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CHAPTER 19
REMOTE CONTROL SYSTEMS
WHY USE THEM?
Radio transmitters and receivers are sometimes located a considerable distance away from the operator's
station.
The CIC-COMBAT INFORMATION CENTER-of an aircraft carrier is a good example of this. At the CIC, the
FIGHTER DIRECTOR OFFICER, FDO, is in constant contact
with the fighter squadrons, receiving reports from them
and giving orders to direct their operations. You won't
always find the TBS or TDQ TRANSMITTERS installed in the
CIC, and yet the FDO must be able to control the transmitter without leaving his station. REMOTE CONTROL
is the answer.
The compartments where the transmitters and receivers are actually installed vary with the class of ship
and the modifications that have been made In the basic
design of the ship. On a BB or a CV, the transmitters
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are usually several decks below. On a DD or a DE, the
transmitter and receiver may be on opposite sides of a
bulkhead on one of the superstructure decks.
REMOTE CONTROL SYSTEMS not only eliminate the
wasted energy of rushing below to start and stop the
transmitter each time a message is to be sent, but they
also permit the radio equipment to be operated from several control points about the ship.
With REMOTE CONTROL the operator can use either code
or voice, can switch from one transmitter or receiver to
another, can start, stop, or key the transmitter and can
handle a number of other tasks necessary to maintaining
communication-all without going near the transmitter
room.
NOT ALL of these operations are completely automatic,
to be achieved by merely punching a button. Several
require the aid of an E TM or another RM to switch the
PATCH CORDS on the TRANSFER PANELS, tune the receivers and transmitters, and make several other necessary operating adjustments.
PARTS OF A TYPICAL REMOTE CONTROL SYSTEM
Remote control systems on all Navy ships follow the
same general pattern. The systems installed in a BB
or CA have many circuits. Those on a DD have the same
variety of parts, but not AS MANY pieces of each type of
part. This relationship may be compared to the telephone systems in a large city and a small town. Both
systems have the same parts-desk sets, switch boards,
wires, and the like-but the larger city will have a greater
number of each of these parts.
In figure 129, you see a typical REMOTE CONTROL SYSTEM
that you will find installed in Navy ships. The circuits
handle one transmitter, one receiver, and a remote station.
If additional transmitters, receivers, and remote stations
are used, the extra units and circuits will be DUPLICATES
of these shown.
In addition to the two major units-the TRANSMITTER
and the RECEIVER-a remote control system has a number
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FOLDOUT-Figure 129.-Typical remote control system.
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of other parts. In figure 129, the RECEIVER UNIT is in the
lower left-hand corner. A KEY CONTROL PANEL is next
to the receiver. From the key panel you can start, stop,
and key the transmitter.
A JACK BOX with a receiver OFF-ON switch is connected
to the receiver OUTPUT. The box has two outlets so
that you can use two sets of headphones.
Another key control panel and jack box is indicated in
the upper left-hand corner. This tells you that several
of these units may be installed at various stations in the
ship.
The TRANSMITTER-VOICE AMPLIFIER-MODULATOR UNIT is
in the lower right-hand corner of figure 129.
The FREQUENCY METER between the transmitter and receiver units is used to check the frequency of the transmitter. This check can be made locally or, with some
installations, from one of the remote stations.
The upper right hand corner of figure 129 contains a
RADIOPHONE UNIT, with the controls necessary for maintaining both VOICE and C.W. COMMUNICATION.
Three TRANSFER PANELS-RECEIVER, TRANSMITTER, and
RADIOPHONE-extend across the center section of the illustration. These panels are SWITCH BOARDS, similar to
those used with telephone circuits. The E TM or RM
who mans these boards can switch from one transmitter
or receiver to another by pulling the PATCH CORDS out of
one jack and inserting them in another.
CONNECTING CABLES and TERMINAL STRIPS for connecting the cables make up the rest of the remote control
system.
KEY CONTROL PANEL
Figure 130 is a top and a sectional view of a KEY
CONTROL PANEL. This unit is mounted so that the top of
the panel is FLUSH with the top of the operator's desk.
Notice that this panel contains the OFF-ON switch and
INDICATOR light to show whether the transmitter is turned
on or not. With the newer systems all you need to do to
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Figure 130.-Key control panel.
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start the transmitter is press the ON button. And pressing the OFF button shuts it down.
RADIOPHONE UNIT
Figure 131 is the front panel of a RADIOPHONE UNIT.
The unit is provided with a cover that is water-tight when
closed and locked.
The radiophone has a combination microphone-and-receiver, similar to a handset telephone. When not being
used, the handset is held in place on the unit by a clamp
hook. When you remove the handset from the hook, a
switch is closed, just as it is when you pick up the handset
of a regular telephone. The "CARRIER-ON" BULB lights up
when the handset is removed from the hook, indicating
that power is being applied to the handset.
The intensity of sound produced by the earphone is
regulated by the knob marked "EARPHONE LEVEL," near
the center of the panel.
Two plugs for 5-tip jacks are mounted at the bottom of
the panel. These are for use with extension handset or
breastset phones.
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The KEY CIRCUIT OFF-ON SWITCH is used only when you
wish to send a C.W. message instead of a voice message.
The KEY is a separate unit and may be installed some distance away from the RADIOPHONE UNIT.
