Kenwood TM-241A User manual

aan
144MHz
FM
TRANSCEIVER
TM-241A/241E
TM-541A/541E
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
| transceiver to get warm.
Do
not
place
the
transceiver
where
the
heat
sink
(rear
panel)
might
come
in
contact
with
plastic
or
vinyl
surfaces.
l
|HI power mode might cause the rear of this |
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)
TM-441A:
440MHz
FM
TRANSCEIVER
(U.S.A.
only)
TM-441A:
430MHz
FM
TRANSCEIVER
(General
markets)
TM-441E:
430MHz
FM
TRANSCEIVER
(U.K.
and
European
markets)
TM-541A: 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
modifications
are
expressly
approved
in
the
instruction
manual.
The
user
could
lose
the
authority
to
operate
this
equipment
if
an
unauthorized
change
or
modification
is
made.

CONTENTS
Hold/Resume
Programming
...........
25
. BanGScany ase tacnegt esate qnnahadiede 26
1. BEFORE OPERATION ................. 4 Programmable Band Scan ............. 26
2.
SPECIFICATIONS
................00065
6
Memory
Channel
Scan
.........--..--.
27
Memory Channel Lockout ............- 27
3.
ACCESSORIES
...................00005
7
Priority
Alert
Function
..............5:
228
4.
INSTALLATION
INSTRUCTIONS
......
7
REPEATER
OPERATIONS
Transmitter Offsets .................-. 28
5.
OPERATION
Reverse
Function
..............0000
eee
29
CONTROL
FUNCTIONS...........0000008
10
Tone
Operation
.........ecce
cece
e
eee
29
RECEIVER
OPERATION
Tone
Frequency
Selection
.............
29
Reception
.....
pees
t
eee
16
Autopatch
(U.S.A.
version
only)
.......-
30
Frequency
Selection
st
pthe
seats
Sun
aug
ee
17
TONE
/
CTCSS
OPERATION..........
30
Frequency
Step
Selection
............6.
17
DTSS
(Dual
Tone
Squelch
System)
Programmable
VFO
Tuning
Limits
......
18
OPERATION
..........
0.
cece
eee
eee
31
ALT(TM-541A/E
only)
B
Sadia
sei
sceaategevemedye
eaue.
de
19
DRS
(Digital
Recording
System)
TRANSMITTER
OPERATION
.............
20
OPERATION
.....ccccccececceceveeees
34
Time-out
Timer
(TOT)
..-.-
+++
see
e
eee
20
PAGING
peecg
suede
ucts
paces
Ree
41
MEMORY
TONE
ALERT
SYSTEM
...............
47
Microprocessor
Memory
back-up
.......
21
APO
(Automatic
Power
Off)
............
48
Initial
State
2.0.0.0...
eee
21
DIMcDimmer)
Ee
PONT
ee?
oy
er
48
Microprocessor
Initialization
...........
21
BEEP
............
cc
ccccccucccveccuceues
49
Memory
Channel
........-........---5
21
LOCK
/ALOCK
Anitascecs
ae
eeeniaes
49
M ry Contents .........2..2..000005 22
MEISE)
EREV
scacls
cca)
meen
22-6.
BLOCK
DIAGRAM
and
Memory
Channel
Recall
...............
24
SCHEMATIC
DIAGRAM
..
Another
sheet
Memory
Shift
..........-....-.---.
00:
24
7.
MAINTENANCE
.................-...
50
SCAN IN CASE OF DIFFICULTY ........... 51
Scan Operation .............-- cece eee 25
8.
OPTIONAL
ACCESSORIES
...........
52

A WARNING); 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 pull 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.
lf 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.
2.
Turn the power off, before cleaning the unit.
Do
not
use
any
type
of
abrasive
pad,
thinner,
benzine
or
any
substances
which
may
damage
the
unit.
Wipe the front panel and other exterior surfaces of
the
unit
with
a
soft
dry
cloth
or
a
soft
cloth
lightly
moistened with water.

