Kenwood TM-241A User manual

COO/AN3»
144MHz
FM
TRANSCEIVER
TM-241A/241E
430/440MHz
FM
TRANSCEIVER
TM-441A/441E
1200MHz
FM
TRANSCEIVER
TM-S41A/S41E
(
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.
CAUTION:
Long transmission or extended operation in the |
ІНІ power mode might cause the rear of this |
i
i transceiver to get warm.
Do
not
place
the
transceiver
where
the
heat
sink
(rear
panel)
might
come
in
contact
with
plastic
ог
vinyl
surfaces.
This
instruction
Manual
covers
the
following
models.
TM-241A: 144MHz FM TRANSCEIVER
(U.S.A. and general markets)
TM-241E: 144MHz FM TRANSCEIVER
(U.K. and European markets)
ТМ-441А:
440MHz
FM
TRANSCEIVER
(U.S.A.
only)
TM-441A:
430MHz
FM
TRANSCEIVER
(General
markets)
ТМ-441Е:
430MHz
FM
TRANSCEIVER
(U.K.
and
European
markets)
ТМ-541А:
1200MHz
FM
TRANSCEIVER
(U.S.A.
only)
TM-541E:
1200MHz
FM
TRANSCEIVER
(European markets)
NOTE:
lf disregarded, inconvenience only, no risk of
equipment damage or personal injury.
CAUTION:
Equipment
damage
may
occur,
but
not
personal
injury.
FCC WARNING
This
equipment
generates
or
uses
radio
frequency
energy.
Changes
or
modifications
to
this
equipment
may
cause
harmful
interference
unless
the
expressly
approved
іп
the
modifications — are
instruction manual. The user could lose the authority
to operate this equipment if an unauthorized change
or modification is made.

CONTENTS
1.
gr de а.
BEFORE OPERATION ......... sac ts ње 4
SPECIFICATIONS уснаа NE RS 6
ACCESSORIES аа istbeses 7
INSTALLATION INSTRUCTIONS ...... 7
OPERATION
CONTROL ЕЏМСТОК5.................. 10
RECEIVER OPERATION
Reception ............... ——— 16
Frequency Selection ................... 17
Frequency Step Selection .............. 17
Programmable VFO Tuning Limits ...... 18
АіТ(ТМ-541А/Е опіу).................. 19
TRANSMITTER OPERATION ............. 20
Time-out Timer (TOT) ................. 20
MEMORY
Microprocessor Memory back-up ....... 21
Initial State acc. аз VR En ES qa utat ud 21
Microprocessor Initialization ........... 21
Memory Channel ..................... 21
Memory Contents «coss EXER 22
Memory Entry: соқалар eei di ovs 22
Memory Channel Recall ............... 24
Memory Sit: о ou за ier E s 24
SCAN
Scan Operation сеанса ues а Sa 25
6.
7.
Hold/Resume Programming ........... 25
Band Scam. oos terza daten Е ло 26
Programmable Band Scan ............. 26
Memory Channel Scan ................ 27
Memory Channel Lockout ............. 27
Priority Alert Function ................ 28
REPEATER OPERATIONS
Transmitter Offsets ................... 28
Reverse Function ..................... 29
Ттопе:Ореѓапоп:. “асьохтаедфь жееытжа 29
Tone Frequency Selection ............. 29
Autopatch (U.S.A. version only) ........ 30
TONE / CTCSS OPERATION.......... 30
DTSS (Dual Tone Squelch System)
OPERATION зена RR 31
DRS (Digital Recording System)
OPERATION: „о RE RR des 34
PAGING): аон оо ован EV 41
TONE ALERT SYSTEM ............... 47
APO (Automatic Power Off) ............ 48
DIMCUimmab). оа ба xe eet cater danse 48
ВЕЕР essai  49
LOCK/A.LOOK ....................... 49
BLOCK DIAGRAM and
SCHEMATIC DIAGRAM Another sheet
MAINTENANCE ..................... 50
IN CASE OF DIFFICULTY ........... 51
8.
OPTIONAL
ACCESSORIES
...........
52

A WARRING); BEFORE OPERATION
TO PREVENT ELECTRIC SHOCK, FIRE AND OTHER
INJURY. PLEASE NOTE THE FOLLOWINGS:
To avoid risk of electric shock,under no circumstances
should the unit be opened.
Do not place this unit,where it will be exposed to direct
sunlight or close to heating appliances.
To ensure good ventilation, do not put anything on top
of the cabinet and allow at least 15 cm (6 Inches) of
space behind the unit.
The power requirement is 13.8 VDC.
Never attempt connection to a 24 VDC source.
Do not place the unit in areas off excessive dust, high
humidity or on unstable surfaces.
Do not drop pieces of metal, needles, coins and other
electrically conductive materials into the unit.

