On Mon, 15 Oct 2007 09:06:49 -0700, Jim Lux
wrote:

hear the tocks fairly clearly and even understand the voice. (Who
knew the announcer's phrase for UTC "Coordinated Universal Time"?).

UTC is not an acronym. It's a madeup identifier that matches neither
the English (Coordinated Universal Time) or the French (T U C.. I won't
even attempt to figure out what it is..).

Hi All,

In fact, UTC is an acronym (already anticipated by Frnak and
explicitly stated every minute). It is but one of several, this one
being rather genericized (because any longer would force a lot of
talking, and minute passes by pretty quickly). The others would
include: UTC(NIST), UT1; and the academic UT0, and UT2.

The reason for the initials order is that there is an hidden comma.
Universal Time, Coordinated. Wikipedia reports this as an erroneous
expansion, but Wikipedia wasn't there in my Metrology classes (a
couple dozen miles from NBS) where we worked with these NBS standards.
It wasn't there when (1974) I performed the second leap second on my
Cesium Beam Standard which was calibrated through WWVB (taking about
half an hour, part of which was waiting during the roughly 15 minute
intervals between TOCs). My antenna was so far away (on the fantail
of the ship in another "time zone"), that I had to slip the time by
100nS.

Knowing that Arthur only reads his own threads, I won't have to
anticipate his rejection of the following efficiency reports for a
non-gaussian antenna. From NIST (the people who know efficiency)
about their 60KHz antenna system:

"Each antenna is a top loaded monopole consisting of
four 122-m towers arranged in a diamond shape.
A system of cables, often called a capacitance hat or
top hat, is suspended between the four towers.
This top hat is electrically isolated from the towers,
and is electrically connected to a downlead suspended
from the center of the top hat. The downlead serves
as the radiating element.

"Ideally, an efficient antenna system requires a
radiating element that is at least one-quarter wavelength
long. At 60 kHz, this becomes difficult. The wavelength is
5000 m, so a one-quarter wavelength antenna would be
1250 m tall, or about 10 times the height of the WWVB
antenna towers. As a compromise, some of the missing
length was added horizontally to the top hats of this
vertical dipole, and the downlead of each antenna is
terminated at its own helix house under the top hats.
Each helix house contains a large inductor to cancel
the capacitance of the short antenna and a
variometer (variable inductor) to tune the antenna
system.

"Using two transmitters and two antennas allows the
station to be more efficient. As mentioned earlier, the
WWVB antennas are physically much smaller than
one quarter wavelength. As the length of a vertical
radiator becomes shorter compared to wavelength,
the efficiency of the antenna goes down. In other words,
it requires more and more transmitter power to increase
the effective radiated power. The north antenna system
at WWVB has an efficiency of about 50.6%, and the
south antenna has an efficiency of about 57.5%.
However, the combined efficiency of the two antennas
is about 65%. As a result, each transmitter only has to
produce a forward power of about 38 kW for WWVB to
produce its effective radiated power of 50 kW."

73's
Richard Clark, KB7QHC