The NOISE SUPPRESSOR is normally ON. This device reduces the level of the audible message, as well as the level
of the noise. When the messages are at low-level intensity, you PRESS the button to CUT-OFF the noise suppressor
so that the message will be stronger. When you release
the button, the noise suppressor is automatically CUT-IN
to the circuit.
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Figure 131.-A water-tight radiophone unit.
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The POWER START-STOP BUTTON arrangement is just the
same as on the key control panel.
JACK BOXES
Two types of JACK BOXES are used with most remote
control systems. The type with a switch, identified by
number 49029 in figure 129, is shown in figure 132. The
other jack, identified in figure 129 by number 49063, is
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Figure 132.-Jack box with switch.
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shown in figure 133. This type has six jacks, but no
switch. It is used in figure 129, to connect the frequency
meter to the transmitter.
TRANSFER PANELS
TRANSFER PANELS are sheets of bakelite or some other
insulating material equipped with jacks or sockets to receive the PATCH CORD PLUGS.
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Figure 133.-Shielded jack box.
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The RECEIVER TRANSFER PANEL uses jacks of the type
shown in figure 133. At each end of the cords is a plug
of the type shown in figure 134.
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Figure 134.-Two-contact plug.
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If the operator at the radiophone unit, in figure 131,
wishes to check the frequency of the transmitter, he will
insert one end of the patch cord in jack C and the other
end in jack I.
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If the operator wishes to cut-in on the receiver, he will
plug one end of the patch cord into jack H, the other end
into jack C.
The transfer panels for the TRANSMITTER and RADIO-PHONE unit are slightly different from the RECEIVER panel.
The SOCKETS resemble vacuum tube sockets. The PLUG is
similar to the base of a vacuum tube. The plug is prevented from slipping out of the socket by a COLLAR that
fits over the plug and screws tightly to the base.
The spacing and the size of holes in the sockets prevent
you from inserting the plug into a socket incorrectly.
THE RELAY
The RELAY is the device that really makes a remote CONTROL system work. You first heard about the relay in
BASIC ELECTRICITY. Here is a brief explanation of its
principles.
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Figure 135.-Basic relay circuit.
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In figure 135 when switch SW is closed, the electromagnet is energized and pulls the armature TOWARD the
core of the magnet. When this happens, the contacts on
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the armature close the circuit and turn on the light.
When the switch is opened, the contacts open and the
light goes out.
The relay in figure 135 is a single-contact, single-acting
type. In addition to this type, the Navy uses many
multiple contact and multiple pole relays. Some are designed to open one circuit and at the same time close
another. Others close two and open one.
RELAY CLASSIFICATION
Relays used with Navy radio equipment are divided
into three classes-OPERATIVE, PROTECTIVE, and CONTROL-according to their USE. The wide variety of applications is responsible for the many modifications in the
basic design of the relay.
RELAY KEYING
Practically all Navy equipment uses a RELAY CIRCUIT
to make-and-break the transmitter circuit in forming the
dits and dahs of a code message. The use of a KEYING
RELAY has two decided advantages-SAFETY, and CONVENIENCE of installation.
The potential used to energize the relay is Low, usually
less than 10 volts a.c. or d.c. While a potential of 110
volts is not dangerous IN MOST CASES, relay keying gives
assurance to the operator that he can touch any part of
the key safely and without receiving a painful shock.
The transmitter usually is located some distance from
the operator's desk. If a relay is not used, it is necessary
to run the HIGH-VOLTAGE lines a considerable distance to
reach the key. But when a relay is used, the high voltages are kept completely inside the transmitter cabinet
where they belong, and you avoid the task of installing a
high-voltage line.
The use of a relay requires additional equipment, but
the convenience of installation, and the safety achieved,
more than compensate for the additional expense. Seldom will you find a keying circuit that does not use a
relay. The keying relay is an example of the OPERATIVE
TYPE of relay.
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PROTECTIVE RELAYS
A PROTECTIVE RELAY safeguards a piece of electrical
gear from damage that may be caused by excessive current drainage. Some relays are designed to break the
circuit INSTANTLY; others have TIME DELAY features that
will permit small overloads for short periods of time.
Still others are designed to DELAY the TURNING-ON of a
high voltage until a certain length of time has elapsed.
The DELAYED ACTION RELAY POSTPONES the CLOSING of a
circuit for a certain number of seconds after the operating button is punched. This type of relay is used in
starting the transmitters. One of its actions is to defer
the turning on of the high voltage until the filaments of
the tubes are hot. Its action is not dependent upon the
overloading of a circuit, as is true with the inverse-time-delay relay.
CONTROL RELAYS
CONTROL RELAYS are used to START and STOP electric
motors. The heavy relay that actually applies the power
to the motor is the MAIN LINE CONTACTOR. The relays
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Figure 136.-Sequence closing relays used with grid and plate circuits.
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that control the main line contactors are usually SERIES or
SHUNT RELAYS. All of the relay units are referred to collectively as MAGNETIC CONTROLLERS.
SEQUENCE OF CLOSING RELAY SYSTEMS
Many circuits require that the voltages be turned on in
the proper order. The grid and plate circuits of a transmitter are examples of this. If the plate potential is
turned on before the grid voltage, the tube may be damaged by excessively high current. In figure 136, the
potential applied to the grid circuit closes the plate circuit.
If anything happens to make the bias voltage fail, the
plate circuit will open, preventing damage to the tube.
Without relays, remote control systems would not be
possible, and this in turn would greatly add to the task
of operating transmitters.
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