PC78LTW - Walkie-talkie UNIDEN - Free user manual and instructions

Product Type	CB Radio (Two-Way Radio)
Brand	Uniden
Model	PC78LTW
Channels	40 CB Channels (26.965 - 27.405 MHz)
Modulation	AM (Amplitude Modulation)
Output Power	4 Watts (AM)
Power Supply	13.8V DC (Negative Ground)
Current Drain (Typical)	Transmit: ~1.5A, Receive: ~0.5A
Dimensions (Approx.)	6.5 x 2.5 x 8.5 inches
Weight (Approx.)	2.5 lbs
Microphone	Dynamic with Coiled Cord
Features	PA Function, ANL, Squelch, RF Gain, Dimmer, S/RF Meter
Antenna Connector	UHF (SO-239)
External Speaker Jack	Yes (3.5mm)
Display	Backlit S/RF Meter
Color	Black
Operating Temperature	-30°C to 50°C
Included Accessories	Microphone, Mounting Bracket, Power Cord, Hardware
Warranty (Estimated)	1 Year Limited
Cleaning	Wipe with dry cloth; avoid liquids
Safety	Do not expose to moisture; use only supplied power; avoid high SWR

Frequently Asked Questions - PC78LTW UNIDEN

How do I install the Uniden PC78LTW in my vehicle?

To install, mount the radio using the supplied bracket and screws. Connect the red power wire to a 13.8V DC source (e.g., ignition or battery positive) and the black wire to ground. Attach the antenna to the UHF connector. Plug in the microphone and ensure the antenna has a low SWR before transmitting.

How do I adjust the squelch?

Turn the Squelch knob clockwise until background noise disappears. For weak signals, slowly turn it counterclockwise until you hear the signal, then adjust slightly clockwise to silence the noise.

What does the ANL button do?

The ANL (Automatic Noise Limiter) reduces ignition and other impulse noises. Press it to enable; the circuit filters out sharp noise spikes, improving reception clarity.

How do I use the PA function?

Connect an external PA speaker to the PA SP jack on the rear panel. Press the PA/CB button to switch to PA mode. Speak into the microphone; your voice will be amplified through the external speaker.

How do I check SWR with this CB radio?

You need an external SWR meter. Connect the meter between the antenna and the radio. Set the radio to channel 20 (27.205 MHz). Key the microphone and note the SWR reading. Adjust the antenna length for a reading of 1.5:1 or lower.

Why is there no sound from the speaker?

Check if the volume is turned up. Ensure the squelch is not set too high. Verify the microphone is plugged in securely. If using an external speaker, check that it is connected to the correct jack and not defective.

How do I change channels?

Rotate the Channel knob to the desired CB channel (1-40). The channel number is displayed on the radio. Note: Channels 9 (emergency) and 19 (truckers) are commonly monitored.

What is the typical range of the PC78LTW?

Range depends on antenna, terrain, and conditions. With a good antenna on flat terrain, expect 3-5 miles reliably. Under optimal conditions, up to 10-15 miles possible. Channel interference and obstacles reduce range.

Can I use an external speaker?

Yes, the radio has an EXT SP jack (3.5mm) on the rear panel. When connected, the internal speaker is disabled. Use an 8-ohm speaker rated for at least 4 watts.

How do I clean the radio?

Use a soft, dry cloth to wipe the exterior. Do not use water, cleaners, or abrasives. For the connectors, use compressed air. Avoid moisture entering the unit.

USER MANUAL PC78LTW UNIDEN

Elimination of Licensing....1

Controls and Functions 2

Installation 4

Mobile Station Installation 4

Mobile Station Antenna 4

Marine Installation 4

Connecting the Power Cords 5

Ground Information 5

Negative Ground System 5

Positive Ground System 5

To Receive 6

Weather Information 7

To Transmit 8

Multi-Function Meter 8

Preventive Maintenance 9

Maintenance 9

Servicing Your Transceiver ....10

Troubleshooting....10

Radio Code Definitions....11

Specifications 12

Two-Year Extended Warranty 13

Unpacking

Carefully unpack your PC78LTW and check the contents against this list:

■ PC78LTW CB 2-way mobile radio
■ Microphone
■ Mounting Bracket Kit
DC Power Cord
■ Reference Guide
■ Part 95 Subpart D (FCC Rules)
■ Product Registration Card

If any items are missing or damaged, contact your place of purchase immediately.

Please be sure to complete and mail your Product Registration Card.

