T.O 12R2-2ART13-2

HANDBOOK

MAINTENANCE INSTRUCTIONS

RADIO TRANSMITTING SET

AN/ART-13A
THIS PUBLICATION REPLACES T.O. 12R2-2ART13-2 (FORMERLY
16-30ART13-4)
DATED 8 MARCH 1949

PUBLISHED UNDER AUTHORITY OF THE SECRETARY OF THE AIR
FORCE
Allied Printing Service, Inc.,
Indianapolis, Ind. Reprint 4900 7/20/56 30 March 1953

TABLE OF CONTENTS
SECTION I GENERAL DESCRIPTION
1. EQUIPMENT SUPPLIED.
2. EQUIPMENT REQUIRED BUT NOT SUPPLIED.
3. GENERAL DESCRIPTION OF EQUIPMENT.
4. INTERCONNECTION OF RADIO TRANSMITTING SET AN/ART-13A WITH
RADIO RECEIVING SET AN/ARR-11 TO FORM COMPLETE RADIO SET AN/ARC-8.

5. INTERCHANGEABILITY OF MAJOR UNITS.
6. ABBREVIATIONS.
7. SYMBOL DESIGNATIONS.
SECTION II INSTALLATION AND ADJUSTMENT
1. UNCRATING.
2. PREPARATION FOR INSTALLATION.
3. INSTALLATION.
4. INTER-UNIT CONNECTIONS.
5. INSPECTION AND TEST AFTER INSTALLATION.
6. ADJUSTMENTS.
SECTION III OPERATION
1. STARTING AND STOPPING THE EQUIPMENT.
2. OPERATION DURING NORMAL USE.
3. CORRECTIVE MEASURES IF NORMAL OPERATION IS NOT OBTAINED.

SECTION IV THEORY OF OPERATION
1. DESCRIPTION OF OPERATION.
2. DETAILED ANALYSIS OF MAJOR CIRCUITS.

Figure 1-1. Radio Transmitting Set, AN/ART-13A -- Major
Assemblies

Figure 1-1A. Radio Transmitting Set, AN/ART-13B -- Major
Assemblies
SECTION I GENERAL
DESCRIPTION
1. EQUIPMENT SUPPLIED.
Radio Transmitting Sets AN/ART-13A and AN/ART-13B, covered by these
instructions, consist of units as listed in tables 1-1 and 1-1A.

TABLE 1-1. AN/ART-13A -- EQUIPMENT SUPPLIED

Quantity

Name of Unit

Overall Dimensions (Inches)

Weight (Pounds)

Reference Symbols

1

Radio Transmitter T-47A/ART-13 which includes the following items as
issued:

23-5/8 x 13-5/8 x 10-3/4

70.0

101 to 199

Audio Amplifier Unit

201 to 299

MCW-CFI Unit

2201 to 2299

Panel MX- 128/ART- 13

Calibration Book

Mounting Plate MT-283/ART-13

1

Mounting Base MT-284/ART-13 for mounting transmitter

20-1/2 x 14-3/4 x 2-1/2

2.94

1

Dynamotor Unit DY-I7/ART-I3A which includes dynamotor machine, control
relays, barometric switch and filters

7-1/8 x 11-7/8 x 8-7/8

28.0

2701 to 2799

1

Mounting Plate MT-164/ART-13 for mounting dynamotor unit

7-1/8 x 11-5/32 x 1-1/4

1.13

1

Control Unit C-87/ART-13

3-1/2 x 6-5/32 x 3-1/4

1.44

601 to 699

1

Mounting Plate MT-163/ART-13 for mounting control unit

3-5/8 x 5-1/4 x 1/4

0.11

1

Control Panel C-405/A

2-1/2 x 5 x 2-5/8

Approx. 1.5

1

Plug U-6/U female cable plug for remote control box, remote control
end

1-5/8 dia. x 2-5/32 lng.

0.20

1

Plug U-7/U female power cable plug, transmitter end

2 dia. x 2-5/16 lng.

0.25

1

Plug U-8/U, male cable plug for remote control, trans mitter end

1-3/4 dia. x 1-31/32 lng.

0.19

1

Plug U-9/U male power cable plug, dynamotor end

2-1/8 dia. x 1-7/8 lng. X 2-3/4 wide

1

Plug U-10/U female primary power input cable plug, dynamotor
end

1-5/6 dia. x 1-7/8 lng. X 1-7/8 wide

1

Handbook of Operating Instructions

8-1/2 x 11

The following two items are required when operation is desired between
2000 Kc. and 3000 Kc. with fixed antennas less than 55 ft.

1

Antenna Shunt Capacitor CU-24/ART-13

5 x 4-1/8 x 4

1.59

1101 to 1199

1

Switch SA-46/ART-13A

6-I/4 x 2 x 4

The following items are required when operation is desired in the range
of 200 Kc. to 600 Kc.

1

Oscillator O-17/ART-13A

2601 to 2699

1

Mounting Base MT-198/ART-13A

22-1/2 x 10-11/16 x 2

1

Antenna Loading Unit CU-32/ART-13A

23-1/2 x 13 x 12

24.75

2501 to 2599

1

Plug U-11/U, male cable plug for antenna loading unit, transmitter
end

1-1/8 dia. x 1-29/32 lng.

0.12

1

Plug U-12/U, female cable plug for antenna loading unit, load unit
end

1-1/8 dia. x 2 x 1-15/32

0.12

TABLE 1-1A. AN/ART-13B -- EQUIPMENT SUPPLIED

Quantity

Name of Unit

Overall Dimensions (Inches)

Weight (Pounds)

Reference Symbols

1

Radio Transmitter T-412/ART-13B which includes the following items as
issued:

23-5/8 x 13-5/8 x 10-3/4

70.0

101 to 199

Audio Amplifier Unit

201 to 299

MCW-CFI Unit

2201 to 2299

Panel MX- 128/ART- 13

Calibration Book

Mounting Plate MT-283/ART-13

1

Mounting Base MT-284/ART-13 for mounting transmitter

20-1/2 x 14-3/4 x 2-1/2

2.94

1

Dynamotor Unit DY-I7/ART-I3A which includes dynamotor machine, control
relays, barometric switch and filters

7-1/8 x 11-7/8 x 8-7/8

28.0

2701 to 2799

1

Mounting Plate MT-164/ART-13 for mounting dynamotor unit

7-1/8 x 11-5/32 x 1-1/4

1.13

1

Control Unit C-87/ART-13 (modified)

3-1/2 x 6-5/32 x 3-1/4

1.44

601 to 699

1

Mounting Plate MT-163/ART-13 for mounting control unit

3-5/8 x 5-1/4 x 1/4

0.11

1

Control Panel C-405/A

2-1/2 x 5 x 2-5/8

Approx. 1.5

1

Plug U-6/U female cable plug for remote control box, remote control
end

1-5/8 dia. x 2-5/32 lng.

0.20

1

Plug U-7/U female power cable plug, transmitter end

2 dia. x 2-5/16 lng.

0.25

1

Plug U-8/U, male cable plug for remote control, transmitter end

1-3/4 dia. x 1-31/32 lng.

0.19

1

Plug U-9/U male power cable plug, dynamotor end

2-1/8 dia. x 1-7/8 lng. X 2-3/4 wide

1

Plug U-10/U female primary power input cable plug, dynamotor
end

1-5/6 dia. x 1-7/8 lng. X 1-7/8 wide

1

Handbook of Operating Instructions

8-1/2 x 11

The following two items are required when operation is desired between
1670 Kc. and 3000 Kc. with fixed antennas less than 55 ft.

1

Antenna Shunt Capacitor CU-24/ART-13

5 x 4-1/8 x 4

1.59

1101 to 1199

1

Switch SA-46/ART-13A

6-I/4 x 2 x 4

1

Crystal Control Unit CDA-T

-3/8 x 9-1/2 x 6-1/2

3.88

801-899

The following items are required when operation is desired in the range
of 300 Kc. to 500 Kc.

1

Mounting Base MT-198/ART-13A

22-1/2 x 10-11/16 x 2

1

Antenna Loading Unit CU-32/ART-13A

23-1/2 x 13 x 12

24.75

2501 to 2599

1

Plug U-11/U, male cable plug for antenna loading unit, transmitter
end

1-1/8 dia. x 1-29/32 lng.

0.12

1

Plug U-12/U, female cable plug for antenna loading unit, load unit
end

1-1/8 dia. x 2 x 1-15/32

0.12

2. EQUIPMENT REQUIRED BUT NOT
SUPPLIED.
Items listed in table 1-2
are used to complete an installation but are not supplied with the
equipment.

TABLE 1-2. EQUIPMENT REQUIRED BUT NOT SUPPLIED

Quantity

Name of Unit

Required Characteristics

1

Microphone T-17 or T-30. (Microphone T-30 requires cord
CD-318 or CD-508)

Carbon microphone with 40 to 100 ohms internal
impedance

1

Key J-37

1

Headset HS-33 or HS-38

300 ohm impedance

1

Antenna Equipment AN/ARA-4 or Antenna Assembly
AS-315/A

Fixed and trailing wire type antennas

1

All Cables and Wiring

Open wiring. See fig. 8-43 all cable and wiring
requirements

*20

Quartz Crystal Units

Type CR-7

*2

Quartz Crystal Units

Western Electric Type 5A

*1

Quartz Crystal Unit, dual type

Western Electric Type
5D

Figure 1-2. Radio Transmitter, T-47A/ART-13

Figure 1-2A. Radio Transmitter,
T-412/ART-13B
3. GENERAL
DESCRIPTION OF EQUIPMENT.
Radio
Transmitting Sets ANttART-13A and AN/ART-13B are medium power, aircraft radio
transmitters, designed to provide radio communication by voice, modulated
continuous wave telegraphy (MCW), or continuous wave telegraphy (CW). Either a
carbon or dynamic microphone may be used for voice emission. The audio system is
capable of modulating the carrier (100 watts nominal) at least 90 percent for
MCW or Voice emission. When operating with CW or MCW emission, entirely
satisfactory performance will be obtained .for keying speeds up to 30 words per
minute. Transmission frequencies differ between the Models AN/ART-13A and.
AN/ART-13B as outlined in the following paragraphs. Shifting from one
transmission to another can be accomplished by the conventional method of
'hand-positioning' the controls or by using the built-in automatic shifting
mechanism known as the "Autotune". This automatic mechanism is also utilized to
provide remote control of functions required to shift transmission
frequency.

Figure 1-3. Radio Transmitter, T-47A/ART-13 -- Units
Removed

Figure 1-3A. Radio Transmitter, T-412/ART-13B and Removable
Units
a. TRANSMITTERS.---Sub-assembly type of construction has been
used extensively in Radio Transmitters T47A/ART-13 and T-412/ART-13B. This type
of construction greatly simplifies the removal of component parts without major
disassembly of the unit. The MCW-CFI, the Audio Amplifier, and the plug-in
oscillator units (Type O-17/ART-13A used in both AN/ART-13A and AN/ART-13B; Type
CDA-T used only in AN/ART-13B) are connected by multi-terminal plugs to
facilitate removal for servicing (see figures 1-3 and 1-3A). Particular
attention was given to accessibility of component parts so that replacement
could be accomplished quickly and easily. Vacuum tubes are accessible by removal
of the top cover of the transmitter case.
(1) TRANSMITTER T-47A/ART-13. Used
as the basic unit of Radio Transmitting Set AN/ART-13A, this transmitter (see
fig. 1-2) provides variable frequency oscillator (VFO) operation with two bands
of transmission frequencies available. Normal frequency range of this unit is
2000 kc. through 18,100 kc. Output may be obtained in the low frequency range of
200 kc. to 600 kc. by using Oscillator O-17/ART-13A which is not a part of the
transmitter but may be installed upon removal of Panel MX-128/ART-13.
(2)
TRANSMITTER T-412/ART-13B.--Used as the basic unit of Radio Transmitting Set
AN/ART-13B, this transmitter (see fig. 1-2A) provides both variable frequency
oscillator and crystal-controlled oscillator operation. Four bands of
transmission frequencies are available. The basic unit, utilizing VFO operation,
covers the frequency range of 2000 kc. to 18,100 kc. Plug-in oscillator units
are required to obtain additional frequency ranges. Low frequency VFO unit
O-17/ART13A covers the range 200 kc. to 600 kc. When the CDA-T unit is utilized,
two crystal-controlled frequency bands are provided, one covering the range
1670kc. to 18,000 kc. and the other 300 kc. to 500 kc.
(a) LOW FREQUENCY
RANGE.--When the transmitter is operated in the radio frequency range 300 kc to
500 kc, Antenna Loading Unit CU-32/ART-13A must be used to tune and deliver
power to either a trailing wire antenna (approximately 200 ft. long) or a fixed
aircraft antenna (from 17 to 65 ft. long).
(b) HIGH FREQUENCY RANGE.--When
the transmitter is operated in the radio frequency range 1670 kc to 18,100 kc
the antenna tuning network, incorporated in the transmitter, is capable of
tuning and. delivering power into fixed aircraft antennas which are between 17
and 65 feet in length. For operation over the radio-frequency range 1670 kc to
5000 kc, Antenna Shunt Capacitor CU-24/ART-13 may be required, in addition to
the antenna tuning network in the transmitter, to tune and deliver power to
fixed aircraft antennas which are between 20 and 60 feet in length.
(3).
CHANGING TRANSMISSION FREQUENCY.--The transmission frequency of AN/ART-13A may
be changed by the conventional method of manually setting each control, or can
be changed to any one of ten predetermined frequencies (eleven, when using the
O-17/ART-13A unit) by means of the automatic tuning system known as the
"Autotune". Radio Transmitting Set AN/ART-13B, when operating VFO, uses the
above procedures. When operating crystal-controlled, the AN/ART-13B controls may
be manually set in the usual manner but use of the "Autotune" provides only
semi-automatic shifting of the frequency, as additional switches on the CDA-T
panel must be operated manually to obtain output in all of the twenty high
frequency and four low frequency channels.
(a) AUTOMATIC TUNING.--The
"Autotune" system has been incorporated in the transmitter to permit rapid
change from one transmission frequency to another. It will operate to change
frequency of transmission in less than 25 seconds at normal temperatures and
battery voltage. This automatic tuning system is electrically controlled by
means of mechanically repositioning adjustable elements such as switches,
variable inductors and variable capacitors. The accuracy of repositioning is of
a very high order and is not seriously affected by wear, humidity or temperature
changes. No tools are necessary to change the settings for any of the
predetermined transmission frequencies. A detailed description of construction
and operation of the Autotune is given in Section IV of this manual.
(b)
MANUAL TUNING.--The transmission frequency may be changed manually if desired.
This is accomplished by first setting the "CHANNEL SELECTOR SWITCH" to the
"MANUAL" position. All control knobs can then be manually operated without
disturbing the settings of the Autotune system.
(4) AUDIO INPUT FOR VOICE
EMISSION.-The audio input circuit incorporated in this equipment permits the use
of either a carbon or dynamic type of microphone.
(5) POWER OUTPUT.--The
power delivered to the antenna varies with frequency and antenna
characteristics. See section VI for typical values of power output.
(a) The
power output is automatically reduced to approximately one-half the full power
output when an altitude between 20,000 and 25,000 feet is reached. This is
accomplished by means of a pressure-operated switch which reduces high voltage
on the plate of the 813 power amplifier tube and the two 811 modulator tubes.
The transmitter will then operate without "flashover" up to an altitude of
40,000 feet above sea level. This "BAROMETRIC" switch reduces power output at
altitudes above 20,000 to 25,000 ft. and permits full power output at altitudes
below this value.
(6) TUBE COMPLEMENT.--The complete vacuum tube complement
for this equipment is given in table 1-3.

Figure 1-4. Dynamotor Unit DY-17/ART-13A
b. DYNAMOTOR
UNIT.--Dynamotor Unit DY17/ART-13A is the power source for Transmitters
T-47A/ART-13 and T-412/ART-13B. It contains the Dynamotor Machine, Barometric
Switch, Control and Overload Relays, Filters and Fuse for overload protection of
the 400 volt supply circuits. A 28 volt direct current power source Is required
for operation of the dynamotor machine as well as for the circuits in the
transmitter. Voltages as low as 24 volts d-c may be used but reduction in power
output and increased time required for Autotune operation will result.
(1)
The dynamotor machine employs an armature With dual windings and two commutators
to give output voltages of 400 and 750 volts d-c. A barometric switch
incorporated in the dynamotor unit chassis connects the two windings of the
dynamotor in series at altitudes below 20,000 to 25,000 feet. At higher
altitudes the series connection is broken. This arrangement provides either 1150
or 750 volts for the high voltage supply circuits of the transmitter, the
voltage being automatically reduced from 1150 to 750 when equipment is operated
at a high altitude.

TABLE 1-4. POWER INPUT REQUIREMENTS

Type of Emission Used

Frequency

Power Input (Watts)

Full Power

Reduced Power

CW

3.0 Mc.

780

700

CW (Stand By)

3.0 Mc.

560

560

MCW

3.0 Mc.

925

760

MCW (Stand By)

3.0 Mc.

560

560

Voice (90% Mod.)

3.0 Mc.

925

760

Voice (Stand By)

3.0 Mc.

250

250

(2) Table 1-4 shows typical power input
requirements for a supply voltage of 28 volts d-c. Data is shown for different
types of emission and for full or reduced power INPUT (reduced power INPUT being
obtained by operation of barometric switch at altitudes above 20,000 to 25,000
feet). All measurements made with power amplifier loaded to rated P.A. plate
current.