2 SPECIFICATIONS
TM-241Awsa‘canaday | TM-241A/E | TM-441Awsavcanada| TM-441A | TM-441E TM-541A/E
| Frequency range MHz 144 to 148 te to 146 j 438 to 450 430 to 440 | 430 to 440 | 1240 to 1300
| Mode F3E(FM)
| Antenna impedance 500
Operating temperature —20°C to + 60°C (—4°F to + 140°F)
cs) | Power requirements 13.8V DC +15%(117~158V)
. Ground Negative
© Current drain | Transmit mode Less than 11A Less than 10A Less than 6A
| Receiver mode Less than 0.6A
Frequency stability Less than +10ppm Less than+3ppm
Dimensions (WXHXD) (mm) (Projections included) 140 X40 X 160(5-1/2" x 1.37/64" x6-19/64") (140 X40 X172(5-1/2" x 1-37/64" X6-25/32")
Weight (kg) 1.2(2.65ibs)
HI 5OW 35W 10W
Output
power
2
MID
Approx
1OW
Approx
10W
=
3 LOW Approx. 5W Approx. 5W 1W
= Modulation Reactance modulation
¢ Spurious radiation Less than — 60 dB
~ | Maximum frequency deviation +5KHz
Audio distortion (at 60% modulation) Less than 3% (300 to 3000 Hz)
Microphone impedance 6000,
f Circuity Double conversion superheterodyne
Intermediate frequency 1st/2nd 30,825MHz/455kHz | 10.7MHz/455kKH2 30.825MHz / 455kHz 159.7MHz/455kHz
g Sensitivity (12 dB SINAD) Less than 0.25nV Less than 0.16 nV
‘@ | Selectivity —6dB: More than 12 kHz -—60dB Less than 24 kHz
& | Squelch sensitivity Less than 0.1 uV Less than 0.177 uV Less than0.1 nV
Output (5% distortion) More than 2 W across 8 © loads
External
speaker
impedance
8Q
‘ Australia: 144 to 148
? 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 in 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
Bracke, .c.i4ecn0tagene
Screw set ...........0--
Self tapping Screw
(U.S.A. CANADA only) ...
Hex wrench
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.
WO01-0414-04 1 ea.
J21-4147-14 2 ea.
Pe eS ae ee cee
DC power Cable ............. E30-2111-05 1 ea.
Fuse (TM-241A/241E: 15A).. FO5-1531-05 1 ea.
(TM-441A/441E: 10A).. FO5-1031-05 1 ea.
(TM-541A/541E: 8A)... FO5-8021-05 1 ea.
Instruction Manual ........... B62-0031-XX 1 copy
Warranty Card ........c ccc cece ccc eeeee 1 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 tc 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.
eee Ae Mec
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 bah eee nie Passenger compartment
Fuse
Fuse it =
ey
Select a location where j ~
the power cable is pro-
: tected from heat, mois-
a
| ture of abrasion when
securing the cable.
a
Red
4
\ To the
\ transceiver
Make sure the cable does
not directly contact the
edge of the hole by using
| a grommet.
Chassis or \——_-_—-____/
fire wall
Battery
@ [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.
1. Never connect the AC power cable to the AC
outlet until all 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.

5 OPERATION
5-1-1 CONTROL FUNCTIONS
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SLORTE
@ 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. :
@ 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 (Squeich) control
This control is used to select the desired squelch
threshold level.
&) LOW/DIM key
LOW
This function is used to select the transmit output
power level (HI, 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.
© Microphone connector
Attach the supplied microphone to this connector.
The pin out of the connector is shown in the
accompanying illustration.
@
GND
@
GNO
{Microphone
audial
D
MIC
:
‘audio}
7
(Microphone
Audio)
®
AX
Audio
Output
2)
PTT
(Approx
100
mV/10
k
ohm)
(Push
to
Talk)
@ DWN
uP
5) 8 VDC (Max 150 mA)

Er
@ VFO/MP 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
call
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
POWER
switch
you
will
clear
all
the
microprocessor’s
operator
programmed
memory
section.
@) 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)

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@ 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 ‘ower limit for the
programmable VFO tuning limit function.
& 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, ie. “+’ 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.
© TONE/T.ALT key
TONE function
Pressing this key by itself causes the radio to select
the desired tone signaling mode. When the “T’
indicator is illuminated in the display the transceiver
will transmit the selected subaudible tone. When
the “CTCSS’”’ 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
lf 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)

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@® 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
C
LCD Display Raney
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D
LOCK
On
ties
the
Lock
function
|
has
been
activated.
A.LOCK
On
when
the
All
Lock
function
has
been
activated.
@)
<4
EXRR
RP
9
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.
3 DTSs On when the DTSS function has
_ been activated.
4 DRS On when the Digital Recording Sys-
tem is active.
©
APO
On
when
the
Automatic
Power
Off
function
has
been
activated.
©
On
when
the
squelch
opens.
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This
level
meter
indicates
the
rela-
® LOw MIO
Om T |
By ON AI
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