Do not touch the power plug, when your hands are
wet.
Do
not
ри!
the
power
cord,
when
disconnecting
it
from
the
AC
wall
outlet.
Grasp
the
plug
and
ensure
that
your
fingers
do
not
touch
the
live
pins.
If
an
abnormal
odor
or
smoke
is
detected,
immediately
turn
the
power
off
and
pull
out
the
power
plug.
Contact
the
KENWOOD.
service
station
or
our
dealer.
CLEANING
1. Turn the power off, before cleaning the unit.
2.
Do
not
use
any
type
of
abrasive
pad,
thinner,
benzine
or
any
substances
which
may
damage
the
unit.
3. Wipe the front panel and other exterior surfaces of
the
unit
with
a
soft
dry
cloth
or
a
soft
cloth
lightly
moistened
with
water.

Output (5% distortion)
2 SPECIFICATIONS
ТМ-241А/Е | TM-441Ausaicanaca ТМ-441Е
| Frequency range MHz 430 to 440 | 1240 to 1300
мовам
|
Antenna
impedance
са
аашаа
E
Operating temperature
© | Power requirements
- Ground Negative .
gramen Less than ТОА
Less than 0.6A
Frequency stability Less than +10ppm
Dimensions (WXH XD) (mm) (Projections included) 140 x40 X 160(5-1/2" х1-37/64”х6-19/64”) (140X40X172(51/2"x 1-37/64" X 6-25/32")
Weight (kg)
Hl 50W
Output power 2 MID Approx OW — | aoiw CdS
5 LOW Approx. 5W
E
с Spurious radiation Less than — 60 dB
Е
Audio distortion (at 60% modulation) Less than 3% (300 to 3000 Hz)
Intermediate frequency lst/2nd | 30.825MHz/455kHz
@ | Selectivity —6dB: More than 12 kHz 6008 Less than 24 kHz
d
More than 2 W across 8 Q loads
External speaker impedance
> С 0) = m m — A EN
6
-— ы
со
80
2 Recommended duty cycle: 1 minute Transmit, 3 minutes Reception
Circuits and ratings are subject to change without notice due to advancement in technology.

3 ACCESSORIES
Unpack your new transceiver carefully, and examine it
for visible damage If the equipment has been
damaged іп shipment, notify the transportation
company immediately. Save the boxes and packing
material for future shipping.
The following accessories should be included in the box
with the transceiver.
DTMF Microphone
(U.S.A. CANADA only) .........
or
Dynamic Microphone
(GENERAL market only) .......
or
Dynamic Microphone
(EUROPE market only) ........
Microphone Hook
(U.S.A. CANADA only) ........
Mobile Mounting Kit
Bracket оган
Screw set ..............
Self tapping Screw
(U.S.A. CANADA LL
Hex wrench: оаа saad
Stacking plate
(TM-441A/441E/541A/541E)..
T91-0380-X5 1 ea.
T91-0379-X5 1 ea.
T91-0382-X5 1 ea.
J20-0319-24 1 ea.
J29-0436-03 1 ea.
N99-0331-05 1 ea.
N46-3010-46 2 ea.
W01-0414-04 1 ea.
J21-4147-14 2 ea.
DC power Cable ............. E30-2111-05 1 ea.
Fuse (TM-241A/241E: 15A).. ҒО5-1531-05 1 ea.
(TM-441A/441E: 10A).. FO5-1031-05 1 ea.
(TM-541A/5A1E: 8A)... FO5-8021-05 1 ea.
Instruction Manual ........... В62-0031-ХХ 1 copy
Waranty Card rorot жаа EE Fx MS l ea.
(U.S.A., CANADA , EUROPE market s only)
4 INSTALLATION INSTRUCTIONS
4-1 INSTALLATION
Mounting Bracket
When installing the transceiver in a vehicle consider the
ease of operation and safety when selecting the
location for the mounting bracket.
1. Install the bracket using the supplied flat washers
and self tapping screws ( 4 pcs.each).
2. Attach the transceiver loosely using the 4 SEMS
screws.
3. Align the
grooves in the bracket with the
transceiver's screws ( Fig. A) and slide the transceiver
to the rear.
4. Adjust the viewing angle in the bracket to the
desired position ( Fig. B).
5. Hold the transceiver in place and tighten the 4 SEMS
screws using the supplied wrench.

