AVCO TAR-224 User manual

s●
80045 PRC 31/570
INSTRUCTION MANUAL
FOR
RADIO SETTAR-224
MANUFACTURED BY
if
E L E C T R O N I C S D I V I S I O N
CINCINNATI. OHIO A5241
1JULY 1970
f fi S«

80045 PRC 31/570
INSTRUCTION MANUAL
FOR
RADIO SET TAR-224
15 September 1971
Manufactured
by
AVCO CORPORATION
E L E C T R O N I C S D I V I S I O N
2630 GLENDALE-MILFORD ROAD
CINCINNATI, OHIO 45241

80045 PRC 31/570
RADIO SET TAR-224
INSTRUCTION MANUAL
REVISIONS
SEPTEMBER 15,1971
INSTRUCTION: This package consists of changed Pages and Errata Sheet.
Insert the Changed Pages in the manual and destroy superseded pages.
Incorporate the changes indicated on the Errata Sheets in the manual by
making pen and ink corrections.
1

80045 PRC 31/570
ERRATA NO. 1
ERRATA SHEET
NOTE
Make the following pen and ink changes in Instruction Manual for Radio Set
TA R-22 4 da te d 1J ul y 19 70 . Re ta in t he i nf or ma ti on c on ta in ed o n th is
Errata Sheet by inserting it into the manual. When all indicated changes have
been entered in the manual, anote on the front cover “ERRATA, SHEET
N O . 1 I N F O R M A T I O N H A S B E E N P O S T E D .
Page ii, opposite paragraph 5.3: Change “(1A2)” to “(1A5).
Page 1-1, paragraph 1.2, subparagraph a: Opposite Power requirement, delete “5.4 amperes” and substitute
5.9 amperes.>5
Page 1-3, next to last line: Delete “not less than 20 db between” and substitute “not less than 17.5 db
between.>1
Page 3-3, paragraph 3.4.1: In the second line change “1A1S5” to “1A1S3. 99
Page 3-3, paragraph 3.4.2: In the seventh line of the fir st subp ar agrap h change “1 A3A2R 4” t o
1A3A2R5.
ii 99
Page 3-4, upper left (Local oscillator 1A3A4): Change “C51” to “C15. 99
Page 3-13, second line from top: Change “SI” to “1A4S2” and “R28” to “R18. 99
Page 3-13, subparagraph e: In first sentence delete “The output of the ALC --
output of the ALC —
99 and substitute “The RF
99
Page 3-13, subparagraph e: Add “1A4A7Q8” to the end of the second sentence, making it read
the input to the class Aamplifier stage 1A4A7Q8.
it --and
99
Page 3-13, paragraph 3.6.2: In heading, delete “(Part of 1A4)” and substitute “(Part of 1A4A8).99
Page 3-13, paragraph 3.6.2, third line of first subparagraph: Delete “R1 and LI” and substitute “circuit
assembly 340716.99
Page 3-13, paragraph 3.6.2, fifth line of first subparagraph: Delete “C7, C8, L2, L3, R2 and Rll” and
s u b s t i t u t e “ c i r c u i t a s s e m b l i e s 3 4 0 9 9 9 . 99
Page 3-13, paragraph 3.6.2, second subparagraph: Delete fourth and fifth sentences “Degenerative feedback
-—and C2. Degenerative feedback a n d C 3 . ” S u b s t i t u t e “ D e g e n e r a t i v e f e e d b a c k f r o m t h e c o l l e c t o r t o
base of Q3 and Q4 is achieved by networks 340094-1 and 340094-2. 99
Page 3-13, paragraph 3.6.2, second subparagraph: Add at the end “Resistor RIO provides wideband loading
of T3.
99
Errata 1 Changed 15 September 1971

