Cobra 25 LTD ST User manual

Cobra®, Nothing Comes Close to a Cobra®and the snake design are registered trademarks
of Cobra Electronics Corporation, USA. Cobra Electronics Corporation™is a trademark of
Cobra Electronics Corporation, USA.
Owner’s Manual
813-PK0639-001
© 2023 Cobra Electronics Corporation
For more information or to order any of our products, please visit our website: www.cobra.com
25 LTD AM/FM
Professional CB Radio
4W Power / 40 Channels
Thank you for purchasing the Cobra 25 LTD AM/FM CB Radio
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manual, we are here to help:
Service, Orders & Product Questions
For service, product questions and service hours call 800-543-1608 or go to www.cobra.com
For Assistance Outside the U.S.A.
Contact Your Local Dealer
Customer Support
Our Thanks, The CB Story,
and Customer Assistance
Citizens Band Radio History
Invented by Al Gross in 1945, the CB radio originally served as a method of communication for troops
during World War II. After the war, Gross worked to make two-way radios a way of communication
for personal use and the CB radio service was established by law in the U.S. in 1949. It wasn’t until
the 1970s that technology advanced and the CB market caught on as a method of communication
between drivers to report police speed traps and road hazards.
The Citizens Band Radio Service consists of 40 channel frequencies that are mostly 10 kHz apart.
Transmitter power is limited to 4 watts in the US, and range can vary depending on the terrain and
quality of the product.
Currently, the Citizens Band service does not require a license for operation, regardless of age, as
long as the rules of operation established by the Federal Communication Commission (FCC) are
followed.
Petition For FCC Part 65 Rule Changes
In 2016, Cobra petitioned the FCC to revise Part 95 rules to allow CB radios to use frequency
modulation (FM). Cobra contended that FM offers improved speech quality and lower noise
interference, which improves the standard of two-way radios and is a benefit to the customer.
Through the direct efforts of Cobra Electronics and the enthusiastic support from loyal customers and
the distribution network the FCC granted the request. In 2021, Part 95 officially was updated to
include FM as an option for two-way radio use.
Today, thanks to Cobra Electronics’ petitions to improve the quality of the Citizens Band Radio
Service, users can enjoy the benefits of CB radio communication in a range of industries.
A1

NothingComes Close to a Cobra®
25 LTD AM/FM
Pro Series Features
Product Features and
FCC Regulations
FCC Compliance
Any changes or modifications not expressly approved by Cobra Electronics could void your authority to
operate the equipment.
This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and (2) this device must accept any interference
received, including interference that may cause undesired operation. FCC Compliance
Any changes or modifications not expressly approved by Cobra Electronics could void your authority to
operate the equipment.
Signal Strength Meter
FM
Indicator
LED Channel
Display
RX (Receive)/ TX (Transmit)
LED Indicator
AM/FM
Switch
BRT/DIM Switch
NB/Off Switch
CB/ANL/PA Switch
4-Pin Microphone
Jack
Power On/Off/
Volume/Squelch Control
Dynamike
Control
RF Gain Control AM/FM/Channel Selector
Antenna Connector
Public Address
Speaker Jack External
Speaker Jack
Power Jack
Push-To-Talk (PTT) Button
4-Pin Microphone
Connector
A2 A3 20
Replacement Parts & Accessories
Go to cobra.com for replacement parts and accessories.
Questions or Need Help? Please call Cobra Customer Care at 800-543-1608.
PART/MODEL # DESCRIPTION
251-199-9-001
741-001
426-002-N-001
634-081-9-001
HG M75
HG M73
HG M77
HG S500
HG S300
HG S100
CB MOUNTING BRACKET
MICROPHONE HANGER
BRACKET
48" 12V POWER CORD
THUMBSCREWS TO
MOUNTING BRACKET
PREMIUM 4-PIN
POWER MICROPHONE
(PREMIUM DYNAMIC 4-PIN
REPLACEMENT CB MICROPHONE
REPLACEMENT PREMIUM 4-PIN
NOISE CANCELING CB MICROPHONE
DYNAMIC EXTERNAL SPEAKER WITH
NOISE FILTER AND TALK BACK
DYNAMIC EXTERNAL SPEAKER
WITH NOISE FILTER
DYNAMIC EXTERNAL SPEAKER