Figure 1-5. Control Unit C-87/ART-13
c. CONTROL
UNITS.--Control Unit C-87/ART-13 (see fig. 1-5) used with Radio Transmitting Set
AN/ART-13A and a modified version of this unit (see fig. 1-1A) used with Radio
Transmitting Set AN/ART-13B, provide a means of operating the transmitter from a
remote position. These two controls differ only by the addition of a toggle
switch in the modified version, One knob on each unit permits the power supply
to be turned on and off, and selects the type of emission (CW, MCW or VOICE). A
second knob operates the Autotune and permits selection of any one of eleven
preset frequency channels. The control unit used with AN/ART-13B utilizes a
toggle switch which allows selection of two frequencies for each of the ten high
frequency channels of the Autotune system, provided the remote transmitter is
using crystal controlled operation.
(1) The pilot lamp on the control unit
will operate when the emission selector switch is in any position other than the
"OFF" position (providing Autotune System is at rest). The pilot lamp will light
only when the remote position is in control. The pilot lamp on the transmitter
performs the same function when the transmitter controls are being used. If
Autotune is in process of changing the transmission frequency, the pilot lamp
will remain off until the Autotune cycle is conpleted. Thus, the pilot lamp
serves a dual purpose by indicating that the power supply has been connected to
the equipment and to let the operator know when the Autotune has completed the
change from one transmission frequency to another so that the carrier is again
ready to be keyed or voice modulated.
(2) Both control units mount a key,
used for keying the transmitter on "CW" or "MCW" and a jack for connection of a
microphone for "VOICE" operation.

Figure 1-6. Control Panel C-405/A or C-405A/A
d.
CONTROL PANEL--For installations having standardized control panels, Control
Panel C-405/A replaces and performs all the functions (except key) of Control
Unit C-87/ART-13. See figure 1-6.

Note
Control Panel C-405A/A may be supplied instead of
C-405/A. Control Panel C-405A/A differs from the C-405/A model in that it has an
edge-lighted lucite panel and two lamps. It is mechanically and electrically
interchangeable with the C-405/A except that it has an additional wire to bring
power to the lamps.

Figure 1-7. Antenna Loading Unit CU-32/ART-13A -- Front
View
e. ANTENNA LOADING UNIT.--Antenna Loading Unit CU-32/ART-13A is
required to tune and deliver power to either a trailing wire or fixed aircraft
antenna when the transmitter is operated in the 200 kc to 600 kc frequency
range. This loading unit is designed to accommodate antennas whose
characteristics are within the range shown in table 1-5.

TABLE 1-5. REQUIRED ANTENNA CHARACTERISTICS

Freq. In KC.

Effective Resistance In Ohms

Effective Capacity In Mmfd.

200 to 600

3 to 10

85 to 175

200 to 600

3 to 15

300 to 450

When transmission frequencies in the 200 kc to
600 kc range are selected, the antenna tuning and loading circuits, built into
the transmitter, are not used and the output of the power amplifier is
automatically connected to the loading circuits in the antenna loading
unit.
(1) Controls are provided on the front panel to permit adjustment of
inductive reactance and coupling in order to tune and deliver power to the
antenna. A radio frequency ammeter is used to indicate antenna current.
Selection of either the trailing wire or fixed aircraft antenna is accomplished
by means of a switch located on the front panel of the loading
coil.
(2)Terminal posts on both side panels facilitate connections to a fixed
aircraft antenna, trailing wire antenna, ground (structure of aircraft), the
high frequency antenna terminal of the transmitter, the low frequency terminal
of the transmitter, and to a 28 volt supply source which is controlled by the
output circuit selecting relay (K105) in the transmitter. The 28 volt d-c
source, is "keyed" by microphone or telegraph key and actuates a relay in the
loading unit. This relay either connects the aircraft antenna to the high
frequency antenna terminal of the transmitter or connects aircraft antenna to
the circuits of the loading unit. Thus, automatic selection of the correct
antenna tuning and loading system is accomplished for either high or low
frequency operation when the transmitter controls .are being set to the desired
transmission frequency.
(3) When both the trailing wire antenna and the fixed
antenna are connected to the loading unit, only one or the other is actually in
use for any transmission frequency. The idle antenna is, at all times,
automatically connected to a terminal post on the exterior of the unit. This
terminal (labeled "PLUG PL-259") may be connected to a disassociated
receiver.
(4) A mounting plate, type Mounting Base MT-198/ART-13A, is
supplied for mounting the antenna loading unit to the aircraft
structure.

Figure 1-8. Antenna Shunt Capacitor CU-24/ART-13
f.
ANTENNA SHUNT CAPACITOR.--Antenna Shunt Capacitor CU-24/ART-13 is supplied for
use with the transmitter. It is used whenever required (see section II,
paragraph 6b(2)(jj), to properly tune and deliver power to fixed aircraft
antennas (20 to 60 feet long) operating in 2000 kc to 3000 kc range of
transmission frequencies. The shunt capacitor unit consists of three individual
25 micromicrofarad capacitors, mounted on a plate which serves as a common
connection to one terminal of each unit. The terminal at the top of each
capacitor may be connected individually or collectively to the antenna system,
thus providing capacitance values of 25, 50, or 75 micromicrofarads. Mounting
holes are provided in the base of this unit to facilitate attachment to the
aircraft structure.
g. SIMILAR EQUIPMENT.--Equipment similar to Radio
Transmitting Set AN/ART-13 was purchased before procurement of the latter. This
equipment, known as Radio Transmitting Set AN/ART-13, ATC, or ATC-1 Aircraft
Radio Transmitter in its various models, is substantially the same as Radio
Transmitting Set AN/ART-13A, especially after accomplishment of Technical Order
modifications. See table 1-6 for details.
4. INTERCONNECTION OF RADIO TRANSMITTING SET AN/ART-13A WITH
RADIO RECEIVING SET AN/ARR-11 TO FORM COMPLETE RADIO SET
AN/ARC-8.
The complete Radio Set
AN/ARC-8 includes the radio receiver. The receiving equipment is interconnected
with the transmitting equipment so that they are coordinated for "break-in"
operation. The radio receiver can be operated when the radio transmitter is
either OFF or ON provided that neither the telegraph key nor microphone switch
is depressed. It is impossible for the radio transmitter and receiver to be
operative at the same time except for receiver calibration purposes when a
"NORMAL-MONITOR" switch is used. When the keying relay in the radio transmitter
is actuated, it causes the transmitter to function and at the same time it
open-circuits that receiver screen voltage supply, disconnects the receiver
antenna, and grounds the receiver antenna terminal. Only transmitter sidetone
will then be heard in the headset. When keying relay opens, transmitter output
ceases, receiver screen voltage supply is restored, antenna is reconnected and
ground connection is removed. The receiver is then ready for
operation.
Figure 8-43 illustrates the interconnection of the Radio
Transmitting Set AN/ART-13A with Radio Receiving Set AN/ARR-11, Antenna
Equipment AN/ARA-4, and terminal panel for the Aircraft's Interphone system. The
equipment shown in this illustration constitutes the complete equipment of Radio
Set AN/ARC-8. A detailed description of all cables (wire sizes and points of
connection) and required plugs is given in the tabulation at the side of figure
8-43. The required plugs are shown in greater detail in figure
8-33.
5. INTERCHANGEABILITY
OF MAJOR UNITS.
Although the contents
of this book apply specifically to Radio Transmitting Set AN/ART-13A, the same
general type of equipment is also employed by the Navy Bureau of Aeronautics as
Radio Transmitting Set AN/ART-13. Major units of both equipments are
electrically and mechanically interchangeable. Table 1-6 indicates, by name and
designation numbers, each of the major assemblies of equivalent equipments used
by the different services or of succeeding models of the same equipment,
interchangeability is indicated by the symbol X.

TABLE 1-6. INTERCHANGEABILITY OF MAJOR UNITS

Name of Unit

Type Designation of USAF Item

Type Designation of Navy Item

Interchangeability

Radio Transmitting Set

AN/ART-13A

Navy ATC- 1

See individual components.

Radio Transmitter

T-47A/ART-13

T-47/ART-13

Electrical and mechanical

Dynamotor Unit

DY-17/ART-13A

DY-11/ART-13 and DY-12/ART-13

Electrical and mechanical

Control Unit

C-87/ART-13

C-87/ART- 13

Identical

Control Panel

C-405/A

None

No Navy Equivalent

Antenna Loading Unit (200 to 600 Kc.)

CU-32/ART-13A

CU-25/ART-13 plus SA-22/ART-13

Electrical

Antenna Loading Coil (500 to 1500 kc)

None supplied

CU-26/ART-13

Item dropped by USAF

Oscillator (200 to 600 Kc.)

O-17/ART-13A

O-16/ART-13 (200.to 1500 Kc.)

ElectricaI and mechanical

Antenna Shunt Capacitor

CU-24/ART-13

CU-24/ART-13

Identical

Crystal Unit (200 Kc.)

CR-2B/U

CR-2B/U

Identical

Mounting Plate (on transmitter)

MT-283/ART-13

MT-283/ART-13

Identical

Mounting Base (on transmitter)

MT-284/ART-13*

MT-284/ART-13*

Identical

Mounting Plate (for control unit)

MT-163/ART-13

MT-163/ART-13

Identical

Mounting Plate (for dynamotor unit.)

MT-164/ART-13

MT-164/ART-13

Identical

Mounting Base (for loading unit)

MT-198/ART-13A

None for load unit; FT-142 for SA-22/ART-13

CU-25 and CU-26 mounted directly

Switch

SA-46/ART-13A

None supplied

SA-46 can be used with either

Plugs

U-6/U -- U-12/U

U-6/U -- U-12/U

Identical

*
Denotes MT-284A/ART-13 is interchangeable.
6. ABBREVIATIONS.
Abbreviations of certain radio terms and phrases are used on the control
panels of the equipment and in the following sections of this handbook. These
terms and their definitions are itemized as follows.

Abbreviation

Term

A-F

Audio Frequency

CFI

Calibration Frequency Indicator

CW

Continuous-Wave Type of Emission

D.C. (or dc)

Direct Current

1st Multiplier

First Radio-Frequency Multiplier Stage

GND

Ground (Br. Earth)

H-F Oscillator

High Frequency Oscillator (1000 to 1510
Kc.)

L Frequency

Low Frequency Band (200-600 Kc.)

L-F Oscillator

Low Frequency Oscillator (200-600 Kc.)

Local

Using the Controls on the Transmitter; Not Controlled
from a Remote Control Unit

MCW

Modulated Continuous-Wave Type of
Emission

P.A.

Power Amplifier

R-F

Radio Frequency

Remote

Use of Remote Controls (on Control Unit) to Operate the
Transmitter

2nd Multiplier

Second Radio-Frequency Multiplier Stage

VFO

Variable Frequency Oscillator

Voice

Voice Modulation of Radio-Frequency
Carrier

XTAL

Crystal-controlled

T.S.

Throttle Switch

7. SYMBOL
DESIGNATIONS.
All component parts of
Radio Transmitting Sets AN/ART-13A and AN/ART-13B are identified in this manual
by means of a symbol designation. These symbol designations appear in the text
of the following sections, in illustrations, photographs, schematic circuit
diagrams and in the parts list section. Thus a part shown in an illustration can
be located in the parts list by means of the symbol designation. Complete
descriptions of parts as well as the stock numbers and manufacturer's part
numbers appear in the Table of Replaceable Parts (section VII) of this
manual.
SECTION II INSTALLATION AND
ADJUSTMENT
1.
UNCRATING.
Open packing crates as
outlined below. Use care to avoid damage and search all packing material to be
sure that small packages are not overlooked. All crates are marked with arrows
to indicate the upright position. Cut and remove banding around crates.
a.
TRANSMITTER.--Keep in upright position and open the carton. Take off waterproof
and foil bags. Lift the transmitter out.
b. DYNAMOTOR CRATE.--Keep in upright
position and remove cover of crate. Remove waterproof and foil bags. Remove two
clamps holding dynamotor to base and lift out the dynamotor. Remove Kimpak
wrapper.
c. CONTROL UNIT.--Remove cover of crate. Lift out cardboard carton
containing the unit. Remove unit from carton.
d. ANTENNA LOADING
i3NIT.--Remove cover of crate. Remove foil and waterproof bags.
e. ANTENNA
SHUNT CAPACITOR.--Remove cover of crate. Lift out cardboard carton containing
the unit. Remove unit from carton.
2. PREPARATION FOR INSTALLATION.
The equipment should be checked before installation to make
sure that all parts are operating properly and that no damage occurred during
shipment which might cause early failure in service.
a. MECHANICAL
INSPECTION.

Figure 2-1. Tube Replacement Diagram

Figure 2-1A. Tube Replacement Diagram AN/ART-13B
(1)
TRANSMITTER.
(a) Rotate all switches on the face of the transmitter to see
that they operate freely and the knobs are fastened tightly to their
shafts.
(b) Inspect the terminals at the left end of the transmitter for
proper spring action and broken parts.
(c) Inspect the case and mountings for
dents or bent portions which might interfere with operation.
(d) Make sure
the crystal is in the proper position and clamped securely in place. See Tube
Placement Diagram, figure 2-1.
(e) Make sure all tubes are mounted securely
in the sockets and that tubes JAN-811, JAN-1625, and JAN-837 are locked
properly. See Tube Placement Diagrams, figures 2-1 and 2-1A.
(f) Make sure
the plate connector caps on all tubes employing them are in the proper position
and firm.
(g) Remove the cover from the low frequency oscillator and Check
the tube for proper seating in the socket and firm and proper connection of the
plate cap. Replace the cover.
(h) Check the vacuum switch to be sure it is
not broken.
(2) DYNAMOTOR UNIT.
(a) Check the fuse and spare fuse to see
that they are not blown.
(b) Remove the bottom plate and check all relays and
stand off insulators for broken parts.
(c) Check the relays by closing them
by hand to see that they do not bind and are not bent.
(d) Make sure all
circuit elements are mounted securely. Replace the bottom cover.
(e) Make
sure the end cover mounting bolts are tight.
(3) CONTROL UNIT.
(a) Turn
the switches to make sure they function properly and the knobs are not loose on
the shafts.
(b) Press the key to check the spring action and make sure the
mechanism does not bind and stick.
(c) Remove the back plate and inspect the
switches for broken parts. Replace the plate.
(4) CONTROL PANEL.
(a) Turn
the switches to make sure they function properly and the knobs are not loose on
the shafts.
(b) Inspect the switches for broken parts.
(5) ANTENNA SHUNT
CAPACITOR.
(a) Inspect to see that no parts are bent or broken.
(b) Check
spring action of all terminals.
(6) ANTENNA LOADING UNIT.
(a) Turn the
switches to make sure they function properly and the knobs are not loose on the
shafts.
(b) Check all terminals for broken parts and spring action.
(c)
Remove the cover plate and inspect all switches for broken parts.
(d) Rotate
the variometer and make sure it does not bind.
(e) Make sure vacuum switch is
not broken.
(f) Make sure micalex terminal boards are not broken.
(g)
Check all standoff insulators to see that none are broken and replace the
cover.
b. BENCH TEST.(1) GENERAL.--Check the complete equipment for proper
operation before installation in the aircraft. When numerous installations are
to be made, it is recommended that a test bench be set up.

Note
Adjustment procedures for the equipment must be
thoroughly understood before making any of the following tests. (See par. 6,
this section.)
(2) EQUIPMENT REQUIRED.(a) Complete mock-up
including all necessary cables and plugs and one interphone jack box or panel
with liaison position connected into the mock-up.(b) A 28-volt direct current
power source with a capacity of 35 amperes per transmitter being tested.
(c)
Suitable phantom antenna (Antenna A-58).
(d) Head Set HS-33.(e) Microphone
T-17, or Microphone T-30 with Cord CD-318 or CD-508.(f) Means for checking
continuity. This may be a continuity meter or just a battery and light
bulb.
(g) Plug PL-55 with the terminals shorted.
(3) TEST PROCEDURE MODEL
AN/ART-13A.(a) Connect the components in the beach mock-up with Antenna A-58
connected to the "FIXED ANTENNA" terminal on the antenna loading unit.
(b)
Turn "EMISSION" switch to "VOICE" position and "CHANNEL" switch to position
1.
(c) Set the antenna change-over switch on the antenna loading unit on
"FIXED ANT." position and the switch on Antenna A-58 on position 4. Set and lock
the transmitter controls on 2400 kc (control A on 1) on channel 1 in accordance
with the operating instructions for CW operation and using the crystal frequency
indicator. Check P.A. GRID meter reading to make certain the grid drive to the
final amplifier tube is within limits.
(d) Channel the autotune into channel
I by moving "CHANNEL" switch to position 2 until the autotune motor starts and
then back to position t. Close "TEST" switch after cycling is completed. The
P.A. PLATE reading should be very close to that obtained when the channel was
set up.
(e) Plug the shorted Plug PL-55 into T.S. jack and "KEY" jack in
turn. Power should be delivered to the antenna in each case.

Figure 2-2. Microphone Selector Switch and Sidetone Output
Switch

Figure 2-3. MCW-CFI -- Top View
(f) Lift the
calibration chart on the face of the transmitter and make sure that microphone
selector switch S201 is in "CARBON" position. (See fig. 2-2.) Turn "EMISSION"
switch to "VOICE," plug the microphone into "MICROPHONE" jack, and press the
button. Power should be delivered to the antenna and the plate current should be
slightly above that for CW operation. Speak or whistle into the microphone.
Plate current should rise near or higher than the MCW area on the meter with
modulation.
(g) Place "EMISSION" switch on MCW position and close "TEST"
switch. Power should be delivered to the antenna and the plate current meter
should read 190 or higher. If this reading is not obtained, readjust the MCW
control until a reading of 190 is secured. This adjustment, marked "R2201" in
figure 2-3, is located inside the transmitter. See paragraph 7 in the
MAINTENANCE section (V) which describes this adjustment.
(h) Listen in the
"SIDETONE 1" circuit and key the transmitter on CW, MCW, and modulate on "VOICE"
position. The proper sidetone signal should be heard on all emission positions.
Repeat with headset connected to the interphone jack box, control box or control
panel installed as a pa/t of the mock-up. Lift the calibration chart and set
"OUTPUT" switch S202 on each position in turn. (See fig. 2-2.) The proper
sidetone signal should be heard on each position, being louder the higher the
number of the switch position.
(i) Set up and lock the other channels of the
autotune by loading the transmitter into the phantom antenna, with controls A
and B set as follows:

Channel

A

B

2

2

200

3

3

100

4

4

060

5

5

100

6

6

100

7

7

100

8

8

100

9

9

100

10

10

100

(j) Set up the "L.FREQ." channel on 400 kc using
the internal CFI.(k) Place "CHANNEL" switch on "MANUAL," power level switch on
"TUNE," meter switch on "P.A. GRID," control B on 100, control C on 13, control
A on 11, and close "TEST" switch. The meter should read in or slightly above the
lightly shaded area under "P.A. GRID." Repeat with control A on position
12.
(l) Connect all three sections of the antenna; shunt capacitor between
the "COND" post and ground, and tune the transmitter near 2300 kc. Disconnect
the capacitors.
(m) Turn "EMISSION" switch to "OFF."
(n) Change the
phantom antenna lead from the "FIXED ANTENNA" terminal on antenna loading unit
to the "TRAILING ANTENNA" terminal and set the switch to the "TRAILING ANT."
position.
(o) Set "LOCAL-REMOTE" switch on "REMOTE" position, the emission
switch on the remote control unit on "VOICE," and "CHANNEL" switch on position
1. Then place the emission switch on CW. Wait for the light on the control unit
to come on.

