Kenwood TH-25A Series User manual

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144MHz FM TRANSCEIVER
TH-25A
SERIES
TH-45A SERIES
430/440MHz FM TRANSCEIVER
1200MHz
FM TRANSCEIVER
TH-55A T SERIES
INSTRUCTION MANUAL
KENWOOD CORPORATION
© PR INT ED IN JAPAN BSD-817D-3O(K , M,W,T, X )(T)
89 / 12 11 10 9 8 7 6 S 4 3 2 1 88 112 11 10 9 8 7 6 S 4 3 2

Thank you for purchasing this new transceiver.
IMPORTANT: _________ _
Please read thi s in struction manual carefully before placing
your transceiver in service.
SAVE THIS INSTRUCTION MANUAL.
This Instruction Manual covers the following model s:
TH - 25AT : 144 MHz FM transceiver with DTMF Pad .
TH- 25A : 144 MHz FM transceiver without DTMF Pad .
TH - 25E : 144 MHz FM transceiver with Tone.
(with Tone
Burst for U.K. version)
TH- 45AT :430 / 440 MHz FM transceiver with DTMF
Pad .
TH- 45A : 430 / 440 MHz FM transceiver without DTMF
Pad .
TH-45E : 430 MHz FM transceiver with tone.
(with Tone Burst for U.K. version)
TH- 55AT : 1200 MHz FM transceiver with DTMF Pad .
TH-55E : 1200 MHz FM transceiver with Tone.
(with Tone Burst for U. K. vers ion)
Under normal circumstances, the transceiver will operate in
accordance with these operating instruction s. The
transceiver
has been adjusted at the factory and sh o uld on-
ly be readjusted by a qualified technician with proper test
equipment.
Attempting service
or alignment without factory authoriz a-
tion can void the transceiver's warranty.
CAUTION: ~---------- ___ _
Long transmission or extended operation in the HI power
mode might cause the rear of this transceiver to get warm.
Do not place the transceiver where the heat
sink (rear
panel) might come in contact with plastic or vinyl surfaces.
Use of an external antenna for fixed station is recommended.
Illustrations show the TH- 25A.
CONTENTS
1. SPECIFICATIONS and ACCESSORIES .................... . 4
2. BATTERY PACK.....
................. .... ........ .... ......... ... 6
3. OPERATION
OPERATING CONTROLS...
........ . ..... .... .......... ....... 8
RE CEIVER OPERATION. ................... . ......... .... ....... 12
TRANSMITTER OPERATION
ME MORy ....... ....... ........ ............. ..... .......... ......... 13
AUTOMATIC MEMORY INITIALIZATION
MEMORY ENTRY
MEMORY SHIFT. ........ .... .... ......... ..... ......... ...... 14
MEMORY RECALL
ODD SPLIT
MEMORY CHANNEL LOCKOUT . ........ ....... ...... ... 15
CLEARING ALL MEMORy ....... ... ....... ....... ......... 16
MEMORY BACK- UP BATTERY
SCAN
REPEATER OPERATION.... ........ ....... .............. .. .17
TRANSMITTER OFFSETS
REVERSE FUNCTION
TONE OPERATION
AUTOPATCH ......
.......... .... ............ .. .......... . 19
BEEP TONE
TONE ALERT SYSTEM ....
.......... .... ............ . ...... 20
BATTERY SAVER
AUTOMATIC POWER OFF
BATTERY SAVER and AUTOMATIC POWER OFF
function CANCEL (TH- 55AT /55E only)
4. BLOCK DIAGRAM and
SCHEMATIC DIAGRAM ............ .... ..... ... Another sheet
5. MAINTENANCE .....
....... . ............. .... ......... . .......... 22
IN CASE OF DIFFICULTY ....... . ........... ............... 23
6. OPTIONAL ACCESSORIES ......... . ......... ......Back cover
3