Page 4-9, subparagraph 4.4.1.2 a: Add to test equipment list (after VTVM):
Bird Model 43
Dummy Loa d
Page 4-9, subparagraph 4.4.1.2 b: Add at end of step (1) and prior to “Note”, the following: “This is a
coarse adjustment of forward-power loop-gain. Final adjustment is performed in the Radio Set as outlined
in subparagraph 4.4.1.2i.
Page 4-9, subpeiragraph 4.4.1.2 b: In the note change “point B” to “pin 5.
Page 4-9, subparagraph 4.4.12 c: Delete title “Reflected Power Detector Adjustment” and substitute
Reflected Power Detector Null Adjustment.
Page 4-9, subparagraph 4.4.1.2 d: Delete title “Forward Power Detector Adjustment” and substitute
Forward Power Detector Null Adjustment.
Page 4-12: Add new subparagraph at end of page:
“i. Forward Power Loop Gain Adjustment.
This adjustment can be made only with the RF Sampler Module installed in the Radio Set and a
6.0 MHz crystal installed in the Front Panel. Tune the transmitter of the TAR-224, as described
in paragraph 2.5.3, to afrequency of 12 MHz. Use a50-ohm dummy load as an antenna. With the
transmitter keyed, adjust potentiometer 1A4A2R19 for 20 watts output from the transmitter. >>
Page 5-1, paragraph 5.3: In paragraph heading, deleted “1A2” from end of heading and substitute “(1A5)”.
/
Page 5-14, subparagraph 5.8 c: Delete in its entirity step “(1) Line up the mark on the gear --
substitute “(1) Place wheel in band one position, making sure wheel is detented. Using amarking pen or
other non-conductive marking instrument, place amark on gear tooth and, in line with that mark, place a
mark on the edge of the board (figure 5-10)”.
and
Page 5-18, subparagraph 5.11 a: Add anew step between present steps (6) and (7) as follows: “(7) Remove
t h e t h r e e t u n e r b o a r d s . 99
Page 5-18, subparagraph 5.11 a: Renumber present steps (7) and (8), respectively, to (8) and (9).
Page 5-18, subparagraph 5.11 a: Add anew step after the newly numbered step (9) as follows: “(10)
Unsolder the ground straps from the tuner parent board.99
Page 5-18, subparagraph 5.11 a: Renumber present steps (9), (10), (11) and (12), respectively, to (11),
(12), (13) and (14).
Page 5-19, subparagraph 5.11 b: Add anew step between the present steps (9) and (10) as follows: “(10)
Resolder the ground strap to the tuner parent board. 99
Page 5-19, subparagraph 5.11 b: Renumber present steps (10), (11), (12), (13), and (14), respectively, to
(11), (12), (13), (14), and (15).
Page 5-19, subparagraph 5.11 b: Add anew step after the newly numbered step (15) as follows: “(16)
Replace the three tuner boards and tuner cover. 99
Page 5-19, subparagraph 5.11 b: Renumber present step (15) to step (17).
Errata 2 Changed 15 September 1971

Page 5-19, subparagraph 5.11 b: Add new step (18) after the newly numbered step (17) as follows: “(18)
Check and align bushings on the front panel with tuning capacitor shafts on receiver so that excessive side
pressure is not placed on shafts. Tighten bushings and replace receiver on front panel. 99
Page 5-19, subparagraph 5.11 b: Renumber present step (16) to step (19).
Page 5-20, subparE^raph 5.12 a: Between present steps (4) and (5) add anew step as follows: “(5)
D i s c o n n e c t R F c o n n e c t o r 1 A 1 A 4 J 6 . 99
Page 5-20, subparagraph 5.12 a: Renumber present steps (5) and (6), respectively, to steps (6) and (7).
Page 5-20, subparagraph 5.12 b: Add new step between present steps (4) and (5) as follows: “(5) Replace
R F c o n n e c t o r 1 A 1 A 4 J 6 . 99
Page 5-20, subparagraph 5.12 b: Renumber present steps (5), (6), (7), and (8), respectively, to steps (6),
(7), (8), and (9).
Page 5-20, subparagraph 5.13 a, step (5): In first sentence delete last word “line” and substitute “lines”.
Page 5-22, change call out on right side from “Motor Relay 1A4K2” to “Time Relay 1A4K3”.
Page 5-26, subparagraph 5.13 b: Change step (3) to read: “(3) Connect the key lines, the receiver coax, the
coax to 1A4J6, and the forward and reflected ALC coaxes. 99
Page 5-26, subparagraph 5.16 a: Change step (4) to read: “(4) Unsolder the d-c input wire and the ALC
injection coax leads.99
Page 5-28, subparagraph 5.16 b: Chaise step (3) to read: “(3) Resolder the RF input and output wires and
the ALC injection coax. 99
Page 5-29, subparagraph 5.17 b., step (2) (b): Deltet the second sentence “The screw that is connected to
the rotor tab is anylon screw and has asolder lug under it.99
Errata 3 Changed 15 September 1971