Description

Your Uniden PC78LTW represents the highest quality communications device designed for use in the Citizens Band Radio Service. It will operate on any of the 40 AM frequencies authorized by the Federal Communications Commission (FCC).

The Citizens Band Radio Service is under the jurisdiction of the Federal Communications Commission (FCC). Any adjustments or alterations which would alter the performance of the transceiver's original FCC type acceptance, or which would change the frequency determining method, are strictly prohibited. Replacement or substitution of crystal, transistors, ICs, regulator diodes, or any other part of a unique nature, with parts other than those recommend by Uniden, may cause violations of the technical regulations in Part 95 of the FCC Rules or in violation of type acceptance requirements in Part 2 of the rules.

Elimination of Licensing

The FCC has ruled that CB Radio Service operators are no longer required to obtain an FCC License to operate their CB equipment. In doing so, the FCC also decided to permit CB station operation without station identification.

Elimination of individual station licenses does not reduce the operating privileges or responsibilities of CB users. An operator of a CB radio station is still required to comply with the Communications Act and with the rules of Citizens Band Radio Service.

Uniden is a registered trademark of Uniden America Corporation.

Features, Specifications, and availability of Optional Accessories are subject to change without notice.

Emergency Operation

1. Set the switch to CH9 or turn Channel Selector knob to Channel 9.
2. Press the microphone PTT switch and speak clearly.
3. If there is no response, select an active channel and ask that party to relay your emergency broadcast on Channel 9.

All channels, except Channel 9 may be used for normal communication. Channel 9 is reserved by the FCC for emergency communication involving the immediate safety of individuals or protection of property. Channel 9 may also be used to render assistance to a motorist.

This is an FCC rule and applies to all operators of CB radios.

Controls and Functions

FRONT VIEW - PC78LTW BACKLIGHTED PANEL

1. Microphone Jack
2. ON OFF - VOLUME Turns radio on or off; adjusts speaker volume.
3. SQUELCH Reduces background noise when there is no incoming signal.
4. RF GAIN: Improves reception in strong signal areas.
5. MIC GAIN: Adjusts microphone sensitivity.
6. DELTA TUNE Fine tunes the receiver.
7. SWR: Calibrates the meter for Standing Wave Ratio (SWR) measurements.
8. Weather Channel Knob: Selects weather channel.
9. ChannelKnob: Selects channel.
10. Channel Display: Displays current channel selection.
11. RX/TX Indicator: Red-transmitting; green-receiving.
12. ANT: Indicates a high SWR condition in antenna system. Check antenna, cable and connections.
13. Dynamic Squelch Control (DSC): Automatically sets Squelch to optimal level for stronger signals.
14. CH9/OFF: Turns Channel 9 on or off.
15. BRT/DIM: Adjusts the brightness of LED Channel Display, RX/TX Indicator, and RF Signal Meter.

16. NB/ANL: Reduces external noise and interference from vehicle ignition systems.

17. CB/WX/PA Switch: Selects PA (Public Address) WX (Weather Radio) or CB.

Do not use PA function unless an external speaker is connected.

1. S/RF/SWR/CAL: Selects meter function. S/RF - normal; SWR and CAL are for SWR measurements only. See page 8 for calibration procedures.

2. Multi-function Meter: Measures SWR, RF and S signal strength.

REAR VIEW

1. POWER Connects DC power to transceiver.

2. EXT. SP.: Connects optional 8-ohm 4-watt speaker to remotely monitor receiver.

When the external speaker is plugged in, the internal speaker is off.

1. PA SP.: Connects external 8-ohm, 4-watt speaker.

To prevent acoustic feedback, separate the microphone from the speaker when operating the PA at high output levels.

1. ANT: Connects antenna cable to transceiver.

Installation

MOBILE STATION INSTALLATION

Plan the location of the transceiver and microphone bracket before beginning installation.

1. Select a location that is convenient for operating the radio, but does not interfere with the driver or passenger.
2. Install bracket with self-tapping screws provided.
3. Connect wiring. (See instructions for Connecting the Power Cords).
4. Attach the microphone bracket to the side of the radio.
5. Attach radio to bracket.

Because the maximum power output of the transmitter is limited by the FCC, the quality of your antenna is very important. To achieve the maximum transmission distance, we strongly recommend that you install only a high quality antenna. You have just purchased a superior transceiver - don't diminish its performance by installing an inferior antenna.

Only a properly matched antenna system will allow maximum power transfer from the 50 ohm transmission line to the radiating element. Your Uniden dealer is qualified to help you select the proper antenna for your requirements. A whip style antenna may be used for automobile installation.