Note
If a control panel is used in the mock-up, disregard
the next two steps and check the operation from a microphone connected to the
proper terminals for remote operation.
(p) Press the key on the
control unit. Power should' be delivered to the antenna and the meter should
read in the lightly shaded area marked CW. Meter readings should be very close
to those obtained previously.
(q) Check "VOICE" and MCW operation from the
control unit by means of its emission switch and the microphone jack on
it.
(r) Select channels 2 to L.F. on the control unit in turn, closing the
key each time the autotune completes cycling. Operation should be normal on
each; meter readings, plate and antenna, should be very close to those obtained
previously.
(s) Disconnect the wires from the "ANT." and "LOAD COIL" posts
and check continuity between the "RECEIVER" post and ground. They should be open
with the key up and closed with the key down. Remove the input plug from the
dynamotor unit and then check continuity between the "ANT" and "RECEIVER''
posts. They should he connected.
(4) TEST PROCEDURE--MODEL AN/ART-13B.

Note
For VFO operation, using Oscillator O-17/ ART-13A,
follow instructions as outlined in the preceding paragraph (3) of this section.
For crystal-controlled operation, using Oscillator CDA-T, the following
instructions are applicable.
(a) Connect the components in the
bench mock-up with Antenna A-58 connected to the "FIXED ANTENNA" terminal on the
antenna loading unit.
(b) Turn "VFO-XTAL" switch to "XTAL" position, "A-B"
switch to "A" position, "EMISSION" switch to "VOICE" position and "CHANNEL"
switch to position 1. Set the antenna change-over switch on the antenna loading
unit on "FIXED ANT." position and the switch on Antenna A-58 on position
4.
(e) Check control "A" to be sure it is set on channel 1. Unlock control
**B", operate the test switch and observe the P.A. GRID meter for grid drive
indication. Vary control "B" while observing this meter to obtain maximum
reading. Lock control "B'. If two crystals are in use for channel 1, adjust
control '*B' for maximum grid drive reading and note the control setting. Turn
the 'A-B" switch to 'B" and again adjust control "B" for highest grid drive
indication. Finally, set control 'B" midway between the two settings required to
produce maximum grid drive for each crystal, and lock the control.
(d) With
the 'A-B" switch in the 'A" position, channel the autotune into channel 1 by
moving "CHANNEL'' switch to position 2 until the autotune motor starts and then
back to position 1. Close "TEST" switch after cycling is completed. The P.A.
PLATE reading should be very close to that obtained when the channel was set up.
Switch to crystal "B". It also should retain the reading previously obtained
when the controls were set.
(e) Plug the shorted Plug PL-55 into T.S. jack
and "KEY" jack in turn. Power should be delivered to the antenna in each
case.
(f) Lift the calibration chart on the face of the transmitter and make
sure that microphone selector switch S201 is in "CARBON" position. (See fig.
2-20 Turn "EMISSION" switch to "VOICE," plug the microphone into "MICROPHONE"
jack, and press the button. Power should be delivered to the antenna and the
plate current should be slightly above that for CW operation. Speak or whistle
into the microphone. Plate current should rise near or higher than the MCW area
on the meter with modulation.
(g) Place "EMISSION" switch on MCW position and
close "TEST" switch. Power should be delivered to the antenna and the plate
current meter should read 190 or higher. If this reading is not obtained,
readjust the MCW control until a reading of 190 is secured. This adjustment,
marked "R220t" in figure 2-3, is located inside the transmitter. See paragraph 7
in the MAINTENANCE section (V) which describes this adjustment.
(h) Listen in
the "SIDETONE 1" circuit and key the transmitter on CW, MCW, and modulate on
"VOICE" position. The proper sidetone signal should be heard on all emission
positions. Repeat with headset connected to the interphone jack box, control box
or control panel installed as a part of the mock-up. Lift the calibration chart
and set "OUTPUT" switch S202 on each position in turn. (See fig. 2-2.) The
proper sidetone signal should be heard on each position, being louder the higher
the number of the switch position.
(i) Check channels 2 through 10, as
outlined in paragraph (4) (a) through (e). It should be understood that
"CHANNEL" switch positions will not necessarily correspond with the same
position number of control "A". Control "A" has 12 settings available for the
high frequency band, and any ten of these settings may be utilized for autotune
operation, depending on the crystals in use and the frequency desired.
(j)
Turn the "CHANNEL" switch to L.FREQ. When the autotune cycling is complete,
control "A" should rest on position 13. Four crystal-controlled frequencies are
available, depending on the setting of the 4-position low frequency switch,
located on the CDA-T panel. With the four low frequency crystals in place (one
holder is a dual crystal type), check for grid drive as previously outlined for
the higher frequency ranges. Grid drive may be varied by means of the adjustable
plate choke, L803, of the low frequency oscillator tube, V802. This adjustment
is readily available from the top of the chassis, at the rear of the CDA-T unit.
When more than one low frequency crystal is used, a setting should be selected
that will provide sufficient grid drive to obtain normal transmitter output on
each crystal frequency.
(k) Crystal operation is not possible using the
"MANUAL" setting of the "CHANNEL" switch. This "MANUAL" setting applies only to
VFO operation and should be checked as outlined in paragraph (3) (k).
(l)
Connect all three sections of the antenna shunt capacitor between the "COND"
post and ground. Channel the autotune to a crystal frequency setting near 2300
kc and tune the transmitter. Disconnect the capacitors.
(m) Turn "EMISSION"
switch to "OFF."
(n) Change the phantom antenna lead from the "FIXED ANTENNA"
terminal on antenna loading unit to the "TRAILING ANTENNA" terminal and set the
switch to the "TRAILING ANT." position.
(o) Set "LOCAL-REMOTE" switch on
REMOTE" position, the emission switch on the remote control unit on "VOICE", the
"A-B' switch to "A" and the "CHANNEL" switch to position 1. Then place the
emission switch on "CW". Wait for the light on the control unit to come on.

Note
If a control panel is used in the mock-up, disregard
the next two steps and check the operation from a microphone connected to the
proper terminals for remote operation.
(p) Press the key on the
control unit. Power should be delivered to the antenna and the meter should read
in the lightly shaded area marked CW. Meter readings should be very close to
those obtained previously.
(q) Check "VOICE" and MCW operation from the
control unit by means of its emission switch and the microphone jack on
it.
(r) Turn 'A-B" switch on remote control unit to "B". Check again as
outlined in preceding paragraphs (4) (p) and (q). Operate the "CHANNEL" switch
through positions 2 to L. FREQ., closing the key each time the autotune
completes cycling. Operation should be normal on each; meter readings, plate and
antenna, should be very close to those obtained previously. In the L.FREQ
position, only one frequency check is possible from the remote position, as the
l-position low frequency switch must be manually operated at the transmitter
location.
(s) Disconnect the wires from the "ANT." sad "LOAD COIL" posts and
check continuity between the "RECEIVER" post and ground. They should be 'open
with the key up and dosed with the key down. Remove the input plug from the
dynamotor unit and then check continuity between the "ANT" and "RECEIVER''
posts. They should be connected.
3. INSTALLATION.

Figure 2-4. Transmitting and Mounting Plate MT-283/ART-13,
shown

With Mounting Bases MT-284/ART-13 and
MT-284A/ART-13
a. TRANSMITTER.
(1) Mount the transmitter at a
height convenient for operation of the controls. See figure 8-25 Transmitter
Outline Dimensions with Mounting Base MT284/ART- 13 for ventilation provisions,
clearances required for operation and removal, bonding, and mounting hole size
and placement. The unit may be slid into position from the front or may be
lowered on the mounting two inches forward of the final position and slid
backwards into position. When the unit has been placed, tighten the two locking
knobs on the front edge of the mounting by rotating them clockwise. Tie wire the
locking knobs in position.

Figure 2-5. Dynamotor Unit DY-17/ART-13A with Mounting Plate
MT-164/ART-13
b. DYNAMOTOR UNIT.(1) Locate the dynamotor unit in such
a position that it will be possible to reach the "RESET" buttons and the "FUSE"
on the front of the unit while in flight. Both ends must be at least three
inches from a flat surface to provide sufficient ventilation.
(2) See figure
8-31 Dynamotor Unit Outline Dimensions for plug clearances, bonding, and
mounting hole positions and sizes.
(3) To install the dynamotor unit on
Mounting Plate MT-164/ART-13, set it on the mounting and slide it backward until
the holding pins are engaged; then tighten the two locking knobs on the front of
the unit by turning them clockwise. Tie wire the locking knobs together.

Figure 2-6. Antenna Loading Unit CU-32/ART-13A with Mounting
Plate MT-198/ART-13A
c. ANTENNA LOADING UNIT.
(1) Mount Antenna
Loading Unit at a height convenient for operation of controls and within easy
reach of the transmitter. A clearance of at least 6 inches should be provided
between electrical terminals on each side of this unit and surrounding
objects.
(2) See figure 8-27 for outline dimensions of Antenna Loading Unit
CU-32/ART-l3A and figure 8-28 for outline dimensions of Mounting Base
MT-198/ART-13A. Required clearances, mounting hole location and bonding
instructions are also shown in these figures. The mounting base may be installed
on top of, or hung upside down from, a flat surface. Shock mounts must be
assembled differently when the loading unit is suspended from the mount.
Instructions for proper assembly are shown in figure 8-28. The loading unit may
be mounted on top of the mounting base on its top, bottom or back or it may be
suspended from the mounting by its top, bottom or back.
(3) Mounting Base
MT-198/ART-13A is mounted to the structure of the aircraft by means of four 1/4"
screws (see fig. 8-28 for location of holes).
(4) After mounting base has
been installed, place loading unit in position on mounting plate and secure by
closing all four snap slides (one on each corner of the case). Tie wire the four
snap slides.

Figure 2-7. Control Unit C-87/ART-13 with Mounting Plate
MT-163/ART-13
d. CONTROL UNIT.--Locate the control unit so that the
controls are easily accessible to the operator. Mount it with the key upward
leaving sufficient space for operation of the key.
(1) See figure 8-26
(Control Unit Outline Dimensions) for plug clearances and mounting hole
positions and sizes.
(2) To mount the control unit on Mounting Plate
MT-163/ART-13, place the unit on the mounting and tighten the four screws, one
in each corner.
e. CONTROL PANEL.--Install the panel in the rack. In racks
with threaded holes, mount the panel with screws. In racks with smooth holes and
a wire across the center, the panel needs a small adapter plate equipped with
quick-release fasteners on each side. A half turn clockwise is all that is
necessary to fasten the panel.
f. ANTENNA SHUNT CAPACITOR AND SWITCH.
(1)
Locate the unit as near the left end of the transmitter as possible. Place
between the unit and the transmitter in such a position that vibration will not
cause it to close. The total length of lead from the transmitter to the
capacitor shall not exceed 12 inches.
(2) See figures 8-29 and 8-30 for
bonding and position and size of mounting holes.
g. OSCILLATOR O-17/ART-13A
AND PANEL MX-128/ART-13.--These units are mechanically interchangeable and
electrically always maintain the continuity of the filament string. To remove
panel bIX-128/ART-13 and install Oscillator O-17/ART-13A, proceed as
follows:
(1) Remove the top cover and type 813 tube.
(2) Remove the two
screws holding the rear of the installed unit to the fire wall assembly.
(3)
Remove the seven screws around the front panel of the unit.
(4) Disconnect
the lead to the multiplier section as required.
(5) Lift straight up to
remove.
(6) Before any attempt is made to install new unit, make certain that
the top screws of the autotune cover are loosened on each side of the oscillator
panel.
(7) Tilt the low frequency oscillator forward 15 to 20 degrees and
install the lower lip of the oscillator panel behind the autotune cover.
(8)
Lower the oscillator from its tilted forward position to mate with the Jones
plug. Force should not be used to mate these plugs.
(9) When the oscillator
is in place, replace and tighten the seven screws that hold the Iow frequency
oscillator panel in place.
(10) Tighten screws along top edge of autotune
cover.
(11) Replace and tighten screws that hold the back of oscillator
unit.
(12) Replace JAN-813 power amplifier tube and connect plate
lead.
(13) Connect one end of wire from standoff insulator (Ref. E-109-B,
Figure 8-2) to terminal on right side of oscillator unit.
(14) Replace cover
on Transmitter.
h. OSCILLATOR CDA-T.--This unit, used only in Radio
Transmitting Set AN/ART-13B, is mechanically interchangeable with Oscillator
O-17/ART-13A and Panel MX-128/ART-13 but differs electrically from the latter
units. To remove Oscillator O-17/ART-13A and install Oscillator CDA-T, proceed
as follows:
(1) Remove the transmitter cover and the type 813 power amplifier
tube.
(2) Remove the two screws holding the rear of the installed unit to the
fire wall assembly. Replace the type 813 tube.
(3) Remove the seven screws
around the front panel of the unit. Loosen the top screws of the autotune front
cover on each side of the oscillator panel.
(4) Disconnect the lead from the
insulated standoff terminal on the right side of the oscillator unit.
(5)
Lift straight up to remove.
(6) Tilt the CDA-T unit forward 15 to 20 degrees
and insert the lower lip of the oscillator panel behind the top of the autotune
cover.
(7) Lower the oscillator from its tilted forward position to mate with
the two Jones connectors. Force should not be used to mate these plugs and
receptacles.
(8) When the unit is in place, replace and tighten the seven
screws that hold the oscillator in place and tighten screws along top edge of
autotune cover.
(9) Remove the low frequency oscillator tube (JAN-1625) in
the CDA-T unit. Install screw that holds the back of the oscillator unit to the
fire wall assembly. Replace the JAN-1625 tube and connect its plate
lead.
(10) Connect the two leads to the standoff insulators on the right side
of the CDA-T unit (see figure 8-2A).
(11) Replace cover on
transmitter.
4. INTER-UNIT
CONNECTIONS.
a. Make up the inter-unit
connections when installing the equipment. A drawing of a typical wiring diagram
is shown in figure 8-43. Cut the wires to the proper length for the installation
involved. Allow enough additional length for each cable so that the radius of
any bend in a cable is never less than 8 inches and the cable is not tight
enough to interfere with the action of the shock mounts or to damage the
connectors. Figure 8-33 shows the dimensions of the plugs and outlines the
method of connecting wires to the terminals.
b. Tighten the locking rings on
all plugs and tie wire them in place.
5. INSPECTION AND TEST AFTER
INSTALLATION.
a. Inspect the
inter-connections to check them for conformity to the mock-up of the particular
installation. Check the knobs on the front of the transmitter and dynamotor
unit, the microphone selector switch under the chart, and all connector plug
locking rings for tie wire.
b. Set up the frequencies to be used in the
flight test on the channels desired according to the procedure given in the
"ADJUSTMENTS" section of this book.
c. Set up one frequency in the range 200
to 600 kc and check it for proper operation.
d. Follow the procedure outlined
for DAILY INSPECTION in this Handbook of Maintenance Instructions.
e. Turn on
the receiver, make sure the "NORMAL-MONITOR" switch is in the "NORMAL" position,
and listen in the liaison position of the jack box. The receiver hiss should be
heard with the key up; the proper transmitter sidetone signal should be heard
with the key down. Set the output switch under the calibration chart on the
position that gives the proper volume of sidetone signal when the transmitter is
being operated.
f. Tune the receiver for CW operation on one of the
frequencies set up on the transmitter. Set "NORMALMONITOR" switch in "MONITOR"
position and close the transmitter key. The transmitter should be on CW. It
should be possible to hear a beat note and to tune the beat note to zero by
rotating the receiver dial. Release the transmitter key and return
"NORMAL-MONITOR'' switch to "NORMAL" position.
g. Establish communication
with the ground station on each frequency to be used in the flight test.

