Kenwood TH-25A Series User manual

GOO/ANA»
144MHz FM TRANSCEIVER
-25A
series
430/440MHz FM TRANSCEIVER
-45A\
series
1200MHz FM TRANSCEIVER
-55AT series
INSTRUCTION
MANUAL
KENWOOD CORPORATION

Thank you for purchasing this new transceiver.
IMPORTANT:
Please read this instruction manual carefully before placing
your transceiver in service.
SAVE THIS INSTRUCTION MANUAL.
This Instruction Manual covers the following models:
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. version)
Under normal circumstances, the transceiver will operate in
accordance with these operating instructions. The
transceiver has been adjusted at the factory and should on-
ly be readjusted 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 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 extemal antenna for fixed station is recommended
Illustrations show the TH-25A.
co NTENTS
. SPECIFICATIONS and ACCESSORIES .
2 BATTERY PACK
3. OPERATION
OPERATING CONTROLS ....
RECEIVER OPERATION
TRANSMITTER OPERATION
ORY gsi anan nic teres peateantsconan saapwenasssnasaxsargize sce
AUTOMATIC MEMORY INITIALIZATION
MEMORY ENTRY
MEMORY SHUT ecrritcctiesanctersps pceenester'pegnonn ceases 14
MEMORY RECALL
ODD SPLIT
MEMORY CHANNEL LOCKOUT .. 315
CLEARING ALL MEMORY ..... -16
MEMORY BACK-UP BATTER
SCAN
REPEATERORERATION cascccesscccsssorebodaasaarens canes TH
TRANSMITTER OFFSETS
REVERSE FUNCTION
TONE OPERATION
PRITORP Col cctecaauitas riots reasecsdzoasetacvensdecsssede 19
BEEP TONE
TONEALERT/SYSTEM 3. ..csccscessssessdccveesssecessaseee 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 ............. ve 22
IN CASE OF DIFFICULTY He a
6. OPTIONAL ACCESSORIES .. ...Back cover

1.
SPECIFICATIONS
and
ACCESSORIES
1-1 SPECIFICATIONS
l@ GENERAL
TH-25A/25AT/25E | TH-45A/45AT/45E
2 m Band 70 cm Band
TH-55AT/55E
23 cm Band
FREQUENCY RANGE (MHz)
U.S.A.version
144.000.147.995 | 440.000.449.995
1258.000~1300.000
European and U.K. version
144.000~145.995 | 430.000.439.995
1258.000~1300.000
Others
144.000.147.995 | 430.000.439.995
| 1258.000~1300.000
MODE F3E (FM)
MEMORY
CHANNELS
14
FREQUENCY
STEP
(kHz)
TH-25A/25AT
|TH-25E|TH-45A/45AT|TH
456]
5,10 12.55] 25,5 |12.5,5 ebr2 0
ANTENNA
IMPEDANCE
(9)
50
POWER REQUIREMENT
6.16 (7.2 VDC nominal)
CURRENT DRAIN
HI 12 V (with PB-8 or DC-1)
Less than 1.2 A Less than 1.8 A
Less than 1.0 A
9 V (with BT-6)
Approx. 0.9 A Approx. 1.4 A
Less than 1.0A
7.2 V (with PB-5/6/7/9)
Approx. 0.8 A Approx. 1.1 A
Approx. 0.8 A
LO transmit mode
|__Less than 0.4 A
Less than 0.6 A
Less than 0.6 A
RECEIVE mode with no signal
Approx. 55 mA Approx. 60 mA
Approx. 60 mA
BATTERY SAVER mode
Approx. 16 mA Approx. 17 mA
Approx. 17 mA
AUTOMATIC POWER OFF mode
Approx. 5 mA
FREQUENCY STABILITY (— 10°C ~ + 60°C)
Approx. 6 mA |
+3 ppm
GROUND
Negative
DIMENSIONS (W x Hx D)
Projections not included (mm)
58 x 137.5 x 29.5 (2.3 x 5.4.x 1.2 inch)
58x 157.5x 29.5
Projections included (mm) | A/E
68.5 x 152.0 x 34.5 (2.7 x 6.0 x 1.35 inch)
| AT
68.5 x 152.0x 35.5 (2.7 x 6.0 x 1.4 inch)
68.5 x 172 37.5
(2.7 x 7.0 x 1.5 inch)
WEIGHT
(g)
With
NiCd
Battery
and
Antenna
400
(0.88
Ibs.)
450
(0.99
Ibs)
OPERATING
TEMPERATURE
—20°C
~
+50°C(—4°F
~122°F)
MICROPHONE
IMPEDANCE
2
ka
Mi TRANSMITTER
OUTPUT
POWER
HI
12
V
(with
PB-8
or
DC-1)
More
than
5
W
1W
9
V
(with
BT-6)
Approx.
3.5
W
Approx.
3.5
W
1W
7.2
V
(with
PB-5/6/7/9)
Approx.
2.5
W
Approx. 2
W
Approx.
0.8
W

