[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.


rtxo wrote:

> 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.
> rtxo

More information about the questions mailing list