Kenwood TH-225A User manual

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144MHz FM TRANSCEIVER
TH-225A
INSTRUCTION MANUAL
KENWOOD CORPORATION
©PRINTED IN JAPAN B50-8334- oat P)(T)
90/12 1110987654321 89/21

Thank you for purchasing this new transceiver.
IMPORTANT
Please read this instruction manual carefully before placing
your transceiver in service.
SAVE THIS INSTRUCTION MANUAL.
Under normal circumstances, the transceiver will operate
in accordance with these operating instructions. The tran-
sceiver was preset at the factory and should only be read-
justed by a qualified technician with proper test equipment.
Attempting service or alignment without factory authoriza-
tion can void the transceiver’s warranty.
CAUTION: —
Long transmission or extended operation in the 6 watt 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.
FCC WARNING:
This equipment may generate or use radio frequency ener-
gy. Changes or modifications to this equipment may cause
harmful interference unless the modifications are express-
ly approved in the instruction manual. The user could lose
the authority to operate this equipment if an unauthorized
change or modification is made.
CONTENTS
ACCESSORIES
SPECIFICATIONS .
BATTERY PACK...
Ni-Cd battery
Recharging the battery pack
Manganese/Alkaline batteries
Operating time
CONTROLS AND FUNCTIONS
OPERATION
Receive
Transmit
Frequency selection...2....:cccecseseseeisacse esses 11
R&EPBator: OPEFAtiON :cceis<ssacdesencossecidcenedeoareaurses et 12
Transmitter offsets
Reverse function
Tone operation
Auto patch operations ...
MMQMOLY: :. 226 600sesace cs sdveanimersavedeccuaisaiaasazapeRiiaseacton 15
Memory channels
Memory entry
Memory recall
Odd Split memory channel.
Memory channel lockout ............:eccceeeeeeeeeeee 16
Clearing a specific memory channel
Clearing all memories
Memory back-up battery
Priority alert channel check
Batty SOVGIS. fi5i5 00005055 vend savenveesanssyucds onan 17

MAINTEMANGE s:;..20c:00ccccensecessccsidavannsvenssdcenmenscsees 18
In case of difficulty
Service
OPTIONAL ACCESSORIEG. .............0cccceeeseeeeenteeeeeeenee 19
“Programmable tone decoder unit TSU-4
BLOCK DIAGRAM another sheet
SCHEMATIC DIAGRAM another sheet
ACCESSORIES
Unpack your transceiver carefully and confirm that it is sup-
plied with the following accessories.
1 Antenna for 144 MHz
2 Rubber cap
3 Belt Hook.........
4 Machine Screw
5
6
Spring washer .. ...N16-0030-41
Ni-Cd Battery pack
(BBP 2) at aeeae~sh oon a5 saises6 WO9-0541-05..........
7 Battery charger (120 V)..WO9-0517-05..
8 DC cable (PG-2V)... ..-E30-2078-25
9 Instruction Manual . .-B50-8334-XX
O Warranty Card.....

SPECIFICATIONS
FREQUENCY RANGE (MHz)
144.000 ~ 147.995
MODE
F3E
(FM)
OPERATING
TEMPERATURE
=
20°C
~
+50°C
ANTENNA
IMPEDANCE
5029
POWER REQUIREMENT
BATTERY PACK
6.3 V~15 VDC (12 VDC nominal)
z
DC
IN
7.2
V~16
VDC
(13.8
VDC
nominal)
&
is
Hi
TRANSMIT
MODE
6
W
(13.8
V)
Less
than
1.9A
&
&
=
[Low
TRANSMIT
MODE
0.5
W
(13.8
V)
Less
than
0.7
A
=
c
RECEIVE
MODE
WITH
NO
SIGNAL
Approx.
50
mA
2
BATTERY
SAVER
MODE
(At
1
:
9)
Approx.
11
mA
DIMENSIONS
WxHxD
67x
190
37
(mm)
(PROJECTIONS
INCLUDED)
70x
198
x
40
(mm)
WEIGHT
With
Ni-Cd
battery
and
antenna
Approx.
600
g
OUTPUT
POWER
Hi
13.8
VDC
6W
2
With
PB-1,
with
PB-12
5W
ys
With PB-2
2.5
W
E
With
PB-3,
PB-4
1.5
W
FA
Low
0.5
W
z
MODULATION
REACTANCE
F
|
MAXIMUM
FREQUENCY
DEVIATION
+5
kHz
SPURIOUS
RADIATION
Less
than
—60
dB
CIRCUITRY
DOUBLE
CONVERSION
SUPERHETERODYNE
INTERMEDIATE
FREQUENCY
1st
IF
16.3
MHz
a
2nd
IF
455
kHz
2
|_SENSITIVITY
12
dB
SINAD
Less
than
0.2
nV
8
SQUELCH
SENSITIVITY
Less
than
0.1
nV
©
|
SELECTIVITY
-—6
dB
More
than
12
kHz
—40
dB
Less
than
24
kHz
AUDIO OUTPUT POWER (across 8 2 load 10% distortion)
More than 500 mw
NOTE:
Circuit
and
ratings
are
subject
to
change
without
notice,
due
to
development
in
technology.