4-2 CONNECTION
4-2-1 Mobile Installations
Cautions :
1. Before installing the power cable, be sure to
remove the negative lead from the battery for
safety.
2. After installation and wiring, be sure to double
check for correct installation before reconnecting |
the negative lead to the battery terminal. |
3. If the fuse opens, be sure to check that each .
conductor has not been damaged by short.
circuiting, etc. Then replace with a new fuse of |
the same rating.
4. After completing the wiring, wrap the fuse holder
with heat resistant tape to protect against heat
and moisture.
5. Do not remove the fuse even if the power cable is
too long.
A. Battery Connections
Connect the power cable directly to the battery
terminals. Using of the cigarette lighter socket will lead
to a poor connection, and will result in poor
performance. Pay close attention to the polarity of the
cables when connecting them to the battery.
Make sure the positive { +) and negative (-) lead polarity is correct
when connecting to the battery.
Engine аша ыт сты Passenger compartment
Fuse
R
Select a location whare E
the power cable is pro- l
! tected from heat, mois-
| ture or abrasion when `
, Securing ће the cabe. ,
Red
9
\ To the
\ transceiver
Make sure the cable does
not directly contact the
edge of the hole by using
a grommet.
cable
Chassis
or
ee
PENES,
fire
wall
Battery
W |f the wiring hole in the fire wall or chassis is too small, disas-
semble the fuse holder to thread the wire through the hole.
From passenger
compartment
Thread like this
B. Ignition Noise
This transceiver has been designed to suppress ignition
noise; however, if excessive noise is present, it may be
necessary to use suppressor spark plugs (with resistors).

4-2-2 Fixed Station
A regulated DC power supply (13.8 VDC capable of
supplying at least 11 amperes) is required. PS-33 is
recommended.
outlet until 81 other connections have been
made.
2. Before connecting and disconnecting the power
connector,
be
sure
to
turn
OFF
the
POWER:
switches of both the transceiver and the DC
power supply.
| 3. Observe polarity of the DC power cable. The
' transceiver operates on 13.8 VDC, negative
ground. Battery polarity must be correct. The
power cable is color coded :
Red — + (Positive polarity)
Black —^ — (Negative polarity)
4-2-3 Antenna
The type of antenna that is used will greatly affect the
performance
of
the
transceiver.
Use
a
properly adjusted
antenna, of good quality, to enable your transceiver to
perform at its best. The antenna input impedance is 50
ohms.
Use
50-ohm
coaxial
cable
such
as
RG-8U
or
8D-2V
for this connection. If the antenna is far from the
transceiver the use of low loss coaxial cable, such as RG-
8U
is
recommended.
Match
the
impedance
of
the
coaxial cable and that of the antenna so that the SWR is
less than 1.5 to 1. The protection circuit in the
transceiver
will
activate
if
the
SWR
is
particularly
poor
(greater than 3 to 1).
High
SWR
values
will
cause
the
transmitter
output
to
drop,
and
may
lead
to
TVI
or
BCI
reports.
|
Caution
:
|
|
We
recommend
that
you
install
a
high
quality
lightening
arrestor
in
your
antenna
lines
for
protection
against
fire,electric
_
shock,personal
injury,or damage to the radio itself.
<<
M
Àဗ—Á
——
—
A