6. ADJUSTMENTS.

WARNING
Operation of this equipment involves use of high
voltages which are dangerous to life. Operating personnel must observe all
safety precautions. Whenever the dynamotor is running, there is a potential of
1150 volts applied to the plate caps on top of the tubes.
a. USE
OF CALIBRATION TABLES.(1) In Radio Transmitting Set AN/ART-13A, the low
frequency and high frequency oscillators are variable frequency master
oscillators (VFO) with no provision made for crystal control of the frequency of
either oscillator. Therefore, a crystal controlled frequency standard has been
incorporated in the equipment to be used for the calibration of the variable
frequency oscillators. Radio Transmitting Set AN/ART-I3B uses both
crystal-controlled and variable frequency oscillators. These calibration tables
are necessary for the VFO operation but are not required for crystal-controlled
operation.
(2) Detailed oscillator calibration tables 6-9 and 6-10 are
included in section VI, SUPPLEMENTARY DATA, of this book. Calibrating frequency
"check points" have been indicated in the calibration tables by printing them in
heavy black type. When checking the calibration, it is necessary to use the
checkpoint which is numerically nearest to the transmission frequency that is to
be used. Heavy ruled lines that appear at intervals in the calibration tables,
serve to indicate the direction of the nearest check point. For example - for
frequencies that appear above (or before) this dividing line, use first check
point (heavy type) that is encountered by looking back to succeedingly lower
frequencies. For frequencies that appear below (or after) the dividing line, use
first check point (heavy type) that is encountered by looking ahead to
succeedingly higher frequencies.
(3) The check points are frequencies at
which audio beat notes between the output of the low-frequency oscillator or the
output of the high-frequency oscillator and the harmonics of the crystal
controlled50 kc output of CFI unit may be heard. These "beat notes" are used for
setting the dial and the movable indicator mark is for adjusting the calibration
of the oscillator. The frequency in the tables is given in kilocycles with the
control positions in columns opposite the frequency. The numbers in column B or
G may be considered as combination numbers. For control G, the hundreds figures
(the one or two figures in the third and fourth positions to the left of the
decimal point as underlined in the following example: 724.6 or 1536.4) are set
on the revolution counter near the control and the rest of the number is set on
the dial, estimating the figure to the right of the decimal and setting it
between divisions on the dial. For control B, the hundreds figures are set the
same as for control G, the two figures immediately to the left of the decimal
point (724.6 or 1536.4) are set on the dial and the figure to the right of the
decimal point (724.6 or 1546.4) is set by means of a vernier. To obtain the
settings given in the columns under B and G (B and G represent both dial
designations and calibration table column heading), rotate the control until the
revolution counter indicates the proper number of full revolutions and the dial
indicates the fraction of a revolution. For accuracy in setting control B, a
vernier scale has been provided. To use the vernier, set that part of the number
to the left of the decimal point opposite the zero line on the vernier scale.
Then note the line on the vernier scale that corresponds to the figure to the
right of the decimal point and rotate the dial slightly in a clockwise direction
until that line on the vernier is lined up with the first line on the dial that
approaches it. For example, opposite 3410 kc the reading under B in the table is
1114.1. To obtain this setting of control B, rotate the dial until the
revolution counter indicates that the control has been rotated 11 full
revolutions from the zero setting (see fig. 2-8); then continue to rotate the
control until 14 on the dial appears opposite the zero indicating mark, note
line 1 on the vernier scale and further rotate the dial until the first line
(15) on the dial lines up with line 1 on the vernier.
(4) The transmitter can
be set to frequencies between those given in the table by the following
method:
(a) Find the two frequencies located on either side of the desired
frequency.
(b) Find the difference between the dial settings of control B or
G for these two frequencies.
(c) Multiply this difference by the decimal of a
kilocycle in the desired frequency.
(d) Add this product to the dial setting
for the lower frequency in (a).
(e) Example: It is desired to transmit on
3411.5 kilocycles.

Freq.

A

B

Desired

Frequency

3411.5

3410

3

1114.1

3411

3

1116.6

Difference Between

Dial Settings Is 2.4

3412

3

1119.0

3413

3

1121.5

Setting for desired frequency is obtained thus:

Difference in Dial Settings---

2.4

Decimal in the Desired Frequency---

x .5

Product--

1.20

Dial Setting for Lower Frequency---

1116.60

Dial Setting for Desired Frequency---

1117.80

Figure 2-8. Illustration Showing Setting of Control "B" to
1114.1 (Per Example in the
Text)

Figure 2-9. Radio Transmitter T-47A/ART-13

Figure 2-9A. Radio Transmitter T-412/ART-13B -- Front
View
b. PROCEDURES FOR SETTING THE CONTROLS OF RADIO TRANSMITTER SET
AN/ART-13A (MANUAL OR AUTOTUNE OPERATION)
(1) GENERAL.--The following
procedures are for setting up the transmitter for "MANUAL" or autotune
operation. If "MANUAL" operation is desired it is only necessary to set
"CHANNEL" switch on "MANUAL" position and follow these instructions, except the
locking bars should not be moved. "MANUAL" operation will not interfere with any
of the channels set up for autotune operation if the locking bars are not
loosened, nor will setting up any channel in accordance with the following
procedure interfere with any other channel previously set up. Channeling the
autotune with the locking bars loose will completely eliminate the settings
previously set up for the channel that was cycled and may cause settings for
some or all of the other channels to shift.
(2) "CW" OPERATION INTO FIXED
ANTENNA (2000 to 18100 KC).--The following procedure is to be used for setting
up the transmitter for autotune operation on a desired frequency on any one of
the 10 high-frequency channels.
(a) Place the antenna selector switch on the
antenna loading unit on "FIXED ANT." position.
(b) Make certain that the
microphone, key, and throttle switch (T.S.) jack circuits are open.
(c) Place
"LOCAL-REMOTE" switch in "LOCAL'' position.
(d) Place "EMISSION" switch in
"VOICE" position.
(e) Check primary voltage by moving the meter switch to
"BATTERY-VOLTAGE" position. Usable primary voltage is indicated when the meter
needle is within the light shaded area under "BATTERY." A primary voltage of 28
volts will cause the meter needle to read at the top edge of this shaded area. A
primary voltage of 24 volts will cause the meter needle to read at the lower
edge of this shaded area.
(f) Place "CHANNEL" switch in the position
corresponding to the channel it is desired to set up. (If "MANUAL" operation is
desired, place "CHANNEL'' switch in "MANUAL" position.) If the autotune system
begins to run, allow it to complete the cycle of operation before proceeding.
The red pilot light on the front of the transmitter will light when the autotune
cycle is completed, and the transmitter will be ready for tuning adjustments or
operation.
(g) Unlock all five controls by holding the dial and turning the
locking bar 1/4 turn in a counterclockwise direction. (If "MANUAL" operation is
being used, the locking bars should not be loosened.)
(h) Set control "C" on
position 1. Check the position of the control against the indicator mark on the
transmitter panel. The setting of this control is critical The transmitter will
not operate if control 'C" is not set properly.
(i) Find the desired
frequency in the calibration table and note the nearest crystal checkpoint
marked in heavy black type.
(j) Set control A to the position corresponding
to the number in column A at this crystal checkpoint. Check the position of the
control against the indicator mark on the transmitter panel. The setting of this
control is critical The transmitter will not operate if control A is not set
properly.
(k) Set control B to the position corresponding to the number in
column B at this crystal checkpoint.
(l) Set the power level switch to
"CALIBRATE'' position and listen in the sidetone circuit for a beat note while
rotating control B back and forth about the position given for the crystal check
point. Set control B on the position that gives zero beat and turn the power
level switch to "TUNE" position.
(m) Set the movable indicator mark by means
of the "CORRECTOR" knob near control B to the reading of control B found in
column B at this crystal checkpoint.
(n) Refer to the calibration table and
obtain the correct setting of control "B" for the desired operating
frequency.
(o) Set control B to the reading obtained above. (p) Lock control
A by first noting its reading, rotating dial counterclockwise one-quarter turn,
or against the stop if the stop is within one-quarter turn, and then rotating it
clockwise to, but not past the reading on which it had been set. Hold the knob
and turn the locking bar clockwise until it is tight with a firm but not heavy
pressure. Repeat this procedure for control B. Further pressure on either
control in a clockwise direction should not cause the dial to move beyond the
original setting. If it does, unlock and repeat the locking procedure, making
certain the original dial settings are used. (If "MANUAL" operation i$ being
used, the locking bars should not be bothered.)
(q) Place "EMISSION" switch
on "CW" position.
(r) Check the grid drive to the final amplifier by placing
the meter switch on "P.A. GRID" position, closing "TEST" switch, and noting the
reading on the meter. It should read in, or slightly above, the light shaded
area marked "P.A. GRID." If it does not, operation is not normal. Control A may
not have been positioned accurately or there may be something wrong with the
transmitter. Check the trouble before proceeding. See "Note" in paragraph
6b(2)(hh), this section.
(s) Place the meter switch on "P.A. PLATE"
position.
(t) Place control "D" on zero.
(u) Hold "TEST" switch closed and
rotate control "E" throughout its range, seeking a plate current dip indicating
resonance of the circuit.

CAUTION
Do not move control "E" across the space between
100 and 200 or between 0 and 100 while "TEST" switch, microphone button, or key
is closed. An internal switch will be damaged if this precaution is not
followed.
(v) If no resonance dip is found, set control C on the
next higher position and rotate control E again, seeking a dip in plate
current.(w) Repeat the instructions in paragraph (v), above, until the resonance
dip i$ found or until control C is sec on position 8 and resonance has not been
found.

Note
If frequency of operation is below 3000 kc, see
instructions in paragraph 6b(2)(jj), this section.
(x) If
resonance was found on position 1 to 7, inclusive, on control C, place the power
level switch in "OPERATE" position.
(y) Load the power amplifier by
increasing the reading on control D in steps, re-resonating with control E each
time. When control D had been rotated throughout its range, set control C on the
next higher position, control D on zero and repeat. Continue this process until
the resonance dip falls in the light-shaded area marked "CW" on the plate meter.
Correct loading of the final amplifier tube, when a 28-volt primary voltage is
used, is 100 on the plate meter. It may not be possible in all cases to load the
amplifier tube exactly to this value, but any value of loading which is in the
light-shaded area marked "CW" will be satisfactory.

Note
If the resonance dip causes the plate current to
fall to a very low value, control C may be set to the next higher position
without moving control D, always re-resonating with control E each time as
before. Fine adjustment must still be made by means of control D. On antennas
less than 55 feet in length and on frequencies below 3000 kc, it may not be
possible to load the final amplifier to the light-shaded area marked "CW" before
control E reaches zero. If this happens, set control E on zero and resonate with
control D. This will give the best operation obtainable under these
conditions.
(z) If resonance was not found before control C was
set on position 8, leave control C on position 8, set control E on zero, and
seek the resonance dip in plate current by rotating control D throughout the
range of 0 to 100.
(aa) If resonance is not found, set control C on the next
higher position, rotate control D again, seeking the resonance dip.
(bb)
Repeat paragraph (aa), above, until resonance is found or until control C has
been tried on position 13 without finding a resonance dip.
(cc) If the
resonance dip was not found with control C on position 13, leave that control on
position 13, place control D on 100, and seek the resonance dip with control
E.
(dd) When resonance, is found, place the power level switch on "OPERATE
position.
(ee) Load the power amplifier by increasing the reading on control
E in steps, re-resonating with control D each time until the resonance dip falls
in the light-shaded area marked "CW" on the meter.
(ff) After proper loading
of the final amplifier tube has been found using any of the above procedures,
lock control C by noting its reading, rotating the dial counterclockwise about
one-quarter turn, and then rotating it clockwise to, but not past the reading on
which it had been set. Hold the knob and turn the locking bar clockwise, until
tight, with a firm but not heavy pressure. Further pressure on the dial in a
clockwise direction should not cause the dial to move beyond the original
setting. If it does, unlock and repeat the locking procedure, making certain the
original dial setting is used. Repeat this procedure with controls D and E. (If
"MANUAL" operation is being used, the locking bars should not be
bothered.)
(gg) Check tuning and locking by holding "TEST" switch closed
while placing a small force on each dial in turn in the clockwise direction. If
all dials ate locked properly, no detuning will result. (Do not use this test
when in "MANUAL" position.)
(hh) Repeat the above procedure for each
high-frequency autotune channel it is desired to set up on the transmitter.

Note
The "P.A. GRID" meter reading, with control A on
position No. 7, is usually at the lower edge of the light-shaded area. It is
permissible for the grid meter reading for this particular setting (control A on
No. 7) to be 50 on the meter scale and still be satisfactory. A lower meter
reading is not satisfactory, and the transmitter should be repaired or aligned
according to the instructions in section V of this handbook. If control A is not
set accurately it is possible for some of the multiplier switches to be between
contact positions; this results in loss of grid drive to the final amplifier
tube, and burning of contacts. Set control accurately.
(ii) When
operating in the 2000-kc to 3000-kc range into a fixed antenna, care must be
exercised to avoid operation on a harmonic of the desired frequency. This will
be avoided in most cases by following the outlined procedure for tuning
adjustment into a fixed antenna. However, for frequencies between 2000 kc and
3000 kc on antennas shorter than approximately 50 feet, the antenna may be too
short for the tuning elements in the transmitter to resonate at the fundamental
frequency. Therefore, the first resonance indicated by the tuning adjustment may
be a harmonic of the desired frequency. To determine whether this is true,
follow the tuning procedure outlined in paragraph (jj), below.
(jj) For
operation into short antennas (less than 50 feet) at frequencies between 2000 kc
and 3000 kc, it may be necessary to connect the antenna shunt capacitor to the
"COND." post on the transmitter. This is accomplished by throwing the knife
switch so the capacitors are connected to the transmitter. Table 2-1 may be used
as a guide to determine whether or not use of the capacitor will be necessary
and, if used, how many sections are required for various frequencies and lengths
of antenna.
TABLE 2-1. USE OF ANTENNA SHUNT CAPACITOR WITH ANTENNAS OF
DIFFERENT LENGTHS

Length of Antenna (in feet)

Frequency Range (in kilocycles)

Antenna Shunt Capacitor; No. of Sections Necessary

60 to 65

2000 to 18100

None

53 to 60

2000 to 2100

One

53 to 60

2100 to 18100

None

45 to 53

2000 to 2100

Two

45 to 53

2100 to 2200

One

45 to 53

2200 to 18100

None

36 to 45

2000 to 2100

Three

36 to 45

2100 to 2200

Two

36 to 45

2200 to 2400

One

36 to 45

2400 to 18100

None

27 to 36

2100 to 2200

Three

27 to 36

2200 to 2400

Two

27 to 36

2400 to 2700

One

27 to 36

2700 to 18100

None

20 to 27

2200 to 2400

Three

20 to 27

2400 to 2700

Two

20 to 27

2700 to 3000

One

20 to 27

3000 to 18100

None

To determine the length of the antenna, measure
the total length of wire from the antenna terminal of the transmitter to the
extreme end of the antenna (including the length of the lead inside the
airplane). If the antenna is a "T," disregard the length of wire in the shorter
branch at the top of the "T," or, if the two branches are equal, include the
length of only one of them. The tuning procedure for the transmitter, when using
the shunt capacitor, is identical to the procedure without shunt capacitors. The
use of these antenna shunt capacitors reduces the power output from the
transmitter when used on frequencies higher than those which require its use.
For this reason, it should not be used unless necessary and only on those
channels which require it. This obviously cannot be done if the transmitter is
to be operated from a remote position, since no provisions have been made to
automatically switch the shunt capacitor in or out. In this case the capacitor
should be used only if it is desired to set a channel in the frequency range
wherein the antenna cannot be resonated by the tuning elements in the
transmitter itself, and it must be left in for all channels regardless of the
reduction of power. Only the capacity necessary to tune the lowest frequency
used should be connected. This can be done by connecting one, two, or three of
the capacitors in parallel, according to the amount of capacity needed. Use the
smallest number possible. To determine the lowest frequency that can be tuned
with a given number for a particular antenna, proceed as follows:
1. Connect
the circuit it is desired to check; that is, either no capacitor connected, one
section connected, two sections connected, or three sections connected.
2.
Place 'LOCAL-REMOTE" switch to "LOCAL'' position.
3. Place "EMISSION" switch
on "VOICE" position,
4. Place "CHANNEL" switch on "MANUAL'' position.
5.
Place the meter switch on "P.A. PLATE" position.
6. When the autotune motor
stops and the pilot light comes on, set control A on position 2 and control B on
2000.
7. Tune and load the power amplifier according to instructions
contained in paragraphs 6.b. (2)(q)
thru (y).

Control A

Control B

2

1500

2

1000

2

500

1

1500

1

1000

1

500

1

100

8. Attempt to repeat the above tuning and loading
procedure with each of the following combinations of setting in turn.The setting
of control E for each successive trial will be lower than for the preceding
trial. If one of the above combinations of controls A and B cannot be tuned
without going to a "HIGHER" setting of control C than for the preceding
combination, place control C on position 1, control D on zero, and control E on
zero. Then rotate control B toward a higher reading, while holding "TEST" switch
closed, until the plate current shows a resonance dip. Turn the transmitter off
and look up the frequency in the calibration table corresponding to the
combination of controls A and B found by this process. This installation of the
transmitter, with sections of the antenna shunt capacitor (if used), with this
length of fixed antenna wire in this type of airplane, cannot be tuned to any
frequency below that obtained by this process. It may appear that proper
operation is obtained by continuing the tuning procedure to "HIGHER" positions
of control C, but this results in operation on a harmonic of the desired
frequency and will result in complete lack of communication.
(3) CW OPERATION
INTO TRAILING ANTENNA (2000 KC TO 18,100 KC).
(a) Set controls A and B on the
desired frequency by following instructions in paragraphs 6.b. (2) (b) through
(s).
(b) Connect the "ANT." post on the transmitter to ground with a lead as
short as possible.
(c) Place control D on zero.(d) Hold "TEST" switch closed
and rotate control E throughout its range, seeking a plate current dip
indicating resonance of the circuit.
(e) If no resonance dip is found, set
control C on the next higher position and rotate control E again, seeking a dip
in plate current.
(f) Repeat the instructions in paragraph (e), above, until
the resonance dip is found or until control C is set on position 8.
(g) If
resonance was not found before control C was set on position 8, leave control C
on position 8, set control E on zero, and seek resonance dip in plate current by
rotating control D throughout the range of 0 to 100.
(h) If resonance is not
found, set control C on the next higher position, rotate D again, seeking the
resonance dip.
(i) Repeat paragraph (h), above until resonance is found or
until Control C has been tried on position 13 without finding a resonance
dip.
(j) If the resonance dip was not found with control C on position 13,
leave that control on position 13, place control D on 100, and seek the
resonance dip with control E.

CAUTION

Do not attempt to load the transmitter.

Note
The above procedure may be accomplished on the
ground and controls C, D, and E locked in the positions found for each frequency
on which trailing wire operation is desired. Then, during flight, it will be
necessary to channel the autotune into the channel on which it is desired to
operate; unlock controls C, D, and E and continue with the procedure that
follows. Be sure "EMISSION" switch is on CW, power level switch is on "TUNE,"
and meter switch is on "P.A. PLATE."
(k) When resonance is
obtained, release the "TEST" key and remove the connection between the "ANT."
post and ground and make certain the proper wire is fastened to that
post.
(l) Let out the trailing wire to a counter reading 10 higher than that
shown in the following table of approximate antenna lengths for the desired
frequency.
(m) Hold the "TEST" switch closed and reel the wire in while
watching the plate current meter for a resonance dip.
(n) If no dip is found,
let the wire out to a reading 20 higher than that indicated in the following
table and repeat the reeling-in procedure.