A short 'loaded' whip antenna is easier to install on an automobile. However, the efficiency of the short whip antenna is less than that of a full quarter-wave whip antenna.

MARINE INSTALLATION

Consult your dealer for information regarding marine installation. It is important to adequately ground the system and to prevent electrolysis between the fittings in the hull and the water.

We recommend connecting the power lead to the Ignition Switch Accessory Terminal. This way, the transceiver is automatically turned off when the ignition switch is turned off.

Or, the power cord may be connected to an available terminal on the fuse block, or, to a point in the wiring harness. However, caution must be taken to prevent a short circuit. If in doubt, contact your vehicle dealer for information.

This transceiver may be installed and used in any 12-volt DC negative or positive ground system vehicle.

GROUND INFORMATION

Note: This transceiver may be installed and used in any 12-volt DC negative or positive ground system vehicle.

Most newer U.S. and foreign made cars, and small trucks, use a negative ground system. Some older cars, and some new large trucks, use a positive ground system.

With a negative ground system, the negative (-) battery terminal is usually connected to the vehicle motor block. If you cannot determine the polarity system of your vehicle, contact your vehicle dealer for information.

Negative Ground System

If you have a negative ground system, connect the red DC power cord from the transceiver to the positive (+) battery terminal or other convenient point. Then connect the black power cord to the vehicle chassis or negative (-) battery terminal.

Positive Ground System

If you have a positive ground system, connect the black DC power cord from the transceiver to the negative (-) battery terminal or other convenient point. Then, connect the red power cord to the vehicle chassis or the positive (+) battery terminal.

To Receive

NOTE

Be sure that the power source, antenna, and microphone are properly connected before proceeding.

1. Turn unit ON and set VOLUME Control to a comfortable level.

1. Select CHANNEL.

1. Set switch to NB/ANL.

Dynamic Squelch Control automatically sets Squelch to the optimal level for stronger transmission and signal clarity. To scan for weaker signals, turn Dynamic Squelch Control off and perform the following steps:

4a. Turn SQUELCH fully clockwise so only strong signals can get through.

4b. Turn SQUELCH fully counterclockwise until you hear a hiss. Everything gets through - noise, weak signals, and strong signals.

4c. Turn SQUELCH back clockwise until the hiss stops. Only clearer signals get through.

Set SQUELCH only when the radio is not receiving a strong signal.

1. Adjust RF GAIN knob (small) to optimize reception in strong signal areas.

2. Adjust DELTA knob to reduce or eliminate adjacent channel interference.

3. Set meter switch to S/RF.

Weather Information

Your PC78LTW combines a CB Radio with a Weather Radio and a Weather Alert System. The Weather Radio continually broadcasts weather conditions. The Weather Alert System sounds a seven-second signal in the event of severe weather.

To configure your CB radio to receive weather alerts while using your CB radio:

1. Set the switch to WX.

2. Turn the Weather Channel knob to the channel with best reception.

Left at this setting, you will hear only weather broadcasts and Weather Alert Signals.

To use your CB radio normally while monitoring for weather alerts, set the switch to CB.

When you hear a Weather Alert Signal, and desire to

To Transmit

Perform a voltage Standing Wave Ratio (SWR) measurement prior to using the transmitter. A SWR ratio in excess of 2:1 may damage the transmitter.

Be sure to read and understand Part 95, FCC Rules and Regulations before operating your transmitter.

1. Select a channel.

2. Adjust MIC GAIN

3. When the channel is clear, press the microphone PTT switch and speak.

Multi-Function Meter

SWR Meter: Measures SWR(standing wave ratio) of antenna. Use to check antenna system or to adjust your antenna to the proper length.

To measure SWR:

1. Position meter switch to CAL.

2. Press microphone PTT switch. (Transmit)

3. Calibrate meter with SWR CAL knob by adjusting the needle to the ▼ mark.

4. Move the meter switch to the SWR position while pressing the microphone PTT switch.

A reading below 2 is acceptable. Higher readings indicate a problem in the antenna system. Problems may be caused by humidity, vibration, or corrosion. Check both ends of the coaxial cable connector. Also check for damage to the cable or antenna.

RF Meter: Measures RF Output Power for transmitter. To use, position the meter switch at S/RF. Press microphone PTT switch to read transmitting power.

S-Meter: Measures incoming signal strength. To use, position the meter switch at S/RF. The meter swings to indicate signal strength. i.e. S 3, S 5, S 7 ...