Cobra 29 LTD Classic
Our Thanks,The CB Story, Customer Support .....................................................................A1
Product Features ....................................................................................................................A2
FCC Regulations .....................................................................................................................A3
Installation
Location ............................................................................................................................... 2
Mounting and Connection..................................................................................................... 2
Antennas
Antennas.............................................................................................................................. 4
Operation
Turning On Your CB.............................................................................................................. 5
Setting AM/FM ..................................................................................................................... 5
Setting Channel Selector...................................................................................................... 5
To Receive ........................................................................................................................... 6
S-Meter................................................................................................................................ 6
NB/Off (Noise Blanker Switch) ............................................................................................. 6
Bright/Dim Switch ................................................................................................................ 6
RF Gain Control .................................................................................................................... 7
Setting Squelch.................................................................................................................... 7
To Transmit.......................................................................................................................... 7
Setting Dynamike®............................................................................................................... 8
RF Meter .............................................................................................................................. 8
External Speaker .................................................................................................................. 8
PA (Public Address) .............................................................................................................. 9
ANL (Automatic Noise Limiter) Switch
Base Station Operation .......................................................................................................10
.................................................................................10
Temporary Mobile Operation .............................................................................................. 10
How Your CB Can Serve You................................................................................................ 11
CB 10 Codes ...................................................................................................................... 13
Frequency Ranges ..............................................................................................................14
25 LTD Classic Specifications .............................................................................................15
Limited 2-Year Warranty .......................................................................................................16
Need Help?............................................................................................................................17
FCC Statement ....................................................................................................................... 18
Contents
1
Replacement Parts & Accessories .......................................................................................... 20

Installation Installation
Mounting and Connection
1. Hold the radio with the mounting bracket
in the exact desired location. If there is no
interference, remove the bracket and use
it as a template to mark the location for
the mounting screws.
2. Drill the holes and secure the bracket.
3. Connect the antenna cable plug to the
receptacle marked “ANT” on the back
of the unit.
Location
Plan for the location of the CB transceiver and microphone bracket before starting the
installation. Select a location that is convenient for operation, yetdoes not interferewith
the driver or passenger.
The transceiver is usually mounted to the underside of the dash with the microphone
bracket beside it.
NOTE: The transceiver is held in the universal mounting bracket by two thumbscrews
which allow for adjustment to a convenient angle.
The bracket includes two self-tapping screws and star washers. The mounting must be
mechanically strong and conveniently located.
Installation Installation
4. Connect the red lead of the DC power cord
to an accessory 12 volt fuse or directly to
the battery.
NOTE: Connecting to an accessory fuse
prevents the unit from being left on
accidentally, and also permits operating the
unit without running the engine.
5. Connect the black lead to the negative side
of the vehicle electrical system. This is
usually the chassis.
Any convenient location with a good electrical
contact (remove paint) may be used.
NOTE: Before installing the CB radio, visually check the vehicle’s battery connection to
determine which terminal is positive or negative. A negatively grounded vehicle has its
negative lead grounded to the chassis.
6. Plug power cable into back of unit marked
“Power”. Be sure to observe polarity
markings.
7. The microphone can be mounted to either
side of the CB using the supplied screws.
Alternatively the microphone can be mounted
to the dash or any convenient location.
8. Attach the microphone to the front of the CB.
NOTE: If the microphone is not connected,
audio will not be heard at the speaker.
NORMAL
29 LTD CLASSIC
PUSH
AM/FM
FM
23