BATTERY PACK
Installing the battery pack
Match the concave part at the
bottom of the radio to the
convex part at the top of the ~
battery pack.
Turn the battery pack clock-
wise until it clicks.
Be sure the pack and trans-
ceiver are locked together.
Removing Battery pack
Pressing the battery release
button, turn the battery pack
counterclockwise.
Ni-Cd BATTERY PACK (PB-12)
NOTE:
This battery pack has not been charged at the factory in order to
provide you with the greatest number of charge/discharge cycles.
You must charge the battery before use. The battery pack will re-
quire 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 months it should be recharged before
use.
RECHARGING THE BATTERY PACK
Insert the charge plug from the supplied Battery Charger into
the receptacle on the rear of the battery pack. Then plug the
Charger into the AC line. The LED on the Charger will illuminate
to show that the pack is charging. The LED will remain on
as long as the Charger is connected to the AC power source
and the battery, indicating that the pack is still being charged.
Do not allow the battery to charge for greater than 15 hours.
The useful life and battery performance will be reduced if you
exceed the recommended charge period.
NOTES:
© Turn off the power switch before charging.
@ Recharging should be done within an ambient temperature bet-
ween 10°C ~ 40°C (50°F ~ 104°F). Recharging performed out
of this range may not fully charge the battery.
MANGANESE or ALKALINE BATTERIES
Load 6 x R6 (AA) manganese or
alkaline batteries in series in the sup- Stopper
plied battery case. (Be sure to ob-
serve the polarities.)
(We recommend use of high-
perfomance manganese batteries.)
Battery pack (1) can be inserted in-
to the case (2) only in a specific
direction. Check the shape (top and
bottom) after moving the stopper on
the rear side, then insert the battery q
correctly. Inserting the battery by Battery pack (1)
force without checking the shape
may damage the case.
OPERATING TIME
Batt voltage Transmitting.
7) Receiving .
Ag AF OUTPUT
“Battery voltage is measured at transmis-
sion (Hi).
Case (2)
Ni-Cd battery
L2ZV 500mAn\ ~12V B00mAh (PB-1)
(PB-12)
(Manganese
battery Low
'~ Power)
iH 5G battery 8.4y
Ni-Cd battery 7.2V
1600mAh (PB-4)
Ni-Cd battery 7.2V | |800mAh
6 1(PB-3)
Seu a ne ee are
fan,
PU=NGE9 batiary Lower imit voltage range for transmission
30 60 90 720°" 240. 270
(minutes)
Manganese battery (except Alkaline manganese battery) is
suitable only for LOW power transmission.
Recharge the Ni-Cd battery pack when the BATT indicator
comes on.
We recommend use of the PB-3 or PB-4 Ni-Cd battery pack
for long transmission or extended operation.

