21-1589.fm Page 1 Thursday, August 5, 1999 10:10 AM
Cat. No. 21-1589
OWNER’S MANUAL
Please read before using this equipment.
TRC-494
40-Channel Emergency
Citizen’s Band Weatheradio
21-1589.fm Page 2 Thursday, August 5, 1999 10:10 AM
INTRODUCTION
Your Radio Shack TRC-494 is a 40-
channel emergency citizen’s band
weatheradio that is specially de-
signed for emergency situations. It
comes with a handy carrying case so
you can easily move it from one vehi-
cle to another. And, the TRC-494 is
also a 3-channel weatheradio, which
you can use to receive weather infor-
mation 24 hours a day.
Range Control — lets you eliminate
background noise when no strong
signals are present.
Built-In Ceramic Filters — provide
superior selectivity and prevent adja-
cent-channel interference.
Built-In Automatic Noise Limiter
(ANL) — reduces noise caused by
nearby electrical equipment, such as
motors or automotive ignition sys-
tems.
You can power the TRC-494 from the
cigarette-lighter socket in any vehicle
that has a 12-volt, negative ground
electrical system. You can also pow-
er the CB from the supplied battery
pack.
External Antenna Jack — lets you
connect the TRC-494 to an external
CB radio antenna.
Its features include:
Note: The TRC-494 comes with a
telescoping antenna that you can at-
tach directly to the CB. You can also
attach it to the supplied magnet-
mount base for use when your vehi-
cle is not moving. If you plan to use
the CB when your vehicle is moving,
we recommend that you purchase a
standard mount antenna.
CB/Weatheradio Switch — lets you
quickly switch from the CB to the
weatheradio function.
Emergency Channel 9 Switch —
immediately switches the CB to
Channel 9, the universal emergency
channel.
Important: REACT is a
PLL (Phase-Locked Loop) Fre-
quency Synthesizer — provides re-
liable and exact tuning using a
frequency reference crystal.
nationwide 24-hour net-
work
that
monitors
Channel 9. Switch to
Channel 9 in an emer-
gency, and report the
problem.
Digital Channel-Number Display
— makes it easy to see which chan-
nel is selected.
Note: REACT might not be available
in all areas.
© 1996 Tandy Corporation.
All Rights Reserved.
Radio Shack is a registered trademark used by Tandy Corporation.
2
21-1589.fm Page 2 Thursday, August 5, 1999 10:10 AM
INTRODUCTION
Your Radio Shack TRC-494 is a 40-
channel emergency citizen’s band
weatheradio that is specially de-
signed for emergency situations. It
comes with a handy carrying case so
you can easily move it from one vehi-
cle to another. And, the TRC-494 is
also a 3-channel weatheradio, which
you can use to receive weather infor-
mation 24 hours a day.
Range Control — lets you eliminate
background noise when no strong
signals are present.
Built-In Ceramic Filters — provide
superior selectivity and prevent adja-
cent-channel interference.
Built-In Automatic Noise Limiter
(ANL) — reduces noise caused by
nearby electrical equipment, such as
motors or automotive ignition sys-
tems.
You can power the TRC-494 from the
cigarette-lighter socket in any vehicle
that has a 12-volt, negative ground
electrical system. You can also pow-
er the CB from the supplied battery
pack.
External Antenna Jack — lets you
connect the TRC-494 to an external
CB radio antenna.
Its features include:
Note: The TRC-494 comes with a
telescoping antenna that you can at-
tach directly to the CB. You can also
attach it to the supplied magnet-
mount base for use when your vehi-
cle is not moving. If you plan to use
the CB when your vehicle is moving,
we recommend that you purchase a
standard mount antenna.
CB/Weatheradio Switch — lets you
quickly switch from the CB to the
weatheradio function.
Emergency Channel 9 Switch —
immediately switches the CB to
Channel 9, the universal emergency
channel.
Important: REACT is a
PLL (Phase-Locked Loop) Fre-
quency Synthesizer — provides re-
liable and exact tuning using a
frequency reference crystal.
nationwide 24-hour net-
work
that
monitors
Channel 9. Switch to
Channel 9 in an emer-
gency, and report the
problem.
Digital Channel-Number Display
— makes it easy to see which chan-
nel is selected.
Note: REACT might not be available
in all areas.
© 1996 Tandy Corporation.
All Rights Reserved.
Radio Shack is a registered trademark used by Tandy Corporation.
2
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For your records, we urge you to
record your CB’s serial number in the
space below. The serial number is on
the CB’s back panel.
Your CB might cause TV or radio in-
terference even when it is operating
properly. To determine if your CB is
causing the interference, turn off
your CB. If the interference goes
away, your CB is causing it. Try to
eliminate the interference by:
Serial Number:_________________
• Moving your CB away from the
receiver.
FCC INFORMATION
• Contacting your local Radio
Shack store for help.
The Federal Communications Com-
mission (FCC) does not require you
to have a license to operate this CB.
However, the FCC does require you
to read and know Part 95 of FCC
Rules. These rules apply to the oper-
ation of a Class D CB. We have pro-
vided a copy of these regulations
with your CB.
If you cannot eliminate the interfer-
ence, the FCC requires that you stop
using your CB.
Warning: Do not open your CB to
make any internal adjustments. Inter-
nal adjustments can be made only by
authorized service personnel.
Internal adjustments and/or modifi-
cations can lead to illegal operation
as defined by Part 95 of FCC Rules.
Such illegal operation can lead to
very serious consequences.
