[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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