OUTPUT POWER [to
Approx. 0.5 W Approx. 0.1 W
MODULATION
REACTANCE
MAXIMUM FREQUENCY DEVIATION (kHz)
+5
SPURIOUS RADIATION
Less than —60 dB Less than —50 dB
DUTY CYCLE OPERATION
1
minute
transmission
3
minutes
reception
recommended
l@ RECEIVER
CIRCUITRY
DOUBLE
CONVERSION
SUPERHETERODYNE
INTERMEDIATE
FREQUENCY
1st
IF
(MHz)
16.9
30.825
le
59.7
2nd IF (kHz) 455
SENSITIVITY
12
dB
SINAD
Less
than
0.16
nV
Less
than
0.18
nV
Less
than
0.25
pV
SQUELCH
SENSITIVITY
Less
than
0.1
nV
|
Less
than
0.16
nV
SELECTIVITY
—6
dB
More
than
12
kHz
—40
dB
Less
than
28
kHz
Less
than
32
kHz
RIT variable range
More than +5 kHz
AUDIO OUTPUT POWER (across 8 0 load 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
carefully
and
confirm
that
the
accessories
listed
below
are
included
in
the
box.
1
1
apWNH
6
Antenna
For 144 MHz..
or For 430/440 MHz.
or For 1200 MHz...
T90-0356-05
T90-0355-05
T90-0364-05
Belt Hook... J29-0424-04....
Rubber Cap . BO9-0309-04.
Hand Strap J69-0312-04.
Battery.......
NiCd battery pack (PB-6).
Batten GRard phases dias nooacsensavaxcwerncsnsscy ssadeverrcvessss 4
After unpacking
Shipping
container:
Save
the
boxes
and
packing
in
the
event
your
unit
needs
to
be
transported
for
remote
operation,
maintenance, or service.
for U.S.A. version (120 V) ... WO9-0382-XX
for European version (220 V) .. WO9-0388-XX
for U.K. version (240 V)....... WO9-0387-XX
for Oceania version (240 V).. WO9-0386-XX
for
Other
market
(220
V)
.....
W09-0384-XX
(120 V) WO09-0385-XX
B42-3325-04.
B50-8170-XX...
Tabblo csr tastes
8 Warranty Card..
9 Instruction Manual ..
carasee

2. BATTERY PACK
2-1 NiCd BATTERY PACK (PB-6)
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 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 months it should be
recharged before use.
2-2 RECHARGING yeti
1. Slide the adapter onto the
NiCd battery pack.
2. Plug the supplied charger
into an AC outlet.
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 5°C~40°C
(41°F ~104°F).
Recharging the battery outside
of this range may not allow the
battery to reach full charge.
NiCd battery pack
to AC outlet
2-3 MANGANESE or ALKALINE BATTERIES
(Optional Battery Case BT-6)
Install 6 x R6 (AA) man- Press down on the hook in the
ganese or alkaline batteries in middle of the battery case top
the battery holder. Pay close to open.
attention the battery polari-
ties marked in the holder. We
recommend the use of high
performance manganese bat-
teries for the greatest operat-
ing time.
Ne: ——————
Do not install NiCd batteries and
attempt to charge them with the
supplied charger. There is no
battery protection circuit in the
battery holder.
2-4 INSTALLING THE BATTERY PACK
Align the grooves in the bat-
tery pack with the trans-
ceiver and slide the pack to
the right 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 | 200 :
PB-6 | 5.2] 600
PB-9
PB-7 [1100
pe-8 | 12| 600 | Sooeeneoe | seeeeee
Manganese or Alkaline batteries (Approximate battery con-
dition)
New batteries | Need to replace
BT-6, 9V
2-6 OPERATING TIME
TH-25 series
Batt voltage (V) Transmitting -1 minute
Receiving
3
minutes
AF OUTPU 2Wiso
144
NiCd
battery
12V
“Battery
voltage
is
measured
at
transmis-
600mAh
(PB-8)
sion
(Hi).
12
10
NiCd battery 7.2V
1100mAh
(PB-7)
Lower
limit
voltage
range
for transmission
6
“a " CSSA
4 1 Manganese batt Alkaline manganese
(Low-Power) (BT-6) battery (BT-6)
NiCd battery 7.2V 600mAh (PB-6)
Manganese battery (BT-6)
NiCd battery 7.2V 200mAh (PB-5)
60 120 180 240 300 360 (minutes)
TH-45 series
Batt
voltage
(V)
Transmitting...
Receiving
AF
OUTPUT.
141
Nicd
battery
12V
“Battery
voltage
is
measured
at
transmis-
\_
600mAh
(PB-8)
sion
(Hi).
uccll
|
|
|
NiCd
battery
7.2V
|
1100mAh
(PB-7)
Lower limit voltage range
hoy for transmission
=
See
AA
Alkaline
manga
=" battery (BT-6)
p
|
Manganese
battery
(Low-Power)
(BT-6)
NiCd battery 7.2V 600mAh (PB-6)
| Manganese battery (BT-6)
NiCd battery 7.2V 200mAh (PB-5)
60 120 180 240 300 (minutes)
TH-55 series
Transmitting, <1 minute
Batt
voltage
(V)
Receiving
3
minutes
AF OUTPUT. .2 W/8 2
*B " te
‘ab
NiCd
battery
12V
pA
daa
is
measured
at
transmis-
600mAh (PB-8)
NiCd battery 7.2V 600mAh (PB-6)
NiCd battery 7.2V
1100mAh (PB-7)
Lower limit voltage range for transmission
Manganese
Manganese
battery
AA
Alkaline
manganese
4
battery (BT-6) (Low-Power) (BT-6) battery (BT-6)
60 120 180 240 300 (minutes)
We
recommend
use
of
the
NiCd
battery
pack
for
long
transmission
or
extended
operation.
Manganese battery (except Alkaline manganese battery) is
available for Low position.
7