KC

Counter Reading

1/4 Wave

3/4 Wave

5/4 Wave

2000

101

3000

61

4000

46

150

5000

38

118

6000

90

7000

70

8000

60

9000

48

93

10000

41

76

12000

55

14000

44

16000

37

18000

34

(o) When resonance is found, adjust the length of
the wire to correspond to minimum plate current and set power level switch on
"OPERATE" position.(p) If resonance was found with control C on positions 1 to 7
inclusive, load the power amplifier by increasing the reading on control D in
steps, re-resonating with control E each time. When control D has been rotated
throughout its range, set control C on the next higher position, control D on
zero, and repeat. Continue this process until the resonance dip falls in the
light-shaded area marked "CW" on the plate meter.

Note
If the resonance dip causes the plate current to
fall to a very low value, control C may be set to the next higher position
without moving control D, always re-resonating with control E each time as
before. Fine adjustment must still be made by means of control
D.
(q) If resonance was found with control C on positions 8 to 13
inclusive, load the power amplifier by increasing the reading on control E in
steps, re-resonating with control D each time until the resonance dip falls in
the light-shaded area marked "CW'' on the meter.
(r) Lock controls C, D, and
E. (If "MANUAL" operation is being used, the locking bars should not be
loosened.)

Note
This channel may be used on trailing wire again
without unlocking the dials by cycling the autotune into the channel, placing
the power level switch on "TUNE" position, adjusting the antenna length to the
position corresponding to minimum plate current if frequency is below 10,000 kc
and to maximum antenna current if frequency is above 10,000 kc, and returning
the power level switch to "OPERATE" position. Be sure to use the same number of
quarter wave lengths as in tuning up.
(s) Trailing wire operation
will increase the range of the equipment considerably in the frequency range
2000 to 6000 kc and somewhat in the frequency range above 6000 kc.
(4) CW
OPERATION INTO FIXED OR TRAILING ANTENNA (200 KC TO 600 KC).
The following
procedure is to he used for setting up the transmitter for autotune or manual
operation on a desired frequency in 'the low frequency channel.
(a) Place the
antenna selector switch on the antenna loading unit in the position which
selects the desired antenna.
(b) Make certain that the microphone, key and
throttle switch (T.S.) jack circuits are open.
(c) Place "LOCAL-REMOTE"
switch in "LOCAL'' position.
(d) Place "EMISSION" switch in "VOICE"
position.
(e) Place "CHANNEL" switch in 'L. FREQ." position and wait until
the autotune stops.
(./) Unlock controls A and C, place control A on position
13 and control C on position 8, and lock them in place. (If "MANUAL" operation
is being used, place control A on position 13 and control C on position 8
without unlocking them.)

Note
If the low frequency autotune mechanism should fail,
it is only necessary to switch to "MANUAL" and set control A to position 13 and
control C to position 8, since low frequency operation is only a switching
procedure. It is possible to set the low frequency position on any of the 1 !
channels. It is only necessary to lock control A on position 13 and control C on
position 8, on the channel it is desired to use as a substitute for the "L
FREQ." position.
(g) Find the desired frequency in the
calibration table and note the nearest crystal checkpoint marked in heavy black
type.
(h) Set control F to the position corresponding to the number in column
F at the crystal checkpoint.
(i) Unlock control G by turning the "LOCK" knob
counterclockwise until loose. Then set control G to the position corresponding
to the number in column G at the crystal checkpoint.
(j) Set the power level
switch to "CALIBRATE'' position and listen in the sidetone circuit for a beat
note while rotating control G back and forth about the position given for the
crystal check point. Set control G on the position that gives zero beat and turn
the power level switch to "TUNE" position.
(k) Set the movable indicating
mark by means of the "CORRECTOR" knob near control G to the reading of control G
found in column G at the crystal checkpoint.
(/) Refer to the calibration
table and obtain the correct setting of control G for the desired operating
frequency and set control G to that reading. Lock the dial.
(m) Place
"EMISSION" switch on "CW" position.
(n) Check the grid drive to the final
amplifier by placing the meter switch on "P.A. GRID" position, closing "TEST"
switch, and noting the reading on the meter. It should read in, or slightly
above, the light-shaded area marked "P.A. GRID" on the meter. If it does not,
check the position of controls A and C.
(o) Place the meter switch on "P.A.
PLATE" position.

Note
In certain aircraft an auxiliary plate current meter
is located adjacent to the antenna loading unit for convenience in
tuning.
(p) Place control P on the antenna loading unit on
position 1.(q) Place control Q on position 1.(r) Unlock control R and place it
on zero.(s) Hold "TEST" switch closed and rotate control R throughout its range,
seeking a plate current dip indicating resonance of the circuit.
(t) If no
resonance was found, place control Q on the next higher position, hold "TEST"
switch closed, and rotate control R again, seeking the dip in plate
current.
(u) Repeat paragraph (t) above until resonance is found or until
control Q has been tried on all its positions.
(v) If no resonance was found
in paragraph (u) above, set control P on the next higher position, control Q on
position 1 and repeat paragraphs (s), (t), and (u) above.
(w) Repeat
paragraph (v) above until resonance is found.
(x) When resonance is found,
lock control R in the position giving minimum plate current.
(y) This
completes the tuning procedure, as there is no provision for exact loading of
the transmitter in the frequency range 200 to 600 kc. The plate current may read
anywhere between 10 and 120 for normal operation.
(5) VOICE OPERATION.

Note
Voice and MCW operation on fixed wire antennas in
the 200 kc to 600 kc range is prohibited because the loading unit is not
designed to withstand the high voltages generated with modulation under these
conditions. Use CW only on "FIXED ANT." in the 200 kc to 600 kc
range.
(a) Adjust the transmitter for "CW" operation and place
"EMISSION" switch on "VOICE" position. No further tuning adjustments are
necessary.
(b) Be sure the microphone selector switch under the tuning chart
on the front panel of the transmitter is in the position corresponding to the
type of microphone being used.
(c) Press the button on the microphone or in
its cord and hold it depressed while speaking. Release it to listen.

Note
When the meter switch is in "P.A. PLATE" position,
the meter indicates the sum of the power amplifier and modulator plate currents
and will, therefore, read slightly higher on "VOICE" than on "CW." With normal
modulation the plate current meter will read in the red area above the "CW"
portion and may hit the meter peg with heavy modulation during normal
operation.
(6) "MCW" OPERATION.

Note
Voice and MCW operation on fixed wire antennas in
the 200 kc to 600 kc range is prohibited because the loading unit is not
designed to withstand the high voltages generated with modulation under these
conditions. Use CW only on "FIXED ANT." in the 200 kc to 600 kc
range.
(a) Adjust the transmitter for "CW" operation and place
"EMISSION" switch on "MCW" position. No further adjustments are
necessary.
(b) Key the transmitter for normal operation.

Note
The normal meter reading on "MCW" when the meter
switch is in "P.A. PLATE" position, key down, will be in or slightly above the
light-shaded area marked "MCW."
(7) ADJUSTMENT OF SIDETONE
LEVEL.(a) Lift the chart on the front panel of the transmitter.(b) Listen in the
headphones while holding the "TEST" switch closed and adjust the "OUTPUT"
control for proper volume of signal. Check the volume on each type of emission;
"MCW," "CW," and "VOICE."
(8) USE OF CHART ON FACE OF TRANSMITTER.--After the
transmitter has been set on the desired channels, enter the readings of controls
A, B, C, D, and E, on the chart on the transmitter. Make these entries after the
autotune has been channeled into each channel set up and after the operation has
been checked. Set the indicating mark for control B with the zero line of the
vernier directly above the dial and record the reading of the dial with the
indicating mark in that position. This will enable the operator to check the
settings even after the movable indicating mark has been adjusted to set up
another channel. If the shunt capacitor is necessary on any of the frequencies
set up, write the number of sections required following the number of channel in
the left hand column. Record the settings of controls F, G, P, Q, and R on the
lower line. Set the movable indicating mark on control G directly above the dial
to obtain its reading, then record whether P, Q, and R are settings for fixed or
trailing antenna in the left hand column in the same position used for
indicating sections of the shunt capacitor in the upper lines. To minimize
tuning in the air, leave controls P, Q, and R on the positions for fixed antenna
operation and record the positions for trailing antenna on the chart or reverse
the order if desired. If two frequencies in the range 200 to 600 kc are to be
used, one may be set on the controls (F, G, P, Q, and R) and the other recorded
on the chart. Which of the above methods is chosen for use of the chart for low
frequency operation will depend on tactical considerations.
(9) PREPARATION
FOR OPERATION.--This transmitter uses tubes which require at least 30 seconds to
warm up before operation. If conditions permit, have the transmitter in
readiness for operation by leaving the "EMISSION" switch in "VOICE" position
during the entire flight. This is a "standby" condition and eliminates the 30
second delay waiting for the tubes to warm up.

TABLE 2-2. CDA-T CRYSTAL-CONTROLLED OSCILLATOR/MULTIPLIER
OPERATION

"A" Dial Position

V-801 -- High Freq. Osc.

V-102 -- 1st. Mult.

V-103 -- 2nd. Mult.

Output Frequency Range (Kc)

"A-B" Switch Position

Xtal Frequency Range (Kc)

Xtal Freq.

Frequency Range (Kc)

Xtal Freq.

Frequency Range (Kc)

1

A or B

1670-2400

X 1

1670-2400

1670-2400

2

A or B

2400-3000

X 1

2400-3000

2400-3000

3

A or B

3000-3600

X 1

3000-3600

3000-3600

4

A or B

1800-2000

X 2

3600-4000

3600-4000

5

A or B

2000-2400

X 2

4000-4800

4000-4800

6

A or B

2400-3000

X 2

4800-6000

4800-6000

7

A or B

2000-2400

X 1

2000-2400

X 3

6000-7200

6000-7200

8

A or B

2400-3000

X 1

2400-3000

X 3

7200-9000

7200-9000

9

A or B

3000-3600

X 1

3000-3600

X 3

9000-10800

9000-10800

10

A or B

3600-4000

X 2

3600-4000

X 3

10800-12000

10800-12000

11

A or B

2000-2400

X 2

4000-4800

X 3

12000-14400

12000-14400

12

A or B

2400-3000

X 2

4800-6000

X 3

14400-18100

14400-18100

TABLE 2-3. VFO OSCILLATOR/MULTIPLIER OPERATION

"A" Dial Position

V-101 -- High Freq. Osc.

V-102 -- 1st. Mult.

V-103 -- 2nd. Mult.

Output Frequency Range (Kc)

S-101

C-101

C-135

Switched

Frequency Range (Kc)

M.O. Freq.

Frequency Range (Kc)

M.O.Freq.

Frequency Range (Kc)

1

Closed

In

1000-1200

X 2

2000-2400

1670-2400

2

Open

Out

1200-1510

X 2

2400-3000

2400-3000

3

Closed

In

1000-1200

X 3

3000-3600

3000-3600

4

Open

Out

1200-1510

X 3

3600-4000

3600-4000

5

Closed

In

1000-1200

X 4

4000-4800

4000-4800

6

Open

Out

1200-1510

X 4

4800-6000

4800-6000

7

Closed

In

1000-1200

X 2

2000-2400

X 3

6000-7200

6000-7200

8

Open

Out

1200-1510

X 2

2400-3000

X 3

7200-9000

7200-9000

9

Closed

In

1000-1200

X 3

3000-3600

X 3

9000-10800

9000-10800

10

Open

Out

1200-1510

X 3

3600-4000

X 3

10800-12000

10800-12000

11

Closed

In

1000-1200

X 4

4000-4800

X 3

12000-14400

12000-14400

12

Open

Out

1200-1510

X 4

4800-6000

X 3

14400-18100

14400-18100

c. SIMPLIFIED PROCEDURE FOR SETTING THE
CONTROLS.
(1) GENERAL.--The following procedures are for setting the controls
using the approximate dial settings following the calibration tables.
(2)
"CW" OPERATION INTO FIXED ANTENNA (2000 KC TO 18,100 KC).
(a) Follow
instructions in paragraphs 6b(2) (a) through (s), this section.
(b) Set
controls C, D, and E to the positions indicated in the table of approximate dial
settings for the desired frequency. (Table 6-11 in this manual.)
(c) If
control C is on position 7 or below:
1. Hold "TEST" switch closed and adjust
control E to the position at resonance indicated by the dip in plate
current.
2. Place the power level switch on "OPERATE'' position.
3. If the
plate current meter reading is above the area marked "CW," move control D a few
divisions lower and readjust control E for minimum plate current. Repeat until
the plate current reading is in the area marked "CW." If the plate current meter
reading is below the area marked "CW," move control D a few divisions higher and
readjust control E for minimum plate current. Repeat until the plate current
reading is in the area marked "CW." Do not leave the controls on an) position
other than that at the resonance dip. Lock controls C, D, and E.
(d) If
control C is on position 8 or above:
1. Hold "TEST" switch closed and adjust
control D to the position at resonance indicated by the dip in plate
current.
2. Place the power level switch on "OPERATE'' position.
3. If the
plate current meter reading is above the area marked "CW," move control E a few
divisions lower and readjust control D for minimum plate current. Repeat until
the plate current reading is in the area marked "CW." If the plate current meter
reading is below the area marked "CW," move control E a few divisions higher and
readjust control D for minimum plate current. Repeat until the plate current
reading is in the area marked "CW." Do not leave the controls on any position
other than that at the resonance dip. Lock controls C, D, and E.

Figure 2-10. Antenna Loading Unit CU-32/ART-13A -- Front
View
(3) "CW" OPERATION INTO FIXED OR TRAILING ANTENNA (200 KC TO 600
KC).
(a) Follow instructions in paragraphs 6b(4), steps (a) through
(0).
(b) Set controls P and Q on the positions indicated in the table of
approximate dial settings for the frequency below the desired frequency. Be sure
to use the column under the correct length of antenna.
(c) Follow the
instructions in the regular procedure starting with paragraphs 6b(4) (s), this
section.
d. PROCEDURES FOR SETTING THE CONTROLS OF RADIO TRANSMITTING SET
AN/ART-13B (MANUAL OR AUTOTUNE OPERATION)
(1) GENERAL--Radio Transmitting Set
AN/ ART-13B employs both variable frequency oscillator (VFO) operation and
crystal-controlled (XTAL) operation. When operated as a VFO transmitter,
utilizing Oscillator O-17/ART-13A, procedures for setting all controls are
exactly as outlined for Radio Transmitting Set AN/ART-13A in paragraph b. of
this section. For VFO operation on the high frequency range, with the CDA-T
Oscillator in use, the transmitter controls are set as outlined for the
AN/ART-13A, with the addition of one operation; that is the setting of the
"VFO-XTAL" switch, on the CDA-T panel, to "VFO".
Crystal-controlled operation
is obtainable only with use of the CDA-T Oscillator unit, and its "VFO-XTAL'
switch turned to "XTAL". "MANUAL" operation is not possible with
crystal-controlled operation. All transmitter and loading coil adjustments for
crystal-controlled operation (excepting the frequency controls "A" and "B") are
performed the same as described in paragraph b. of this section.
Crystal-controlled frequency adjustment procedures are as follows.

Figure 2-11. Crystal Controlled Oscillator Unit (CDA-T) -- Front
Side View
(2) FREQUENCY ADJUSTMENTS---CRYSTAL CONTROLLED
OPERATION.--Since manual control is inoperative with crystal-controlled
operation, ten high frequency and one low frequency channels are available with
autotune selection. Through use of an "A-B" switch on the CDA-T panel, two
frequencies are available on each of the ten high frequency "CHANNEL'' switch
positions. A 4-position switch, also on the CDA-T panel, permits selection of
four low frequencies with the "CHANNEL" switch in the "L.FREQ." position.
(3)
HIGH FREQUENCY RANGE.--Utilizing the "A-B" switch, two frequency channels are
available on each of the autotune "CHANNEL" switch positions, 1 through 10.
Selection of frequencies with the 1670 to 18,000 Kc. range are limited only by
the available crystals and the individual range of each setting of the
transmitters "A" control. "CHANNEL" switch positions of the autotune mechanism
are not restricted to any particular setting of the "A" control and several
frequency outputs within a narrow frequency range are possible, providing
crystals are available for each channel desired. The crystal frequency used,
however, must be suitable for the frequency range of the chosen "A" control
setting. Table 2-2 lists the frequency range of each position of control "A" and
the crystal frequency required for each of these output ranges.
(a) Place the
antenna selector switch on the antenna loading unit on "FIXED ANT." position.
Make certain that the microphone, key and throttle switch (T.S.) jack circuits
are open.
(b) Place "LOCAL-REMOTE" switch in "LOCAL'' position, the
"VFO-XTAL" switch in "XTAL" position and the "A-B" switch in the "A" position.
Turn the "EMISSION" switch to "VOICE".
(c) Check crystals for proper seating
and frequency. Channel the autotune to position 1. When cycling has stopped,
check the frequency range of the control "A" setting, to be sure it is suitable
for the crystal employed. If not suitable, change either the crystal or retune
control "A" to the proper frequency range setting. Lock this control. Unlock the
other transmitter controls; set control "C" to position 1.
(d) Place
"EMISSION" switch on "CW" position. Check the grid drive to the final amplifier
by placing the meter switch on "P.A.GRID" position, closing the "TEST" switch,
and noting the reading on the meter. If no reading, or a very low reading is
observed, close the "TEST" switch, at the same time varying the "B" control
setting. The grid drive indication will vary as the 'B" control setting is
changed. Adjust this setting for maximum grid drive reading.
(e) Set the
remaining transmitter loading controls, as described in paragraph b. to obtain
proper P.A. Plate dip indication, and maximum antenna current reading.
(f)
Channel the autotune to channel 2, and when cycling starts, turn the "CHANNEL"
switch back to position 1. Again check the grid drive and P.A. Plate readings,
which should be approximately the same as previously obtained.
(g) Channel
the autotune to each of the remaining nine high frequency channels and tune as
outlined for channel 1.
(h) If two frequency outputs are desired for any one
position of the "CHANNEL" switch, their frequencies should not be separated by
more than 3%. The exact amount of separation possible will be determined by the
output frequency and the antenna characteristics into which the transmitter
operates. Adjust the setting of control "B" as outlined with the "A-B" switch on
"A". Record the setting of this control for maximum grid drive reading. Throw
the "A-B" switch to "B" and determine the setting of control "B" for maximum
grid drive indication. Finally, set control "B" midway between the two settings
obtained with maximum grid drive for the "A" and "B" crystals. Repeat this
procedure for all channel switch positions for which two crystals are in use.