5 OPERATION
5-1-1 CONTROL FUNCTIONS
(22 POWER switch
Press to turn the transceiver on or off.
Press the VFO/MPV or MR/M key and switching the
power on will reset the VFO or MEMORY.
The microphone PF key can be programmed when
the power is switched on.
@ Tuning control
This control is used to select the desired
transmitter /receiver frequency, MHz step, memory
channel, frequency step, tone frequency, scan
direction, etc.
(3 VOL control
This control is used to adjust the volume from the
internal and external speaker (if used). Clockwise
rotation will increase the — volume and
counterclockwise rotation will decrease the volume.
@ SQL (Squelch) control
This control is used to select the desired squelch
threshold level.
10
ALOCK ~ ~ FEV >
99606885588
AL CTCSS g i
Ка Б
5) LOW/DIM key
LOW
This function is used to select the transmit output
power level (НЕ, MID(Except TM-541A/E), or LOW).
DIM
This function is used to select the intensity of the
front panel display illumination. (See page 48)
Pressing the F key for longer than 1 second and then
press the LOW/DIM key while the F indicator is flash-
ing will turn the time-out timer function on and off. |
(6) Microphone connector
Attach the supplied microphone to this connector.
Тһе pin out of the connector is shown in the
accompanying illustration.
%
GND
T
GNO
{Microphone
audio)
$ MIC
(Microphone Audio) (3) RX Audio Output
2 PTT (Approx 100 mV/10 к ohm)
(Push to Talk)
3: DWN
@ UP
5) В VOC (Max 150 mA)

KENWOOD
mm v.
969% ALOCK ~- -  + AL составе Ж
T ЕРЕТІН сод
cxnsessssszessENB СЕА, |
74-24
57 a
2
T бит ITEP 1
рак `
3) (меч)
DIR -
(D VFO/Mb V key
This
key
is
used
to
return
to
VFO
operation
after
operating
in
the
MR
or
CALL
channel
mode.
Pressing
this
key
will
allow
the
tuning
control
and
microphone
UP/DWN
keys
to
increase
or
decrease
the
operating
frequency.
Press
and
hold
the
key
for
longer
than
1
second
to
initiate
VFO
scan.
Pressing
the
key
after
scan
has
been
initiated
will!
cause
scan
to
stop.
Pressing
the
key
within
10
seconds
of
pressing
the
F
key
will
copy
the
memory
channel
or
cal!
channel
data
to
the
VFO.
This
allows
you
to
change
parameters
of
that
channel
without
actually
changing
the
data
that
has
been
stored
in
memory.
Pressing
the
F
key
for
longer
than
1
second
and
then
pressing
the
VFO
key
will
cause
radio
to
toggle
the
hold
/
resume
mode
between
Time
Operated
scan
and
Carrier
Operated
scan.
If
you
press
and
hold
the
VFO
key
while
you
turn
on
the
POWER
switch
you
will
reset
the
microprocessor’s
VFO
memory,
without
destroying
the
memory
channel
or
call
channel
data.
@) MR/M key
This
key
is
used
to
select
MR
(Memory
Recall)
mode
from
the
VFO
mode.
The
tuning
control
can
then
be
used
to
select
the
desired
Memory
channel.
Pressing
the
key
for
longer
than
1
second
will
initiate
memory
channel
scanning.
Pressing
the
key
within
10
seconds
of
pressing
the
F
key
will
store
the
displayed
data
into
memory.
In
the
MR
channel
mode
pressing
the
F
key
for
longer
than
1
second
and
then
pressing
the
MR
key
will
cause
the
Memory
channel
to
skip
during
Memory
channel
scan
mode.
If
you
hold
and
press
this
key
while
you
turn
on
the
PÓWER
switch
you
will
clear
all
the
microprocessor's
operator
programmed
memory
section.
(3) MHz/LOCK key
This
key
is
used
to
tell
the
microprocessor
that
you
wish
to
increase
or
decrease
the
operating
frequency
in
1
MHz
increments.
Pressing
this
key
within
10
seconds
of
pressing
the
F
key
will
cause
the
key
lock
function
to
activate,
protecting
the
currently
displayed
data
from
accidental
erasure.
Pressing
the
F
key
for
longer
than
1
second
and
then
pressing
MHz/LOCK
key
while
the
F
indicator
is
flashing
will
turn
the
AUTOMATIC
POWER
OFF
function
on
or
off.(See
page
48)