1. SPECIFICATIONS and ACCESSORIES
1-1 SPECIFICATIONS
• GENERAL TH-25A 125 AT 125E TH - 45A 1 45AT 145E
TH-55AT I55E
2 m Band 70 em Band 23 em Band
FREQUENCY RANGE (MHz) U.S.A.version
'44 .000,,'47.995
440.000~49.995 1258.()()(h.1300.000
European and U.K. version 144 . 000 " 145.995 430.000~39.995 1258.()()(h.13oo .000
Others 144.00 0" 147 . 995
430 . 000~39.995
1258.()()(h.13oo .000
MODE
F3E (FM)
MEMORY CHANN EL S
14
FREQUENCY STEP (kHz) TH -25A/25AT ITH-25EITH-45A/45ATITH -45 EI
5. 10
112.5. 51
25 . 5 1
12 .5. 51
25 . 12 .5
ANTENNA IMPEDANCE
(01
50
POWER REQUIREMENT
6",16 (7.2 VDC nominal)
CU RRENT DRAIN HI 12 V (with PB-8 or DC - ') Les s than 1 .2 A Less than 1.8 A Less than 1.0 A
9 V (with BT-6) Appro x. 0.9 A Approx. 1.4 A Less than 1
.0 A
7.2 V (with PB-5161719) Approx. O.S A
Approx. 1.1 A Approx. 0.8 A
LO transmit mode Less th an 0.4 A Less than 0.6 A Less than 0.6 A
RECEIVE mode with no signal Approx. 55 rnA Approx. 60 rnA Approx. 60 rnA
BA
TIERY SAVER mode Approx. 16mA Approx. 17 rnA Approx.
17 rnA
AUTOMATIC POWER OFF mode Approx. 6 rnA
Approx. 5 rnA
FREQUENCY STABILITY (
lODe _ + 60
D
C)
±3 ppm
GROUND Negative
DIMENSIONS (W x H x D)
Projections not included {mm} 58 x 13 7.5 x 29.5 (2.3x 5.4 x 1.2 inch) 58 x
157 .5 x 29.5
Projections included (mm) IAlE 68.5 x 15 2.0 x 34.5 (2.7 x 6.0x 1.35 inch)
68.5xl72x37.5
I AT
68.5 x 1 52.0x 35.5 (2.7 x 6.0 x 1.4 inch) (2.7x7.0xl . Sinchl
WEIGHT (g) With NiCd Battery and Antenna
400 (0.88 Ibs.)
450 (0.99 Ibs)
OPERATING TEMPERATURE -
20
De _ +
50°C( -4 ° F -122°F)
MICROPHONE IMPEDANCE 2 kO
.TRANSMITTER
OU TPUT POWER HI 12 V (with PB -8 or DC·' ) More
than 5 W
lW
9 V (with BT·6) Appro x. 3.5 W I Approx. 3.5 W
lW
7.2 V Iwith PB -516 171 9) Appro x, 2.5 W I Approx. 2 W
Approx . 0.8 W
4

OUTPUT POWER I LO Approx.
0.5W
I Appro
x. 0.1 W
MODULATION REACTANCE
MAXIMUM FREQUENCY DEVIATION (kHzl
±5
SPURIOUS RADIATION l
ess than - 60 dB
I Le ss than - 50 dB
DUTY CYC LE OPERATION 1 minute t
ransmiss io n 3 minutes reception recommended
• RECEIVER
CIRCUITRY DOUBLE CONVERSION SUPERHETERODYNE
INTERMEDIATE FREQUENCY I
1st IF (MHzl
16.9
I
30 .8 25
I
59.7
I 2nd IF (kHzl
455
SENSITIVITY 12 dB SINAD
Less than 0.16 p.V I Less than 0 . 18 p.V I Less than
0.25 p.V
SQUELCH SENSITIVITY
Less than 0.1 p.V
I
Less than 0. 16 JlV
SELECTIVITY I
-6 dB More than 12 kHz
I - 40 dB Less than 28 kHz I
Less than 32 kHz
RIT variable range I More than ± 5 kHz
AUDIO OUTPUT POWER (ac ro ss 8 nload 10 % distortion) More than
200 mW
Note: Circuit and ratings are subject to change without notice. due to development In technology.
1-2 ACCESSORIES
Unpack your transceiver ca refully and confirm that the accessories list ed bel ow are included in the box.
1 Antenna ............................... .. ..... ........ ..... ........... 1 for U.S.A . version (120 VI ... WOS - 0382 -XX
For 144 MHz ..................... TSO - 03S6-0S for European version (220 VI .. WOS-0388-XX
or For 430 / 440 MHz ............ .. TSO -03SS-0S for U.K. version (240 Vi ....... WOS-0387 -XX
or For 1200 MHz ..... . ........... .. TSO - 0364-0S for Oceania version (240 VI .. WOS-0386-XX
2 Belt Hook. ........ ..... ..... ........... J2S - 0424-04 ........... 1 for Other market (220 VI ..... WOS-0384-XX
3 Rubber Cap .............. ..... ........ B09 - 030S - 04 ........... 1 (120 Vi ..... WOS-038S- XX
4 Hand Strap ............... .. .. ......... J69 - 0312-04 ........... 1 7 Label .......... . ........ .. ..... .... ...... B42 - 332S-04 ........... 1
S Battery ............ ..... ........... .... ......•......................... 1 8 Warranty Card .......... ............. .. .. . .. ..... ............. .... .. 1
NiCd battery pack
(PB-61 ...... WOS -OS07-0S S Instruction Manual .................. BSO·8170-XX .. ...... .. 1
6 Battery Charger.........
..... ... ............. .... .. ............... ..1
After unpacking
Shipping container: Save the boxes and packing
in the event your unit ne eds to be transported for remote operation,
maintenance,
or service. 5