To be safe and sure:
• Never open your CB’s case.
• Never modify your CB.
3
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For your records, we urge you to
record your CB’s serial number in the
space below. The serial number is on
the CB’s back panel.
Your CB might cause TV or radio in-
terference even when it is operating
properly. To determine if your CB is
causing the interference, turn off
your CB. If the interference goes
away, your CB is causing it. Try to
eliminate the interference by:
Serial Number:_________________
• Moving your CB away from the
receiver.
FCC INFORMATION
• Contacting your local Radio
Shack store for help.
The Federal Communications Com-
mission (FCC) does not require you
to have a license to operate this CB.
However, the FCC does require you
to read and know Part 95 of FCC
Rules. These rules apply to the oper-
ation of a Class D CB. We have pro-
vided a copy of these regulations
with your CB.
If you cannot eliminate the interfer-
ence, the FCC requires that you stop
using your CB.
Warning: Do not open your CB to
make any internal adjustments. Inter-
nal adjustments can be made only by
authorized service personnel.
Internal adjustments and/or modifi-
cations can lead to illegal operation
as defined by Part 95 of FCC Rules.
Such illegal operation can lead to
very serious consequences.
To be safe and sure:
• Never open your CB’s case.
• Never modify your CB.
3
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CONTENTS
PREPARATION ............................................................................................... 5
Supplying Power......................................................................................... 5
Using Vehicle Battery Power ............................................................... 5
Installing the Battery Pack .................................................................. 5
Attaching the Antenna ................................................................................ 6
Attaching the Antenna Directly to the CB ............................................ 6
Using the Antenna’s Magnetic Base ................................................... 7
USING THE CB ............................................................................................... 8
Setting RANGE............................................................................................ 9
USING THE WEATHERADIO ........................................................................ 10
CB OPERATION TIPS .................................................................................... 11
Common Uses for a CB Radio .................................................................. 11
Business Uses ................................................................................... 11
Personal Uses .................................................................................... 11
CB Courtesy ............................................................................................. 12
Maximum Range ...................................................................................... 12
Using Common 10-Codes ........................................................................ 13
TROUBLESHOOTING .................................................................................. 14
Reducing Noise ........................................................................................ 15
MAINTENANCE ............................................................................................ 16
Replacing the Power Cord’s Fuse ............................................................ 17
SPECIFICATIONS ......................................................................................... 18
4
21-1589.fm Page 4 Thursday, August 5, 1999 10:10 AM
CONTENTS
PREPARATION ............................................................................................... 5
Supplying Power......................................................................................... 5
Using Vehicle Battery Power ............................................................... 5
Installing the Battery Pack .................................................................. 5
Attaching the Antenna ................................................................................ 6
Attaching the Antenna Directly to the CB ............................................ 6
Using the Antenna’s Magnetic Base ................................................... 7
USING THE CB ............................................................................................... 8
Setting RANGE............................................................................................ 9
USING THE WEATHERADIO ........................................................................ 10
CB OPERATION TIPS .................................................................................... 11
Common Uses for a CB Radio .................................................................. 11
Business Uses ................................................................................... 11
Personal Uses .................................................................................... 11
CB Courtesy ............................................................................................. 12
Maximum Range ...................................................................................... 12
Using Common 10-Codes ........................................................................ 13
TROUBLESHOOTING .................................................................................. 14
Reducing Noise ........................................................................................ 15
MAINTENANCE ............................................................................................ 16
Replacing the Power Cord’s Fuse ............................................................ 17
SPECIFICATIONS ......................................................................................... 18
4
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PREPARATION
Installing the Battery Pack
SUPPLYING POWER
Your CB uses eight AA batteries for
power. For the best performance and
longest life, we recommend alkaline
batteries, such as Radio Shack Cat.
No. 23-552.
Using Vehicle Battery Power
Follow these steps to power the CB
from your vehicle’s battery.
1. Plug the small end of the sup-
plied power cord into DC 12V on
the side of the CB.
Note: When you connect the DC
power cord to the CB, the battery
pack automatically disconnects.
Follow these steps to install the bat-
teries in the battery pack and attach
the battery pack to the CB.
1. Press down and slide the battery
pack’s latch in the direction of
the arrow. While holding the
latch, slide the battery pack off
to the right.
Caution: Before plugging the
power cord’s cigarette-lighter
plug into your vehicle’s ciga-
rette-lighter socket, make sure
the tip is screwed firmly onto the
plug (see “Replacing the Power
Cord’s Fuse” on Page 17).
2. Plug the other end of the power
cord into the cigarette-lighter
socket.
2. Push down on the center of the
battery pack’s top to remove the
battery holder from the battery
pack case.
Notes:
• If the CB does not operate prop-
erly when you are using the DC
power cord, check that the
lighter socket is clean and free
of ashes or other debris.
• If the unit still does not work,
check the fuse in the DC power
cord (see “Replacing the Power
Cord’s Fuse” on Page 17).
5
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PREPARATION
Installing the Battery Pack
SUPPLYING POWER
Your CB uses eight AA batteries for
power. For the best performance and
longest life, we recommend alkaline
batteries, such as Radio Shack Cat.
No. 23-552.
Using Vehicle Battery Power
Follow these steps to power the CB
from your vehicle’s battery.
1. Plug the small end of the sup-
plied power cord into DC 12V on
the side of the CB.
Note: When you connect the DC
power cord to the CB, the battery
pack automatically disconnects.
Follow these steps to install the bat-
teries in the battery pack and attach
the battery pack to the CB.