CONTROLS AND FUNCTIONS
@ Antenna connector
This jack is used to connect the supplied antenna.
Twist to lock with the BNC connector.
@ DC IN terminal
This terminal is used for an external power supply. Input
voltage is 13.8 VDC nominal. The center is the (+) side and
the sleeve is (—) side.
You should turn the power switch OFF when connecting
this terminal. Pay attention to the polarity.
@~)-O CAUTION: —————_________
As a precaution, do not remove the bat-
£ E tery pack when an external power sup-
Bo ply is used. Use the KENWOOD PG-2V
$2 or PG-3E optional cable for the con-
Teo) ss nection.
9.5 mm
@ MIC jack
This jack is used for connection of an external microphone.
The use of an electret type microphone is recommended.
Input impedance is 2 kQ and the DC voltage on this terminal
is 4V.
@ SP jack
This jack is used for an earphone or external speaker. The
recommended impedance is 8 2 nominal.
® TONE switch
This switch is used to activate the sub-audible tone encoder.
© HI(# )/LOW ( . )switch
This switch is used to select the transmit output power.
@ SQL control
The SQL control is used to eliminate noise during no signal
periods. Normally, this control is adjusted clockwise until
the noise just disappears and the BUSY indicator goes OFF
(Threshold level). For scan operation, this control must be
set to the threshold point. When an incoming signal is weak
or unstable, readjust the squelch for optimum reception.
For tone squelch operation with TSU-4, this control must
be set to the T.SQ position.
@) VOL control
Volume control with power ON/OFF switch.

@) MONITOR switch
Pressing this key will open squelch.
PTT (Push To Talk) switch
For transmission, press this switch and speak into the
microphone.
@) RELEASE button
Used to release the battery.
Depress this button, and turn the battery counterclockwise.
(2 LAMP key
This key controls the lamp on the LCD display.
NOTE:
When the LAMP is on battery drain will be accelerated. Do not use
this feature unnecessarily.
@® OFFSET/F key
The OFFSET/F key is used to select the desired transmitter
offset for repeater operation. Each time the key is pressed,
the mode cycles from + shift, to — shift, to simplex, and
back to + shift. When the offset function is ON, the sym-
bol ‘’+’ or ‘‘—"' is displayed.
Pressing the [E_] and the OFFSET/F key in order is used to
change the desired offset frequency.
R/TONE. F key
This key is used to reverse the transmit/receive frequencies
during repeater operation.
TONE. F: TONE FREQUENCY key
Pressing the [_] and the R/TONE. F key in order is used
to change the frequency of the tone encoder.
() SAVE key
The SAVE key is used to select the power save condition
during the receive mode.
Pressing the [L_] and the SAVE key in order is used to
change the battery saver on/off ratio.
SPEAKER
@ MICROPHONE
BATTERY CASE

@ Display
GOB ®
BAND
SEEK
@ FREQUENCY display
@ |[PRIO}
@ (uTo) Save
: Displays the operating frequency.
: ON when the Priority Alert function is
active.
Flashes when the channel is busy.
: Displays the selected power save con-
dition;
(AUTO/, SAVE] for auto save mode,
SAVE] for save mode, and no indicator
for OFF.
: ON whenever the squelch opens dur-
ing receive.
: ON all the time if the squelch control
is rotated counterclockwise, and the
T.SQ is off.
: ON during transmit mode.
@-+
@R
@M
JD |MEMO| PROG
SEEK! TIME| CAR
(Oe Key Lock]
:
Used
to
indicate
the
relative
receive
signal strength, or as an indication of
transmitting.
:
Indicates
the
selected
frequency
step.
:
Indicates
the
selected
memory
channel
number.
:
Indicates
for
approx.
5
seconds
after
pressing the [E_] key.
:
Displays
the
selected
offset,
minus
or
plus,
and
no
indicator
for
simplex.
:
On
whenever
the
REVERSE
function
is
active.
:
Indicates
for
approx.
5
seconds
after
pressing the [4] key.
:
Indicates
the
selected
scan
mode.
Indicates
the
selected
scan
stop
mode.
Flashes
during
scan.
:
Indicates
that
the
transmitter
has
been
disabled by the TX.STOP key.
:
Indicates
that
all
keyboard
functions
except
LAMP
key
has
been
disabled
by
the
KEY
LOCK
is
activated.
:
ON
when
the
battery
voltage
falls
be-
low
the
level
for
good
communications.
Recharge/replace
the
battery
pack.