Indicates the active memory channel
number. * indicates that the chan-
nel is locked out.
C is displayed during call channel.
Either PO, P1, 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-
@ lected. ;
7 Q On when the Tone Alert function is
active. The indicator flashes when
signal has been received.
a@ CTCSS On when the Tone Decode and En-
t code function has been activated.
On when the Tone Encode function
has been activated.
aF |
1 AL On when the Priority Alert function
has been activated.
i REV On when the Reverse function has
been activated.
Q- + Display the selected transmitter off-
set direction.
Both — and + light at the same
time during split channel! operation.
@® sp9 8A YYs Displays the operating frequency to
the nearest kHz digit; or the tone
‘ frequency etc.
The indicator flashes when scan-
ning.
5-1-3 Rear Panel
Ii Lal ma
om
@ ANTENNA connector
Attach an antenna with a
impedance of 50 ohms.
@ 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.
@ Fuse holder
Contains a requaired fuse.
TM-241A: 15A, TM-441A: 10A, TM-541A: 8A
Do not use a larger fuse as damage might result to
the transceiver.
@ 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
Bax: - U.S.A.
European version version
@@Q@UP/DOWN switches
These switches can be used to increase or decrease
the VFO frequency, the Memory channel number,
and the Tone frequency, etc..
@) 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.
@CALL key (except European version)
This key functions just like the CALL key on the front
of the radio. _
1750 key (European version)
The transceiver will transmit with 1750 Hz repeater
access tone whenever this switch is depressed.
&) VFO key
This key functions just like the VFO key on the front
of the radio.
© MR key
This key functions just like the MR key on the front of
the radio.
@ 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
or
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.
®
16-Tone
DTMF
keypad
(U.S.A.
and
CANADA
version
only)
These
buttons
are
used
to
activate
the
DTMF
encod-
er.
© 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 pane!
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 Receptoin
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.1 shows examples of
frequencies that will appear on the various models.
In
addition
to
the
frequency
you
may
see
one
or
more control indicators illuminats on the display.
TM-441A
TM-241A/241E
“(ULS.A.
version)
TM-541A/541E
if |
4008
oe
wGboE
eGGEE
TM441A/TM-441E
(ass
Note
The frequencies shown above are the default
frequencies after a microprocessor reset. If the
display
shows
incomplete
data
or
you
think
the
'
displayed
frequency
is
in
error
you
should
reset
the
|
Microprocessor. Memory Initialization on page 21.
3.
Rotate the VOL contro! 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 SQL 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 property.
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.

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.
~ ~ VFO mode
MR aia key
Frequency Selection
VFO key CALL key
\
bs Se wn CALL key
[MEMORY channel mode fxg———} CALL channel mode
= MR key
@ VFO Mode Operation Frequency Selection
1. Press the VFO/MPV key to select the VFO mode.
2. 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. wo
@ CALL Channel Selection
Press the CALL key to select the Call channel.
nr@
5-2-3
The frequency step is indicated in the chart below.
Frequency Step Selection
57 102715220E12.5225
TM-241A/E
Cor
SG
eo
aS
CG a)
TM-441A/E
oh Se 5)
To select the desired tuning or 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.
TM-541A/E x CO)

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.
5,10,15,20
to
12.5,25
12.5,25
to
5,10,15,20
0,5,10,15
0
an)
0
20,25,30,35
|
25
125
10
40,45,50,55.
|
+50
25
20
60,65,70,75,
375
30
80,85,90,95
75
50
50
62.5
60
75
70
375
80
5-2-4
Programmable
VFO
Tuning
Limits
The
TM-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.
Press
the
VFO/MPV
key
to
select
the
VFO
mode.
2.
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.
3. Press the F key for longer than 1 second. The F
indicator should begin flashing.
4.
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.
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.
The F
Press the key for longer than
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
the
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.
<a>
!
Turns on when the transmit
frequency of the distant
station is lower than your
receive frequency.
Turns on when the transmit
frequency of the distant
station is higher 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

5-3. TRANSMITTER OPERATION
Caution
1. Ensure that an antenna with a low standing wave
ratio (SWR) is attached to the antenna connector i
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.
|
: Note
| The use of LOW power is recommended whenever
possible, to avoid interfering with other stations.
5-3-1 Transmit Basics
1. Select the desired operating frequency using any of
the methods previously discussed.
2. Press the ne ey to select the desired transmit
output.
4558
20
3. Check the frequency to see if it is occupied before
you transmit.
4, Press the PTT switch. The ON AIR indicator will tight,
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 HI power has been
selected the RF meter will deflect full scale.
5. Speak into the microphone. The recommended
distance to the microphone is 5 cm (2 inches).
5-3-2 Time-out Timer (TOT)
The TOT 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 serie. repeat the operation.
eran
oo
/
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.