1. Press down and slide the battery
pack’s latch in the direction of
the arrow. While holding the
latch, slide the battery pack off
to the right.
Caution: Before plugging the
power cord’s cigarette-lighter
plug into your vehicle’s ciga-
rette-lighter socket, make sure
the tip is screwed firmly onto the
plug (see “Replacing the Power
Cord’s Fuse” on Page 17).
2. Plug the other end of the power
cord into the cigarette-lighter
socket.
2. Push down on the center of the
battery pack’s top to remove the
battery holder from the battery
pack case.
Notes:
• If the CB does not operate prop-
erly when you are using the DC
power cord, check that the
lighter socket is clean and free
of ashes or other debris.
• If the unit still does not work,
check the fuse in the DC power
cord (see “Replacing the Power
Cord’s Fuse” on Page 17).
5
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3. Install the batteries in the holder
as indicated by the polarity sym-
bols (+ and –) marked on the
holder.
ATTACHING THE
ANTENNA
You can attach the supplied tele-
scoping antenna to the supplied
magnetic base or directly to the CB.
In either case, fully extend the anten-
na for maximum range.
Attaching the Antenna
Directly to the CB
4. Slide the battery pack’s case
over the holder until it snaps into
place.
To attach the antenna directly to the
CB, simply screw the antenna into
ROD ANT
the CB’s
jack.
Note: The case slides over the
holder in only one direction. If it
doesn’t slide into place on the
first try, do not force it! Turn the
case over and try again.
5. From the right side of the CB,
slide the battery pack onto the
bottom of the CB until it clicks
into place.
BATT
To test the batteries, press
TEST
on the battery pack. If the indi-
cator lights, the batteries are still
good. If the indicator does not light,
replace all eight batteries.
6
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3. Install the batteries in the holder
as indicated by the polarity sym-
bols (+ and –) marked on the
holder.
ATTACHING THE
ANTENNA
You can attach the supplied tele-
scoping antenna to the supplied
magnetic base or directly to the CB.
In either case, fully extend the anten-
na for maximum range.
Attaching the Antenna
Directly to the CB
4. Slide the battery pack’s case
over the holder until it snaps into
place.
To attach the antenna directly to the
CB, simply screw the antenna into
ROD ANT
the CB’s
jack.
Note: The case slides over the
holder in only one direction. If it
doesn’t slide into place on the
first try, do not force it! Turn the
case over and try again.
5. From the right side of the CB,
slide the battery pack onto the
bottom of the CB until it clicks
into place.
BATT
To test the batteries, press
TEST
on the battery pack. If the indi-
cator lights, the batteries are still
good. If the indicator does not light,
replace all eight batteries.
6
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3. Plug the magnetic base’s wire
Using the Antenna’s
Magnetic Base
into EXT ANT.
Note: The supplied magnetic mount
base is designed for emergency use
only while your vehicle is stopped. If
you want to use the CB when the ve-
hicle is moving, you need an optional
standard mount antenna (available
at your local Radio Shack store). You
also need a plug adapter (Cat. No.
278-208) to connect the standard an-
tenna’s PL-259 plug to EXT ANT on
your CB.
1. While your vehicle is stopped,
screw the antenna into the hole
on top of the magnetic base.
2. Place the base as near as possi-
ble to the center of your vehi-
cle’s roof.
Warning: Do not remove the
metallic backing on the bottom
of the magnetic base.
7
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3. Plug the magnetic base’s wire
Using the Antenna’s
Magnetic Base
into EXT ANT.
Note: The supplied magnetic mount
base is designed for emergency use
only while your vehicle is stopped. If
you want to use the CB when the ve-
hicle is moving, you need an optional
standard mount antenna (available
at your local Radio Shack store). You
also need a plug adapter (Cat. No.
278-208) to connect the standard an-
tenna’s PL-259 plug to EXT ANT on
your CB.
1. While your vehicle is stopped,
screw the antenna into the hole
on top of the magnetic base.
2. Place the base as near as possi-
ble to the center of your vehi-
cle’s roof.
Warning: Do not remove the
metallic backing on the bottom
of the magnetic base.
7
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USING THE CB
Before you start using your CB, you
should know how to use it effectively
and courteously. “CB Operation
Tips” contains information that will
help you use and enjoy your CB.
Note: To eliminate background
noise, see “Setting Range.”
4. Select a channel as follows:
• To immediately select Chan-
nel 9, set CH 9 to IN. Channel
9 is used for emergencies and
traveler assistance.
Note: Before you operate the CB, be
sure you connect a power source
and an antenna to the CB.
• To select any other channel,
set CH 9 to OUT. Then press
CHANNEL UP or DOWN to
select a channel.
1. Turn VOLUME clockwise to turn
on the CB. The volume level
appears in the VOLUME win-
dow.
Note: To check the selected
channel number, press DISPLAY
on the side of the CB. The num-
ber appears for 20 seconds.
5. To transmit, hold the CB 2-3
inches from your mouth, press
and hold down PUSH TO TALK
on the side of the CB, and speak
directly into the built-in micro-
phone.
2. Set WEATHERADIO-ABC/CB to
CB.
3. Turn RANGE fully counterclock-
wise to set it to 10.
8
21-1589.fm Page 8 Thursday, August 5, 1999 10:10 AM
USING THE CB
Before you start using your CB, you
should know how to use it effectively
and courteously. “CB Operation
Tips” contains information that will
help you use and enjoy your CB.
Note: To eliminate background
noise, see “Setting Range.”