Antennas
CB Antenna
Since the maximum allowable power output of the transmitter is limited by the FCC, the
antenna is critical in affecting transmission distance. Only a properly matched antenna
system will allow maximum power output. Cobra loaded type antenna models are highly
recommended for most installations. Consult your Cobra dealer for further details, or call
800-543-1608 and speak to a Cobra representative. A standard antenna connector is
provided on the transceiver for easy connection.
For optimum performance in passenger cars the ideal antenna location is on the center
of the roof. Second choice is on the center of the trunk. Because many newer trucks
feature fiberglass door skins, the outside mirror must be grounded to the chassis via a
ground strap when the antenna is mounted on the mirror bracket.
3-way combination antennas are also available which allow reception on the AM
and FM commercial broadcast bands and support receive and transmit operation
on the CB radio band. However, this type of antenna usually results in less than
optimal receive and transmit performance range when compared to a dedicated,
high performance CB radio antenna.
Cobra offers CB antenna and mounting solutions that can be purchased online.
Please visit www.cobra.com, or if you'd like to speak with an expert, please call
1-800-543-1608 and our Customer Care Group can assist.
4
1. The CB/PA button should be in the
CB position.
2. Rotate the On/Off Volume knob clockwise
to a normal listening level.
Setting AM/FM
The 25 LTD AM/FM CB allows for
communications on either AM or FM modes.
Each mode operates under Channels 1 - 40.
AM is the default mode.
To change between AM and FM modes move the
AM/FM slide switch to the desired operating mode.
Once selected a green indicator will appear
to the right of the displayed channel and
indicate you are in FM Mode.
Turning On Your CB
Make sure the power cord, antenna and microphone are connected to their proper
connectors before starting.
Setting Channel Selector
Select one of forty channels. The selected
channel is indicated by the LED readout
directly above the channel selector knob.
Operation
5
AM
FM
FM
AM
AM
FM
AM
FM
AM
FM

Operation
67
Operation
To Receive
Rotate the On/Off Volume knob clockwise.
While receiving the RX/TX LED will be
illuminated and the lower portion of the
meter will show the incoming signal strength.
S-Meter
The S-Meter swings proportionately to
the strength of the incoming signal when
receiving.
NB/OFF (Noise Blanker) Switch
When switched to NB the RF Noise
Blanker is activated, providing increased
noise filtration.
When switched to OFF all noise filtration will
be turned off.
NOTE: The RF noise blanker is very effective
in reducing repetitive noises such as ignition
interference.
Bright/Dim Switch
Switch to BRT or DIM to control the brightness
of the channel indicator and multi-function
meter for day or nighttime driving.
RF Gain Control
The RF Gain is used to optimize reception in
strong or weak signal areas.
Rotate the RF Gain knob counterclockwise
to reduce gain in strong signal areas. In weak
signal areas turn clockwise to increase gain.
Setting Squelch
Squelch (SQ) is used to cut off or eliminate
background noise in the absence of an
incoming signal (when you are not talking).
1. Full clockwise rotation closes the “gate”
allowing only very strong signals to enter.
2. Full counterclockwise rotation opens
the “gate” allowing all signals in.
3. To achieve the Desired Squelch Setting
(DSS), turn the Squelch control
counterclockwise until you hear noise.
Now turn the control clockwise just until
the noise stops. This is the DSS.
To Transmit
1. Select the desired channel.
CAUTION: Be sure the antenna is properly connected
to the radio before transmitting. Prolonged transmitting
without an antenna or a poorly matched antenna could
cause damage to the transmitter.
Be sure to read the FCC Part 95 Rules and
Regulations before transmitting.
AM
FM
AM
FM
AM
FM
AM
FM
AM
FM
AM
FM
AM
FM
AM
FM

Operation
8
Operation
9
Setting Dynamike®
This controls the microphone sensitivity
(outgoing audio level).
2. Initially, set fully clockwise so that the
maximum voice volume is available.
Dynamike®may have to be reduced in
some conditions.
3. Push and hold the mic button to transmit.
When transmitting, hold the microphone
two inches from your mouth and speak in
a clear, normal voice. Release the mic
button to receive.
RF Meter This meter swings proportionately
to the RF output (outgoing signal) while
transmitting.
External Speaker
Connecting an external speaker can provide
louder and clearer incoming audio.
Connect an external speaker to the
external
speaker jack on the rear panel.
NOTE: The external speaker should have
8-ohm impedance and be rated to handle
at least 4.0 watts. When the external
speaker is plugged in, the internal speaker is
automatically disconnected.
Cobra external speakers are rated at 10 watts.
PA (Public Address)
1. Connect an external PA speaker to the PA
jack on the rear panel.
NOTE: The speaker should have 8-ohm
impedance and be rated to handle at least
4.0 watts.
2. Set the CB/PA switch to the PA position.
NOTE: The speaker should be directed away
from the microphone to prevent acoustic
feedback.
3. Push and hold the microphone button and
speak in a normal voice. Your voice will
now transmit through the PA speaker.
4. Adjust the PA speaker volume with the
Dynamike®control.
AM
FM
AM
FM
AM
FM