(4) LOW' FREQUENCY RANGE.--Utilizing the 4-position selector switch, located
on the CDA-T panel, four low frequency outputs within the range of 300 to 500
Kc. are possible. It will be noted that only three low frequency crystal sockets
are provided, requiring the use of a dual crystal holder in one socket. Due to
the physical limitations of this holder, its two crystals must be within the
range of 400 to 500 Kc. Remote control of Iow frequency operation is possible,
only on one frequency, as the 4-position switch must be operated manually and
its setting will determine the frequency obtained by the remote control
operator.
(a) Place the antenna selector switch on the antenna loading unit
in the fixed antenna position. Make certain that the microphone, key and
throttle switch (T.S.) jack circuits are open. Place "LOCAL-REMOTE" switch in
"LOCAL" position, the "EMISSION'' switch in "VOICE" position, the "VFO-XTAL"
switch in "XTAL" position, and the 4-position low frequency selector switch in
position 1.
(b) Place "CHANNEL" switch in "L.FREQ." position and wait until
the autotune stops. Control "A" should stop on position 13. If not in this
position when cycling is complete, unlock control and set to 13. Set control "C'
to position 8. (Control "B" is not required for low frequency crystal
operation.)
(c) Place the meter switch on "P.A. GRID"; the "EMISSION" switch
on "CW", and check for grid drive by closing the "TEST" switch and noting the
meter reading. P.A.GRID meter readings will be lower than those obtained for the
high frequency ranges.
(d) Adjust the variable choke, L-803, located at the
top rear corner of the CDA-T unit, to obtain maximum grid drive
indication.
(e) Turn the 4-position switch to the remaining three positions,
and check for grid drive. Adjust the variable choke, as required, to obtain
maximum grid drive reading for each switch position. This choke setting will
vary slightly for each of the low frequency output frequencies, and should
finally be set to obtain sufficient grid drive with all crystals
employed.
(/) Set all other transmitter and loading coil adjustments as
outlined in paragraph b. (4) (a) through (y) of this section, to obtain proper
P.A. Plate dip indication and maximum antenna current reading. When more than
one low frequency crystal is employed, optimum transmitter performance on any
one frequency requires readjustment of the variable choke (for grid drive
peaking) and the transmitter loading controls, with a resultant lowering of
output at the remaining low frequency channels.
SECTION III OPERATION

CAUTION
No transmissions mill be made on emergency
(distress) H.F. channels except for emergency purposes. For testing,
demonstration or drill purposes, radio equipment will be operated into a
non-radiating dummy load instead of an antenna to prevent transmission of false
distress signals.

WARNING
This equipment utilizes high voltages which are
dangerous to life. Operating personnel must observe all safety regulations. Be
sure to turn off the entire equipment before opening top cover of transmitter.
High voltage (1150 volts) connections are made to the caps at the tops of some
tubes.
1.
STARTING AND STOPPING THE EQUIPMENT.
a. TO START.--Turn "EMISSION" switch to "VOICE" position.
b. TO
STOP.--Turn "EMISSION" switch to "OFF" position.
2. OPERATION DURING NORMAL
USE.
a. Check "LOCAL-REMOTE" switch to
make sure it is in the proper position according to whether operation is from
the transmitter panel or from the remote control unit.
b. Place the emission
switch on "VOICE" and "CHANNEL" switch on the position corresponding to the
frequency on which transmission is desired. This may be found on the chart on
the front panel of the transmitter.
c. When the red pilot light comes on (it
will take about 25 seconds for the Autotune to seek the proper position), place
the emission switch on the position corresponding to the type of emission
desired, either "VOICE," "CW," or "MCW."

Note
Voice and MCW operation on fixed wire antennas in
the 200 kc to 600 kc range is prohibited because the loading unit is not
designed to withstand the high voltage generated with modulation under these
conditions. Use CW only on "FIXED ANT." in the 200 kc to 600 kc
range.
d. The transmitter is now ready for operation. Use either
a key or a standard microphone as required by the type of emission chosen.

CAUTION
Under no circumstances should the transmitter be
actually operating (key down or microphone pushbutton closed) when "EMISSION"
switch is being operated. Such operation, especially at high altitudes, can
cause an arc to occur and damage the contacts of
relays.
3.
CORRECTIVE MEASURES IF NORMAL OPERATION IS NOT OBTAINED.
a. FUSE OR CIRCUIT BREAKER FAILURE.
(1) If Autotune does
not run and tubes do not light, press the "TRANS. RESET" button on the front of
the dynamotor unit.
(2) If Autotune runs and tubes light but dynamotor does
not start, press the "DYNA. RESET" button on the front of the dynamotor
unit.
(3) If Autotune runs, tubes light, and dynamotor starts but no
transmission is obtained, first check the position of control C by unlocking the
dial and rotating it back and forth through a small range while holding "TEST"
switch closed. If this results in normal operation, lock control C near the
proper number but in such a position that the transmitter will operate even if
not exactly on the indicated position. If rotating control C does not result in
normal operation, check the fuse on the front panel of the dynamotor unit and if
it is blown, replace it with the SPARE fuse.
b. REMOTE CONTROL UNIT OR CABLE
FAILURE.
(1) Place "LOCAL-REMOTE" switch on the transmitter panel in "LOCAL"
position and operate transmitter from its panel.
c. TUBE FAILURES.
(1) LOW
FREQUENCY OSCILLATOR.--Replace with one of the multiplier tubes. This will
provide low frequency operation only.
(2) ONE MULTIPLIER TUBE.--Interchange
with the low frequency oscillator tube. A tube with a good filament must be in
the low frequency oscillator socket at all times. This will provide high
frequency operation only.
(3) TWO MULTIPLIER TUBES OR ONE MULTIPLIER TUBE AND
THE LOW FREQUENCY OSCILLATOR TUBE.--Put the good tube in the first multiplier
socket. Tubes with good filaments must be in the low frequency oscillator and
the second multiplier sockets. This will provide operation in the frequency
range 2000 to 6000 kc.
(4) SPEECH AMPLIFIER.--Use "CW" operation. No sidetone
signal will be available.
(5) AUDIO DRIVER.--Interchange it with the sidetone
amplifier. There must be a tube with a good filament in the sidetone socket.
This will provide normal operation with the exception of a sidetone
signal.
(6) MODULATOR.--Use "CW" operation. The modulator tubes must have
good filaments.
(7) DETECTOR AND MCW AUDIO OSCILLATOR.--Interchange it with
the crystal oscillator tube. If there is a tube with a good filament in the
crystal oscillator socket, all operation will be normal except
the "CFI" will
be inoperative. If the tube in the crystal oscillator socket does not have a
good filament, only "VOICE" and "CW" operation are possible.
(8) ANY
COMBINATION (INCLUDING ALL) OF CRYSTAL OSCILLATOR, MIXER, DETECTOR AND "MCW'
AUDIO OSCILLATOR, SIDETONE AMPLIFIER.--There must be a tube with a good filament
in the sidetone amplifier socket. "VOICE" and CW operation are available.
(9)
ANY COMBINATION (INCLUDING ALL) OF CRYSTAL OSCILLATOR, MIXER, DETECTOR AND MCW
AUDIO OSCILLATOR, SPEECH AMPLIFIER, DRIVER, SIDETONE AMPLIFIER,
MODULATORS.--There must be tubes with good filaments in the modulator sockets.
CW operation is available.
(10) HIGH FREQUENCY OSCILLATOR.--Interchange with
the low frequency oscillator. The robe in the low frequency oscillator socket
must have a good filament. It may be necessary to reset the frequency of
operation since this interchange will cause the oscillator to shift from the
original frequency. The tube must be replaced with the proper type as soon as
possible. This interchange will provide high frequency operation only.
d.
AUTOTUNE FAILURE.--If the Autotune fails to position all dials properly, proceed
as follows until proper positioning is obtained.
(1) First turn all controls,
that did not position properly, in the extreme counterclockwise direction by
hand and then turn them clockwise until they stop.
(2) If that fails, turn
"CHANNEL" switch to "MANUAL" and set the controls on the proper position as
indicated by the chart on the transmitter and re-resonate by adjusting the
tuning control (either D or E) to the plate current dip.
(3) If controls are
tight and above procedure fails, loosen the locking bars and set the controls as
for "MANUAL" position.
e. ANTENNA LOADING UNIT FAILURE.--Connect the "ANT."
post on the transmitter directly to the antenna lead-in. This will provide high
frequency operation only.
f. VACUUM SWITCH FAILURE.--Remove the wire from the
"ANT." post and connect it to the "COND." post. Add a wire from the "RECEIVER"
post on the transmitter to the antenna (either fixed or trailing) not being used
for transmission. Be sure the trailing wire is reeled out. This operation may
result in damage to the receiver especially if the same frequency is being used
for transmission and reception. As a precaution, the wire may be disconnected
from the antenna (A) post on the receiver during each transmission period.
g.
COLD WEATHER FAILURE:---On certain frequencies where Dial D tunes very sharply,
difficulty may be experienced if those frequencies are set up in moderate
ambient temperatures and subsequently operated at extremely cold temperatures,
or vice versa. This is due to change of inductance with temperature. The
condition will occur only in extremes of temperature and can be corrected by
resetting Dial D.
SECTION IV THEORY OF
OPERATION

Figure 4-1. Radio Transmitting Set AN/ART-13A -- Block
Diagram

Figure 4-1A. Radio Transmitting Set AN/ART-13B -- Block
Diagram
1.
DESCRIPTION OF OPERATION.
a.
GENERAL.--A detailed analysis of the theory and function of all parts of Radio
Transmitting Sets AN/ART-13A and AN/ART-13B is presented in this section. Model
AN/ART-13B duplicates all functions of Model AN/ART-13A, differing from the
latter model by the addition of a crystal-controlled oscillator unit, known as
the CDA-T. Any reference to the Model AN/ART-13B or crystal-controlled
operation, which does not apply to the AN/ART-13A, will be indicated by a
separate paragraph with an appropriate sub-title.
Both equipments are
designed to provide radio communication by voice, modulated continuous wave
telegraphy, or continuous wave telegraphy employing VFO operation over the
frequency ranges 200 kc to 600 kc and 2000 kc to. 18,100 kc. In addition to the
VFO operation, Model AN/ART-13B provides crystal- controlled operation over the
frequency ranges 300 to 500 kc and 1670kc to 18,000 kc. These equipments
function as medium power transmitters intended primarily for aircraft use. A
distinguishing feature of this equipment is the automatic tuning system known as
the "Autotune". By means of the Autotune, the manual functions that are
performed to change transmission frequency, can be made automatic and any one of
eleven preset transmission channels may be selected. Approximately 25 seconds is
required for the Autotune to reset transmitter controls for operation on a new
transmission frequency. Remote control of operations required to change the
transmission frequency is also made possible with the aid of the Autotune
system.
An understanding of the theory and performance of the circuits can be
more easily obtained by first examining the contribution made by each major
circuit and by following the signal path from origin to the antenna. This can be
accomplished by a study of the block diagrams, figures 4-1 and 4-1A; and with
the aid of the explanation in the following paragraphs.
b. ORIGIN OF CARRIER
FREQUENCY.--The Carrier frequency of both transmitters, for VFO operation, is
generated in either of two variable frequency oscillators, depending on the
transmission frequency that is selected. One oscillator, which covers the range
200 kc to 600 kc is known as the low frequency oscillator, or "LFO Unit". The
second VFO oscillator, covering the range of 1000 kc to 1510 kc, utilizes one or
more frequency multiplier stages to produce the high frequency range of 2000 kc
to 18,100 kc. For crystal controlled operation (Model AN/ART-13B only), a
plug-in crystal unit known as the CDA-T, provides a low frequency output of 300
kc to 500 kc, coupled direct to the Power Amplifier stage and a high frequency
output which utilizes one or more of the transmitters frequency multiplier
stages to cover a frequency range of 1670kc to 18,000 kc. Tables 2-2 and 2-3
indicate the basic oscillator frequencies for each of the twelve high frequency
dial positions, along with the multiplication factors, the frequency multiplier
stages used and their frequency output.
(1) VFO OPERATION--MODELS AN/ART- 13A
AND AN/ART-13B
(a) HIGH FREQUENCY OSCILLATOR AND MULTIPLIER STAGES.--When
transmission frequencies in 2000 kc to 18,100 kc range are required, the V1O1
High Frequency Oscillator is used. Output of this oscillator is fed into the
First Frequency Multiplier stage where the frequency is doubled, tripled, or
quadrupled as required. Further frequency multiplication is required to obtain
frequencies above 6.0 megacycles and a Second Frequency Multiplier stage is
provided for that purpose. The second multiplier acts only as a frequency
tripler and is not used for generation of transmission frequencies below 6.0
megacycles. Thus, for transmission frequencies in the range 2.0 to 6.0
megacycles, the Second Frequency Multiplier is disconnected and the output of
the First Frequency Multiplier is fed directly to the Power Amplifier stage. For
transmission frequencies in the range 6.0 to 18.1 megacycles, the Second
Frequency Multiplier is connected into the system and the output of the First
Frequency Multiplier is fed to the Second Frequency Multiplier. Output of the
Second Frequency Multiplier is then coupled to the Power Amplifier stage.
(b)
LOW FREQUENCY OSCILLATOR.--When transmission frequencies in the 200 kc to 600 kc
range are required, the Low Frequency Oscillator is used. Output of this
oscillator is fed directly to the Power Amplifier Stage. The High Frequency
Oscillator and both multiplier stages are not used.
c. MODULATION.--The
carrier frequency may be "keyed" for Continuous Wave (CW) or Tone Modulated
Continuous Wave (MCW) emission. Voice modulation may also be accomplished. The
three types of emission, CW, MCW, or VOICE are selected by means of a manually
operated switch knob on the control panel of the transmitter or the control
panel of the Control Unit.
d. FIRST AUDIO AMPLIFIER, AUDIO DRIVER, AND
MODULATOR.--When voice is used, the input from either a carbon or dynamic
microphone is coupled to the First Audio Amplifier Stage. Output of the
amplifier is fed to the Audio Driver Stage which develops sufficient audio power
to "drive" the Modulator Stage. The Modulator Stage is then coupled to the Power
Amplifier to accomplish Voice modulation of the carrier.
e. MCW
OSCILLATOR.--A separate audio oscillator, known as the MCW Oscillator, is
provided to generate approximately a 1000 cycle tone that is used for modulation
of the carrier frequency when MCW emission is selected. The output of the MCW
oscillator is coupled to the input of the First Audio Amplifier when transmitter
is used for CW or MCW emission. This audible tone then passes through Audio
Driver Stage, Modulator Stage, and to Power Amplifier to modulate the carrier.
(NOTE: When using CW emission, modulator stage is not in operation thus
preventing this audible tone from modulating the carrier.) Operation of the
telegraph key will "key" the MCW Oscillator as well as the Carrier Oscillator
(High or Iow Frequency Oscillator) and the Power Amplifier Stage.
f. POWER
AMPLIFICATION AND ANTENNA COUPLING.--The Power Amplifier Stage provides for
power amplification of the modulated carrier. Output of this stage is connected
to an antenna loading circuit where power is delivered to the antenna. Two
separate antenna loading circuits are provided. The loading circuits in Radio
Transmitters T-47A/ART-13 (AN/ART-13A) and T-412/ART-13B(AN/ART-13B) are used
for transmission frequencies in the range 1670 kc to 18,100 kc. A separate unit
known as Antenna Loading Unit CU-32/ART-13A is equipped with the loading
circuits for transmission frequencies in the range 200 kc to 600 kc. Separate
output terminals on the transmitter are used to connect both the low frequency
and high frequency output to two separate terminals on Antenna Loading Unit
CU-32/ART-13A. The low frequency input connects to the loading circuits within
the loading unit. Output from these circuits passes to a "break-in" relay also
incorporated in the loading unit. This relay also handles the high frequency
output of the transmitter. When transmitter is operated in the 1670 kc to 18,100
kc frequency range, the "break-in" relay in Antenna Loading Unit CU-32/ART-13A
is not operated and its contacts provide a closed path for connection of high
frequency terminal to the antenna directly. When transmitter is operated in 200
kc to 600 kc frequency range, the relay in Antenna Loading Unit CU-32/ART-13A is
operated by the telegraph key or microphone switch. The antenna is then
connected to the output of the low frequency loading circuits in the unit; thus
permitting power to be delivered to antenna whenever the telegraph key or
microphone switch is depressed. When the telegraph key or microphone switch is
released, the relay reconnects the antenna to the high frequency antenna
terminal of the transmitter. The high frequency antenna terminal of the
transmitter is connected to the receiver antenna terminal whenever the telegraph
key or microphone switch is released thus providing for "break-in" operation of
an associated radio receiving set.
g. ANTENNAS.--The output of the Antenna
Loading Unit may be connected to either a Trailing Wire or a Fixed Aircraft
Antenna. Two separate antenna terminals are provided. A manually operated switch
on the Loading Unit is used to select either antenna.
h. SIDETONE
AMPLIFIER.--A portion of the output from the Audio Driver Stage is coupled to a
separate audio amplifier known as the Sidetone Amplifier. Output from this
amplifier is used to operate the headset or a speaker. The Sidetone Amplifier
provides for monitoring the code or voice that modulates the carrier. It also
provides a means of listening to the output of the CFI Unit that is used in
checking calibration of the high or low frequency oscillators. This action is
described more fully in the following paragraph.
i. CALIBRATION FREQUENCY
INDICATOR ("CFI") UNIT.--This unit, used only with VFO operation, consists of
four major circuits which operate to provide a constant 50 kc signal (rich in
harmonics) that is then mixed with output of either the high or low frequency
oscillator to produce an audible beat note. Calibration of the carrier frequency
oscillator can then be checked at numerous points by "zero beating" the 50 kc
standard against the carrier frequency oscillator. A beat note will be heard
when the carrier frequency or its harmonics are approximately equal to some
harmonic of the 50 kc standard.
j. GENERATION.--Generation of the 50 kc
signal in the CFI Unit is accomplished by using a circuit known as a
regenerative frequency divider. The circuit produces a 50 kc fundamental
frequency and harmonic output voltages while using a 200 kc crystal as the
controlling standard. The output of the 200 kc Crystal Controlled Oscillator and
the 150 kc output of a Frequency Triplet Stage are both fed to a Mixer Stage.
The difference frequency (50 kc) is present in the output of the Mixer Stage. A
portion of this 50 kc signal is fed back to the Frequency Tripler Stage to
provide the 150 kc output of that stage. It is the 50 kc signal that is obtained
from' the Mixer Stage that i$ used to "beat against" (or mix with) the carrier
frequency oscillator of the transmitter and is introduced into the Signal
Detector Stage in the CFI Unit to produce an audible beat note.
k.
OUTPUT.--Output from the Signal Detector in the CFI Unit is coupled to the First
Audio Amplifier. The audible beat note is further amplified in passing through
the Audio Driver Stage and the Sidetone Amplifier to the headset.(2)
CRYSTAL-CONTROLLED OPERATION-MODEL AN/ART-13B
(a) HIGH FREQUENCY OSCILLATOR
AND MULTIPLIER STAGES.--The high frequency oscillator of the CDA-T unit covers a
frequency range of 1670 kc to 3600 kc, and its output is fed to the First
Frequency Multiplier stage. The First Frequency Multiplier stage functions as a
straight through amplifier or as a doubler, for transmission frequencies in the
range of 1.67to 6.0 megacycles, the output of this First Frequency Multiplier
stage couples directly to the Power Amplifier. If frequencies between 6.0 and
18.0 megacycles are desired, the output of the First Frequency Multiplier stage
is fed to the Second Frequency Multiplier stage which functions as a frequency
tripler, whose output couples to the final amplifier.
(b) LOW FREQUENCV
OSCIllLATOR.--When transmission frequencies in the 300 kc to 500 kc range are
required, the low frequency oscillator of the CDA-T unit is utilized. Output of
this oscillator ii fed directly to the Power Amplifier stage. The high frequency
oscillators and the multiplier stages are not used.
(3) CRYSTAL-CONTROLLED
OPERATION-HIGH FREQUENCY.--The high frequency oscillator of the CDA-T unit, in
conjunction with the frequency multiplier stages of the basic transmitter
provide twenty crystal-controlled output frequencies in the range 1670 kc to
18,000 kc. Utilizing the autotune selection system and manually operated
controls on the CDA-T panel, any one of these 20 preset frequencies may be
selected without circuit readjustments.
(a) Utilizing a modified Pierce
crystal oscillator circuit, this high frequency oscillator employs a Type
JAN-6AQ5 tube (V801) and operates over the range of 1670 kc to 4000 kc. The
output frequency of the oscillator will always be the frequency of the crystal
in the circuit. The twenty crystals utilized to cover the above range are
divided into two groups, "A" and "B", with ten crystals in each group. Group
selection is accomplished by manually operating the "A-B" switch, S801, located
on the CDA-T panel. This switch actuates the "A-B" relay (K811) which selects
one group of crystals, shorting out the other group. Individual selection of
crystals within a group functions through the autotune system, using positions I
through 10 of the "CHANNEL" switch. When the autotune has cycled control "A" to
the desired position, switch S109 which is mechanically, coupled to the "A"
control autotune motor, supplies relay operating voltage to one of the ten
crystal relays (KS01 through KS10) which connects the selected crystal to the
grid circuit of oscillator tube, V801. Oscillator operation is controlled by
opening the cathode lead of V801 as previously described in this section,
paragraph 2.d.(2a). Oscillator frequency range for each of the 12 positions of
the "A" control are outlined in table 2-2.
(b) The output Of the crystal
oscillator is coupled through capacitor C150 and resistor R139 to the input of
the First Frequency Multiplier stage. For transmitter output frequencies between
1.67and 6.0 megacycles, this frequency multiplier stage couples directly to the
Power Amplifier stage. For frequencies between 6.0 and 18.0 megacycles, the
output of the First Frequency Multiplier stage is fed to the Second Frequency
Multiplier. The First Frequency Multiplier operates as a straight through
amplifier or as a frequency doubler, depending on the transmitter output
frequency range desired. For positions 1 through 3 and 7 through 10 of the :"A"
control, it is an amplifier with its frequency output the same as the crystal.
In positions 4 through 6, 11 and 12 of the "A' control, it .is a frequency
doubler, with its output frequency twice that of the crystal.
(c) The .Second
Frequency Multiplier stage always operates as a frequency tripler and is used
for positions 7 thiough 12 of the "A" control. Its output couples to the Power
Amplifier.
(d) All Power Amplifier and Output circuits operate exactly as
outlined previously in paragraph 2.g.(6) of this section.
(4)
CRYSTAL-CONTROLLED--LOW FREQUENCY.--The low frequency oscillator of the CDA-T
unit employs a Type JAN-1625 beam pentode tube V802 in a modified Pierce
oscillator circuit to cover the frequency range of 300 to 500 kc. Three crystal
sockets, one of which accommodates a dual type crystal holder, permit four
channel low frequency operation. Switching from one frequency to another is
accomplished through the 4-position rotary switch (S802) which shunts out all
crystals not in use. An iron core plate choke (L803) may be varied to obtain
resonance and provide maximum oscillator output. Screen and plate voltage for
V802 is obtained from a tap on the dynamotor low voltage bleeder. Oscillator
operation is controlled by opening the cathode lead of V802 as indicated in
figure 4-5A. This cathode returns to ground through switch S114 (which is
mechanically operated by the "A" control); through relay K106 (controlled by the
"VFO-XTAL" switch S802), and finally through the keying relay contacts K102E.
For low frequency operation, control "A" must be in position 13, which couples
the oscillator output through the Second Multiplier range switch S103, to the
grid of the Power Amplifier tube, V104. Frequency output of this oscillator is
always the frequency of the crystal in the circuit.
2. DETAILED ANALYSIS OF MAJOR CIRCUITS.