4. Select a channel as follows:
• To immediately select Chan-
nel 9, set CH 9 to IN. Channel
9 is used for emergencies and
traveler assistance.
Note: Before you operate the CB, be
sure you connect a power source
and an antenna to the CB.
• To select any other channel,
set CH 9 to OUT. Then press
CHANNEL UP or DOWN to
select a channel.
1. Turn VOLUME clockwise to turn
on the CB. The volume level
appears in the VOLUME win-
dow.
Note: To check the selected
channel number, press DISPLAY
on the side of the CB. The num-
ber appears for 20 seconds.
5. To transmit, hold the CB 2-3
inches from your mouth, press
and hold down PUSH TO TALK
on the side of the CB, and speak
directly into the built-in micro-
phone.
2. Set WEATHERADIO-ABC/CB to
CB.
3. Turn RANGE fully counterclock-
wise to set it to 10.
8
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In an emergency, broadcast
your “CLIP”:
SETTING RANGE
Call sign — identify yourself
Location — be exact
Injuries — number of injured,
type of injuries, and so on
Problem
—
give complete
details. Give information calmly,
clearly, and in as few words as
possible
Because this is primarily an emer-
gency CB, we suggest you leave
RANGE
set to 10 when you store the
6. When you finish transmitting,
CB. This ensures the maximum re-
ception range in an emergency.
PUSH TO TALK
release
now receive
VOLUME
. You can
transmissions.
to the desired
Adjust
If you want to eliminate background
noise when you are not receiving a
strong signal from another CB, wait
until you are not receiving a call and
listening level.
VOLUME
7. To turn off the CB, turn
counterclockwise (toward the
top of the CB) until you hear it
click and OFF appears in the
VOLUME window.
RANGE
turn
clockwise until the back-
ground noise stops.
VOLUME
RANGE
only af-
Note:
and
fect reception. They have no effect
on transmissions.
9
21-1589.fm Page 9 Thursday, August 5, 1999 10:10 AM
In an emergency, broadcast
your “CLIP”:
SETTING RANGE
Call sign — identify yourself
Location — be exact
Injuries — number of injured,
type of injuries, and so on
Problem
—
give complete
details. Give information calmly,
clearly, and in as few words as
possible
Because this is primarily an emer-
gency CB, we suggest you leave
RANGE
set to 10 when you store the
6. When you finish transmitting,
CB. This ensures the maximum re-
ception range in an emergency.
PUSH TO TALK
release
now receive
VOLUME
. You can
transmissions.
to the desired
Adjust
If you want to eliminate background
noise when you are not receiving a
strong signal from another CB, wait
until you are not receiving a call and
listening level.
VOLUME
7. To turn off the CB, turn
counterclockwise (toward the
top of the CB) until you hear it
click and OFF appears in the
VOLUME window.
RANGE
turn
clockwise until the back-
ground noise stops.
VOLUME
RANGE
only af-
Note:
and
fect reception. They have no effect
on transmissions.
9
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USING THE WEATHERADIO
In the USA, detailed weather infor-
mation is continuously broadcast on
372 government weather stations.
Each station broadcasts on A —
162.400, B — 162.475, or C —
162.550 MHz.
2. Set WEATHERADIO-ABC/CB to
A, B or C.
Most weather stations use frequency
C, but in locations where there might
be interference between stations, the
other two frequencies might be used.
Choose the frequency that provides
the best reception at your location.
3. Adjust VOLUME to the desired
listening level.
Notes:
Follow these steps to receive weath-
er information.
• If reception is poor, try one of the
other two weather station fre-
quencies.
Note: Before you use the weathera-
dio, be sure you connect a power
source and an antenna to the CB.
• CH9, CHANNEL UP/DOWN, PUSH
TO TALK, DISPLAY, and RANGE
have no effect on weatheradio
operation.
1. Turn VOLUME clockwise to turn
on the weatheradio.
10
21-1589.fm Page 10 Thursday, August 5, 1999 10:10 AM
USING THE WEATHERADIO
In the USA, detailed weather infor-
mation is continuously broadcast on
372 government weather stations.
Each station broadcasts on A —
162.400, B — 162.475, or C —
162.550 MHz.
2. Set WEATHERADIO-ABC/CB to
A, B or C.
Most weather stations use frequency
C, but in locations where there might
be interference between stations, the
other two frequencies might be used.
Choose the frequency that provides
the best reception at your location.
3. Adjust VOLUME to the desired
listening level.
Notes:
Follow these steps to receive weath-
er information.
• If reception is poor, try one of the
other two weather station fre-
quencies.
Note: Before you use the weathera-
dio, be sure you connect a power
source and an antenna to the CB.
• CH9, CHANNEL UP/DOWN, PUSH
TO TALK, DISPLAY, and RANGE
have no effect on weatheradio
operation.
1. Turn VOLUME clockwise to turn
on the weatheradio.
10
21-1589.fm Page 11 Thursday, August 5, 1999 10:10 AM
CB OPERATION TIPS
Like most activities, CB radio use has
its customs and courtesies. The fol-
lowing tips will help you get the most
enjoyment from your CB.
Personal Uses
• Keep in touch with home while
driving to work, to the store, or to
a social activity. Let your family
know you are tied up in traffic or
that you will stop by the store on
the way home.
COMMON USES FOR A
CB RADIO
• If you are a two-car (or more)
family, CBs are great for com-
municating with family members
while they are in their cars.