Preventive Maintenance

Every six months:

1. Check the Standing Wave Ratio ( SWR).
2. Be sure all electrical connections are tight.
3. Inspect antenna coaxial cable for wear or breaks in shielding.
4. Be sure all screws and mounting hardware are tight.

Maintenance

The PC78LTW is designed to give you years of trouble-free service. There are no user-serviceable parts inside. Except for the fuse in the DC power cord, no maintenance is required.

To replace a blown fuse:

1. Press ends of the fuse holder together. Twist to open. Carefully separate the two pieces.

1. Remove the fuse and inspect. If blown, replace with the same type fuse.

Use only the fuse specified for your PC78LTW. Failure to do so may void your warranty.

Troubleshooting

Problem Suggestion
Unit does not power up	☐ Check the ignition key position.☐ Check power cord connections.☐ Check fuse.☐ Check vehicle electrical system.
No reception	☐ Check microphone connection.☐ Set CB/WX/PA switch to CB.☐ Check VOLUME and SQUELCH.☐ Check antenna.☐ Check antenna connection.☐ Set RF GAIN to MAX.
Poor Reception	☐ Check VOLUME and SQUELCH.☐ Be sure antenna SWR is normal.☐ Set RF GAIN to MAX.☐ Check and adjust DELTA TUNE
No Transmission	☐ Set CB/WXPA switch to CB.☐ Check microphone connection.☐ Check MIC GAIN and adjust to MAX.
Low Transmission	☐ Be sure antenna SWR is normal.☐ Check MIC GAIN and adjust to MAX.

If you do not get satisfactory results after performing the above checks, call the Uniden Customer Service Center at 1-800-297-1023, 8:00 a.m. to 5:00 p.m. CST, Monday through Friday.

Servicing Your Transceiver

Technical information, diagrams, and charts are provided on request. It is the user's responsibility to see that this radio is operating at all times in accordance with the FCC Citizens Radio Service regulations. We highly recommend that you consult a qualified radio/telephone technician for servicing and aligning this CB radio product. Please read the Warning information on page 1 of this Guide.

When ordering parts, be sure to specify the correct model number and serial number of the unit.

Radio Code Definitions

The following list contains common "10-Codes" used by CB radio operators for faster communication and better understanding.

Code	Meaning	Code	Meaning
10-1	Received poorly	10-35	Confidential information
10-2	Receiving well	10-36	Correct time is
10-3	Stop transmitting	10-37	Wrecker needed at
10-4	OK, message received	10-38	Ambulance needed at
10-5	Relay message	10-39	Your message is delivered
10-6	Busy, stand by	10-41	Please turn to channel
10-7	Out of service, leaving air	10-42	Traffic accident at
10-8	In service, subject to call	10-43	Traffic tie up at
10-9	Repeat message	10-44	I have a message for you
10-10	Transmission completed, standing by	10-45	All units within range please report
10-11	Talking too rapidly	10-50	Break channel
10-12	Visitors present	10-60	What is next message number
10-13	Advise Weather/ Road conditions	10-62	Unable to copy, use phone
10-16	Make pickup at	10-63	Net directed to
10-17	Urgent business	10-64	Net clear
10-18	Anything for us?	10-65	Awaiting your next message/assignment
10-19	Nothing for you, return to base	10-67	All units comply
10-20	My location is	10-70	Fire at
10-21	Call by telephone	10-71	Proceed with transmission in sequence
10-22	Report in person to Stand by	10-77	Negative contact
10-23	Completed last assignment	10-81	Reserve hotel room for
10-24	Can you contact	10-82	Reserve room for
10-25	Disregard last information	10-84	My telephone number is
10-26	I am moving to channel	10-85	My address is
10-27	Identify your station	10-91	Talk closer to microphone
10-28	Time is up for contact	10-93	Check my frequency on this channel
10-29	Does not conform to FCC rules	10-94	Please give me a long count
10-30
10-31	I will give you a radio check	10-99	Mission completed, all units secure
10-32
10-33	EMERGENCY TRAFFIC
10-34	Trouble at this station	10-200	Police needed at

Specifications

General

Channels: 40

CB Frequency Range: 26.965 to 27.405 MHz

Weather Frequency Range: 162.400MHz (WX CH1)

162.425MHz (WX CH2)

162.450MHz (WX CH3)

162.475MHz (WX CII4)

162.500MHz (WX CH5)

162.525MHz (WX CI16)

162.550MHz (WX CH7)

Frequency Control: Phase Locked Loop (PLL) synthesizer

Frequency Tolerance: ±0.002%

Operating Temperature: -30°C to +60°C

-10°C to +60°C (DSC on)

Microphone: Plug-in type; 600 ohms dynamic

Input Voltage: 13.8 VDC nominal (positive or negative ground)

Current Drain: TX: AM full modulation, 2.2 A (max.)