L I S T O F E F F E C T I V E P A G E S
Date of Issue
Original —1July 1970
Change —15 Sept. 1971
T O T A L N U M B E R O F P A G E S I N T H I S P U B L I C A T I O N I S 1 3 3 C O N S I S T I N G O F T H E F O L L O W I N G
Page Issue Page Issue
Title ..15 Sept. 71
..15 Sept. 71
..15 Sept. 71
.. 1 July 70
..15 Sept. 71
. . l J u l y 7 0
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
.. 1 July 70
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
. . l J u l y 7 0
..15 Sept. 71
.. 1 July 70
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
.. 1 July 70
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
. . l J u l y 7 0
..15 Sept. 71
6-1 thru 6-8 .. . . lJuly 70
. . lJuly 70
..15 Sept. 71
. . lJuly 70
..15 Sept. 71
A7-1
7-2
1
7-3 thru 7-6 .
8-1 thru 8-35
11
m
IV . .
1-1
1-2
1-3 thru 1-4 ..
2-1
2-2 thru 2-5 ..
2-6 thru 2-8 ..
2-9 thru 2-10 .
3-1 thru 3-4 ..
3-5 1
3-6 thru 3-8 .
3-9 thru 3-12
3-13
3-14. ...
3-15 thru 3-17
4-1
4-2 .
4-3
4-4 .. .
4-5 thru 4-7
4-8
4-9
4-10
4-11 thru 4-12 .
5-1
5-2 thru 5-6 ..
5-7 thru 5-10 .
5-11 thru 5-12 .
5-13 thru 5-14 .
5-15 thru 5-16 .
5-17 thru 5-20 .
5-21
5-22 thru 5-24 .
5-25
5-26 thru 5-30 .
5-31 thru 5-33 .
AChanged 15 September 1971

T A B L E O F C O N T E N T S
Page
INTRODUCTION VI
CHAPTER 1DESCRIPTION AND LEADING PARTICULARS
1.1 Description of Radio Set TAR-224 .
C h a r a c t e r i s t i c s o f R a d i o S e t T A R - 2 2 4
1-1
1.2 1-1
CHAPTER 2OPERATION
2.1 Scope
Operation Procedure
F r o n t P a n e l C o n t r o l F u n c t i o n s . . . .
Receiver Operation
Readout Dial Calibration
Amplitude Modulation Reception ...
Continuous Wave Reception
Transmitter Operation
Antenna and Counterpoise Deployment .
Transmitter Frequency Source Operation
Frequency Synthesizer
CS-224
Front Panel Crystal
Transmitter Tuning
Transmitter Keying
Front Panel Key .
External Key
Medium Speed Keyer
Amplitude Modulation Operation ...
Power Sources
Internal Battery
Internal Battery Charging
External Source
2-1
2.2 2-1
2.3 2-1
2.4 2-5
2.4.1 2-5
2.4.2
2.4.3
2-6
2-7
2.5 2-7
2.5.1
2.5.2
2.5.2.1
2.5.2.2
2.5.2.3
2-7
2-7
2-7
2-7
2-8
2.5.3 2-8
2.5.4
2.5.4.1
2.5.4.2
2.5.4.3
2.5.5
2-8
2-9
2-9
2-9
2-9
2.6 2-9
2.6.1
2.6.1.1
2.6.2
2-9
2-9
2-10
CHAPTER 3 RADIO SET TAR-224 CIRCUIT DESCRIPTION
3.1 Scope
TAR-224 Radio Receiver-Transmitter Circuit Description ....
RR-224 Receiver Functional Block Diagram Description ....
RR-224 Receiver Individual Circuit Description
Antenna Matching Network Detailed Description (1A3A2)....
RF Amplifier Detailed Description (1A3A3)
Local Oscillator Detailed Description (1A3A4)
IF Mixer, IF Filter, IF Amplifier Detailed Description (1A3A7) ..
AM Detector (1A3A8A1), AM Automatic Gain Control (1A3A8A2)
Detailed Description
Beat Frequency Oscillator (1A3A6A2) and Product Detector
(1A3A8A2) Detailed Description
Audio Amplifier Detailed Description (1A3A8A1)
3-1
3.2 3-1
3.3 3-1
3.4 3-3
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3-3
3-3
3-3
3-7
3-7
3.4.6
3-8
3.4.7 3-8
Changed 15 September 1971
1