Business Uses
• Truck drivers and delivery per-
sonnel can learn road and traffic
conditions and get assistance in
locating destinations. A CB is
also good company on those
“long hauls.”
• Contact friends or neighbors —
find out “what’s happening” or
plan a get-together.
• Ever have car trouble or run out
of gas on the highway? What a
relief it is to be able to radio for
assistance!
• On construction crews, a CB
quickly pays for itself when you
are calling for additional materi-
als or coordinating the activities
of different work crews.
• Camping, fishing, and other
sports are more fun with a CB.
Locate a buddy or find out
“what’s cooking” back at camp.
• For security officers, a CB is
more than a convenience — it is
a must for both safety and effi-
ciency.
11
21-1589.fm Page 11 Thursday, August 5, 1999 10:10 AM
CB OPERATION TIPS
Like most activities, CB radio use has
its customs and courtesies. The fol-
lowing tips will help you get the most
enjoyment from your CB.
Personal Uses
• Keep in touch with home while
driving to work, to the store, or to
a social activity. Let your family
know you are tied up in traffic or
that you will stop by the store on
the way home.
COMMON USES FOR A
CB RADIO
• If you are a two-car (or more)
family, CBs are great for com-
municating with family members
while they are in their cars.
Business Uses
• Truck drivers and delivery per-
sonnel can learn road and traffic
conditions and get assistance in
locating destinations. A CB is
also good company on those
“long hauls.”
• Contact friends or neighbors —
find out “what’s happening” or
plan a get-together.
• Ever have car trouble or run out
of gas on the highway? What a
relief it is to be able to radio for
assistance!
• On construction crews, a CB
quickly pays for itself when you
are calling for additional materi-
als or coordinating the activities
of different work crews.
• Camping, fishing, and other
sports are more fun with a CB.
Locate a buddy or find out
“what’s cooking” back at camp.
• For security officers, a CB is
more than a convenience — it is
a must for both safety and effi-
ciency.
11
21-1589.fm Page 12 Thursday, August 5, 1999 10:10 AM
CB COURTESY
MAXIMUM RANGE
• Wait for a pause in someone
else’s transmission before you
ask for a break.
The maximum range and quality of
CB transmissions vary depending on
these conditions:
• If you do not receive an answer
to your call after a second
attempt, sign off and wait sev-
eral minutes before trying again.
• The type and quality of antenna
used
• The height of the antenna’s
mounting location — the higher
the antenna, the better the sig-
nal’s range
PUSH TO
• Do not hold down the
TALK
button when you are not
talking. (This is called dead key-
ing.)
• The surrounding terrain
mountains and tall buildings limit
the range
—
• Assist callers with directions,
road conditions, and any other
reasonable requests.
• Weather conditions
RANGE
• The current setting of
your CB
on
• The number of nearby CBs
operating on the same channel
• Standing Wave Ratio (SWR)
between the antenna and the
CB. You can check the SWR
between the CB and a mobile
antenna using an SWR tester
(Cat. No. 21-523). Follow the
instructions supplied with the
SWR tester and the mobile
antenna to change the SWR, if
necessary.
12
21-1589.fm Page 12 Thursday, August 5, 1999 10:10 AM
CB COURTESY
MAXIMUM RANGE
• Wait for a pause in someone
else’s transmission before you
ask for a break.
The maximum range and quality of
CB transmissions vary depending on
these conditions:
• If you do not receive an answer
to your call after a second
attempt, sign off and wait sev-
eral minutes before trying again.
• The type and quality of antenna
used
• The height of the antenna’s
mounting location — the higher
the antenna, the better the sig-
nal’s range
PUSH TO
• Do not hold down the
TALK
button when you are not
talking. (This is called dead key-
ing.)
• The surrounding terrain
mountains and tall buildings limit
the range
—
• Assist callers with directions,
road conditions, and any other
reasonable requests.
• Weather conditions
RANGE
• The current setting of
your CB
on
• The number of nearby CBs
operating on the same channel
• Standing Wave Ratio (SWR)
between the antenna and the
CB. You can check the SWR
between the CB and a mobile
antenna using an SWR tester
(Cat. No. 21-523). Follow the
instructions supplied with the
SWR tester and the mobile
antenna to change the SWR, if
necessary.
12
21-1589.fm Page 13 Thursday, August 5, 1999 10:10 AM
USING COMMON 10-
CODES
Code
Meaning
10-14 Information.
Citizen’s band operators have largely
adopted the 10-codes for standard
questions and answers. Their use
permits faster communication and
better intelligibility in noisy areas.
10-15 Message delivered.
10-16 Reply to message.
10-17 En route.
10-18 Urgent.
This table lists the codes adopted by
the Associated Public Safety Com-
munications Officers (APCO).
10-19 Contact __________.
10-20 My location is __________.
10-21 Call ________ by tele-
phone.
Code
Meaning
10-1
Cannot understand your
message.
10-22 Cancel last message.
10-23 Arrived at the scene.
10-24 Assignment complete.
10-2
10-3
10-4
Your signal is good.
Stop transmitting.
10-26 Estimated time of arrival is
_________.
Message received and
understood.
10-30 Use caution.
10-31 Pick up.
10-5
Relay information to
__________.
10-6
I am busy.
10-33 Emergency traffic. Clear the
channel.
10-7
Out of service.
In service.
10-34 The time is _____.
10-8
Note: Although this table lists the 10-
codes’ meanings in the form of a
statement, they can also be phrased
as questions (10-6: Are you busy?,
10-20: What is your location?).
10-9
Repeat last message.
Negative (No).