ps A
аах
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7 - LEE  
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= sep...
@ CALL key
Press this key to activate the call channel function.
Press the F key momentarily and then press the
CALL key to store the currently displayed data into
the CALL channel. The radio will allow you up to 10
seconds to press the CALL key after pressing the F
key.
Pressing the F key for longer than 1 second and then
pressing the CALL key will store the currently
displayed data as the lower limit for the
programmable VFO tuning limit function.
(5) SHIFT/AL key
SHIFT function
Pressing this key alone to select the desired
transmitter offset.direction. Pressing the key will
cause the radio to-shift from one offset direction to
the next, іе. “+” to “--"" to simplex where no
indicator shows. ('—'to"— —" for European
versions)
AL function
Pressing the F key momentarily and then pressing
the SHIFT/AL key will cause the radio to activate the
Priority Alert function. When this function is active
the radio will scan memory channel 1 at approxi-
mately a 5 second interval. If there is activity on the
frequency a beep will sound from the speaker.
Pressing the same key sequence again will cancel
the function.
Pressing the F key for longer than 1 second and then
pressing the SHIFT/AL key will store the currently
displayed data as the upper limit for the program-
mable VFO tuning limit function.
6) TONE/T.ALT key
TONE function
Pressing this key by itself causes the radio to select
the desired tone signaling mode. When the “Т”
indicator is illuminated in the display the transceiver
will transmit the selected subaudible tone. When
the “СТС55” indicator is illuminated the transceiver
will both transmit the subaudible tone and will also
remain squelched until the proper subaudible tone
is received.
TONE frequency selection
Pressing the F key for longer than 1 second and then
pressing the TONE/T.ALT key will allow you to select
the desired tone frequency. To change to a
different tone frequency rotate the tuning control
or press the UP/DWN switches on the microphone
until the desired tone frequency appears in the
display. To return to the normal frequency display
you can press any front panel key except the power
Switch.
TONE ALERT function
If you press the F key momentarily and then press
the TONE / T.ALT key, T.ALT function will be
activated. This function will cause the radio to emit
a series of beeps when an incoming signal is
received. (See page 47)

4. CTCSS 4| Ў
QU =
Еғва8 888588.
qgnesenesenuss6Al EE... ,
“4-2444 ^L “2.1 step È ;
D REV/STEP key
This
key
is
used
to
reverse
the
transmit
/
receive
frequencies
during
repeater
operation.
If
you
have
selected
simplex
this
key
will
not
function!
Pressing
the
F
key
momentarily
and
then
the
REV/STEP
key
will
allow
you
to
select
the
desired
VFO
tuning
step
and
Scan
step
size.
Use
the
tuning
control
to
select
the
desired
tuning
step
and
then
press
any
front
panel
key
except
the
POWER
switch
to
return
to
the
normal
frequency
display.
Pressing
the
F
key
for
longer
than
1
second
and
then
pressing
the
REV/
STEP
key
will
turn
the
BEEP
function
Off
or
ON.
(&
DR/DT/ALT
key(ALT:
TM-541A/541E
only)
DR/DT function |.
Pressing
this
key
alone
to
select
the
DTSS(Dual
Tone
Squelch
System)
function
or
DRS
(Digital
Recording
System
)
function.
ALT function
Pressing
the
F
key
momentarily
and
then
the
DR/DT/ALT
key
will
cause
the
ALT(Automatic
Lock
Tuning)
function
of
the
TM-541A/541E
to
activate.
Pressing
the
F
key
for
longer
than
1
second
and
then
pressing
the
DT
/
DR/
ALT
key
will
turn
the
DRS
function
ON
or
OFF.
5-1-2
D LOCK
© & ©
da
«o
A.LOCK
«Exi»
DTSS
DRS
APO
ee UVER —
LOW MIO
LCD Display Panel
DECLA a» 439
v &
On
when
the
Lock
function
has
been
activated.
On when the & Lock function has
been activated.
On when the Automatic Lock Tun-
ing function is active. When the ALT
system is operating the direction in-
dicator
will
turn
on
if
the
system
shifts
the
receiver
frequency.
On when the DTSS function has
. been activated.
On when the Digital Recording Sys-
tem is active.
On when the Automatic Power Off
function has been activated.
On when the squelch opens.
This level meter indicates the rela-
tive receiver signal strength or the
relative transmitter power output.
Indicates the relative output power
setting
for
transmit.
No
indicator
for high power.
On when the Time Out Timer func-
tion has been activated.
On during transmit.
13