TABLE OF CONTENTS (Cont)
Page
CHAPTER 3 RADIO SET TAR-224 CIRCUIT DESCRIPTION (Cont)
3-83.4.8 Internal Calibration Circuit Detailed Description (1A3A6A1) .
RT-224 Transmitter Functional Block Diagram Description .
RT-224 Transmitter Circuit Description
Low Level Module Detailed Description (1A4A7)
Driver-Final Amplifier Assembly Detailed Description
(Part of 1A4)
Keyer Module Detailed Description (1A4A5)
Modulator Module Detailed Description (1A4A5)
RF Sampler Detailed Description (1A4A2)
Antenna Matching Network Detailed Description (1A4A8). .
Antenna Tuning Module Detailed Description (1A4A1) ...
Motor Control Circuitry Detailed Description
Power Supply Circuitry (Part of lAl)
Battery Protection Circuit
Battery Charging Circuit Description (Part of 1A1A3) . . .
3-9
3.5
3-9
3.6
3-9
3.6.1
3.6.2
3-13
3-14
3.6.3
3.6.4 3-14
3-14
3.6.5
3-15
3.6.6
3-15
3.6.7
3-15
3.6.8
3-163.7
3-16
3.7.1
3.7.2 3-17
CHAPTER 4ALIGNMENT AND ADJUSTMENT
4-1
4.1 Scope
TAR-224 Radio Set Electrical Alignment
TAR-224 Radio Receiver Electrical Alignment Procedure
Test Equipment
Local Oscillator Alignment
RF Amplifier Alignment
BFO Alignment
IF Amplifier Alignment
R T- 2 2 4 R a d i o T r a n s m i t t e r E l e c t r i c a l A d j u s t m e n t . . .
Transmitter Adjustments
Low Level Module Adjustments (1A4A7)
RF Sampler Module Adjustments
4-1
4.2
4-14.3
4-1
4.3.1
4-1
4.3.2
4.3.3
4.3.4
4-3
4-5
4-5
4.3.5
4-5
4.4
4-8
4.4.1
4.4.1.1
4.4.1.2
4-8
4-9
RADIO SET TAR-224 DISASSEMBLYCHAPTER 5
5.1 Scope
Battery Removal and Replacement
Case Removal and Replacement (1A2)
RR-224 Receiver Removal and Replacement
IF Amplifier Removal and Replacement (1A3A7)
BFO and Internal Calibration Module Removal and
Replacement (1A3A6)
Audio Amplifier and AGC Module Removal and Replacement
(1A3A8)
Antenna Matching Module (1A3A2), RF Amplifier Module (1A3A3), and
Loc al Osci lla tor M od ule R emo val a nd R epl ace men t (1 A3A 4) .. ..
Interwiring Board Removal and Replacement (1A3A1)
Removal and Replacement of Receiver Tape Readout.
Receiver Tuning Capacitor Removal 2md Replacement
RT-224 Transmitter Removal and Replacement (1A4)
Low Level Module Removal and Replacement (1A4A7)
Keyer Module Removal and Replacement (1A4A6)
5-1
5.2 5-1
5-15.3
5.4 5-4
5-65.5
5.6
5-6
5.7
5-9
5.8
5-9
5.9 5-14
5.10 5-17
5.11 5-18
5.12 5-19
5.13 5-20
5.14 .5-26
11

TABLE OF CONTENTS (Cont)
Page
CHAPTER 5 RADIO SET TAR-224 DISASSEMBLY (Cont)
5.15 RF Sampler Module (1A4A2), Motor Control Module (1A4A3),
Motor Control Module (1A4A4), and Modulator Module
Removal and Replacement (1A4A5)
Antenna Tuning Module Removal and Replacement (1A4A1)
Antenna Matching Network Removal and Replacement ...
Parent Board Removal and Replacement (1A4A9)
Driver-Final Section Shield Removal and Replacement ...
Battery Protection Circuit Parts Removal and Replacement
(lAlAl)
VFO Coupler (Part of Crystal Switch Assembly) Removal and
Replacement (1A1A2)
Relay Mounting Bracket Parts Removal and Replacement
(1A1A3)
Dessicant Removal and Replacement
5;26
5.16 5-26
5.17 5-28
5.18 5-29
5.19 5-30
5.20
5-30
5.21
.5-30
5.22
5-32
5.23 5-33
CHAPTER 6 TAR-224 RADIO SET MAINTENANCE
6.1 Scope
R e c e i v e r M a i n t e n a n c e . .
IF Amplifi e r S e c t i o n . .
B F O a n d C a l i b r a t o r S e c t i o n
Audio and AGC Section .
T r a n s m i t t e r M a i n t e n a n c e
6-1
6.2 6-1
6.3 6-1
6.4 6-3
6.5 6-3
6.6 6-5
CHAPTER 7 CS-224 CIRCUIT DESCRIPTION AND MAINTENANCE
7.1 General
Circuit Description
Crystal Replacement
Oscillator Alignment
Maintenance
CS-224 Disassembly and Assembly
7-1
7.2 7-1
7.3 7-1
7.4 7-1
7.5 7-4
7.6 7-4
CHAPTER 8 P A R T S L I S T A N D L I S T O F M A N U F A C T U R E R S
8.1 Parts List
List of Manufacturers
8-1
8.2 8-1
LIST OF ILLUSTRATIONS
Figure Title Page
1-1 Radio Set TAR-224
Radio Set TAR-224, Section Location
RR-224 Block Diagram
RR-224 Schematic Diagram
TAR-224 Front Panel Schematic Diagram
RR-224 Wiring Diagram
RT-224 Block Jliagram
1-2
2-1 2-2
3-1 3-2
3-2 3-4
3-3 3-5
3-4 3-6
3-5 3-10
Changed 15 September 1971
m