_____________ in service.
Stand by.
10-10
10-11
10-12
10-13
Report ___________ condi-
tions.
13
21-1589.fm Page 13 Thursday, August 5, 1999 10:10 AM
USING COMMON 10-
CODES
Code
Meaning
10-14 Information.
Citizen’s band operators have largely
adopted the 10-codes for standard
questions and answers. Their use
permits faster communication and
better intelligibility in noisy areas.
10-15 Message delivered.
10-16 Reply to message.
10-17 En route.
10-18 Urgent.
This table lists the codes adopted by
the Associated Public Safety Com-
munications Officers (APCO).
10-19 Contact __________.
10-20 My location is __________.
10-21 Call ________ by tele-
phone.
Code
Meaning
10-1
Cannot understand your
message.
10-22 Cancel last message.
10-23 Arrived at the scene.
10-24 Assignment complete.
10-2
10-3
10-4
Your signal is good.
Stop transmitting.
10-26 Estimated time of arrival is
_________.
Message received and
understood.
10-30 Use caution.
10-31 Pick up.
10-5
Relay information to
__________.
10-6
I am busy.
10-33 Emergency traffic. Clear the
channel.
10-7
Out of service.
In service.
10-34 The time is _____.
10-8
Note: Although this table lists the 10-
codes’ meanings in the form of a
statement, they can also be phrased
as questions (10-6: Are you busy?,
10-20: What is your location?).
10-9
Repeat last message.
Negative (No).
_____________ in service.
Stand by.
10-10
10-11
10-12
10-13
Report ___________ condi-
tions.
13
21-1589.fm Page 14 Thursday, August 5, 1999 10:10 AM
TROUBLESHOOTING
If your CB is not working as it should, follow the suggestions below to see if you
can eliminate the problem. If you cannot, take the CB to your local Radio Shack
store for assistance.
Symptom
Remedy
CHANNEL UP/DOWN buttons do
• If CH 9 is set to IN, set it to OUT, then use the
not work.
CHANNEL UP/DOWN buttons.
• Set WEATHERADIO-ABC/CB to CB.
No channel display.
Not transmitting well.
• Press DISPLAY. The CB displays the channel.
• Set WEATHERADIO-ABC/CB to CB.
• Set WEATHERADIO-ABC/CB to CB.
• Fully press PUSH TO TALK.
• Secure the antenna connection.
• Fully extend the antenna.
Not receiving well.
• Set WEATHERADIO-ABC/CB to CB.
• Properly adjust RANGE.
• Properly adjust VOLUME.
• Secure the antenna connection.
• Fully extend the antenna.
No weatheradio reception.
CB does not operate at all.
• Set WEATHERADIO-ABC/CB to WEATHERADIO-
A, B, or C.
• Set it to the channel that provides the best
reception.
• Fully extend the antenna.
• Check the DC power connection.
• Replace the blown fuse in the power cord.
• Insufficient battery pack power. Press BATT
TEST to check, and replace the batteries, if
necessary.
• Turn on VOLUME.
14
21-1589.fm Page 14 Thursday, August 5, 1999 10:10 AM
TROUBLESHOOTING
If your CB is not working as it should, follow the suggestions below to see if you
can eliminate the problem. If you cannot, take the CB to your local Radio Shack
store for assistance.
Symptom
Remedy
CHANNEL UP/DOWN buttons do
• If CH 9 is set to IN, set it to OUT, then use the
not work.
CHANNEL UP/DOWN buttons.
• Set WEATHERADIO-ABC/CB to CB.
No channel display.
Not transmitting well.
• Press DISPLAY. The CB displays the channel.
• Set WEATHERADIO-ABC/CB to CB.
• Set WEATHERADIO-ABC/CB to CB.
• Fully press PUSH TO TALK.
• Secure the antenna connection.
• Fully extend the antenna.
Not receiving well.
• Set WEATHERADIO-ABC/CB to CB.
• Properly adjust RANGE.
• Properly adjust VOLUME.
• Secure the antenna connection.
• Fully extend the antenna.
No weatheradio reception.
CB does not operate at all.
• Set WEATHERADIO-ABC/CB to WEATHERADIO-
A, B, or C.
• Set it to the channel that provides the best
reception.
• Fully extend the antenna.
• Check the DC power connection.
• Replace the blown fuse in the power cord.
• Insufficient battery pack power. Press BATT
TEST to check, and replace the batteries, if
necessary.
• Turn on VOLUME.
14
21-1589.fm Page 15 Thursday, August 5, 1999 10:10 AM
• If problems persist, check your
alternator/generator and regula-
tor gauges. Noise from these
sources can be reduced or elimi-
nated using bypass capacitors
at the various voltage points.
REDUCING NOISE
Because your CB is exceptionally
quiet, any noise you hear is probably
from an external source in your vehi-
cle — the ignition, another radio,
spark plugs, and so forth.
Note: Your local Radio Shack store
has a wide selection of noise-sup-
pression equipment.
You can determine the source of the
noise by turning off the engine and
operating the CB with the ignition set
to ACC. If most or all of the noise
goes away, the problem is in your ve-
hicle’s ignition or electrical system.
Here are a few hints to help you re-
duce or eliminate such noise:
• Do not route the DC power cord
next to the antenna wire.
• Be sure the antenna’s magnetic
base is securely attached to a
metallic surface. If you use an
antenna other than the mag-
netic-mount type, be sure that
the vehicle battery’s ground con-
nection is secure.