@ DOUBLE ROLE KEYS
PRIORITY BEEP. STEP
all yy LCA pg ee
. BAND MEMORY PROGRAM
ce)
CARRIER
These 13 keys except the E]) and keys, have two
functions.
The 1st function is printed on the key.
The 2nd function is printed above the key.
All these 2nd functions are active for approx. 5 seconds af-
ter pressing the key.
@ Numeric keys: ~-E,f
These keys are used to select the desired operating fre-
quency and/or memory channel number.
Memory channel 1, 8, and 9 also serve additional functions
as discribed below.
M. channel 1 is used to store the Priority Alert channel in-
formation.
M. channel 8 is used to store the lower, and M. channel 9
the upper limit frequency for the programmable band scan.
© UP/DOWN keys: 1, EJ
These keys are used to increase or decrease the operating
frequency, offset frequency, tone frequency, or the power
saver circuit rate.
@ F: Function exchange key
The [] key is used to activate the 2nd function.
The F indicator is displayed for approx. 5 seconds after
pressing the key.
CAUTION:
You must press the 2nd function while the F indicator is lit, or the
radio will perform the function printed on the key, rather than the
function printed above it.
@ M: Memory key
The [4] key is used to select the desired memory
channel.
The operation is similar to that of the _] key, in that, the
M indicator will illuminate for 5 seconds in the LCD display.
CAUTION:
The memory channel must be selected within 5 seconds of press-
ing the key.
@ ENTER key
The key is used to enter a frequency selected by the
numeric keys.
@ SCAN key
The key is used to start or stop the scan function.
© PRIORITY CHANNEL CHECK key: [-_] then 1/PRIO
These keys are used to monitor whether the priority chan-
nel (CH 1) is busy or not. When this function is activated,
the radio will switch to CH 1 approximately once every 10
seconds.
To cancel this function, press these keys again.

© BEEP key: then 2/BEEP
Each time these keys are pressed, the audio annunciator will
be turned ON or OFF alternately.
© (FREQUENCY) STEP key: then 3/STEP
Each time these keys are pressed, the frequency scanning
step size will be increased 5 kHz.
Several different scan function keys and scan stop keys are
provided.
© BAND SCAN key: [-_] then 4/BAND
@ MEMORY SCAN key: then 5/MEMORY
@ PROGRAMMABLE BAND SCAN key: [Z] then
6/PROGRAM
@ SEEK OPERATED SCAN key: [-_] then 7/SEEK
@ TIME OPERATED SCAN key: [_] then 8/TIME
© CARRIER OPERATED SCAN key:[-_] then 9/CARRIER
For additional information on this function refer to page 14.
©@ TX. STOP key: then M/TX. STOP
Pressing these keys will prevent accidental transmission.
To cancell this function, press these keys again.
© KEY LOCK key: [E] then ENTER/KEY LOCK
Depress
these
keys
and
the
frequency
and
other
settings
will
remain
unchanged
by
keyboard
operation
except
the
LAMP
key.
To cancel this function, press these keys again.
© FAST [7] key: then V/FAST
© FAST [{] key: then A/FAST
© LOCK OUT key: then 0/L.OUT
Each time these keys are pressed, the Memory channel lock
out function will be turned ON or OFF.
10
OPERATION
@ RECEIVE
After
power
and
antenna
connections
have
been
completed,
set the switches as follows:
1.
Turn
the
VOL
control
clockwise
to
turn
on
power.
The
frequency
on
the
LCD
display
will
show
the
transceiver
is
operating.
2.
As
the
VOL
control
is
turned
clockwise,
either
back-
ground
noise
or
a
QSO
will
be
heard.
3.
To
eliminate
the
no-signal
noise
turn
the
SQL
control
clockwise.
4. Enter the desired frequency.
@ TRANSMIT
Precaution:
Check
the
intended
transmit
frequency
before
operating
to
prevent
interference
with
other
stations.
If
you
are
using
T.
SQ
(Tone
Squelch)
press
the
MONITOR
key
to
allow
the
Squelch
to
open.
1.
Simply
depress
the
PTT
switch
and
the
indicator
will
light.
2.
Speak
into
the
microphone.
Recommended
distance
to
the
microphone
is
approximately
2
inches
(5
cm).
CAUTION:
Long
transmission
or
extended
operation
in
the
6
watt
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.