3. OPERATION
3-1 OPERATING CONTROLS
@ 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.
@SAQL control
This control is used to select the desired Squelch
threshold level.
@Mhbz 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
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)
\TH-25A/25AT| TH-25E/45E |TH-45A/45AT| TH-55AT/55E|
STEP SIZE 5/10 12.5/5 25/5 25/12.5
Pressing this key for longer than 1 second will initiate
the Band Scan function.
0) as
® all (Se 988's
® fray ®
® = @
© © @
@ 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.
Pressing this key for longer than 1 second will initiate
the Memory Scan function.
(8) 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.
(0 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
1750 Hz is activated.
U.K. version: This key is used to activate the
1750 Hz tone burst.

LCD display
ET a0 0 yo Ee
=
®
li
ass“
sansan
—_
=
066
©
O8
@
()
&
+
(European
version:
=
—
)
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.
(2 Frequency display
Displays the operating frequency to the nearest kHz.
TH-55AT/55E:
Displays
the
operating
frequency
from
10 MHz digit. -—---- =
~~ | 86.088
L Js d a_i]
(3 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.
(OMT |
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.
(8 Hz dot
This
indicator
lights
during
CTCSS
frequency
selec-
tion, 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.
5 kHz tuning step indicator
This indicator lights during VFO operation when tuning
zt in 5 kHz steps.
20 500 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 CTCSS function is ac-
tive.
T. ALT indicator @
This indicator is ON when the Tone alert system is ac-
tive. The indicator will flash when a signal is received.
@
rz)
@) Memory channel indicator
@
© ©
oS
This indicator is used to show the selected memory
channel number.
Memory indicator
This indicator lights during Memory Recall mode, and
flashes during Memory entry.

RS)
@ Release button
ip Press this button up to
release the battery pack.
KENWOOD
THASA
c) @) F. Lock key
le This key will deactivate
all functions except the
i
:
NESp zee
Lamp, MONI, PTT func-
e tions.
430MHz FM TRANSCEIVER
6) Speaker
62 Microphone
63 Battery case
84 SP jack
This jack is used to con-
TH-454
@ MONITOR switch
10
When operating in the CTCSS (Tone Squeich) 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.
TH-45AT
nect an external speaker
or earphone. The recom-
mended impedance is
8a.
@) MIC jack
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 kQ and the DC voltage on this ter-
minal is Approx. 4 V (MAX 3.5 mA).
Note:
The use of a dynamic microphone is not recommended.
Speaker 1
sp tN, &
Ground &
* i
5V '
5V
MIC
MIC 13)
PIT =
PIT
H
fe
H ‘4
Pa