• Replace old ignition wires with
new, high-voltage, noise-sup-
pression ignition wires.
• Install noise suppressors on
your spark plugs or install spark
plugs that have built-in suppres-
sors.
15
21-1589.fm Page 15 Thursday, August 5, 1999 10:10 AM
• If problems persist, check your
alternator/generator and regula-
tor gauges. Noise from these
sources can be reduced or elimi-
nated using bypass capacitors
at the various voltage points.
REDUCING NOISE
Because your CB is exceptionally
quiet, any noise you hear is probably
from an external source in your vehi-
cle — the ignition, another radio,
spark plugs, and so forth.
Note: Your local Radio Shack store
has a wide selection of noise-sup-
pression equipment.
You can determine the source of the
noise by turning off the engine and
operating the CB with the ignition set
to ACC. If most or all of the noise
goes away, the problem is in your ve-
hicle’s ignition or electrical system.
Here are a few hints to help you re-
duce or eliminate such noise:
• Do not route the DC power cord
next to the antenna wire.
• Be sure the antenna’s magnetic
base is securely attached to a
metallic surface. If you use an
antenna other than the mag-
netic-mount type, be sure that
the vehicle battery’s ground con-
nection is secure.
• Replace old ignition wires with
new, high-voltage, noise-sup-
pression ignition wires.
• Install noise suppressors on
your spark plugs or install spark
plugs that have built-in suppres-
sors.
15
21-1589.fm Page 16 Thursday, August 5, 1999 10:10 AM
MAINTENANCE
Your TRC-494 is an example of superior design and craftsmanship. The follow-
ing suggestions will help you care for your TRC-494 so you can enjoy it for years.
Keep the TRC-494 dry. If it gets wet, wipe it dry immediately. Liq-
uids might contain minerals that can corrode the electronic cir-
cuits.
Handle the TRC-494 gently and carefully. Dropping it can damage
circuit boards and cases and can cause the TRC-494 to work im-
properly.
Use and store the TRC-494 only in normal temperature environ-
ments. Temperature extremes can shorten the life of electronic
devices and distort or melt plastic parts.
Keep the TRC-494 away from dust and dirt, which can cause pre-
mature wear of parts.
Wipe the TRC-494 with a damp cloth occasionally to keep it look-
CLEANER
ing new. Do not use harsh chemicals, cleaning solvents, or strong
detergents to clean the TRC-494.
Modifying or tampering with the TRC-494’s internal components can cause a
malfunction and might invalidate your TRC-494’s warranty and void your FCC
authorization to operate it. If your TRC-494 is not performing as it should, take it
to your local Radio Shack store for assistance.
16
21-1589.fm Page 16 Thursday, August 5, 1999 10:10 AM
MAINTENANCE
Your TRC-494 is an example of superior design and craftsmanship. The follow-
ing suggestions will help you care for your TRC-494 so you can enjoy it for years.
Keep the TRC-494 dry. If it gets wet, wipe it dry immediately. Liq-
uids might contain minerals that can corrode the electronic cir-
cuits.
Handle the TRC-494 gently and carefully. Dropping it can damage
circuit boards and cases and can cause the TRC-494 to work im-
properly.
Use and store the TRC-494 only in normal temperature environ-
ments. Temperature extremes can shorten the life of electronic
devices and distort or melt plastic parts.
Keep the TRC-494 away from dust and dirt, which can cause pre-
mature wear of parts.
Wipe the TRC-494 with a damp cloth occasionally to keep it look-
CLEANER
ing new. Do not use harsh chemicals, cleaning solvents, or strong
detergents to clean the TRC-494.
Modifying or tampering with the TRC-494’s internal components can cause a
malfunction and might invalidate your TRC-494’s warranty and void your FCC
authorization to operate it. If your TRC-494 is not performing as it should, take it
to your local Radio Shack store for assistance.
16
21-1589.fm Page 17 Thursday, August 5, 1999 10:10 AM
REPLACING THE
POWER CORD’S FUSE
The TRC-494’s 2-amp fuse helps
protect your CB from power surges
and short circuits. If the fuse is blown,
replace it with a 2-amp, 250-volt,
fast-acting fuse (Cat. No. 270-1052).
Follow these steps to replace the
fuse.
1. Unplug the power cord from the
vehicle’s cigarette lighter and be
sure the CB is turned off.
2. To open the cigarette-lighter
plug and remove the fuse, turn
either end counterclockwise and
release it.
3. If the fuse is blown, replace it.
Caution: Make sure you replace
the fuse only with another fuse
of the same type and rating.
4. To close the cigarette-lighter
plug, put the open ends
together, then turn either end
clockwise.
17
21-1589.fm Page 17 Thursday, August 5, 1999 10:10 AM
REPLACING THE
POWER CORD’S FUSE
The TRC-494’s 2-amp fuse helps
protect your CB from power surges
and short circuits. If the fuse is blown,
replace it with a 2-amp, 250-volt,
fast-acting fuse (Cat. No. 270-1052).
Follow these steps to replace the
fuse.
1. Unplug the power cord from the
vehicle’s cigarette lighter and be
sure the CB is turned off.
2. To open the cigarette-lighter
plug and remove the fuse, turn
either end counterclockwise and
release it.
3. If the fuse is blown, replace it.
Caution: Make sure you replace
the fuse only with another fuse
of the same type and rating.
4. To close the cigarette-lighter
plug, put the open ends
together, then turn either end
clockwise.
