April 1932 Radio News
Wax nostalgic about and learn from the history of early
electronics. See articles from
Radio & Television News, published 1919-1959. All copyrights hereby
Of course if you listen to any of the
radio broadcasts on the Internet, they are recorded version of shows
made long ago. However, back in the day those shows were first performed
live in front of microphones and recorded in a broadcast studio. With
a cast of two or three or even more, the actors would voice their lines
with as much talent and effort as those performing for movies. The crew
usually included a group of people responsible for creating background
sound effects like horses running, car horns tooting, airplanes buzzing
by, and dogs barking. All was done real-time with split-second timing
required to pull it off and sound convincing. Radio audiences were unaware
of all the work required as they sat intently listening to the Adventures
of the Lone Ranger and The Shadow. Behind the scenes were
dozens of engineers and technicians tending local radio broadcasting
equipment and all-important telephone landlines used for synchronizing
stations across the country. Being the primary form of long-distance
communications connecting communities, radio stations had in addition
to entertainment and advertising the duty of maintaining a constant
vigil for SOS signals that might be transmitted from ships at sea, airplanes,
and even Zeppelins. If received, the U.S. Navy intervened to determine
authenticity and to usurp, if necessary, the airwaves in order to conduct
rescue activities. It was the glory days of radio, before television
entered the scene.
It's a Man's Job Behind That Microphone
By Albert Pfaltz
Although Seldom Heard of, These Men Make Broadcasts Realistic
Scene in the Sound Effects Studio, where these wide-awake
young fellows, happy in the knowledge that they are adding to
your enjoyment of the radio programs, are busily engaged making
the sounds of train and boat whistles, horses galloping, airplanes
buzzing, chains rattling, the bustle of traffic, etc., to accompany
the oral text of a broadcast playlet. Theirs is not an easy
task, as they have to listen-in with headphones for their cues,
which must be followed immediately by the proper sound, made
in the proper way upon the correct "gadgets."
Tending the Land Lines
Have you wondered just how that program
from cross country is switched so quickly and at exactly the
right instant to your local station's antenna? Here are engineer
workers who tend the line terminal equipment panels in connecting
the proper stations with the desired program, although they
may be separated by thousands of miles.
Transmitting Room at WEAF
Shown at the control panel is Gerald
Gray, in charge of the station, and, standing, Raymond Guy,
radio engineer of the NBC. These men are ill charge of complete
operations and repair of the powerful 50-kilowatt transmitter
shown at center. At the left is the low-powered unit panel,
including modulators and frequency-controlling devices. At the
right is the power-control equipment and a dummy antenna system.
Program Circuits at New York
Figure 1. This schematic diagram
shows the NBC program circuits in New York City, including nine
studios and three audition studios, connecting to the main control
At the Control Panel
Fred Hanek seated at the control apparatus
at Bellmore. He is looking at the oscillograph, on which a continuous
moving picture of the broadcast's signals may be observed.
Special Broadcast Switchboard
These panels, connected in
circuit, took care of the broadcast of an "Air Raid" over New
York City. Seated at the board are George Milne, division engineer;
Ferdinand Wankel, engineer, and William B. Miller, director
of special broadcast events of the NBC system.
Lonely, But Important
Here is Engineer Dietsch, who has
complete control and operation to the cooling equipment in the
pump room of the WEAF transmitter building. If this equipment
failed for only a short period of time, the transmitter would
go off the air and thousands of dollars' worth of tubes and
associate apparatus would be ruined.
A $1,500 Vacuum Tube
Here are the station engineers holding
the largest size transmitting tube and comparing it with the
small 199 receiving tube employed in early battery operated
Control Room of Times Square Studio
You never think of these
watchful engineers on duty when you listen to a program from
this famous studio, but they are there with eyes, ears and brains
alert to conquer any emergency that might tend to interfere
with the broadcasts.
An Interesting Story of the Little-known But Important Jobs at
Which Many Efficient Radio Men Toil in Bringing Broadcasting to Its
Present-day Position of Perfection. It Is Entirely Possible That There
Are Numbers of Our Readers Who Could Qualify, After a Bit of Efficient
Study, for Some of These Positions Which Are Full of Interest and Remunerative.
In the theatre the inspiring cry has always been, "The Show must
go on!" In broadcasting - a show business on an international scale
- the same spirit prevails. And it is the radio engineer and his associates
who now manipulate the intricate networks of the present day, who plan
and execute the broadcasting of world news events, who make possible
the maintenance of high quality radio service.