Simplified schematic diagrams of the
basic circuits are presented to complement the discussion. Where Eicor Dynamotor
Unit DY-17A/ART-13A is used, basic theory and function apply, but there are
differences in reference symbols and circuitry. Referring to Figure 8-41A
schematic diagram, note that S2701, S2702 and S2703 correspond to K2705, K2706
and K2704 respectively; also, the filters are sealed assemblies.

Figure 4-2. Power Control Circuits
a. POWER CONTROL
CIRCUITS.--Primary power to the dynamotor is controlled by contactors located in
Dynamotor DY-17/ART-13A. All relays and contactors which require energizing
operate from the 28 V d-c power source. Relays K2705 and K2706 are
thermal-operated, overload relays which protect the equipment from damage due to
overloads. Relay K2704 is a pressure-operated switch which requires no power; it
operates when the atmospheric pressure is reduced to that corresponding to
altitudes between 20,000 and 25,000 feet above sea level. Complete control of
all power contactors is possible from either the transmitter or the remote
position.
(1) Figure 4-2 shows a simplified schematic of the power control
circuits.
(2) Relays K2705 and K2706 are normally closed and operate to break
the primary circuits when an overload occurs. These relays may be returned to
the normal position by pressing the "RESET" buttons located on the Dynamotor
Unit. Primary overload relay K2705 is designated as TRANSMITTER RESET and
dynamotor overload relay K2706 as DYNAMOTOR RESET. With the overload relays
K2705 and K2706 in normally closed positions and the "LOCAL-REMOTE" switch,
S107, in the "LOCAL" position, placing the "EMISSION" selector switch, S110, in
the "VOICE" position will complete the circuit necessary for the operation of
the primary power contactor, K2702. The primary power contactor coil, K2702A, is
energized by the circuit through LOCAL-REMOTE switch S107, EMISSION selector
switch S110, primary power contactor coil K2702A and the contacts of primary
overload relay K2705. When the power control relay, K2702, has operated, the
circuit necessary for the operation of the "voice" relay, K104, is completed
through the contacts of primary overload relay K2705, primary power contactor
contacts K2702B, "voice" relay coil K104A, the contacts of EMISSION selector
switch S110, and the contacts of LOCAL-REMOTE switch S107. If the power level
switch, S106, is in either the "TUNE" or "OPERATE'' position, it is necessary to
operate the TEST switch, S104, or to complete the circuit through the throttle
switch jack, J 101, MICROPHONE jack J 102, or KEY jack J103, before the
dynamotor input relay, K2703A, will operate.
(3) Operating the EMISSION
selector switch, SI 10, to the CW position completes the circuit necessary for
the operation of CW relay K103, through the contacts of LOCAL-REMOTE switch
S107, EMISSION selector switch SILO, and CW relay coil K103A. When the CW relay,
K103, has operated, the coil of dynamotor input relay K2703 is energized through
the contacts of CW relay K103B, dynamotor input relay coil K2703A, the contacts
of safety interlock switch Sl17, the contacts of Autotune limit switch section
Sill, motor control relay contacts KIO1B, primary power contactor contacts
K2702B, and the normally closed contacts of overload relay K2705.
(4) If the
EMISSION selector switch, SI10, is operated to the MCW position, the primary
power contactor K2702, is operated by the circuit through the normally closed
contacts of overload relay K2705, the coil of primary power contactor K2702, the
contacts of EMISSION selector switch SI 10, and the contacts of LOCAL-REMOTE
switch SI07. Dynamotor input relay K2703 is energized by the circuit through the
normally closed contacts of primary overload relay K2705, motor control relay
contacts KIOIB, the contacts of Autotune limit switch section S1 l l, the
contacts of safety interlock switch SI 17, dynamotor input relay coil K2703A,
the contacts of EMISSION selector switch SI10, and the contacts of LOCAL-REMOTE
switch S107. The operation of dynamotor input relay K2703 closes the contacts of
this relay and applies power to the motor section of dynamotor D2701 through the
normally closed contacts of dynamotor overload relay K2706.
(5) If the power
level switch S106 is operated to the "CALIBRATE" position, CW relay K103 is
operated through the normally closed contacts of primary overload relay K2705,
primary power contactor contacts K2702B, CW relay coil K103A and the contacts of
power level switch S106. The dynamotor input relay, K2703, is operated by the
circuit through the normally closed contacts of primary overload relay K2705,
primary power contactor contacts K2702B, Autotune motor control relay contacts
K101B, the contacts of Autotune limit switch section S111, the contacts of
safety interlock switch S117, dynamotor input relay coil K2703A, and CW relay
contacts K103B.
(6) With LOCAL-REMOTE switch S107 in the local position the
primary power contactor, KI70I, and the transmitter panel pilot lamp, I101, will
be energized when the EMISSION selector switch, SI 10, is in any position other
than the "OFF' position. Primal, power contactor K2702 will be operated by the
circuit through the normally closed contacts of primary overload relay K2705,
primary power contactor coil K2702A, the contacts of EMISSION se. lector switch
Sll0, and the contacts Of LOCAL-REMOTE switch S107. The pilot lamp, Il01, will
be energized through the normally closed contacts of primary overload relay
K2705, primary power contactor contacts K2702B, Autotune motor control relay
contacts K101B, the contacts of Autotune limit switch section SI 11, the
contacts of safety interlock switch SI 17, the pilot lamp series resistor, R136,
the contacts of LOCAL-REMOTE switch S107 and the contacts of EMISSION selector
switch SI 10.
(7) When the LOCAL-REMOTE switch, S107, is placed in the
"REMOTE" position, control of all power circuits is transferred from the
transmitter panel controls to the controls located on the remote control
unit.

Note
Operation of the control panel is identified to that
of the control box described below except that there is no key or microphone
jack on the panel.
(8) If the EMISSION selector switch, S602, is
placed in the "VOICE" position, the primary power contactor, K2702, is energized
by the circuit through the normally closed contacts of primary overload relay
K2705, primary power contactor coil K2702A, the contacts of EMISSION selector
switch S602, and the contacts of LOCAL-REMOTE switch S107. To complete the
circuit necessary for the operation of the dynamotor input relay, K2703, the
telegraph key, S603, must be operated or the microphone jack, J602, circuit must
be completed. The "voice" relay, K104, is operated by the circuit through the
normally closed contacts of primary overload relay K2705, primary power
contactor contacts K2702B, "voice" relay coil K104A, the contacts of EMISSION
selector switch S602, and the contacts of LOCAL-REMOTE switch S107. The
dynamotor input relay, K2703, is operated by the circuit through the normally
closed contacts of primary overload relay K2705, primary power contactor
contacts K2702B, Autotune motor control relay contacts K10IB, the contacts of
Autotune limit switch section Sill, the contacts of safety interlock switch
S117, dynamotor input relay coil K2703, "voice" relay contacts KI04C and
telegraph key S602 or microphone jack J602.
(9) When the EMISSION selector
switch, S602, is operated to the CW position, the CW relay, Kl03, is operated by
the circuit through the normally closed contacts of primary overload relay
K2705, primary power contactor contacts K2702B, CW relay coil KIO3A, the
contacts of EMISSION selector switch S602 and the contacts of LOCAL-REMOTE
switch S107. The operation of CW relay KI03 completes the circuit necessary for
the operation of dynamotor input relay K2703. Dynamotor input relay K2703 is
operated by the circuit through the normally closed contacts of primary overload
relay K2705, primary power contactor contacts K2702B, Autotune motor control
relay contacts KIO1B, the contacts of Autotune limit switch section S111, the
contacts of safety interlock switch S117, dynamotor input relay coil K2703A and
CW relay contacts K103B. The operation of the dynamotor input relay, K2703,
applies power to the motor section of dynamotor D2701 through the normally dosed
contacts of dynamotor overload relay K2705 and dynamotor input relay contacts
K2703B.
(10) If the EMISSION selector switch, S602, is operated to the MCW
position, primary power contactor K2702 is held operated and dynamotor input
relay K2703 is energized through the normally closed contacts of primary
overload relay K2705, primary power contactor contacts K2702B, Autotune motor
control relay contacts K101B, the contacts of Autotune limit switch section
S111, the contacts of safety interlock switch S117, dynamotor input relay coil
K2703A, the contacts of EMISSION selector switch S602 and the contacts of
LOCAL-REMOTE switch S107.
(11) LOCAL-REMOTE CIRCUITS
(a)
AN/ART-13A
With LOCAL-REMOTE switch S107 in the "REMOTE" position the primary
power contactor, K2702, and the pilot lamp, I601, are energized when EMISSION
selector switch S602 is in any position other than the "OFF" position. Primary
power contactor K2702 is energized through the normally dosed contacts of
primary overload relay K2705, primary power contactor coil K2702A, the contacts
of EMISSION selector switch S602, and the contacts of LOCAL-REMOTE switch S107.
The pilot lamp, I601, is energized by the circuit through the normally closed
contacts of primary overload relay K2705, primary power contactor contacts
K2702B, Autotune motor control relay contacts K101B, the contacts of Autotune
limit switch section S111, the contacts of safety interlock switch S117, pilot
lamp series resistor R136, the contacts of LOCAL-REMOTE switch S 107 and the
contacts of EMISSION selector switch S602.
(b) AN/ART-13B
Supplementing
the LOCAL-REMOTE circuits as outlined in the preceding paragraph, the AN/ART-13B
utilizes an additional single pole, double throw wafer on "LOCAL-REMOTE" switch
S107. For crystal-controlled operation, this wafer connects to an "A-B" toggle
switch on the remote control unit and to the "A-B" relay (K811) and "A-B" switch
(S801) of the CDA-T unit. With the "LOCAL-REMOTE" switch in the "LOCAL"
position, S801 controls operation of the "A-B" relay, changing the group of
crystals as desired. With the "LOCAL-REMOTE" switch in the "REMOTE" position,
the "A-B" toggle switch of the remote unit controls the crystal group
switching.
(12) The power change relay, K2701, operates when the pressure is
reduced to a pressure corresponding to altitudes between 20,000 and 25,000 feet
above sea level by the operation of the pressure operated relay, K2704. If the
transmitter is operating with VOICE emission, power change relay coil K2701A is
energized by the circuit through the normally closed contacts of primary
overload relay K2705, primary power contactor contacts K2702B, Autotune motor
control relay contacts K101B, the contacts of Autotune limit switch section
S111, the contacts of safety interlock switch Sl17, power change relay coil
K2701A, the contacts of pressure operated relay K2704, the contacts of "voice"
relay KI04 and the closed circuit of MICROPHONE jack J102. If the transmitter is
operating with CW emission and pressure operated relay K2704 has operated, the
operating circuit for power change relay IC2701 is through the normally closed
contacts of primary overload relay K2705, primary power contactor contacts
K2702B, Autotune motor control relay contacts K10IB, the contacts of Autotune
limit switch section Sill, the contacts of safety interlock switch S117, power
change relay coil K2701A, the contacts of pressure operated relay K2704 and CW
relay contacts K103B. If the transmitter is operating with MCW emission, the
energizing circuit for power change relay K2701 is through the normally closed
contacts of primary overload relay K2705, primary power contactor contacts
K2702B, Autotune motor control relay contacts KIO1B, the contacts of Autotune
limit switch section S111, the contacts of safety interlock switch S117, power
change relay coil K2701A, the contacts of pressure operated relay K2704, the
contacts of EMISSION selector switch SIIO or S602 and the contacts of
LOCAL-REMOTE switch S107.

Figure 4-3. Filament Circuits

Figure 4-3A. Filament Circuits -- AN/ART-13B
b.
FILAMENT CIRCUITS.--The filament power circuits of the transmitter are a
combination of series and parallel connections. The filaments are supplied with
power from the 28 volt d-c source. Figure 4-3, covering Model AN/ART-13A and
Figure 4-3A covering Model AN/ART-13B, show the filament circuits in simplified
form. All filament power is controlled by primary Power contactor contacts
K2702. The primary overload relay, K2705, operates to break the filament circuit
when an overload occurs in the filament or associated circuits.