5)
ж
t
A
ty
ws
Indicates the active memory channel
number. ж indicates that the chan-
nel is locked out.
C is displayed during cal! channel.
Either РО, Р1, P2, P3, or PA is dis-
played during paging.
On whenever the F key has been de-
pressed. Also shows the last memory
channel number that had been se-
B lected. |
5 S On when the Tone Alert function is
active. The indicator flashes when
signal has been received.
42 CTCSS On when the Tone Decode and En-
| code function has been activated.
On when the Tone Encode function
has been activated.
2F |
19 AL On when the Priority Alert function
has been activated.
15 REV On when the Reverse function has
been activated.
(0)
=F
Display
the
selected
transmitter
off-
set direction.
Both — and + light at the same
time during split channel operation.
4 ‚2288885 Displays the operating frequency to
the nearest kHz digit; or the tone
| l frequency etc.
The indicator flashes when scan-
ning.
5-1-3 Rear Panel
D ANTENNA connector
Aitach an antenna with a
impedance of 50 ohms.
(2) 13.8 VDC power input connector
Connect the supplied DC power cable to this
connector.
Pay close attention to the polarity. Red is positive and
black is negative. |
(3) Fuse holder
Contains a requaired fuse.
ТМ-241А: 15A, TM-441A: 10A, ТМ-541А: ВА
Do not use a larger fuse as damage might result to
the transceiver.
(2) External speaker jack
This jack is used to connect an external speaker. The |
speaker should have an impedance of 8 ohms.
low SWR and an

5-1-4 Microphone
= A o
|
]
ж
$
(8)
m
а
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European version version
QAUP/DOWN switches
These switches can be used to increase or decrease
the VFO frequency, the Memory channel number,
and the Tone frequency, etc..
(3) PTT (Push to Talk) switch
The transceiver will transmit whenever this switch is
depressed. Scan operations may be canceled by press-
ing this switch without transmitting.
(4) CALL key (except European version)
This key functions just like the CALL key on the front
of the radio. we
1750 key (European version)
The transceiver will transmit with 1750 Hz repeater
access
tone
whenever
this
switch
is
depressed.
(5) VFO key
This key functions just like the VFO key on the front
of the radio.
(6) MR key
This key functions just like the MR key on the front of
the radio.
(7) PF (Programmable Function) key
This key can be programmed to perform any of the
following functions:
MHz
key
(Initial
setting
from
the
factory);
or
SHIFT-
key;
or
TONE
key;
or
REV
key;or
DR/DT
key
;
or
LOW
key.
To program the key use the following procedure:
1. Turn the POWER switch on the transceiver OFF.
2. Press and hold the key on the front panel of the
set
that
corresponds
with
the
function
you
wish
to
program the microphone key to perform.
3.
Turn
on
the
POWER
switch
while
the
key
on
the
front
panel
is
held
in.
4. Release the front panel key.
One additional function can be programmed that is
not
included
on
the
front
panel
of
the
transceiver.
This
is
known
as
the
MONITOR
function.
This
will
al-
low
you
to
open
squelch
to
check
the
band
for
a
clear
frequency.
This
will
function
even
if
you
are
operat-
ing
in
the
CTCSS
decode
mode
ог
DTSS
mode
or
PAG-
ING mode.
MONITOR programming
Press
and
hold
the
F
key
on
the
front
panel
as
you
turn
on
the
POWER
switch
of
the
transceiver
and
then release the F key.
(8)
16-Tone
DTMF
keypad
(U.S.A.
and
CANADA
version
only)
These
buttons
are
used
to
activate
the
DTMF
encod-
er.
($9 LOCK key
This
key
will
deactivate
all
functions
of
the
micro-
phone
except
the
PTT
function
and
DTMF
key
pad.
15