2. BATTERY PACK
2-1 NiCd BATTERY PACK (PB-G)
This battery pack has not been charged at the facto ry in
order
to provide you with the greatest number of
charge/discharge cycles. You must charge the battery
before use. The battery pack will require several
charge/discharge cycles before you can expect
to see the
maximum operating period between charges. If the battery
will be stored for greater than 2 month s it should be
re charged before use.
2-2 RECHARGING
1. Slide the adapter onto the
NiCd battery pack.
2. Plug
the supplied charger
into an AC o utlet .
3. Do not allow the battery
to charge for greater than
15 hours.
The useful life and battery
performance will be reduc-
ed if you exceed the recom-
mended charge period.
Note: -- -- ------
Recharging should be performed
within an ambient temperature
range of between 50 C - 40 °C
(41°F_104° F ).
Recharging the battery outside
of this range ma y n ot allow the
battery to reach full cha rge.
6 to
AC outlet
2-3 MANGANESE or ALKALINE BATTERIES
(Optional Battery Case BT
-G)
In st all 6 x A6 (AA) man- Press down on the hook in the
9anese or alkaline batteries in middle of the battery case top
th e battery holder. Pay close to open.
attention the battery polari-
tie s marked in the holder. We Hook
re c ommend the use of high
performance manganese bat-
teri es for the greatest operat-
ing time .
Note:
---------
Do not install NiCd batteries and
att e mpt to charge them with the
supplied charger. There is no
ba tt ery protection circuit in the
ba tt ery holder.
2 -4 INSTALLING THE BATTERY PACK
Align the grooves in the bat-
tery pack with the trans- Release button
ceiver and slide the pack to
th e r ight until it locks in
place.
To remove the battery pack
push up on
the release button
and slide the pack to the left.

