Kenwood TM 421 A Owners Manual

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Thank you for purchasing the new transceiver. This
unit has been carefully engineered and manufac-
tured to rigid quality standards, and should give you
satisfactory and dependable operation for many
years.

IMPORTANT: %

1. Please read this Instruction Manual carefully
before placing your transceiver in service.

2. Save this Instruction Manual.

This Instruction Manual covers the following
models:

TM-221A : 144MHz FM transceiver (45W)
(U.S.A. and general markets)

TM-221ES: 144 MHz FM transceiver I45W)
(U.K. and European markets)

TM~321A :220 MHz FM transceiver (25W)
(U.S.A. only)

TM-421A :430 MHz FM transceiver (35W)
(General markets)

TM-421A :440 MHz FM transceiver 135W)
(U.S.A. only)

TM-421ES : 430 MHz FM transceiver (35W)
(U.K. and European markets)

TM-521A : 1200 MHz FM transceiver (10W)
(U.S.A. only)

TM-521E : 1200 MHz FM transceiver (10W)
(European market)

When there are differences in operation,
separate instructions will be given for each
model. Illustrations show the TM~221 A.

The following explicit definitions apply in this

manual:

Warning: Risk of fire or electric shock may occur.
Do not disregard !

Caution : Equipment damage may occur, but not
personal injury.

Note : If disregarded, inconvenience only, no risk
of equipment damage or persona) injury.

TM-221ES/421ES MODEL IDENTIFICATION NOTES.
Please note that these model numbers do not appear
on the front panel of the radio. It will appear on the
Model Number Plate on the bottom of the radio and
on the shipping box. The front panel will only say
TM-221E or TM-421 E.

1. BEFORE OPERATION ...................................
2. SPECIFICATIONS AND ACCESSORIES
2-1 .
2-2.
3. INSTALLATION AND CONNECTION ..
3-1 .
3-2,
4. OPERATION .................................
4-1 ,
4-2.
4-3.
4~4,
45,
4-6.
4-7.
4-8.
5. MAINTENANCE AND ADJUSTMENT.
5-1 .

CONTENTS

SPECIFICATIONS ......
ACCESSORIES .........

INSTALLATION ....................
CONNECTIONS .........................

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CONTROL FUNCTIONS . ..
RECEPTION ...................................... 1 1
TRANSMISSION .................................... 13
MEMORY ......
SCAN ........................................
REPEATER ...............................
TONE FREQUENCY SELECTION.
TONE SQUELCH (CTCSS) ......

GENERAL INFORMATION . ..

5-2. SERVICE ..........................

5-3, CLEANING ..................................

54. IN CASE OF DIFFICULTY ...................

5-5. MICROPROCESSOR BACKUP LITHIUM

BATTERY REPLACEMENT ....................... 19

5-6. FUSE REPLACEMENT ....... ..19

5-7. ORDERING SPARE PARTS. .19

5-8. ADJUSTMENTS ........... ..19
6. OPTIONAL ACCESSORIES ........................... 20

6-1. TSU-5 PROGRAMMABLE TONE

62.
6-3.
7. BLOCK DIAGRAM AND CIRCUIT DIAGRAM
7-1 ,
7-2.
8. REFERENCE .............
8-1 .
8»2.

DECODER UNIT ..................................... 20
M0433 HAND MICROPHONE
OTHER ACCESSORIES ........

BLOCK DIAGRAM ...........................
CIRCUIT DIAGRAM .

ANTENNA .......... ..
MOBILE INSTALLATION HINTS ................. 30

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(D SHIFT indicator

Turns on during repeater offset operations. See Sec-
tion 4-6 REPEATER for additional information on this
indicator.

® REV (Reverse) indicator
Turns on when the reverse function has been
selected.

(3 AL (Alert) indicator (TM-221ES/421 ES only)
Turns on when the alert function has been selected.

@ SCAN indicator
Turns on to indicate the scan function has been
selected.

(5) CTCSS (Continuous Tone Coded Squelch
System) indicator (TM-221A/321A/421A/521A
only)

Turns on to indicate the CTCSS function is active.

© TONE indicator (Excludes TM«221ES/421ES
European versions and TM-521 E)
Turns on to indicate the tone function is active.

(D M (Memory In) indicator
On whenever the M.|N key has been depressed.

Memory Channel Number display
Indicates the selected Memory Channel Number.

(9) * indicator

The 1k indicator indicates the Memory Channel cur-
rently in the display will be skipped during Memory
Channel scan.

® ON AIR indicator
0n during transmit operations.

® 8 81 RF meter

This level meter indicates the relative receive input
signal strength or transmitter RF output.

During low power operations this meter functions as
a microphone input level meter to check for proper
microphone operation.

62 BUSY indicator
On whenever the squelch is open.

® Frequency display

Displays the transmit/receive frequency, Frequency
Step, or Tone Frequency (TM-221A/321A/421A/
521A only).

® ALT and Direction indicators (TM~521 series only)
ALT indicator:

Turns on to indicate the Auto Lock Tuning function
has been selected.

Direction indicator:

When the ALT system is operating the Direction in»
dicator will turn on if the system shifts the receiver
frequency.

Please refer to Section 4-2»4 ALT System for addi-
tional information.

4-1-2. Rear Panel

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G) ANT (Antenna) connector
Attach an antenna with an impedance of 50 ohms to
this connector.

® SP (Speaker) jack
This jack is for connection of an 8-ohm external
speaker.

® Fuse holder

Contains one of the following fuses:
TM7221/421 series : 10A
TM-321A and TM-521 series : 8A

G) 13.8 VDC power input connector

Connect the supplied DC Power Cable to this con-
nector. Pay close attention to the polarity (the DC
Power Cable is color-coded; red is positive and black
is negative), when connecting the cable to the power
source.

4-1-3. Microphone

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7. BLOCK DIAGRAM AND CIRCUIT DIAGRAM

7-1. BLOCK DIAGRAM

7-1-1. TM-221 series

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Block Diagram is subject to change without notice due to advancements in technology.

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