@) CTCSS key
This key is used to select the CTCSS (Tone squelch)
function.
@9 SHIFT key
This key is used to select the desired transmitter offset
for repeater operation. When the offset function is ON,
* or © will be displayed in the display.
@ REV key
Pressing the REV key allows you to reverse the
KENWOOD
TH-55AT
.
transmit/receive
frequencies
during
repeater
opera-
faker
nia
tions.
This
will
allow
you
to
check
the
input
of
the
68)
repeater or to
operate
on a
reverse repeater pair.
SL)
-
oe
eee
@
HILO
switch
F
5 |
This
switch
is
used
to
select
the
transmit output
a
cas,
power.
TH-25A/45A
SERIES
TH-55AT
SERIES
HILO tO Hi
@ RIT control (TH-55AT/55E only)
'y
TH-45A
TH-55AT
When
the
transmit
frequency
of
the
distant station
DTMF
PAD
(with
the
TH-25AT/45AT/55AT
rifts
a
little
bit
during
the
,
but
you
do
not
wish
to
D
H-2'
T,
drift:
piecinrte
‘he
QSO,
b
d
ish
. .
pi
.
- 5
alter
your
transmit
frequency
to
compensate,
you
may
Pina
#
pt
puso
poh
rninseets
wittip'a
Tepeatet.to
wich
_
make
use
of
the RIT
control
function.
This
con-
c
trol
allows
shifting
the
receive
frequency
apploximate-
6)
M
(Memory)
key
f
ly
+5
kHz
without
shifting
the
transmit
frequency.
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.
11

3-2 RECEIVER OPERATION
Connect the battery pack, and the supplied antenna.
Set the controls as follows:
1. Rotate the POWER (VOL) control clockwise to turn the
transceiver ON. A frequency will appear in the display.
2. As the VOL control is rotated clockwise either
background noise or a QSO will be heard coming from
the speaker, provided the CTCSS and Squelch are not
ON.
3. To eliminate the no signal noise turn the SOL control
clockwise to the point the background noise just disap-
pears. This point is known as the Squelch Threshold
point.
4. Select the desired operating frequency using the tuning
control.
Frequency Selection
Press the VFO key. An operating frequency will appear in
the display.
@ VFO Mode
1. Press the VFO key.
2. Turn the tuning control to increase/decrease the fre-
quency. The step size is determined by the location of
the VFO indicators (See Step Size Selection below).
@ MHz Mode
1. Press the MHz key. The MHz indicator will begin
flashing.
2. The tuning control will now increase/decrease the
operating frequency in 1 MHz increments.
3. The tuning step will revert to the VFO mode 5 seconds
after you stop turning the tuning control.
12
Step Size Selection
1. Press the VFO key.
2. Press the M key.
3. Within 5 seconds of pressing the M key press the MHz
key. The VFO indicator will toggle between 5 kHz and
10 kHz (See the chart below for your transceiver.) each
time this sequence is performed.
(kHz)
'TH-25A/25AT| TH-25E/45E |TH-45A/45AT| TH-S5AT/S5E
STEP SIZE 5/10 12.5/5 25/5 25/12.5
Note:
If you are already in the VFO mode you can skip step number 1.
3-3 TRANSMITTER OPERATION
CAUTION:
Ensure that an antenna with a low standing wave ratio
(SWR) is attached to the antenna connector before attemp-
ting to transmit. Failure to provide proper termination may
result in damage to the final amplifier section.
Always check to ensure the frequency is clear before
transmitting.
1. Select the desired operating frequency using any of the
methods described above.
2. Check the frequency to see if it is occupied before you
transmit. If you are using CTCSS (Tone Squelch) press
the MONITOR key to allow the Squelch to open.
3. Press the PTT switch. The TX indicator will light.
4. Speak into the microphone. The recommended distance
to the microphone is 5 cm (2 inches). Talking closer
may result in overdeviation of your transmit signal, and
talking too far away may result in reports of weak audio.
5. Release the PTT switch to return to the receive mode.
The TX indicator should go out.

3-4 MEMORY
The transceiver provides 14 memory channels. In addition
to serving as a normal memory channel some of the
memory channels serve a dual purpose to specify other
parameters.
* Memory channel 13 and 14 are used to store both a
transmit and a receive frequency for ODD SPLIT
operations.
@ Memory channel contents
Each memory channel is capable of storing;
* Frequency * CTCSS status
* Tone status (Excluding European Versions)
* Tone frequency * SHIFT status
3-4-1 AUTOMATIC MEMORY INITIALIZATION
CAUTION:
This
procedure
will
erase
all
of
the
current
data
in
memory
channels 1 thru 10.
This transceiver can automatically store data in memory
channels 1 thru 10 in the following steps.
TH-25A/25AT]
TH-26E
_|
TH45A/45AT/45E/55AT/55E
MR
key
15
kHz
12.5
kHz
VFO
key
20
kHz
25
kHz
epi
This automatic storage will begin from the frequency that
appeared in the display before the transceiver was turned
OFF.
1. Press and hold either the
MR or the VFO key and MR or VFO
and Power ON
turn ON the power.
2. Release the MR or the
VFO key. The memory
channel 1 indicator will be
on.
3. Rotate the tuning control
to confirm data entry in
the remaining channels (2
thru 10).
3-4-2 MEMORY ENTRY
1.
Select
the
desired
opera-
oO
ting
frequency,
offset,
tone
frequency,
etc.
(For
example
145.600
MHz)
Van
2. Press the M key to select
the Memory Entry Mode. eo
ing the M key rotate the
tuning control until the
desired memory channel
number appears in the
display. (For example Ch.
12)
3. Within 5 seconds of press- «>
4. Press the MR key within 5
seconds of selecting the Flashes
Memory channel number.
If you do not press the MR oO
key within 5 seconds data ™R
will not be stored into
memory.
13