2-5 BATTERY VOLTAGE LEVEL METER
The S meter indicates the relative battery voltage during
transmit.
Recharge/replace the batteries when the level reaches the
low indicator.
NiCd Battery pack
MODEL V mAh Fully charged Fully discharged
PB·5
~
...... . "~ .... ~~
..•
PS-6
01
..
7.2 600
........ :-;:-;~
••••
-.- ..
PB~9 .
PB -7
r;-;oo
P8 -8 12
600
..........-
........ :::::: .
..
Manganese or Alkaline battenes (ApprOXimate battery con
dition) -
New batteries
BT -S, 9 V
•••••••• [::u~
2-6 OPERATING TIME
TH-25 series
Batt vohage IVI
Transmitting •.
Receiving .
AFOU1PUT ..
Need to replace
...... :.:::;:::~-::
....................... 1 minute
3 minutes
0 .2 W/8 0
14 NiCd battery 12\1
I\, SOOmAh IPB-BI
,,1 '
• Battery voltage is measured 81 transmis-
sion (Hi).
10
NiCd battery 7.2\1
8 ~~", §''?-='''':-t~ 1 ~Ioo=m=A=h:..c.IP~ .. ~7~I_,
6 ., ••• ':\'-=..~~, '\
lower ~mjt voltage range
for transmissiOn
4 1
,1 '••••/.... r 'J;;,;,~;;.~ b'''~
--....
\ ( low - Power ) 18T 6)
N,Cd battery 7 2V 600mAh IPS-51
Manganese battery ( 8T 6)
Alkaline manganese
battery \8T-6)
L
!N~;C~d~b.~'~'.~~~7.~2~v~2~OO2?m~A~h~I~P~8·r5~' ____ ~~ ____ ~~ __ -:~
60 120 180 240 300 360 (minu18$)
TH-45 series
Batt Voltage (V)
TransmIttIng .............................. 1 minute
Receiving ............................... 3 minutes
AF OUTPUT .............. . ...... .. 0.2 W/8 0
'4 NoCd battery 12V
600mAh IPB-B)
• Battery vonaga is measured at transmis-
SIOn (Hi) ,
"
10
8
6
4
NiCd battery 7.2V
1100mAh (Pe-7) lower limrt voltage range
for transmIssion
...... _._ ~AA Allr;eIihe manganese
/
'-1' r'" -.,.- --' - ,,,,..., '8T·S'
Manganese battery (Low'Power) IBT-6)
N,Cd battery 7
2V 800mAh IPS-s)
Manganese battery (8T 6)
N, Cd battery 7.2V 200mAh IPS-5)
60 120 180
240
300 (minutes)
lH·55 series Transm'tling
.............................. 1 minute
B
att vohage IV)
Receiving ·................................3 mil'll1t8S
14
12
10
8
6
4
NiCd
banery 12V
600mAh IPB ·B )
NiCd battery
72V 200mAh
IPS-51
'- -
AF OUTPUT.. ................... 0.2 W/B 0
• Banery voltage is measured al transmis-
sion IHi).
NiCd battery
7.2V 600mAn IPS-6)
NiCd battery 7.2V
11DOmAh IPS-7)
-:----
'.
lower ~mit voltage range for transmission
e- ~~-.~--~-=====~===-=== __ ~~
Manganese Manganese battery AA Alkeline manganese
ba ttery IST-61 (Low 'P ower) IBT-61 battery (BT.6)
60
120 18 0 240
300 Iminutes)
We r ecommend use of the NiCd battery pack. for long
tran smission or extended operation.
Man ganese battery (except Alkaline manganese battery) is
available for Low position. 7

3. OPERATION
3-1 OPERATING CONTROLS
CD Antenna connector
Connect the antenna that is supplied to this jack. Twist
to lock.
® TX indicator
ON whenever the transceiver is in the transmit mode.
®Volume control/Power switch
The volume control and power switch are combined.
Rotating
the control clockwise will turn ON the
transceiver.
Advancing the control further clockwise
will increase the volume.
@SOL control
This control is used to select the desired Squelch
threshold level.
@MHz key
This key is used to select the tuning rate of the Tuning
control. When the MHz indicator is lit, the Tuning con-
trol will cause the transceiver to increase or decrease
in 1 MHz step.
®VFO key
8
This key is used to switch back to VFO operation after
operating in the MR (Memory Recall) mode. The tuning
control will increase or decrease frequency in accor-
dance
with the VFO indicator. See the chart below for
your transceiver. (kHz)
Pressing this key for longer than second will initiate
the Band Scan function.
(j) MR key
This key is used to switch from the VFO mode to the
MR (
Memory Recall) mode. The tuning control may be
used to select the desired memory channel in this
mode.
Pre ssing this key for longer than 1 second will initiate
the
Memory Scan function.
® Tuning control
Rotate this control clockwise to increase frequency
and counterclockwise
to decrease the transmit /receive
frequency.
This control is also used
to select the desired memory
channel and the scan direction.
® Tone Alert key
This key is used to activate the Tone Alert function .
®Tone key
u.s. version: This key is used to activate the
subaudible tone encoder.
European version: This key is used to transmit a Tone
signal. When the key is depressed
the repeater control signal of
'750 Hz is activated .
U.K. version: This key is used
to activate the
'750 Hz tone burst.