LIST OF ILLUSTRATIONS (Cont)
Figure Title Page
3-6 RT-224 Schematic Diagram
RT-224 Wiring Diagram
RF Amplifier and Local Oscillator
Antenna Matching Network and Parent Board
Calibrator and BFO
Circuit Board Assembly
Modulator, RF Sampler and Motor Control Boards No. 1
and No. 2
RF Sampler Test Equipment Set-up
Transceiver TAR-224
TAR-224 Exploded View
TAR-224 Module Location (bottom view)
RR-224 Receiver Assembly
RR-224 Module Location (bottom view)
RR-224 Module Location (right side view)
RR-224 Module Location (bottom side view)
RR-224 Module Location (left side view)
TAR-224 Module Location (top side view)
RR-224 Tuner
RR-224 Receiver Assembly, Exploded View
TAR-224 Front Panel (bottom view)
TAR-224 Module Location (right side view)
Transmitter Assembly
RT-224 Low Level Module and Keyer Module (shield installed)
RT-224 Low Level Module and Keyer Module (shield removed)
RT-224 Module Location (bottom side view)
Back Panel Assembly
IF Amplifier Module
AGC Board and Audio Board
Antenna Matching Module Location
CS-224 Schematic Diagram
CS-224 Assembly
3-11
3-7 3-12
4-1 4-2
4-2 4-4
4-3 4-6
4-4 4-7
4-5
4-10
4-6 4-11
5-1 5-2
5-2 5-3
5-3 5-5
5-4 5-7
5-5 5-8
5-6 5-10
5-7 5-11
5-8 5-12
5-9 5-13
5-10 5-15
5-11 5-16
5-12 5-21
5-13 5-22
5-14 5-23
5-15 5-24
5-16 5-25
5-17 5-27
5-18 5-31
6-1 6-2
6-2 6-4
6-3 6-6
7-1 7-2
7-2 7-5
LIST OF TABLES
Table Title Page
2-1 TAR-224 Controls and Functions
Local Oscillator Adjustment
RF Amplifier Adjustment
IF Amplifier 1A3A7 DC Voltage
Calibrator Board (1A3A6A1) DC Voltages
BFO Board (1A3A6A2) DC Voltages
Audio Amplifier Board (1A3A8A1) DC Voltages ..
AGC Board (1A3A8A2) DC Voltages
CS-224 Transistor Terminal Voltages
List of Units in Radio Set TAR-224
Front Panel lAl (Dwg. No. 340603) and Subassemblies
lAlAl thru 1A1A3
2-1
4-1 4-3
4-2 4-5
6-1 6-1
6-2 6-3
6-3 6-3
6-4 6-3
6-5 6-3
7-1 7-4
8-1 8-5
8-2
8-5
IV

LIST OF TABLES (Cont)
Page
TitleTable
Crystal Oscillator 1A2 (Dwg. No. 340569)
Receiver 1A3 (Dwg. No. 340601) and Subassemblies
1A3A1 thru 1A3A8
Transmitter 1A4 (Dwg. No. 340602) and Subassemblies
1A4A1 thru 1A4A8
8-9
8-3
8-4
8-10
8-5
8-23
V