5-2 RECEIVER OPERATIONS
Audio confirmation is provided whenever a front panel
key
is
depressed.
You
can
disable
this
function
by
pressing the F key for longer than 1 second and then
pressing the REV/STEP key.
5-2-1
1. Connect the power supply, antenna, and microphone
and then adjust the controls as follows:
Power Switch ........ OFF
Vol Control Full Counterclockwise
Power switch of power supply
(Fixed station) ....... OFF
SQL Control ........ Full Counterclockwise
2. Turn on the Power Supply and then turn on the
transceivers POWER switch. The display should
indicate a frequency. Fig.l shows examples of
frequencies that will appear on the various models.
In addition to the frequency you may see one or
more control peleas ominas on the display.
TM-241A/241E
'(U.S.A.
version)
TM-541A/541E
Receptoin
nnnn
IYUL L L
П
| чење c ——a —a s. avra |
M
TM441A/TM-441E
fo] =  22
nnnn i
43U.L Li Li i
| т vee
Fig. 1
| Note
The frequencies shown above are the default -
frequencies
after
a
microprocessor
reset.
If
the
Rotate the VOL control clockwise until a signal or
noise is heard coming from the speaker.
Rotate the tuning control or press the microphone
UP/DWN switches to select an open channel. Then
rotate the SOL control clockwise until the noise just
disappears and the BUSY indicator turns off. This
point is known as the Squelch Threshold point. The
squelch control must be adjusted to this setting for
the Scan functions to operate properly.
select the desired operating frequency using the
microphone or tuning control. When a signal is
received the S-meter will deflect and the BUSY
indicator will turn ON.
Caution
Turn off the transceivers POWER switch before you
start or stop your vehicles engine, or your home
power supply.
| display shows incomplete data or you think the —
displayed frequency is in error you should reset the .
| Microprocessor. Memory Initialization on page 21.

5-2-2
You can change the dial frequency while in the VFO
mode. The frequency can then also be stored in
memory, or in the call channel using the techniques
that will be described in this manual.
T “VFO mode
Frequency Selection
MR key VFO key VFO key CALL key
M CALL key
MEMORY channel mode 4 —— — — САШ channel mode
us и MR key
@ VFO Mode Operation Frequency Selection
1. Press the VFO/MPV key to select the VFO mode.
Rotate the tuning control or press the microphone
UP/DWN switches to select the desired frequency.
Memory Channel Selection
Press the MR/M key.
Rotate the tuning control or press the microphone
UP /DWN switches to select the desired memory
channel.
@ CALL Channel Selection
Press the CALL key to select the Cail channel.
N - Ф
5-2-3
The frequency step is indicated in the chart below.
Frequency Step Selection
—
ТМ-241А/Е
ТМ-441А/Е
ТМ-541А/Е
To select the desired tuning ог scan step size use the
following procedure:
1. Press the VFO/MP V key to select the VFO mode.
2. Press the F key momentarily. The F indicator should
light in the display.
3. Press the REV/STEP key within 10 seconds of pressing
the F key. The current frequency step size will be
displayed.

4.
Rotate
the
tuning
control
or
press
the
UP
/
DWN
switches
on
the
microphone
until
the
desired
tuning
step
size
appears
in
the
display.
5.
To
compiete
the
programming
of
the
step
size
you
can
press
any
key
on
the
front
panel
except
the
POWER
key,
or
simply
wait
10
seconds
and
the
microprocessor
will
automatically
return
to
the
normal
frequency
display.
The
chart
below
shows
how
the
microprocessor
will
correct
a
new
step
size.
9,10,15,20
to
12.5,25
12.5,25
to
5,10,15,20
0,5,10,15
20,29,30.35-
|
40,45,50,55
|
60,65,70,75,
80,85,90,95
5-2-4
Programmable
VFO
Tuning
Limits
The
ТМ-241/441/541
series
radios
provide
the
capabil-
ity
of
programming
the
VFO
tuning
range,
in
1
MHz
band
segments,
as
well
a
providing
a
separate
program-
mable
band
scan
function(See
page
26).
For
example
you
could
tell
the
transceiver
that
you
only
wish
to
tune
the
144
MHz
and
145
MHz
band
segments.
The
tuning
controls
and
microphone
UP/DWN
switches
would
then
only
tune
within
these
specific
frequency
limits.
The
procedure
for
specifying
these
limits
is
described
below.
1:
2.
Press the VFO/MPV key to select the VFO mode.
Rotate
the
tuning
control
or
press
the
microphone
UP
/
DWN
switches
until
the
desired
lower
tuning
range appears in the frequency display.
For
example
with
the
TM-241
you
might
want
to
select
the
144
MHz
band,
and
dial
up
144.100
MHz.
.
Press
the
F
key
for
longer
than
1
second.
The
F
indicator should begin flashing.
.
Press
the
CALL
key
within
10
seconds.
A
long
beep
will
sound
and
the
F
indicator
will
turn
off
in
the
display.
This
indicates
that
the
lower
limit
has
been
successfully
stored
in
memory.
1 second.