The casual studio engineer may notice the control room engineer sitting
behind the glass window of his booth busy at the monitoring panel. He
may also notice the announcer's apparatus with its switches and tiny
colored lights. His main interest, of course, is in the program this
side of the microphone. If he is the average radio fan he knows nothing
whatever about what happens to the program between the two physical
points - one of them visible to him of the studio microphone and the
antenna of the broadcast transmitter. What happens to the sound in that
comparatively short and instantaneous travel is not his concern in the
slightest. It is one of those things that he takes for granted.
An Important Work
And yet the safeguarding of a program between those two points is
a work of engineering art as important, in every respect, as that of
the artists and announcers. Scores of trained engineers are constantly
on the job, planning, testing, monitoring. Taken in toto their work
may be described as designed to preserve two things in any given broadcast-fidelity
Broadcast programs originate either in a studio or in the field,
the latter being otherwise known as "Nemo" pickups.
The first named type is comparatively simple. For a brief picture
of the engineering methods employed let us look in at 711 Fifth Avenue,
in New York, NBC headquarters.
It is the announcer who actually controls the switching of a program
from the studio, where a broadcast is about to begin or end. Let us
assume that the artists, the announcer and the control room engineer
are waiting for the preceding program to end and receive their cue to
begin. The announcer, who is standing before a row of push-buttons and
lights on a little panel, is listening by means of headphones to the
concluding minutes of a program coming from another studio. At the conclusion
he receives a signal which tells him that the other program has been
completed and that his studio now "has the air."
Accurately Timed Switching
Our announcer now strikes the familiar four-note chimes and gives
the station identification. These chimes are utilized as switching cues
by individual stations and supplementary networks joining or leaving
the chain. A problem of synchronization arises here as the smaller chains
which tap the basic networks at a distance from New York may take program
service from either the basic Red or Blue networks. If one network program
finishes a few seconds ahead of schedule the announcer for the other
network takes control of both for the time necessary to give the chimes.
All personnel - announcers. control room engineers, etc. - are in possession
of essential information concerning the distribution of a program and
either the announcer or the studio engineer can set up or release the
required program channel.
The duties of the studio engineer who monitors the program from the
control room are fairly familiar. It is his job to control sound levels
and faithfully follow his program cues, such as those calling for the
fading down of music behind an announcement or the balancing of microphones.
Each studio has a twenty-four-hour reserve storage-battery supply
for use in case of failure of the commercial power source.
So much for the individual studio set-up - and there are eight such
at headquarters in New York.
Because of the fact that several
programs may be on the air simultaneously, from either studio or Nemo
points of origin and that combinations of local transmitters and networks
are continually shifting, it may safely be said that the main control
room at headquarters is the nerve center of operations. Responsibility
for the operation of studios and the distribution of programs is centered
Some idea of the complexity of the layout immediately surrounding
the main control room may be obtained from Figures 1 and 2.
Through constant supervision at this point, programs are dispatched
to designated places at proper levels and at definite times. This requires
two things - an interlocking system for transferring the outputs of
various studios to one or more distribution channels and facilities
for checking the program at important points.
The control room supervisor has available volume indicators and a
loudspeaker, the former showing output levels of studio and line amplifiers
while the latter may be connected to either of these points. In addition,
the signal light shows whether the local transmitters, WJZ and WEAF,
are "on" or "off" the air, and a neon lamp indicates whether the carrier
is being modulated and, roughly, the degree of modulation. A circuit
can be quickly patched around any faulty unit as the input and output
connections of most of the equipment in each studio appear on jacks
in the control-room apparatus.
Furthermore, telephone connections to all monitoring booths and telegraph
circuits to all networks and local transmitters are available to the
Present-day broadcasting depends, very largely for uninterrupted
service, on the efficiency of the network of telephone lines which connect
cities, studios and transmitters. The telephone company is responsible
for the maintenance of program service between network stations. Few
persons realize that dozens, and sometimes hundreds, of wiremen are
stationed at strategic points during an important network program where,
because of the single factor of geography, almost any kind of climatic
condition may be encountered - to say nothing of an "act of God" which
might cause a truck loaded with high-explosives to collide with a telephone
However, engineers of the broadcasting company frequently check the
transmission characteristics of all long-line networks. The shorter
local lines, which seldom give trouble, are checked daily and then rechecked
immediately prior to a broadcast. Frequency characteristics are also
taken covering the entire circuit from microphone to antenna.
Before outlining the more intricate problems involved in the handling
of a big news event broadcast, such as the arrival of the air armada
over New York or the initial trip of the Graf Zeppelin, let us consider
the transmitter - the comparatively new WEAF, for example, which is
the last step in the engineering chain required to put a program on
The new 300,000 watt transmitter was installed in a recently constructed
wing of the WEAF operating building at Bellmore, Long Island. O. B.
Hanson, manager of plant operation and engineering, and Raymond Guy,
radio engineer, declare that this apparatus, which embodies the latest
ideas of radio transmission, now makes every sound picked up by the
microphone audible to listeners as far away as New Zealand.
