Evening star., 1922-10-22

These clocks are regulated daily by
J the signals brOadcasted from stations
| whose transmitters are associated di-
rectly with the pendulums Of the mas
ter clocks at the Washington and
Mare Island obServatories.
! Darien and Pearl Harbor regulate
their master clocks daily by the sig
nails sent out by Annapolis and San
Francisco, respectively. and then
! broadcast their time signals at a
later hour.
! Exactly five minutes prior to the
designated intervals the pendulums
| of the master clocks are associated.
through land line telegraph circuits.
/ with the radio transmitters at the
designated stations. through relays at
! these stations.
| Circuits Closed.
} Once each second the electric cir
cult is momentarily closed by the cir
cult maker of the clocks pendulums
| and the relays at the radio stations
| are energized. These. in turn. mo-
| mentar1ly close the circuits OF the
! radio installations. and a short i'm
! pulse or dot is created in the ether
; which travels away from the station
| in all directions with the speed OF
/ light. These impulses follow in Sc
I Quence with each swing of the clocks
pendulums corresponding to the regis
| terlns OF one second of time. The
! circuit makers OF the clocks pendu-
lums are so arranged that the cir
! cults remain open during the interval
| corresponding to the twenty-ninth
/ second of each of the five minutes.
| likewise during the last five seconds
| OF the first four minutes and finally
during the last ten seconds of the last
| minute.
Then at the time of the exact hour
| the circuits are closed for an interval
equivalent to about two dots" re-
sultins in an impulse oi longer dura-
| ton, or dash" being created in the
| ether, which denotes the eXaI- hour
! of time
| Colncidentally with the receip, -
the dash" in the radio receiver the
mariner marks the time shown by his
chronometer. and hence knows Its
error.
The breaks in the sequence OF
! dots" of the time signals are for the
purpose of enabling the listener at a
distant receiving station to follow
the signals inteliigently and prepare
for the reception of the final dash,
even though he had not tuned in
when the initial signal was trans
II trrd
Not only the chrOnometers on ships
Il SEA. but even the master clocks al
the observatories, may have an error
Ia III" latter event. information con
cerning it is sent out from time to
Line.
Errors are also introduced by the
lag inherent in the various relays the
land line electrical circuits traverses
This error is well known. and is con-
stant for a given station, however
and is published in advance for the
! Information of mariners and others
concerned
Foreign Stations.
The lag Ga the time signal over the
land telegraph circuit between the
observatory at Washington and the
radio station at Key West. Fla, Is
.2s of a second. for example. hence
the signals broadcasted from Key
| West are about % of a second be-
hind those broadcasted from Airing
ton, there being very slight lag
even in the Arlington signals. occa-
stoned by the relay a that station.
! Some foreign radio stations also
! send out time signals in a manner
! somewhat similar to that described
Most of them use different systems OF
| dots and dasnes. however, hence a
! knowledge of the various procedures
used is essential before the service
can be utilized by mariners or others
American ships need depend only
! on the Nays stations for time sig
nal service. because the procedure fol-
| lowed by this service is well known
from long usage. and the service Is
available IN all waters OF the globe
The following schedule will indicate
how completely the waters of the At
lantic and Pacific oceans, the Gulf OF
Mexico, the Caribbean sea, and even
the great lakes. are covered by the
time signal service. The signals from
these different stations reach out to
all the waters of the globe.
| Arlington (NAA), 11:55 to noon and
9:55 to 10 pm. on 1850 meters.
| Annapolis (NSS). same as Arling-
ton, but on 17.l45 meters.
Key West, Fla. (NAR), same as Ar