3-4-3 MEMORY SHIFT
It is possible to copy the contents of a memory channel to
the VFO without erasing the memory channel.
1. Select the desired Memory
Channel. (For example Ch.
12)
2. Press the M key.
3. Within 5 seconds press
the VFO key to copy the
data.
3-4-4. MEMORY RECALL
1. Press the MR key. The
memory channel that was
active before return to the
VFO mode will appear in
the display. (For example
Ch. 12)
2. Rotate the tuning control
until the desired Memory
channel number appears
in the display. (For exam-
ple Ch. 5)
Note: ———————______
If a channel contains no data
it cannot be displayed using
this procedure.
3. To return to the VFO
mode, press the VFO key.
14
3-4-5 ODD SPLIT
Memory channels 13 and 14 store both a transmit and a
receive frequency. These channels allow operation on
““Odd Split’’ repeater channels.
@ Data entry
1. Select the desired receiver
frequency, tone frequen-
cy, and tone status. (For
example 145.080 MHz)
2. Enter the data into either
memory channel 13 or 14
as described previously.
(For example Ch. 13)
3. Select the desired trans-
mitter frequency by press-
ing the VFO key and then
rotating the tuning control.
(For example 145.300
MHz)
4. Press the M key. Memory
channel 13 will appear in
the display.
*
hime
Oa] &
aa] ea
rhos
“%
ey Ca
(|
pind
a £3 Oa 3
0G
Flashes

5. Press and hold the PTT PTT switch
key. and
6. Press the MR key and then |
release
both
keys.
pes
arenere-atraan
(a Britt
us
UN ULL
MR
Nts
a
PTT
switch
The PTT switch will not initiate
transmit during this operation. SS +
The I and indicators
will
be
on
to
indicate
that
this
wh
33
‘a
4
+
memory
channel
now
contains
b
=
odd
split
frequency
data.
|
SEeeeeeene
@ Release
To
cancel
this
Odd
Split
data
simply
store
a
new
frequency
into
the
memory
channel
using
the
normal
memory
channel
method.
Note:
*
Only
the
receiver
frequency
will
be
transferred
to
the
VFO
during
a Memory Shift operation.
°TH-45A/45AT/55AT:
During
Odd
Split
operation
the
SHIFT
key
does not work.
3-4-6 MEMORY CHANNEL LOCKOUT
The Memory Channel Lockout function allows you to tem-
Porarily skip unwanted Memory Channels except Channel 1.
1. Press the MR key and Sek
select the memory chan- uh 59s. %
nel
you
wish
to
skip.
(For
ey
ee
example Ch. 13)
for longer
than 1 second
2. Press the M key for longer
than 1 second. Both the
channel number and the
Memory indicator (A) will |
flash.
3. Press the MR key within 5
seconds. The selected
memory channel number
will
disappear
and
the
u
nnn
channel
number
of
the
4
AN
LILS
‘
next
active
memory
chan-
ra
nel
will
appear.
(For
exam-
Ne
ple Ch. 1)
for longer
than 1 second
@ Release
1. Press the MR key to select
the
MR
mode.
su
Y
nmr
‘
¢ LN LOLS t
2. Press the M key for longer
than 1 second. Both the
channel
number
and
the
Flash
Memory indicator (A) will
flash.
15

