[time-nuts] WWVB Clocks don't sync anymore (revisited)

Brucekareen at aol.com Brucekareen at aol.com
Wed Mar 20 12:12:40 EDT 2013

Our favorite La Crosse bedroom projection clock stopped synchronizing about 
 the time WWVB implemented phase-modulation.  However, even unlocked, it  
keeps pretty accurate time.  When Daylight time comes or goes, in the  spring 
and fall, I have to take the clock out on the deck and remove and  replace 
the batteries.  This causes the clock to immediately try  to synchronize 
with WWVB, rather than waiting until midnight.
The clock spends the first five or ten minutes acquiring a signal from  its 
remote, outside 450 MHz temperature/humidity sensor.  When  acquisition is 
completed, the radio symbol on the clock begins flashing  indicating the 
clock is attempting to acquire the WWVB signal.  This  typically requires five 
to ten minutes.  When WWVB is acquired, the clock  displays the correct time 
and the wireless symbol stays on  steadily. 
I have had to do this a number of times, and at different times of the  
day.  Thus I am led to conclude successful locking is not related to WWVB  
phase-modulation being turned off, but rather to improved signal strength or  
signal/noise ratio out on the deck.  It seems likely that computers  and TVs, 
and even electrical appliances, generate a lot of VLF hash in the  house.
Many years ago, while working in the broadcast industry, we had to receive  
an AM radio signal deep underground in a BART tunnel.  I solved this by  
using a three-foot diameter resonant-ring antenna (series-resonant at the  
desired frequency) at the underground location.  Bringing portable  radios 
within a few feet of the properly oriented resonant-ring produced loud  and 
clear reception.  Something similar can probably be done for WWVB  reception.  A 
hidden loop of wire that is series resonant for WWVB could be  coupled to 
the radio-clock.
Bruce, KG6OJI

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