INTRODUCTION
This instruction manual contains aU the information necessary to operate zind maintain Radio Set
TAR-224. Chapter 1gives the description and leading particulars of Radio Set TAR-224. Operation
instructions are given in Chapter 2. The description and theory of operation are in Chapter 3. Chapter 4
contains alignment and adjustment procedures. Assembly and disassembly instructions are given in Chapter
5. Radio set maintenance instructions are contained in Chapter 6. Chapter 7describes the crystal selector
CS-224. Parts listings and procurement data are contained in Chapter 8.
VI

CHAPTER 1
DESCRIPTION AND LEADING PARTICULARS
1.1 Description of Radio Set TAR-224
Radio Set TAR-224 (figure 1-1) is aminiature, all solid-state transmitter-receiver capable of operating in the
2MHz to 24 MHz frequency range. The TAR-224 consists of atransmitter (RT-224), receiver (RR-224),
and abattery (TYPE-224) all housed in one case. The radio is designed to accommodate exter.ial frequency
sources such as acrystal selector (CS-224), afrequency synthesizer, or an external crystal (CR-18/U).
Provisions are ;ilso made for operating from an external power source.
The RT-224 transmitter is in the right hand portion of the front panel, with the crystal selector above and
the RR-224 receiver to the left. The battery compartment is directly below the receiver mounted against
the side of the case. The battery and crystal selector can be removed from the case without removing the
front panel.
The radio set is waterproof when all the compartment covers are in place. Adust cover is supplied to cover
the entire front panel.
1 . 2 C h a r a c t e r i s t i c s o f R a d i o S e t T A R - 2 2 4
a . R T- 2 2 4 T r a n s m i t t e r C h a r a c t e r i s t i c s
Transistorized; crystal controlled
with provision for VFO excitation;
CW, AM, or Medium Speed Key
operation.
Type
2to 24 MHz in two bands (2 to
12 MHz and 12 to 24 MHz)
Frequency range
20 watts, nominal
20 watts, nominal
12 vdc, nominal, at 5.4 amperes,
maximum
40 ohms ±45° to 250 ohms
±45°
Power output
AM peak power output
Power requirement
Antenna impedance
Bu il t- in h an d ke y or e xt er na l
key. External keying at rates
up to 300 words per minute.
Dynamic microphone
Keying
A M S o u r c e
Long wire
Antenna type
1. Front panel crystal
Type
Frequency
Input sources
CR-18/U
2to 12 MHz
1-1

■»vsiAt «-RfOUtN' f
A U ( X A V I O N
0 ! 7
0
7i
-- -f - ■■ —
3■
il'
4‘
5
■'t
:6
7
9I
i - n w n e / i B f J
Figure 1-1. Radio Set TAR-224
1-2 Changed 15 September 1971

b. RR-224 Receiver Characteristics (Cent)
Detector AM: Diode envelope detector
Product detector
CW/SSB;
Audio output Headphones; Nominal, 1mw
into 500 ohms
Maximum, 2mw
into 500 ohms
5 0 0 k H z ± 0 . 0 1 %
Transmitter
frequency source
Calibration Internal:
Transmitter spot:
Beat frequency
oscillator (BFO)
range
± 3 k H z m i n i m u m
Size 7-1/4 inches by 12-1/4 inches
by 4-3/4 inches overall
including the upper protrud¬
ing corners.
c . P o w e r C h a r a c t e r i s t i c s
Input power External: +12 vdc
Receive:
Transmit:
50 ma
4.3 amp, nominal
Internal: +12 vdc battery
Receive:
Transmit;
50 ma, nominal
4.3 amp, nominal
d. Physical Characteristics
TAR-224 -including CS-224
and battery TYPE-224:
13.2 pounds
Weight
1-4