3. Select the desired channel
number using the tuning
control. You will be able to
see all channel numbers
with this procedure. (For
example Ch. 13)
4. Press the MR key within 5
seconds. The Memory
channel number will ap-
pear in the display.
3-4-7 CLEARING ALL MEMORY (Microprocessor
initialization)
To erase the data from all memory channels at the same
time you can reset the microprocessor. This will remove
any programmed information that you have entered.
1. Turn the Power switch OFF.
2. Press and hold the M key.
3. Turn ON the power switch and then release the M key.
4. The display will show: 144.000 (TH-25A/25AT/25E)
430.000 (TH-45A/45E)
440.000 (TH-45AT)
60.000 (TH-55AT/55E)
3-4-8 MEMORY BACK-UP BATTERY
A lithium battery is contained in the transceiver to retain
memory. Turning off the power switch, changing or fully
discharging the normal battery will not erase the memory.
The battery should last for approx. 5 years. When the bat-
tery discharges, an erroneous display may appear in the
display. (For the lithium battery replacement, refer to IN
CASE OF DIFFICULTY. Page 23)
16
3-5 SCAN
For proper scan operation the squelch must be adjusted to
the threshold point.
The MHz dot will flash ON and OFF as a visual indication
that the transceiver is scanning.
@ Scan Modes
Band Scan: Scans the entire band.
Pressing the VFO key for longer than 1 se-
cond will initiate Scan. The scan step size
depends upon the current step programming.
Memory Channel Scan: Scans those memories that ac-
tually have data and have not been locked
out.
Pressing the MR key for longer than 1 second
will initiate Scan.
@ Scan Hold
Scan will stop on a busy channel and hold for approximate-
ly 5 seconds. Scan will resume even if the station is still
present. You can manually cause scan to resume by
rotating the Tuning control.
@ Scan Direction
Scan will begin in an upwards direction. You can reverse
the direction by rotating the Tuning control counter-
clockwise.
@ Scan Release
Scan can be released by pressing PTT switch (no transmit-
ting) or any key except the LAMP, or MONI key.

3-6 REPEATER OPERATION
3-6-1 TRANSMITTER OFFSETS
All amateur radio repeaters utilize a separate receiver and
transmitter section. The receiver frequency may be either
above or below the transmitter frequency.
For most repeaters offsets are as follows:
\ Model | TH-25A TEASE
Dis \ | TH-25AT | THASA European U.K. TH-5S5AT | TH-55E
play \\| TH-25E Ear version version
= | +600kHz | +5MHz +1.6MHz | +12MHz | +36MHz
(=) | -600KH2 | —5MHz | —1.6MHz | —1.6MHz | —12MHz | —6MHz
i} —7.6MHz L
©@ Offset Direction
To select the desired transmitter offset direction press the
SHIFT key. Each time you press the key the transceiver will
advance from one offset to the other, i.e. < to
( © to © with TH-45E European version) to no offset
(simplex).
The transceiver allows you to store the frequency, offset in
memory, or you can select these functions directly from the
keyboard.
®@ Auto-Offset (TH-25AT only)
The TH-25AT has been programmed according to the stan-
dard ARRL Band Plan, regarding transmitter offsets. Please
see the accompanying chart for additional information. You
can, of course, override this by using the SHIFT function, if
desired.
144.00 145,10 146.00 146.60 147.40 148.00
Ss
Ps
inl
s]
[s]
—
Ts
|
S: Simplex Channel 145.50 146.40 147.00 147.60
3-6-2 REVERSE FUNCTION
Some
repeaters
utilize
a
‘’Reverse
pair’’,
i.e.
the
trans-
mit/receive
frequencies
are
exactly
the
reverse
of
another
repeater.
For
example
repeater
A
uses
146.000
for
a
transmit
frequency
(OUTPUT)
and
146.600
for
receive
(INPUT).
Repeater
B
uses
146.000
for
its
receive
and
146.600
for
its
transmit
frequency.
It
would
be
inconve-
nient
to
have
to
reprogram
the
transceiver
each
time
if
you
were
in
range
of
both
repeaters.
The
REV
key
allows
you
to
reverse
the
transmit
and
receive
frequencies.
To
use
the
REVERSE
function
press
the
REV
key.
The
offset
indicator
(
or
=)
/
&
or
©)
will
flash
OFF
and
ON
in
the
display
to
remind
you
that
you
are
working
a
reverse
repeater
pair.
To
return
to
normal
offsets
press
the
REV
key
again.
This
function
is
also
useful
to
check
the
input
frequency
of
the
repeater,
so
that
you
can
determine
if
you
are
within
SIMPLEX
communications
range.
3-6-3 TONE OPERATION
Some
repeaters
require
the
use
of
a
control
signal
to
activate
the
repeater.
Several
versions
are
currently
in
use
worldwise.
In
the
United
States
sub-audible
tones
are
sometimes
used.
With
the
TH-25A/25AT/45A/45AT/55AT
37
different
sub-
audible
tone
frequency
selections
are
possible
with
the
use
of
the
optional
sub-audible
tone
encoder/decoder
(TSU-6).
This
accessory
also
allows
for
CTCSS
(Tone
Squelch)
opera-
tions.
When
this
option
is
activated
the
squelch
of
the
transceiver
will
only
open
when
the
proper
sub-audible
tone
is
received.
(17