17
21-1589.fm Page 18 Thursday, August 5, 1999 10:10 AM
SPECIFICATIONS
RECEIVER
Frequency Coverage ...............................................(CB) 26.965 to 27.405 MHz
(Weatheradio) 162.400, 162.475, 162.550 MHz
Sensitivity (Maximum) ............................................................................ 0.25 uV
Adjacent Channel Selectivity ................................................. . 60 dB (at 10 kHz)
Squelch ........................................................................................................1 mV
Audio Output ..........................................................................0.28 W (10% THD)
Current Drain ................................................................................. 85 – 550 mA
TRANSMITTER
Frequency Coverage ....................................................... 26.965 – 27.405 MHz
Power Input (at 12 V DC).............................................................................. 5 W
Power Output..............................................................................................2.5 W
Spurious Emission ..................................................................................... 70 dB
Type of Modulation.........................................................................................A3E
Frequency Tolerance ............................................................................. ±100 Hz
Antenna............................................................................................. Telescoping
Impedance ..............................................................................................50ohms
Current Drain at No Modulation ............................................ 600 mA to 800 mA
Current Drain at Full Modulation ...........................................900 mA to 1200 mA
Weight........................................................................................ 15 oz. (425 gm)
5
11
9
Dimensions (HWD) ................................................................... 9 /8 x 2 /16 x 1 /16
(245 x 68 x 40 mm)
Specifications are typical; individual units might vary. Specifications are subject
to change and improvement without notice.
18
21-1589.fm Page 18 Thursday, August 5, 1999 10:10 AM
SPECIFICATIONS
RECEIVER
Frequency Coverage ...............................................(CB) 26.965 to 27.405 MHz
(Weatheradio) 162.400, 162.475, 162.550 MHz
Sensitivity (Maximum) ............................................................................ 0.25 uV
Adjacent Channel Selectivity ................................................. . 60 dB (at 10 kHz)
Squelch ........................................................................................................1 mV
Audio Output ..........................................................................0.28 W (10% THD)
Current Drain ................................................................................. 85 – 550 mA
TRANSMITTER
Frequency Coverage ....................................................... 26.965 – 27.405 MHz
Power Input (at 12 V DC).............................................................................. 5 W
Power Output..............................................................................................2.5 W
Spurious Emission ..................................................................................... 70 dB
Type of Modulation.........................................................................................A3E
Frequency Tolerance ............................................................................. ±100 Hz
Antenna............................................................................................. Telescoping
Impedance ..............................................................................................50ohms
Current Drain at No Modulation ............................................ 600 mA to 800 mA
Current Drain at Full Modulation ...........................................900 mA to 1200 mA
Weight........................................................................................ 15 oz. (425 gm)
5
11
9
Dimensions (HWD) ................................................................... 9 /8 x 2 /16 x 1 /16
(245 x 68 x 40 mm)
Specifications are typical; individual units might vary. Specifications are subject
to change and improvement without notice.
18
21-1589.fm Page 19 Thursday, August 5, 1999 10:10 AM
NOTES
19
21-1589.fm Page 19 Thursday, August 5, 1999 10:10 AM
NOTES
19
21-1589.fm Page 20 Thursday, August 5, 1999 10:10 AM
RADIO SHACK LIMITED WARRANTY
This product is warranted against defects for 90 days from date of pur-
chase from Radio Shack company-owned stores and authorized Radio
Shack franchisees and dealers. Within this period, we will repair it with-
bring your Radio Shack sales
out charge for parts and labor. Simply
slip
as proof of purchase date to any Radio Shack store. Warranty does
not cover transportation costs. Nor does it cover a product subjected to
misuse or accidental damage.
EXCEPT AS PROVIDED HEREIN, RADIO SHACK MAKES NO
EXPRESS WARRANTIES AND ANY IMPLIED WARRANTIES ARE LIM-
ITED IN DURATION TO THE DURATION OF THE WRITTEN LIMITED
WARRANTIES CONTAINED HEREIN. Some states do not permit limita-
tion or exclusion of implied warranties; therefore, the aforesaid limita-
tion(s) or exclusion(s) may not apply to the purchaser.
This warranty gives you specific legal rights and you may also have other rights which vary
from state to state.
We Service What We Sell
9/94
RADIO SHACK
A Division of Tandy Corporation
Fort Worth, Texas 76102
5A5
Printed in Hong Kong
21-1589.fm Page 20 Thursday, August 5, 1999 10:10 AM
RADIO SHACK LIMITED WARRANTY
This product is warranted against defects for 90 days from date of pur-
chase from Radio Shack company-owned stores and authorized Radio
Shack franchisees and dealers. Within this period, we will repair it with-
bring your Radio Shack sales
out charge for parts and labor. Simply
slip
as proof of purchase date to any Radio Shack store. Warranty does
not cover transportation costs. Nor does it cover a product subjected to
misuse or accidental damage.
EXCEPT AS PROVIDED HEREIN, RADIO SHACK MAKES NO
EXPRESS WARRANTIES AND ANY IMPLIED WARRANTIES ARE LIM-
ITED IN DURATION TO THE DURATION OF THE WRITTEN LIMITED
WARRANTIES CONTAINED HEREIN. Some states do not permit limita-
tion or exclusion of implied warranties; therefore, the aforesaid limita-
tion(s) or exclusion(s) may not apply to the purchaser.
This warranty gives you specific legal rights and you may also have other rights which vary
from state to state.
We Service What We Sell
9/94
RADIO SHACK
A Division of Tandy Corporation
Fort Worth, Texas 76102
5A5
Printed in Hong Kong
|