RX: Squelched, 0.25 A; with maximum audio output, 1.2A (nominal)

Size: 7-9/32" W x 8-57/64" D x 2-13/64" II

Weight: 4 lbs. 3 oz. with microphone

Antenna Connector: UHF, SQ-239

Meter: Illuminated; indicates relative power output and received

signal strength SWR.

Transmitter

Power Output: 4 watts

Modulation:

Frequency Response: 300 to 3000 Hz

Output Impedance: 50 ohm, unbalanced

Receiver

Sensitivity:

Selectivity:

Image Rejection:

Adjacent-Ch. Rejection:

IF Frequencies:

Automatic Gain Control (AGC):

High- and low-level, Class B amplitude modulation

注：

d

RF Gain Control:

Delta Tune Range:

Noise Blanker:

Squelch:

Audio Output Power:

Frequency Response: 300 to 3000 Hz

Distortion:

Internal Speaker:

External Speaker:

(not supplied)

PA System

Power Output: 4 walls into external speaker

External Speaker for PA

speaker:

(not supplied)

Less than 1 μV for 10 dB, (S+N)/N

6 dB @ 7 kHz, 60 dB; @10 kHz

80 dB typical

60 dB typical

Double Conversion: 1st: 10,695 MHz; 2nd: 455 kHz

Less than 10 dB change in audio output for inputs from

10 to 50,000 μV

Adjustable for optimum signal reception

±1.5 kHz, continuously adjustable

RF type

Adjustable: threshold less than 1 μV

4 watts

Less than 7% at 3 watts, 1000 Hz

16 ohms, round

8 ohms, disables internal speaker when connected

Specifications shown are typical and subject to change without notification.

Two-Year Extended Warranty

Important: Evidence of original purchase is required for warranty service.

WARRANTOR: UNIDEN AMERICA CORPORATION ("Uniden")

ELEMENTS OF WARRANTY: Uniden warrants, for two years, to the original retail owner, this Uniden Product to be free from defects in materials and craftsmanship with only the limitations or exclusions set out below.

WARRANTY DURATION: This warranty to the original user shall terminate and be of no further effect two years after the date of original retail sale. The warranty is invalid if the Product is (A) damaged or not maintained as reasonable or necessary, (B) modified, altered, or used as part of any conversion kits, subassemblies, or any configurations not sold by Uniden, (C) improperly installed, (D) serviced or repaired by someone other than an authorized Uniden service center for a defect or malfunction covered by this warranty, (E) used in any conjunction with equipment or parts or as part of any system not manufactured by Uniden, or (F) installed or programmed by anyone other than as detailed by the owner's manual for this product.

STATEMENT OF REMEDY: In the event that the product does not conform to this warranty at any time while this warranty is in effect, warrantor will either, at its option, repair or replace the defective unit and return it to you without charge for parts, service, or any other cost (except shipping and handling) incurred by warrantor or its representatives in connection with the performance of this warranty. Warrantor, at its option, may replace the unit with a new or refurbished unit. THE LIMITED WARRANTY SET FORTH ABOVE IS THE SOLE AND ENTIRE WARRANTY PERTAINING TO THE PRODUCT AND IS IN LIEU OF AND EXCLUDES ALL OTHER WARRANTIES OF ANY NATURE WHATSOEVER, WHETHER EXPRESS, IMPLIED OR ARISING BY OPERATION OF LAW, INCLUDING, BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. THIS WARRANTY DOES NOT COVER OR PROVIDE FOR THE REIMBURSEMENT OR PAYMENT OF INCIDENTAL OR CONSEQUENTIAL DAMAGES. Some states do not allow this exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you.

LEGAL REMEDIES: This warranty gives you specific legal rights, and you may also have other rights which vary from state to state. This warranty is void outside the United States of America.

PROCEDURE FOR OBTAINING PERFORMANCE OF WARRANTY: If, after following the instructions in the owner's manual you are certain that the Product is defective, pack the Product carefully (preferably in its original packaging). The Product should include all parts and accessories originally packaged with the Product. Include evidence of original purchase and a note describing the defect that has caused you to return it. The Product should be shipped freight prepaid, by traceable means, to warrantor at:

Uniden America Corporation

Parts and Service Division

4700 Amon Carter Blvd

Fort Worth, TX 76155

[phone], 8 a.m. to 5 p.m., Central,

Monday through Friday

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