Operation
10
Base Station Operation
(From 120V AC House Current)
To operate the transceiver from home or
office you will need a 13.8 volt DC Power
Pack rated at a minimum of 2 amps, and a
properly installed base station antenna.
WARNING: Do not attempt to operate this
transceiver by connecting it directly to 120VAC.
1. Simply connect the red (+) and black (-)
leads of the transceiver to the
corresponding terminals of the power pack.
Temporary Mobile Operation
For temporary mobile operation you may want
to purchase an optional automobile power
adapter from your Cobra dealer. This adapter
and a magnetic mount antenna allow you to
quickly “install” your transceiver for temporary
use.
How Your CB Can Serve You
Your CB Radio Can:
• Warn of traffic problems
• Provide weather and road data
• Provide help in event of an emergency
• Provide direct contact with home or office
• Assist police by reporting erratic drivers
• Get “local information” to find destination
• Communicate with family and friends
• Suggest spots to eat and sleep
• Keep you alert while traveling
A Few Rules You Should Know:
A. Conversationscannot last more than 5 minutes with another station. A one minute
break is required to let others use the channel.
B. You cannot blast others off the air by use of illegally amplified transmitters or illegally
high antennas.
C.
You cannot use CB to promote illegal activities.
D. Profanity is not allowed.
E. You may not transmit music with a CB.
F. Selling of merchandise and/or services is prohibited.
Set Channel 9 For Emergencies
Be sure antenna is properly connected.
CB Distress Data
When transmitting an emergency, youshouldrequest a “REACT BASE” and provide the CB
distressdata (called CLIP):
Call Sign Identify yourself.
Location Be exact.
Injuries Number. Type. Trapped?
Problem Give details and help needed.
Transmit CLIP repeatedly so any monitor can assist.
NOTE:
If no response on channel 9, try channels 19 or 14.
11
2. Plug the power cable into the back of
the unit marked “Power”. Be sure to
observe polarity markings.
3. Connect a properly installed and matched
base station antenna.
ANL (Automatic Noise Limiter) Switch
When switched to CB/ANL the Automatic
Noise Limiter is activated. This helps reduce
noise created by the vehicle’s electronics.
AM
FM

Operation Operation
How Your CB Can Serve You
12 13
Permitted Example Message
Yes “Tornado sighted six miles north of town.”
No “Post number 10. No tornado sighted.”
Yes “Out of gas on I-95 at mile marker 211.”
No “Out of gas in my driveway.”
Yes “Four car accident on I-94 at Exit 11. Send police and ambulance.”
No “Traffic moving smoothly on I-94.”
Yes “Weather Bureau has issued thunderstorm warning.
Bring sailboat into port.”
No “Attention motorists. Weather Bureau advises snow tomorrow will
accumulate 4 to 6 inches.”
Yes “Fire in building at 539 Main, Evanston.”
No “Halloween patrol number 3. All quiet.”
The FCC gives these examples of permitted and prohibited messages for channel 9.
These are only guidelines and not all-inclusive:
CB 10-Codes
10-1 Receiving poorly
10-2 Receiving well
10-3 Stop transmitting
10-4 OK, message received
10-5 Relay message
10-6 Busy, stand by
10-7 Out of service, leaving
10-8 In service, subject to call
10-9 Repeat message
10-10 Transmission completed standing by
10-11 Talking too rapidly
10-12 Visitors present
10-13 Advise weather/roads
10-16 Make pick up at
10-17 Urgent business
10-18 Anything for us?
10-19 Return to base
10-20 My location is
10-21 Call by phone
10-22 Report in person to
10-23 Stand by
10-24 Completed last assignment
10-25 Can you contact
10-26 Disregard last info
10-27 Moving to channel
10-28 Identify your station
10-29 Time is up for contact
10-30 Does not conform to FCC rules
10-33 Emergency traffic
10-34 Trouble at this station
10-35 Confidential information
10-36 Correct time is
10-37 Wrecker needed at
10-38 Ambulance needed
10-39 Message delivered
10-41 Turn to channel
10-42 Traffic accident at
10-43 Traffic tie up at
10-44 Have a message for
10-45 All units within range please report
10-50 Break channel
10-60 What is next message number?
10-62 Unable to copy. Use phone
10-63 Net directed to
10-64 Net clear
10-65 Awaiting your next message/assignment
10-67 All units comply
10-70 Fire at
10-71 Proceed, transmission in sequence
10-77 Negative contact
10-81 Reserve hotel room for
10-82 Reserve room for
10-85 My address is
10-91 Talk closer to mic
10-93 Check my frequency on this channel
10-94 Give me a long count
10-99 Mission completed, all units secure
10-200 Police needed at
Citizen Bands have adopted the “10-CODES” for standard questions and answers.
These codes provide quick andeasy communication, especially in noisy areas.
The following are some of the more common codes and meanings:
Code Meaning Code Meaning