®@ Tone Activation
To
activate
the
TONE
function
depress
the
TONE
switch
on
the
top
of
the
transceiver.
The
tone
indicator
will
appear
in
the
display
to
signify
the
tone
has
been
activated.
To
turn
the tone OFF press the TONE key again.
Tone frequency selection
1.
Press
the
CTCSS
key
for
Tone
Frequency
longer
than
1
second.
67.0
He]
110.9
Hz
|
173.8
)Hz
The
current
tone
fre-
ue
Be
ee
a
8
He
: :
: : 2
Hz
quency
will
be
dis-
77.0
Hz
|
123.0
Hz
|
192.8
Hz
played.
:
79.7 Hz
|
127.3
Hz
|
203.5
Hz
2.
Rotate
the
Tuning
con-
2.5
Hz
|
131.8Hz
|
210.7
Hz
trol
until
the
desired
85.4
Hz
|
136.5
Hz
|
218.1
Hz
tone
frequency
appears
88.5
Hz
|
141.3
Hz
|
225.7
He
in
the
display.
91.5Hz
|
146.2
Hz
|
233.6
Hz
Re
Press
the
TONE
key
to
94.8
Hz
151.4
Hz
241.8
Hz
turn
to
the
normal
fre-
|
100-0H#
en0.3
te
quency
display.
103.5
Hz
|
162.2
Hz
107.2
Hz
|
167.9
Hz
4. lf CTCSS (Tone Sque-
Ich)
is
not
desired
press
the
CTCSS
key
to
cancel
the
function.
The
transmit
tone
will
still
be
active.
Note:
When
no
Tone
Unit
is
installed,
pressing
the
TONE
key
will
not
transmit
a
subtone,
even
if
the
indicator
is
ON.
In
Europe
a
1750
Hz
tone
is
used
in
transmit.
Press
and
hold
the
TONE
key
to
transmit
the
access
tone,
then
press
the
PTT
switch.
In
the
United
Kingdom
a
1750
Hz
tone
burst
at
the
beginn-
ing
of
each
transmission
is
used.
Press
the
Tone
key.
Since
use
of
this
tone
is
required
in
the
Europe
and
the
United
Kingdom,
an
1750
Hz
tone
encoder
is
encluded
as
standard
equipment.
18
@
CTCSS
(Tone
Squelch)
Operation
.
To
actuate
the
CTCSS
(tone
squelch)
function
(decode)
select
the
desired
tone
frequency
as
described
above
but
do
not
press
the
CTCSS
key
the
second
time.
2.
Squelch
will
now
open
only
when
the
transceiver
receives
the
same
subtone
frequency.
3.
To
release
tone
squelch
operation
press
the
CTCSS
key.
The
CTCSS
indicator
should
go
out.
It
is
a
good
operating
practice
to
check
the
frequency
before
transmitting.
A
MONITOR
switch
has
been
provided
for
this
purpose
when
using
the
CTCSS
(tone
squelch)
function.
Pressing
this
switch
will
open
the
squelch
so
you
can
check
for
activity.
=i
@ TSU-6 (option) Installation
1. Remove the backing from
the
cushion
(large)
that
Terminal
plate
g
was
provided
the
TSU-6
Spring
and
attach
it
to
the
back
A
of the TSU-6.
2. Remove the Battery Pack
and
remove
the
four
incer
phillips
head
screws
from
connecter
the terminal plate of the
transceiver. Sa
3.
Turn
the
terminal
plate
‘
over
and
take
out
the
Pr
cable
as
shown
in
the
diagram.
lear tube x
4.
Remove
the
clear
tube
~~
fe
covering the connector,
and the resistor inserted
into the connector.
“Cushion
(large)
_
Attach
the
cable
from
TSU-6
as
shown
in
the
diagram.
-
Remove
the
backing
from
the
other
side
of
the
cushion
and
attach
the
TSU-6
to
the
transceiver.
on