5.
Now
select
the
desired
upper
tuning
limit
using
the
MHz
key
and
tuning
control,
or
microphone
UP/DWN
switches.
With
our
example
TM-241
we
want
the
upper
band
limit
to
be
in
the
145
MHz
band,
and
therefore
dial
up
145.100
MHz.
6. Press the F key for longer than 1 second. The F
indicator will again begin flashing.
7.
Press
the
SHIFT/AL
key
within
10
seconds.
A
long
beep
will
sound
and
the
F
indicator
will
turn
off
in
the
display.
This
indicates
that
the
upper
limit
has
been
stored
in
memory.
1 second.
8.To confirm that the programming was properly
performed
rotate
the
tuning
control
or
press
the
UP/DWN switches. The transceiver should not go
above or below the programmed band limits.
9. To clear both programmed limits simultaneously you
should initialize the VFO memory using the
procedures
discussed
on
page
21.
You
can
reprogram
either
limit
independently
by
following
һе
appropriate instructions above.
5-2-5 ALT (TM-541A/541E only)
The
ALT
system
operates
similar
to
an
AFC
(Automatic
Frequency Control) system. This system is useful when
the frequency of either station starts to drift. When this
occurs distortion of the signal is the usual result. The
ALT system will detect the drift and shift the frequency
to compensate.
To activate the ALT function
1. Press the F key momentarily. The F indicator will turn
on in the display.
2. While the F indicator is on press the DR/DT/ALT key.
The ALT indicator will turn on and the receiver will
automatically center itself on the incoming signal.
ЧЕТИ)
|
Turns on when the transmit
frequency of the distant
station is higher than your.
receive frequency.
Turns on when the transmit
frequency of the distant
station is lower than your
receive frequency.
| Note:
The frequency display will not actually change, even though the |
receive frequency might shift in order to properly tune the |
incoming signal. When the ALT system is operating the Direction |
indicator in the display will turn on to signal a change in the
receiver frequency. The direction indicator will show you if the
incoming signal was higher or lower than the displayed frequency.
3. To release the ALT function press the F key
momentarily and then the DR/DT/ALT key.
19

9-3 TRANSMITTER OPERATION
Caution
1. Ensure that an antenna with а low standing wave |
ratio
(SWR)
is
attached
to
the
antenna
connector
|
before attempting to transmit. Failure to provide |
proper
termination
may
result
in
damage
to
the
final amplifier section.
2. Always check to ensure the frequency is clear
before transmitting.
. Check the frequency to see if it is occupied before
you transmit.
. Press the PTT switch. The ON AIR indicator will light,
and the RF meter will deflect to the right.
If you have selected the LOW power position, the low
indicator will appear in the display and the RF meter
will only deflect slightly. When НІ power has been
selected the RF meter will deflect full scale.
. Speak into the microphone. The recommended
distance to the microphone is 5 cm (2 inches).
possible,
to
avoid
interfering
with
other
stations.
Е аел елаша. мои.
5-3-1 Transmit Basics
1.
Select
the
desired
operating
frequency
using
any
of
the
methods
previously
discussed.
2. Press the HOM ad to select the desired transmit
output.
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
20
: Note
|
The
use
of
LOW
power
is
recommended
кə
5-3-2 Time-out Timer (TOT)
Тһе ТОТ can limit the continuous transmission time to
30 minutes.
1. Press the F key for longer than 1 second, then press
the LOW/DIM key. The T indicator will light. To cancel
the setting, tepgan the PAO
Press the key for longer than
1 second.
2. When the time-out timer reaches the transmission
time limit, a beep will sound and the transceiver will
return to the receive mode. To transmit again,
release the PTT switch and press it again.