The station operates with a maximum power of 50,000 watts. With the
modulation increased from less than fifty to one hundred percent, listeners
receive the signals several times louder. High and low notes, sibilants
and certain sounds, heretofore heard indistinctly or lost entirely,
now are transmitted perfectly. The equipment includes the latest refinement
in crystal-control apparatus to hold the station on its assigned wavelength,
giving increased frequency stability. Careful observations show that
the fluctuation is only ten cycles in 660,000. The transmitter employs
two 100-kilowatt type tubes which stand five feet high and require thirty
gallons of water, per-minute, to cool them.
The central control panel gives the operator an unobstructed view
of the apparatus, while an oscillograph gives a moving picture of the
Every possible safeguard is present to insure continuous operation
of the large water-cooled tubes. Tube failure may often endanger surrounding
apparatus. For one thing, the supply of cooling water must be adequately
sustained. Furthermore, operational steps must be taken in the proper
order - as, for example, the application of filament power only when
an adequate flow of water is assured and the application of plate power,
after that of grid-bias voltage. An interlocking relay system functions
in the event of failure, or overloading, of any unit, thus disconnecting
service before any serious damage can result.
Tube replacement is handled by a push-button arrangement on the desk
of the transmitter engineer. Duplicate units and rapid replacement facilities
are also provided for other apparatus.
Lightning has long been a great danger to a transmitting station
- and still is - although radio engineers have recently developed certain
safeguards. Charges of lightning which have entered the station on the
lead-in have been known to melt 30-inch condenser plates to molten liquid.
Today the modern set-up includes static drains which consist of a coil
and a resistor, across the apparatus from antenna to ground.
But what happens when an SOS signal is on the air?
Every broadcast transmitter is equipped with a special receiving
set, adjusted for the reception of 600-meter waves, the wavelength assigned
by international agreement, for SOS signals. A big loudspeaker is placed
at an advantageous point so that the transmitter crew can hear any signals
that come through. The operators, who work in eight-hour shifts, are
constantly alert to any signals received. If any signal even remotely
suggesting an SOS is heard, the station immediately telephones the nearest
U. S. Navy Yard for advice. If the station operators are confident of
the signal they immediately discontinue broadcasting, otherwise they
await orders from the Navy Yard. Broadcasting is resumed when the Navy
department sends out permission to resume by 600-meter signals.
The ordinary distribution problem involved in a network broadcast
is difficult enough but in point of complexity the Nemo broadcast, often
requiring seven or eight announcers, a corps of engineers and the supplementary
use of short waves, takes the grand prize. Engineers and announcers
have often spent days of preparation and rehearsal in advance of such
Before describing some of the interesting engineering hook-ups used
on important news broadcasts, it is necessary to speak of the piece
of apparatus, recently designed, that serves as the nerve center coordinating
all activities in the field.
Technically known as the "semi-portable Nemo switching equipment,"
the extremely flexible, compact and efficient apparatus developed and
built by the engineers is a miniature broadcasting studio.
This apparatus, supplied with batteries for use where regular power
supply is unavailable, is contained in a box measuring approximately
2½ x 4 x 7 feet and weighing a half ton. The "box" may be shipped
to any desired centralized point from which wires are radiated to whatever
locations participate in the broadcast.
When completely installed, the equipment is capable of providing
ten-way communication, among as many locations. Ten announcers, within
any radius - even scattered throughout the country - could talk among
themselves and also to the broadcast listeners. This intercommunication
is accomplished by means of special "feedback" amplifiers which permit
each point to hear every other point. Inter-communicating telephone
circuits are also provided. Each of these ten broadcast circuits may
be controlled for volume, or switched "on the air," separately or simultaneously.
The program director at the central control point can talk to any
of the distant announcers by means of the feedback amplifiers and, unknown
to the listening radio audience, can direct the entire broadcast.
Provision is made for testing a set of circuits while the others
are being used, for broadcast and testing equipment is provided for
the rigorous checking of telephone circuits required in the broadcast
It is probable that only a small fraction of the millions of listeners
have the slightest knowledge of the men sweating behind the scenes,
in radio. They listen to a broadcast as a simple, matter of fact and
connected narrative, without realizing that many men have worked for
days - or, at the very least, for hours - to make it possible. That
is as it should be.
But it is these "unknown" workers, unseen, unheard and unsung, who
have produced a radio-minded nation which today accepts with utter calmness
the voice of Col. Lindbergh speaking from Tokyo, music from Chicago
or an address from Rome.
Control Panel Circuits
Figure 2. Schematic
diagram of the actual program circuits
to the studios and to the
channels of the control room shown
as part of the diagram in Figure
Posted October 20, 2013