CHAPTER 2
OPERATION
2.1 Scope
This section describes the operating procedures for TAR-224.
2.2 Operation Procedure
To place the TAR-224 in operation proceed as follows:
Select asuitable site. The site preferably should be in an open area with no physical obstructions
a.
nearby.
b. Deploy the antenna.
Choose apower source as detailed in this section, paragraph 2.6.
Perform the tuning and adjustment procedures as detailed in this section, paragraphs 2.4 and/or
c.
d.
2.5.
WARNING
High voltage exists at the antenna terminals while transmitting. To prevent injury to
personnel or damage to equipment, do not come in contact with these terminals.
2.3 Front Panel Control Functions
The functions of the external controls, switches, plugs, and meter are given in table 2-1 and the front panel
is shown in figure 2-1.
T A B L E 2 - 1 . T A R - 2 2 4 C O N T R O L S A N D F U N C T I O N S
Control Function
POWER connector
(1A1J5)
Connector for d-c input power from an
external source. Battery can be
charged through this power connector.
BATTERY TEST switch
(push to operate)
(1A1S5)
Test switch to check the d-c power
source voltage level as indicated
o n t h e T U N E / V O LT S m e t e r.
POWER mode switch
(rotary switch)
(1A1S2)
Position: Function;
CHG/OFF De-energizes all power to
the radio set but per¬
mits the battery to be
ch ar ged fro m an e xtern al
source.
2-1

II 1 I I I I I I I 1 II 1 1 I
11I
TRANSMITTtR
SECTION
CS-224 PANEL
to
pi O CQ
(t>
H
M> Wpi
to to I. o
f
O
II
Q§
OR)
a W
●a
<t> 3 cr «D CASE
-4 BATTERY

TABLE 2-1. TAR-224 CONTROLS AND FUNCTIONS (Cont)
FunctionControl
p o w e r m o d e s w i t c h
(rotary switch)
(1A1S2) (cont)
Position Function;
RCVR Permits continuous opera¬
tion of the receiver
only.
RCVR/XMTR Permits operation of the
t r a n s m i t t e r w i t h t h e
receiver. The receiver
is normally on, but the
transmitter is permit¬
t e d t o b r e a k i n .
PHONE/KEY connector
(lAlJl)
Cormector permits the use of an
external keying device, microphone,
earphones or handset.
Connector permits the use of an ex¬
ternal keying device, microphone,
earphones, or ahand set.
PHONE/KEY connector
(1A1J2)
BFO (potentiometer)
(lAlRlO)
Varies the frequency of the beat
frequency oscillator (BFO)
±3. 0 kHz from th e cent er fre ¬
quency indicated on dial read¬
out.
RCVR (rotary switch) Position: Function:
(1A1S3) AM S e t s t h e r e c e i v e r f o r
AM reception.
CAL Energizes the internal
calibrator oscillator
with check frequencies
every 500 kHz.
CW S e t s r e c e i v e r f o r C W
reception.
Energizes the selected
transmitter frequency
d r i v e s o u r c e a s a c a h -
bration signal.
SPOT
When depressed, the receiver frequency
readout dial and the TUNE/VOLTS
m e t e r a r e i l l u m i n a t e d .
LIGHTS (push to
operate switch)
(1A1S6)
T U N E k n o b T u n e s t h e r e c e i v e r o v e r t h e s e l e c t e d
frequency band.
Changed 15 September 1971
2-3

TABLE 2-1. TAR-224 CONTROLS AND FUNCTIONS (Cont)
Function
Control
Adjusts the frequency readout dial
reference pointer to acrystal
reference.
CAL ADJ (mechanical
control)
In fully counterclockwise position,
activates the automatic gain con¬
trol (AGC); in other positions,
adjusts the level of RF gain.
RF -AGC
(potentiometer
and switch)
(1A1R5/1A1S7)
Adjusts audio output power level to
the headset.
AF (potentiometer)
(1A1R8)
Moves the frequency dial readout mask
opening and selects correlated
receiver band.
BAND switch, receiver
mechanical rotary
control and switch.
Band;
Position Color:
2.0 to 3.7 MHz
frequency band
Orange (Band 1)
3.7 to 6.9 MHz
frequency band
Blue (Band 2)
6.9 to 12.9 MHz
frequency band
Yellow (Band 3)
12.9 to 24.0 MHz
frequency band
Green (Band 4)
Pr ovi des con nec tion fo r an ex terna l
crystal (Type CR-18/U or
equivalent)
CRYSTAL (socket)
(1A1A2)
Function:
Position:
BAND switch,
(transmitter)
(rotary switch) P e r m i t s t h e t r a n s m i t t e r
doubler-amplifier to
perform as an amplifier
in the 2to 12 MH z band.
2-12
P e r m i t s t h e t r a n s m i t t e r
doubler-amplifier to
operate as adoubler
in the 12 to 24 MHz
band.
2-24
Normally indicates the transmitter
tuning condition; when the POWER
TEST switch is depressed the meter
indicates d-c level of power source.
TUNE / VOLT S ( met e r )
(lAlMl)
Changed 15 September 1971
2-4