Evening star., 1924-03-09
RADIO SHOW OFFERS
PRIZES WORTH $1,000
Apparatus to Be Given Away In.
cludes Indoor Loop
Antenna.
DONATED BY DR.. ROGERS
Fred S. Lincoln to Tell of Show
From WRC Tuesday.

More than 1000 worth OF radio ap-
paratus will be awarded as prizes
during Washington's first annual
radio show at Convention Hall the
week of March 10 TO 26, it was an
nounced last night by Alfred L.
Stern, director of the show. The
prizes range from expensive receiv-
ing. sets to head phones and access
SorieS.
The most valuable of all prizes
will be unique indoor loop an
tenna designed and built by DR. J.
harris Rogers Of Hyattsvil1e, Md T..
discoverer of the underground and un
derwater SYSTEMS of wireless signaling
me aerial, which bears resemblance to
an elaborate musical instrument. has
been donated by DIR. Rogers to the COM
mlttee in charge of the show.
Award On Closing Night.
Dr. Rogers loop aerial will be on
exhibition during the show. and on
: inc one ciosing night will be awarded to
one or the lucky radio fans who visit
the exhibit. The network of wires
and the manner of their arrangement
around the framework give a combi-
NATION eject of cage and loop or coil
antenna. There are ten convolutions
or w1ndings of wire, each convolu-
tion consisting of twelve single wires
all theHwire entering into the con-
structlon of this indoor antenna
formed a continuous wire extending
IN straight line. its length could be
measured in fractional mileage in
stead of feet. Like wheel. six
apokes or wooden supports extend
radially from the axis. At the upper
terminus of each spoke is a circular
RIM composed OF ten tiny disks
through which the copper wires are
threaded singly.
Interference Is Eliminated.
From the sporting base. which is
readily placed in a stationary posi-
1ion on the floor, there is projected
= round wooden stick on which the
nub OF the framework is mounted.
Ihis arrangement serves both as
support and as means for revolving
the coil at varying angles, so that
the directional characteristics of the
loop antenna may be advantageously
used. When the coil is turned to a
plan parallel to the direction of the
wireless transmitting station from
which communications are to be in
tercepted, the clearness of the radio
signals is appreciably strengthened
similarly, to relative degree. in
reference usually encountered from
hroadcaSting station located in a
different direction is reduced or
eliminated.
Design Is Achievements.
This device of DR.. Rogers repre-
GIL icHleNement IN indoor
aerlalS. Special attachments are
provided at the base of the coil for
instantly connecting it to any stan
dard radio telephone receiving equip
ment.
When atmospheric disturbances do
not interfere. by use of this indoor
aerial in conjunction with six stages
OF amplification-three of radio fire.
quency, two of audio frequency and
detector-music and speech trans
m1tted from high-powered stations
may be heard distinctly. In fact, with
sufficient amplification, signals from
the high-powered European stations
may be heard in Washington.
Fred S. Lincoln, general chairman
OF the committee in charge of the
show. will broadcast the fourth of
his series of addresses on the forth
coming event from station WRC
tuesday night. He will explain some
OF the features of the event.