7. Push up on the release button and set the terminal plate
in the hole of the release button. Replace the terminal
plate and tighten the screws to complete the installa-
tion. Do not pinch the wiring when closing the terminal
plate.
3-6-4 AUTOPATCH
(TH-25AT/45AT/55AT U.S.A. version only)
Some
repeaters
offer
a
service
known
as
autopatch.
This
allows
you
to
dial
a
telephone
number
from
your
transceiver
and
carry
out
a
telephone
conversation,
much
like
a
car
telephone,
or
cellular
telephone.
This
function
re-
quires
the
use
of
a
DTMF
(Dual
Tone
Multi
Frequency)
pad.
In
addition
to
the
normal
12
keys
that
are
found
on
your
telephone
the
transceiver
also
provides
4
additional
keys,
A,
B,
C,
and
D.
These
keys
are
required
by
some
repeater
systems
for
various
control
functions.
You
should
check
with
the
control
operator
of
your
repeater
to
determine
if
their
use
is
required.
A
chart
is
provided
that
lists
the
tones
that
are
generated
when
you
press
each
key.
1.
To
activate
the
DTMF
pad,
press
and
hold
the
PTT
switch.
2.
Now
press
the
keys
just
as
you
would
dial
a
telephone.
Audio tones (Hz)
Note:
Some repeaters will require a fer] 1209 | 1336 | 1477 | 1633
Row
special sequence of keys to ac-
tivate the Autopatch. Again
you should check with the con- 507 u 2 i) A
trol operator of your repeater | 770 4 S 6 B
for this sequence. 852 7 8 9 c
941 * 0 # D
3-7 BEEP TONE
If
you
would
like
audio
confirmation
when
a
function
is
ac-
tivated
press
the
M
and
then
the
T.ALT
key.
The
transceiver
will
then
supply
audio
confirmation
according
to
the
chart
below.
Pressing
the
same
combination
again
will
turn
the
function
OFF.
Scale Frequency Key operation
(He)
A 440.00 | CALL, REV, T.ALT, TONE, CTCSS, MHz, M, SCAN
OFF
B 493.88 | SCAN STOP
ce 523.25 | VFO MODE SELECTION, MEMORY SHIFT
cH 564.37 | — OFFSET
D 587.33 | SIMPLEX
Dé 622.26 | + OFFSET
E 659.25 | MR MODE SELECTION
F 698.46 | To complete the MEMORY Entry
To complete the CTCSS Frequency selection
6
783.98
|
CALL,
REV,
T.ALT,
TONE,
CTCSS,
MHz,
M,
SCAN
ON
G# 830.61 | MEMORY CHANNEL selection
CTCSS Frequency selection
A 880.00 | M, ODD SPLIT
Af 932.33 | STEP SIZE selection
B_|__987.77__| AUTOMATIC POWER OFF
F 1396.91 _| Key operation without effect
2000 T.ALT alarm
19

3-8 TONE ALERT SYSTEM
The Tone Alert function will provide an audible ‘’alarm’’ to
signal
when
someone
is
transmitting
on
the
frequency
you
are monitoring.
For proper tone alert system operation the squelch must be
set to the threshold point.
1. Press the T.ALT key. The T.ALT indicator will light.
2. When a signal is present:
The T.ALT indicator will flash.
The busy indicator will light.
The transceiver will beep ON and OFF for about 5
seconds.
3. The T.ALT function can be released by pressing the
T.ALT key again.
Note:
¢ The tuning control, PTT switch, and all the keys except MONI,
LAMP are not effective during the T.ALT operations.
©
Turning
on
the
power
switch
while
the
T.ALT
function
is
on
may cause the BELL indicator to flicker.
If this happens, turn the T.ALT off, and then back on.
3-9 BATTERY SAVER
The transceiver provides a battery saver mode to conserve
on battery power.
The transceiver will activate the battery saver circuit 10
seconds after the last key operation with the squelch clos-
ed.
ON OFF ON OFF
The function will be released by key operation or when
squelch opens.
The function cannot operate during scan or tone frequency
selection.
Note:
It
is
possible
that
you
might
press
the
MONI
switch
during
the
OFF
period. Squelch would not open during this period.
3-10 AUTOMATIC POWER OFF
The
transceiver
also
provides
an
Automatic
Power
OFF
cir-
cuit.
The
circuit
action
is described
below.
1.
A
5
second
audio
confir-
mation
alert
will
sound
nec
after
59
minutes
if
no
or
tong
rc
signal
has
been
received
|
"ot
a
and
if
you
have
not
per-
formed
any
key
operation.
\
2.
1
minute
after
this
alert
signal
the
transceiver
will
shut
itself
OFF
except
for
enough
power
to
show
“‘po
OFF’
in
the
LCD
display.
Release
The function can be released by pressing the MONI key or
turhing the Power switch OFF and back ON.
The function can not be activated during scan or Tone Alert
System operation.
Note:
To conserve battery life even more simply turn the transceiver
OFF when you are not using it.

3-11
BATTERY
SAVER
and
AUTOMATIC
POWER
OFF
function
CANCEL
(TH-55AT/55E
only)
have been cancelled.
1. Turn the Power switch OFF.
2. Press and hold the MHz key.
3.
Turn
on
the
Power
switch
and
then
release
the
MHz
key.
4.
The
Hz
dot
will
light
as
a
———_—_—_
visual reminder that the |
Battery
Saver
and
Auto-
|
9S
a
eitys
matic
Power
OFF
function
|
boedie-y
is
Hz dot
The
function
can
be
restored
by
this
same
procedure.
The
function
cannot
be
activated
during
Tone
Alert
System
operation,
or
when
F.LOCK
is
ON.
21