LCD display
(jJ) EI + (European version: EI _)
Displays the selected transmitter offset direction.
When neither indicator is
ON the transceiver is in the
Simplex mode. When both indicators are ON the
transceiver is in the Split Channel mode.
When a indicator flashes the transceiver is in the
Reverse
function.
@ Frequency display
Di splays the operating frequency to the nearest kHz.
TH-55AT/55E: Displays the operating frequency from
10 MHz digit. r aBBBB
L ______ ~- _______ 1
(jji Busy indicator
ON whenever there is a Signal present strong enough
to open the squelch. or when the squelch is not ac-
tivated. and the CTCSS key is OFF.
@ ••••••••••-
Used to indicate the relative receive signal strength, or
as an indication
of the battery voltage level during
transmit.
@ MHz indicator
This indicator flashes during MHz tuning steps.
@ MHz dot
This indicator flashes during scan operations.
@ VFO indicator
This indicator lights during VFO operation.
@ Hz dot
This indicator lights during cress frequency selec-
ti on, and is used to show the 1 Hz digit.
TH-55AT/55E: Additionally ON when the Battery
Saver and Automatic Power Off function have been
cancelled.
(jji 5 kHz tuning step indicator
This indicator lights during VFO operation when tuning
in 5 kHz steps.
@ 500 Hz dot (TH-25E/TH-45E only)
This indicator show 500 Hz.
@ T indicator
This indicator is ON when the Tone function is active.
@ CTCSS indicator
This indicator is ON when the CTeSS function is ac-
ti ve. ...(1
@ T. ALT indicator ~
This indicator is ON when the Tone alert system is ac-
ti ve. The indicator will flash when a signal is received.
@ Memory channel indicator
This indicator is used to show the selected memory
channel number.
@ Memory indicator
This indicator lights during Memory Recall mode, and
fl ashes during Memory entry.
9

@ !
KENWOOD
nl "~'"
® @
@ @
@
430MHz FM TRAN SC [IV {A
TH· 45A
@ MONITOR switch
When operating in the CTCSS (Tone Squelch) mode
you can use this key to determine if the frequency is in
use
before transmitting. Pressing this key will disable
the CTCSS function as long as the key is held depress-
ed.
® lamp switch
This switch is used to control the night lamp on the
LCD display. The lamp will turn itself OFF automatical-
ly 5 seconds after the last key operation.
@ PTT (Push To Talk) switch
Press this switch whenever you wish to transmit.
10
TH-45AT
GI GI
®l Release button
Press this button up to
release the battery pack.
@ F. Lock key
This key will deactivate
all functions except the
Lamp, MONI, PTT func ·
tions.
@ Speaker
@ Microphone
@ Battery case
@ SP jack
This jack is used to con-
nect an external speaker
or earphone. The recom-
mended impedance is
8 n.
@ MICjack
This jack is used for con-
nection of an external
microphone. The use of
an electret type micro-
phone is recommended.
Input impedance is 2 kG and the DC voltage on this ter-
minal is Approx. 4 V (MAX 3.5 mA).
Not.: ---- ________________________________ __ __
The use of a dynamic microphone is not recommended.
Speaker ,
,
..
SP
V
~
'"
¢2 .5
Ground Plug x
w
,!;
,
5V
, u
,
5V
M~C
V ~
. ~
!
~
•
MIC
1=
II
~
PIT PIT , +
10
::;
,
, x
w

•
~
u 4
KE NWOOO
TH · 55AT
TH· 45A TH · 55AT
@ DTMF PAD (with the TH-25AT/45AT/55AT)
This key pad is used in conjunction with a repeater to
provide AUTO PATCH capabilities.
@ M (Memory) key
This key is used to enter a frequency, offset, etc. into
the desired Memory channel..
When this key is pressed during Memory channel
operation
the contents of the Memory channel are
duplicated in the VFO, and
the transceiver returnes to
VFO operation. .
The
contents of the memory are not lost during this
procedure.
@ CTCSS key
This key is used to select the CTCSS (Tone squelch)
f
unction.
I3l SHIFT key
This key is used to select the desired transmitter offset
for repeater operation. When the offset function is ON,
+ or Gi3 will be displayed in the display.
@ REV key
Pressing the REV key allows you to reverse the
transmit/receive frequencies
dur ing repeater opera-
ti ons. This will allow you to check the input of the
repeater
or to operate on a reverse repeater pair.
® HI-LO switch
This switch is used to select the transmit output
p ower .
T
H·25A/45A SERIES
TH-55AT SERIES
(II)
HI La
(II)
LO HI
@ RIT control (TH-55AT/55E only)
When the transmit frequency of the distant station
d
rifts a little bit during the OSO, but you do not wish to
a lter your transmit frequency to compensate, you may
wish to make use of the RIT control function. This con-
tr ol allows shifting the receive frequency apploximate-
Iy ± 5 kHz without shifting the transmit frequency.
11