14 15
Frequency Ranges
CB Channel Channel Freq. In MHz CB Channel Channel Freq. In MHz
1 26.965
2 26.975
3 26.985
4 27.005
5 27.015
6 27.025
7 27.035
8 27.055
9 27.065
10 27.075
11 27.085
12 27.105
13 27.115
14 27.125
15 27.135
16 27.155
17 27.165
18 27.175
19 27.185
20 27.205
21 27.215
22 27.225
23 27.255
24 27.235
25 27.245
26 27.265
27 27.275
28 27.285
29 27.295
30 27.305
31 27.315
32 27.325
33 27.335
34 27.345
35 27.355
36 27.365
37 27.375
38 27.385
39 27.395
40 27.405
The Cobra 25 LTD Classic transceiver represents some of the most advance AM/FM
two-way radios used as a Class D station in the Citizens Band Radio Service.
These model features an advanced Software Defined frequency synthesizer IC
providing high stability coverage of all 40 CB channels.
Specifications
GENERAL
Channels CB - 40 CH
Frequency Range CB - 26.965 to 27.405 MHz
Frequency Tolerance 0.005 %
Frequency Control PLL (phase lock loop) Synthesizer
Operating Temperature Range -30° C to + 50° C
Microphone Plug-in dynamic
Input Voltage 13.8VDC nom. (negative ground)
Current Drain Transmit: AM full mod., 1.5A (maximum)
Receive: Squelched, 0.3A;
full audio output, 1.2A (nominal)
Size 2.25” D x 7.25” W x 9.25” H
Weight 5.6 lbs.
Antenna Connector UHF; SO-239
Meter illuminated: indicates power output and relative received
signal strength
TRANSMITTER
Power Output 4 watts
Modulation AM (Amplitude Modulation) and FM (Frequency Modulation)
Frequency Response 300 to 3000 Hz
Output Impedance 50 ohms, unbalanced
RECEIVER
Sensitivity AM Sensitivity Less than 1uV for 10 dB (S+N)/N
Selectivity 6 dB @ 7 kHz, 60 dB @ 10 kHz
Image Rejection 80 dB, typical
Adjacent-Channel Rejection 60 dB, typical
IF Frequencies Double Conversion: 1st: 10.695 MHz, 2nd: 455 kHz
Automatic Gain Control (AGC) Less than 10 dB change in audio output for inputs from
10 to 50,000 microvolts
RF Gain Control Adjustable for optimum signal reception
Noise Blanker RF type
Squelch Adjustable; threshold less than 1µV
Audio Output Power 4 watts
Frequency Response 300 to 3000 Hz
Distortion Less than 5% @3 watts @ 1000 Hz
Built-in Speaker 8 ohms, 5w
External Speaker (Not supplied) 8 ohms; disables internalspeaker when connected
PA SYSTEM
Power Output 4 watts into external speaker
External Speaker for PA 8 ohms, when PA-CB switch is in PA
(SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE)
FM Sensitivity -116 dBm @ 12 dB SINAD typical