Figure 4-4. High Voltage Circuits
c. HIGH VOLTAGE
CIRCUITS.--Figure 4-4 shows, in simplified form, the high voltage circuits
employed in the equipment.(1) The dynamotor employs an armature with dual
windings and two commutators to give output voltages of 400 volts d.c and 750
volts d-c. (The unit has slightly higher output voltages of 410 ans 780.) To
obtain the high voltage necessary for application to the power amplifier and
modulator tubes, the 400 volt .output is connected in' series with the 750 volt
output of the dynamotor. On the diagrams, figure 4-4 and figure 8-42 the low
voltage section of the dynamotor is designated as G1 and the h{gh Voltage
section is designated as G2. When the power change relay, K2701, is in the
normal position the positive lead from low voltage dynamotor section G1 is
connected to the negative lead of high voltage dynamotor section G2 through the
contacts of power change relay K2701, and milliammeter multiple resistor R2701B.
The circuit necessary to energize the coil of power change relay K2701 is
completed by the operation of the pressure-operated relay, K2704. When power
change relay K2701 operates, the negative lead of high voltage dynamotor section
02 is disconnected from the positive lead of low voltage dynamotor section G1
and is grounded through milliammeter multiplier resistor R2701A and B and the
contacts of power change relay K2701. Spark suppressing circuits have been
incorporated in the output circuits of the dynamotor to suppress the sparks
generated at the motor and generator brushes.
d. EMISSION SELECTION AND
CARRIER CONTROL.(1) The "EMISSION" selector switch SI10 is a combination
transmitter "ON-OFF" switch and "EMISSION" selector switch. Operating "EMISSION"
selector switch S110 to the "VOICE," "CW" or "MCW" position will operate the
primary contactor K2702 (see fig. 4-5). (Note: Refer to paragraph 3a, this
section for detailed explanation of the operation of primary power cootactor
K2702.) Selecting "VOICE" emission by the operation of "EMISSION" selector
switch S110 operates "VOICE" relay K104. "VOICE" relay contacts K104B disconnect
the output of the "MCW" oscillator tube, V2203, from the input to the speech
amplifier. "VOICE" relay contacts KI04C connect the coil of dynamotor input
relay K2703 to the emission control circuits of throttle switch jack J101,
"MICROPHONE" jack J102, "KEY" jack J103 and the "TEST" switch, S104. Selecting
"CW" emission completes the circuit necessary for the operation of "CW" relay
KI03. "CW" relay contacts K103D complete the circuit necessary for the operaiion
of dynamotor input relay K2703 which, in turn, applies primary power to the
dynamotor, D2701. Selecting "MEW" emission operates dynamotor input relay K2703
directly.

Figure 4-5. Emission Selection and Carrier Control Circuits
AN/ART-13A

(2)MODEL AN/ART-13A (Fig. 4-5).--The r-f carrier is
keyed by opening the cathode circuit of the oscillator and removing the screen
voltage from the power amplifier. The keying relay, gl02, has six sets of
contacts. The contacts K102E complete the oscillator cathode circuit by
grounding resistor RI31. Keying relay contacts KIO2E and resistor R131 serve as
a cathode return for both the h-f oscillator tube, V101, and the l-f oscillator
tube, V2601. The desired oscillator circuit is selected by the operation of
oscillator selecting switch 5114 which operates in conjunction with Control
A.

Figure 4-5A. Emission Selection and Carrier Control Circuits
AN/ART-13B
(3A) MODEL AN/ART-13B (Fig. 4-5A).--The r-f carrier is
keyed by opening the cathode circuit of the oscillator and removing the screen
voltage from the power amplifier. Selection of the channel and method of
operation (VFO or XTAL) is accomplished by switching the cathode ground return
lead to the desired oscillator. Switch SI14, mechanically controlled by the "A"
control dial, selects the frequency band. Positions 1 through 12 of control "A"
permit operation in the high frequency band; position 13 the Iow frequency band.
Choice of operation, XTAL or VFO, is controlled by switch S802 and relay K106.
With switch 5802 turned to "XTAL", relay K106 is energized. This relay shorts
out RI31, and depending on the setting of the "A" control, grounds the crystal
oscillator cathode (V801 or V802) through S114 and keying relay contacts K102E.
With switch S802 turned to "VFO", the cathode of the high frequency oscillator
V101 is grounded through K106A, S1l14, R131 and K102E.
(4) The "MCW"
oscillator tube, V2203, is in operation whenever keying relay K102 is in the
operated position. The voltage developed across the resistor, R2201, is applied
to the input of the 1st Audio Amplifier through "VOICE" relay contacts K104B,
the contacts of power level switch: S106 and the input transformer, T201. Keying
relay contacts K102F apply plate voltage to MCW oscillator tube V2203. During
periods of "CW" transmission the output of the "MCW" oscillator is fed through
the First Audio Amplifier and Audio Driver to the sidetone amplifier and the
keying may be monitored by listening to the output of the sidetone amplifier.
When power level switch S106 is in the "CALIBRATE" position, the circuit from
the output of the "MCW" oscillator to the input of the First Audio Amplifier is
broken. Also, with the power level switch S106 in the "CALIBRATE" position,
voltage is removed from the screen grid of power amplifier tube V104 and this
grid is connected back to the control grid of the same tube through a pair of
contacts on switch St06. This connection permits negative voltage on control
grid to be applied to screen grid and thereby cuts off output from power
amplifier stage. The keying relay, K102, may be operated by closing the circuits
of the Throttle Switch jack, J101, the "MICROPHONE" jack, J102, or the "KEY"
jack, J103, or by operating the "TEST" switch, S104. Keying interlock switch S
113D is operated in conjunction with output network switch S113, and breaks the
energizing circuit to the coil of keying relay K102 when output network switch
S113 is operated, thus removing excitation from the R-F circuits to prevent
arcing at the switch contacts. The Autotune limit switch section, S111l, and
Autotune motor control relay contacts K101C are also connected in series with
keying relay coil K102A so that when Autotune limit switch section S111 or
Autotune motor control relay K101 operates, the holding circuit for keying relay
K102 will be broken arid arcing at all switch contacts will be
prevented.

Figure 4-6. Speech Amplifier Circuits
e. AUDIO
CIRCUITS.--The audio system consists of a two stage speech amplifier, push-pull
modulators, a sidetone amplifier, and an "MCW" audio tone oscillator, See
simplified circuit in figure 4-6. (1) SPEECH AMPLIFIER.--Either of two types of
microphones may be used with the equipment. The input to the speech amplifier
has been designed so that by operating a switch, proper connections are made to
the "MICROPHONE" jack J102, to match the output of either a carbon or dynamic
type of microphone. The microphone circuit selector switch, S201, is located
beneath the tuning chart on the front panel of the transmitter (see fig. 2-2).
If microphone circuit selector switch S201 is placed in the "CARBON" position,
the bleeder composed of R201, R202, R203, and R204 connected between the
positive terminal of the 28-v d-c power source and ground (Br. earth) provides
the voltage necessary for the operation of the carbon type of microphone. The
operation of microphone circuit selector switch S201 also connects limiting
resistor R203 between "MICROPHONE" jack J102 and the input circuit of the speech
amplifier to reduce the level of the output of the carbon microphone to the
level of the output of a dynamic microphone. Thus, no audio gain control has
been provided because the level of the input to the speech amplifier is the same
when using a dynamic microphone as it is when using a carbon microphone. If
microphone circuit selector switch S201 is placed in the 'DYNAMIC' position, the
voltage is removed from the input circuit and the "MICROPHONE" Jack, J 102, is
connected in series with limiting resistor R216 and the primary of the input
transformer T201. The two stage speech amplifier employs a Type JAN-12SJ7 1st
Audio Amplifier tube, V201, and a Type JAN-6V6GT audio driver tube, V202. The
output of the microphone is coupled by the input transformer, T2015 to the grid
of 1st Audio Amplifier tube V201. The output nit 1st Audio Amplifier tube V201
is coupled to the grid of audio driver tube V202 by the capacitor C204. The
output of audio driver tube V202 is coupled to the grids of the modulator tubes,
V105 and �106, by driver transformer T202.

Figure 4-7. Modulator Circuit
(2) MODULATOR.--The
modulator employs two Type JAN-811 high-mu triodes connected in push-pull, and
operating Class B. The modulators are capable of modulating the carrier (100
watts nominal) at least 90% with full voltage applied to the power amplifier.
While the JAN-811 is essentially a zero bias tube when used with plate voltages
as high as 1150 volts d-c, it becomes necessary to apply some bias to the grid
of the tube to keep the static plate current as low as practicable. In this
application the bias is obtained from the 28-volt d-c supply by utilizing the
average voltage drop through the filaments of the tubes to obtain equal voltage
for application to the grids of both modulator tubes. The output of the
modulators is coupled to the r-f circuit by modulation transformer T101 (see
fig. 4-7). Both the screen and plate of the final amplifier tube, V104, are
modulated. The full output voltage of the dynamotor 1150 volts d-c, is applied
to the plates of the modulator tubes, V105 and V106. "CW" relay contacts K103B
remove plate voltage from the modulators when 'CW" emission is selected.

Figure 4-8. Sidetone Amplifier Circuit

(3)
SIDETONE AMPLIFIER.--A sidetone amplifier is incorporated in the same unit as
the two stage speech amplifier.
The amplifier employs a Type JAN-6V6GT beam
pentode tube, V203. The output of the audio driver tube, V202, in addition to
being applied to the primary of driver transformer T202, is applied to a voltage
dividing system consisting of C206, R211 and R212. (See fig. 4-8). The grid of
the sidetone amplifier tube, V203, is coupled to the junction of R211 and R212
and the voltage developed across resistor R211 drives the grid of V203 to
provide sufficient output from the sidetone amplifier to operate headphones or
speaker. The output of sidetone amplifier tube V203 is coupled to the "SIDETONE"
jack, J104, by "SIDETONE" impedance matching transformer T203 through sidetone
"OUTPUT" switch S202 and keying relay contacts K102C. The turns-ratio of
"SIDETONE" impedance matching transformer T203 may be varied by operating the
sidetone "OUTPUT" switch S202. The output of the sidetone amplifier is keyed by
the operation of keying relay K102. The "SIDETONE" jack, J 104, may be connected
in parallel with auxiliary jack J105 by connecting a jumper between terminals 26
and 27 of cable connector Jl06. The necessary plate and screen voltages for the
sidetone amplifier are obtained by tapping the bleeder system of the low voltage
output of the dynamotor.

Figure 4-9. MCW Oscillator Circuit
(4) "MCW"
OSCILLATOR.--The "MCW" audio tone oscillator utilizes a Type JAN-12SLTGT dual
triode tube, V2203. One triode section of this tube is used for the "MCW" audio
oscillator and the other triode section is used in conjunction with the CFI Unit
which is described in the next paragraph. The "MCW' oscillator is in operation
whenever keying relay contacts K102F apply voltage to the plate of "MCW"'
oscillator tube, V2203, when keying relay K102 is operated (see fig. 4-9). The
audio frequency output of the "MCW" oscillator is controlled by varying "MCW"
output control resistor R2201. A screwdriver slot for varying resistor R2201 is
accessible through ú hole at the rear of the "MCW-CFI" Unit. The voltage
developed across MCW output control resistor R2201is coupled to the input of the
speech amplifier through "VOICE" relay contacts K104B and the contacts of power
level switch, S106. When "VOICE" emission has been selected, "VOICE" relay
contacts K104B disconnect the output of the "MCW" oscillator tube., V2205, from
the input circuit of the speech amplifier. During periods of "CW" transmission
the "MCW" oscillator is keyed and the output is fed to the input of the speech
amplifier. The output of the sidetone amplifier provides a means of monitoring
the keying.

Figure 4-107. CFI Oscillator Circuit
/. "CFI"
CALIBRATION OSCILLATOR UNIT.--A regenerative frequency divider circuit is
employed in the "CFI" Unit to obtain a stable 50-kc fundamental frequency and
harmonics that are used to check the frequency of the carrier oscillator of the
transmitter. The circuit utilizes a 200-kc crystal as the controlling standard.
A simplified schematic diagram of this oscillator is shown in figure 4-10. Both
triode sections of a JAN-12SL7GT tube, V2201, a JAN-12SA7 pentagrid converter
tube, V2202, and one section of another JAN-12SL7GT tube, V2203, are used in the
calibration oscillator. Plate voltage is supplied to these tubes from the low
voltage output section of the dynamotor and is applied when the power level
switch S106 is operated to the "CALIBRATE" position. Operating power level
switch S106 to "TUNE" or "OPERATE" positions removes the plate voltage from the
"CFI" tubes and disables the circuit.
(1) The application of plate voltage to
the oscillator section of JAN-12SL7GT tube V2201, starts the 200-kc crystal
oscillator. This produces a frequency of 200 kc, plus random tube and circuit
noises, to appear on the injector grid of JAN-12SA7 mixer tube V2202. The random
noises appearing on the plate of JAN 12SA7 excites frequency tripler section of
JAN 12SLTGT tube V2201. Since the plate circuit of this section of JAN-12SL7GT
tube V2201 is tuned to 150 kc, only the 150-kc components of the random noises
are amplified. This 150-kc component of random noise is then impressed on
control grid of JAN-12SA7 mixer tube. Since the plate circuit of the JAN-12SA7
is tuned to 50 kc, the 50-kc difference frequency produced by the combination of
a 200-kc voltage and a 150-kc voltage appearing in the JAN-12SA7 tube, is the
frequency amplified. This 50-kc voltage continues to excite the second triode
section of V2201, which because of its tuned 150-kc plate circuit, triples the
frequency and sustains the 150-kc voltage on the JAN 12SA7 grid. The 50-kc
voltage appearing on the JAN12SA7 plate becomes the calibration
frequency.
(2) One triode section of the second JAN 12SL7GT tube, V2203, is
employed as a signal detector. A portion of the 50-kc voltage appearing on the
plate of JAN-12SA7 tube, V2202, is coupled to the grid of V2203 by capacitor
C2204. Depending upon the transmission frequency selected, a portion of the
output of the low frequency oscillator or the high frequency oscillator is
coupled to the grid of V2203 by capacitor C2206 or C2205. The beat note that is
generated in the signal detector is coupled to the input of the first amplifier
by capacitor C2209.
(3) When power level switch S106 is operated to the
"CALIBRATE" position, the circuit from capacitor C2209 to the input of the first
audio amplifier is completed and the output of the signal detector will be heard
through the sidetone circuits of the transmitter.
(4) The second triode
section of V2203 is utilized as the "MCW" audio oscillator. A description of
this circuit is given in paragraph 2e(4) entitled "MCW OSCILLATOR."
(5) The
inductor tuning screws that protrude through the sides of the shield cans
containing tank circuits Z2201A, Z2201B, Z2202A and Z2202B should not be
disturbed for any reason unless the alignment procedure is thoroughly
understood. The alignment of these circuits is described in the Maintenance
section of this manual.
g. RADIO FREQUENCY CIRCUITS RADIO TRANSMITTING SET
AN/ART-13A.--Radio Transmitter T-47A/ART-13 employs two r-f systems. One system
covers the frequency range 200 kc to 600 kc and the other system the frequency
range 2000 kc to 18,100 kc. Separate oscillator tubes are employed for each
frequency range. The same power amplifier tube serves both systems.

Figure 4-11. VFO Low Frequency R-F Circuits
AN/ART-13A
(1) LOW FREQUENCY R-F CIRCUITS.--The l-f oscillator
employs a Type JAN-1625 beam pentode tube, V2601. This oscillator operates in
the frequency range 200 kc to 600 kc. Frequency range is covered in three bands
which have the following individual ranges:

200 kc to 285 kc

285 kc to 415 kc

415 kc to 600 kc
A combination of capacitive and inductive
grid tuning is employed. The l-f oscillator "COARSE" tuning switch, S2601
(control "E"), varies the grid circuit capacity, by increasing the number of
padding capacitors connected in the circuit as the switch is rotated toward the
lowest frequency position (see fig. 4-11). Trimmer capacitors have been
connected in parallel with the padding capacitors to provide means of fine
adjustment of grid circuit capacity. These trimming capacitors are of the
ceramic type and the capacity of each may be varied by rotating one plate with
respect to the other. In spite of the small physical size, this type of
capacitor provides a means of varying the capacity over a wide range. With the
end points of the frequency band set and the trimmer capacitors adjusted to give
some overlap in each position of l-f oscillator "COARSE" tuning switch S2601,
all fine frequency adjustments within the frequency range of each switch
position are made by varying the inductance of the inductor L2602. The
inductance of L2602 is altered by adjusting the position of the core, which is
actuated by a tuning screw. The position of the tuning core within the inductor
is determined by control G. When l-f operation is desired and the l-f (13)
position of control A has been selected, the cathode circuit of the l-f
oscillator tube, V2601 is coupled through the contacts of oscillator selecting
switch S114 and bias resistor R131 to keying relay contacts KI02E of keying
relay K102. Operation of keying relay K102 completes the cathode circuit to
ground. Screen voltage for l-f oscillator tube V2601 is obtained by tapping the
dynamotor Iow voltage output bleeder. The output of l-f oscillator tube V2601 is
coupled to the grid of the final amplifier tube, V104, by second multiplier
range switch S103 when control A is operated in the l-f position. Selecting l-f
operation operates output circuit selecting relay K105 which connects the plate
circuit of final amplifier tube V104 to the external loading circuits in Antenna
Loading Unit CU-32/ART13A. The h-f output network is completely removed from the
circuit by the operation of output circuit selecting relay K105. Output circuit
selecting relay contacts K105D remove the shorting connection across the plate
choke, L109. Screen voltage for final amplifier tube V104 is obtained from the
low voltage output of the dynamotor. The full voltage of the high voltage
section of the dynamotor is applied to the plate of final amplifier tube V104.
The external loading coil in addition to being an antenna loading coil is also
the power amplifier plate tank circuit. A tapped inductor and variometer
provides means of adjusting the power amplifier plate tank tuning.
(2) HIGH
FREQUENCY R-F CIRCUITS.--The h-f oscillator employs a pentode Type JAN-837 tube,
VI01, in a variable frequency oscillator circuit. The oscillator operates within
the frequency range 1000 kc to 1510 kc. This frequency range is covered in two
bands, 1000 kc to 1200 kc, and 1200 kc to 1510 kc. The band of frequencies
within which output is obtained, is dependent on the position of h-f oscillator
range switch S101. Capacitors C101 and C135, (see fig. 4-12) are connected in
the grid circuit of the h-f oscillator tube V101, by h-f oscillator range switch
S101 which is operated by control A. Alternate positions of control A add or
remove the padding capacitors C101 and C135. With control A in the 2.0-mc to
2.4-mc position h-f oscillator range switch S101 is closed, giving the maximum
grid circuit capacitance