The Washington times., 1922-04-06
RADIO EXPERT
DESCRIBES BELL
CONF ANY PLANT.
New Broadcasting Station to
Be Marvel of Wide
Possibilities.
by Cosmopolitan News Service.

NEW YORK, Aprh 6.-For Me
inf forn,ation of amateur radio
operators throughout the country,
Cosmopolitan Ne,Os SerUtce had 90.
tanned technical description Of
the great neaO Bell telephone
system broadcasting plant, phtch
,ciU be opened IN a fortnight as the
first out and out chemical expert
ment in use of radio telephony.
The nature of the business that
may be done, and the possible
future of this venture Were de-
scribed in an article by John G..
Klein.
Technical details are here giren
by the man lOho designed the plant:
BY w. X. KEING,
Radio Expert for the American Tele-
phone and Telegraph Company.
Written for Cosmopolitan News Service.
The apparatus which is being in
stalled at Walker street fof radio
broadcasting will represent the best
which both the radio and the acoustic
arts provide at the present time. The
radio equipment is of the vacuum
tube type and will deliver 12kw. of
modulated power TO the antenna. The
system ,of modulation used is that
known as the constant current type.
The radio transmitter and modulator
will consist of four 250-watt tubes,
two serving to generate the high
frequency oscillations and two as the
modulator OF these oscillations.
Describes Details.
The antenna is of the TT type,
with 200-foot span, and is supported
on towers 100 feet high. These tow
ers are being erected on the roof of
the long-distance telephone exchange
in Kew York city, which is over 800
feet high, thus placing the antenna
45O feet above the ground. There
are four span wires in the antenna,
consisting of stranded and hard.
drawn copper wire.
The radio equipment and its power
plant are located in rooms which are
entirely separated from the studio.
1t is planned to have in the studio
only the microphone transmitter and
the artists supplying the program.
The acoustic properties of the studio
have been the subject of special in
vestigations, with the result that the
room has been brought to the Condi.
tion which is most suitable for the
reproduction of music and speech.
The studio and radio apparatus are
installed on the top floor of the build
ing Immediately below the antenna.
Have Wide Scope.
The microphone transmitter and
the intermediate speech amplifier
which is used to magnify the cur
rents coming from it to a value suit
able to operate the modulator of the
radio system are of the type used
in connection with the public ad-
dress system which has been devel-
oped by the Bell system engineers
and which was so successfully used
on Armistice Day when President
words at Arlington were
transmitted and amplified for large
Francisco as well as Arlington.
The broadcasting apparatus has
been so designed that speech
path" which includes the entire
band OF frequencies which, occurring
in speech and music, is provided
from the miCrophone through the
to the oscillator and modu.
lator.
AS result, provided proper re.
ceiving equipment is used. programs
are broadCasted from this station
and picked up many miles away
will sound as natural as though
the listener were present in the
studio.