Kenwood TH-31A User Manual
430/440 MHz FM TRANSCEIVER
TH-41A
TH-41BT
TH-41E
220 MHz FM TRANSCEIVER
TH-31A
TH-31BT
144 MHz FM TRANSCEIVER
TH-21A
TH-21BT
TH-21E
INSTRUCTION MANUAL
KENWOOD CORPORATION
©PRINTED IN JAPAN B50-8132-00(K,M,W)(G)
87/12 11 10 987654321 86/12 11 10 9
Before operation
• Ensure the supplied whip
antenna is securely tight
ened.
• The trimmers and cores in
side the unit are factory ad
justed. Do not touch them.
• Should the unit require ser
vice, contact your author
ized dealer.
This Instruction Manual covers the following models:
Illustrations show the TH-41 BT.
TH-41A 430/440 MHz FM transceiver
TH-41 BT 430/440 MHz FM transceiver with DTMF
TH-41 E 430/440 MHz FM transceiver with 1750 Hz tone
TH-31A 220 MHz FM transceiver
TH-31 BT 220 MHz FM transceiver with DTMF
TH-21A 144 MHz FM transceiver
TH-21 BT 144 MHz FM transceiver with DTMF
TH-21 E 144 MHz FM transceiver with 1 750 Hz tone
Contents
1.
Accessories............................................................................................................. 3
Specifications.......................................................................................................... 4
2.
Battery notes........................................................................................................... 5
3.
Controls and their functions.................................................................................. 6
4.
Operation............................................................................................................... 10
5.
5-1. Reception....................................................................................................... 10
5-2. Transmission................................................................................................. 10
5-3. DTMF key pad operation............................................................................... 10
Optional accessories........................................................................................... 11
6.
7.
Block Diagram...................................................................................................... 11
1. Accessories
Confirm that the accessories shown below are included.
Whip antenna................................................................................................................. 1
Ni-Cd battery pack......................................................................................................... 1
Battery charger.............................................................................................................. 1
Earphone (TH-41A/41 BT/31A/31 BT/21A/21 BT)........................................................ 1
Hand strap...................................................................................................................... 1
Instruction Manual......................................................................................................... 1
Warranty card (For users in USA only)............................................................. 1
The carton box and packing materials should be retained for future tran
sportation.
Note:
The TH-31A/31BT does not operate above 224.995 MHz, since
this is the upper limit of the 220 MHz band.
Attempting to operate above this frequency will not produce any re
ceive or transmit functions.
Remember the radio is designed to operate from 220.000 MHz thru
and including 224.995 MHz only.
2. Specifications
TH-41A/41BT/41E
430MHz
version
General
Frequency range 430MHz
Signal type F3 (FM)
Operating tempera
ture
Antenna impedance
Power supply voltage
Power consumption At reception standby; Less than 30 mA
Dimensions
Weight
Transmitter section
Output power Hi; 1.0W, Low; approx. 1 50 mW
Modulation system
Max. frequency de
viation
Unwanted reflection Less than -60 dB
Microphone
Receiver section
Reception system
Intermediate fre
quency
Sensitivity
Squelch sensitivity
Selectivity
AF output
to
440MHz
-20X ~ +50°C
50i3
5.8V - 10.OV (rating voltage; 7.2V)
At transmission (Hi); Less than 650 mA
W 57 (65.5) X H 120 (127.5) x D 28 (32) mm
The numbers in the parenthesis include projections.
Approx. 290 g (including antenna and Ni-Cd batteries)
Reactance modulation
±5 kHz
Condenser type
Double superheterodyne
1st: 21.6MHz
2nd: 455kHz
S/N more than 26 dB
at -6dB// (0.5 ^V) input
12 dB SINAD; less than -1 2 dB/i (0.25 //V)
Less than 0.2^V
-6 dB at more than 12 kHz
-40 dB at less than 28 kHz
More than 250 mW (8Q load, distortion 10%)
440MHz
version
440MHz
to
450MHz
(Low); About 350 mA
TH-31A/
31 BT
220MHz
to
225MHz
1 St:
16.9MHz
2nd:
455kHz
S/N more than 28dB at-6dB|t/
(0.5/c/V) input
'’^^0^2^V 1 0.25//V
TH-21A/
21 BT
144MHz
to
148MHz
Less than 28 mA
Less than 600 mA
About 300 mA
1st: 16.3MHz
2nd: 455kHz
TH-21E
144MHz
146MHz
to
Design and specifications subject to change without notice.
3. Battery notes
3.1. Recharging the battery pack
• Plug the BC-3 into the AC line outlet and interconnect the adapter to
the battery pack PB-21. At this time, be sure the polarities. While re
charging is correctly in progress, the red LED on the BC-3 lights.
However, the LED remains lits while the BC-3 is still connected to the
AC line outlet. Therefore, unplug the BC-3 after 8 hours of recharging.
Notes:
1. Recharging should be done within ambient temperature between
10°C and 40°C. Recharging performed out of this range may not
fully charge the battery pack.
2. Excessive charging, if happened, the battery performance and its
life may lessen.
• Align the grooves in the bat
tery case and unit and slide
in the battery case to the
right. Slide to the left to re
move the battery case.
3.2. Operation time with AAA batteries
The operation time with a repeated 1 minute TX and 3 minute RX cy
cle is approximately 40 minutes with manganese batteries and about
90 minutes with alkaline manganese batteries.
To communicate over a short distance, set the Hi/Low switch to
I LOW I to conserve power and thus extend operation time. When the
batteries are exhausted and the [ON AIR| indicator lights dimly, replace
the batteries with new ones.
5
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