Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-05-03
Behind the MicrophOne
BY THE RADIO EDITOR.

other phenomena?
Upon exact knowledge Of the
sunSpot-cycle, the seasonal and
! The diurnal changes in the height
Of this ceiling" depends whether
scientists can determine exactly
how a particular radio channel
can be expected to perform at a
particular time. It has been eSti-
mated variously at between so
and rs miles.
Cooperating with ections of
| the international Scientific Radio
, Union in various parts of the
world, the Naval Rearch Labora-
tory and Bureau OF Standards at
Washington have been making
measurements Of the height of
the Kennedy Heaviside layer by
means Of the echo" method.
This method consists Of receiv-
ing and recording on an oScillo-
graph signals from a high-power
station which sends out pulses
of peaks of extremely short dura-
ton with relatively long ennis
SionS between pulses" Calcula-
tions of the layers height are
measured by the time interval
between the main pulse and first
echo. The tranSmiSSionS are fur
niShed by the naval laboratory on
two 20,000-watt stations operat-
ing, respectively, on 4,045 and
$3.50 kilocycles, and the records
are obtained at the Bureau of
Standards field listening post, -
about eight miles away.
Data Is exchanged information
ally, for it is to the benefit of all
that the influence SunSpotS, ter
restial magnetism and other fac
tors have upon wire as well as
radio communication should be
generally known.
| ~
THE presentation of radio en-
L tertainerS in their own Is
minute programs, a policy inaug-
urated by the Columbia Broad
casting System at the beginning
Of the year, has gained favor sc
rapidly that by now six hours OF
broadcasting time every week are
taken up in such features
The latest additions to the ar
ray Of radio artists, whose SuS-
tanning broadcastS are listed In
their own names, are Kate Smith
known as the Washington Song
bird" and two international stars
of musical comedy and vaudeville
Beth and Betty Dodge, who are
not only sisters, but twins.
Kate Smith and her Swanee
music, ushered in by the singers
own composition, when the
Moon Comes Over the Mountain,
is now heard over Columbia every
Sunday and Friday. She features
both preSent-day songs and ira
ditionaI Southern airs.
The Dodge Twins, for several
years continental favoriteS and
erstwhile stars of the ~FolieS
Bergere," In Paris, made their
radio debut as guest artists with
the radio Roundup" April 2
Following the acclaim that greet
ed their program negotiations
were begun to obtain their Serv-
ices as staff artists with Column
bia. Arrangements were COM
pleted and they now are heard In
harmonies and character delinea-
tons every Monday and Friday.
| A NEW use has been found fol
IA that little piece of South
American mineral, not much big
ger than a silver dollar, that Is
now used in most broadcasting
and radio telegraph stations to
keep them from wandering on
their assigned wave lengths. Be-
cause they can maintain So-called
frequencieS" so faithfully, quartz
crystals are being applied to the
regulation Of clocks and make it
possible to keep them from vary
ing more than one or two hun
dredthS Of a second per day, re-
ports the bulletin Of the United
State Nays communications
service.
| 1.-THE apparatus as originally
designed" states the bulletin, "iS
for use as a frequency reference
standard. 1t consists Of reSona-
vacuum tube oscillating circuit
controlled by the crystal, an cleo
trical circuit to obtain low fire.
Quency at an exact Submultiple of
the crystal and a time-indicating
mechanism operating from this
low frequency by a small syn
chronous motor.
These clocks may be operated
at almost any place, as they are
not subject to the forces Of graV-
ity, may be shielded from cleo
troStatic effects, and large moving
masses In their immediate vicin-