interference (RFI) from noisy power lines, in particular
from computer battery backup (UPS) systems. I recently made a survey of
our campus looking for RFI from various sources and found by far the
worst offenders were the UPSes in our compouter machine room. I have
three UPS systems for various systems in my home; they kill not only
WWVB, but most of my ham radio gear as well.
At one time the principal RFI to WWVB was the 63-kHz second harmonic of
the 31.5-kHz horizontal flyback frequency used by computer CRT monitors.
Then it was the alleged electric arc welding equipment used in the local
Chrysler plant. Now it is the burgeouning UPS population. The good news
for a right-coast 40-kHz WWVB clone is that it would be closer and not
fall victim of CRT monitors.
I somehow doubt there will be a stampede to manufacture quality 40-kHz
WWVB receivers and suspect the primary target is consumer electronics.
In fact a competition grade WWVB reciever could be built today using a
good analog switch/mixer and DSP program.
> Seen on "rwonline" web site:
> “The proposed new East Coast broadcast will operate with the same time
> code format
> as the present WWVB signal, however at a different carrier frequency,
> potentially at 40 kHz,”
> John Lowe, the WWVB station manager, told RW.
> Lowe is seeking comments about the possibility and asks that readers
> write to him.
> His e-mail address is lowe at boulder.nist.gov.
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