Uniden PC-78LTXFM CB-Radios Export Radio Owner’s Manual
- June 9, 2024
- Uniden
Table of Contents
Uniden PC-78LTXFM CB-Radios Export Radio
DESCRIPTION
Your Uniden PC78LTXFM is a high-quality communications device designed for use
in the Citizens Band Radio Service. It will operate on any of the 40 AM/FM
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.
EMERGENCY OPERATIONS
- Set the switch to CH9 or turn Channel Selector knob to Channel 9.
- Press the microphone PTT switch and speak clearly.
- 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 others.
This is an FCC rule and applies to all operators of CB radios.
FEATURES
- CB AM & FM 40 CH (4W)
- PA (Public Address)
- Channel 9 Direct Tune
- TX/RX Multicolor LED (RED and GREEN)
- AWI (Antenna Warning Indicator) LED (RED)
- ANL (Automatic Noise Limiter)
- NB (Noise Blanker)
- HI CUT Adjustment
- Dimmer Control
- RF Gain Control (Variable)
- MIC Gain Control (Variable)
- Multi-Function Meter: RF Power, Signal strength, and SWR
- Volume Control (Variable)
- Squelch Control (Variable)
- 4-Pin Microphone Jack
WHAT’S IN THE BOX
Carefully unpack your PC78LTXFM and check the contents against this list:
- PC78LTXFM CB 2-way mobile radio
- Microphone
- Mounting Bracket Kit
- DC Power Cord
- Owner’s Manual
- Part 95 Subpart D (FCC Rules)
If any items are missing or damaged, visit our website at www.uniden.com for further information.
Never use damaged products!
FRONT VIEW
Item | Definition |
---|---|
1 | Multi-function meter: Measures SWR, RF and S signal strength. |
2 | Microphone jack |
3 | ON OFF – VOLUME/SQUELCH : Turns radio on or off; adjusts speaker |
volume and squelch level (reduces background noise when there is no incoming
signal).
4| MIC GAIN knob: Adjusts microphone sensitivity
5| RF GAIN knob: Improves reception in strong signal areas.
6| HI CUT knob: Adjust clockwise to reduce high frequency noise.
7| SWR CAL : Calibrates the meter for Standing Wave Ratio (SWR)
measurements. (See page 12.)
8| Channel knob: Selects channel.
9| ANT LED: Indicates a high SWR condition in antenna system. Check antenna,
cable, and connections.
10| Channel Display: Displays current channel selection
11| RX/TX LED: Red-transmitting; green-receiving.
12| AM/FM switch: Toggle between AM or FM modulation.
13| CH9/OFF switch: Instantly tunes to emergency CB Channel 9. Turn
off to resume normal channel operations.
14| BRT/DIM switch: Adjusts the backlight LED brightness.
15| CB/PA : Selects CB (Citizen’s Band) or PA (Public Address).
Do not use PA function unless an external speaker is connected.
16| NB/ANL/ANL/OFF switch: Reduces external noise and interference
from vehicle ignition systems.
17| S/RF/SWR/ CAL switch: Selects meter function. S/RF- normal;
SWR and CAL are for SWR measurements only. See page 12 for
calibration procedures.
REAR VIEW
Item | Definition |
---|---|
18 | Antenna socket: Connects antenna cable to transceiver. |
19 | PA SP. jack: 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.
20| EXT. SP. jack: Connects optional 8-ohm 4-watt speaker to remotely monitor the receiver.
When the external speaker is plugged in, the internal speaker is off.
21| POWER connector: Connects DC power to transceiver.
INSTALLATION
MOBILE INSTALLATION
Plan the location of the transceiver and microphone bracket before beginning installation.
- Select a location that is convenient for operating the radio, but does not interfere with the driver or
- Install bracket with self-tapping screws
- Connect power cords (see page 10).
- Attach the microphone bracket to the side of the
- Attach radio to bracket
Mobile Antenna
WARNING! The antenna used for this radio must be installed at least 16.92
inches (43 cm) away from all persons. The antenna must not be collocated r
used with any other antenna or transmitter.
CAUTION: Never operate your radio with no antenna or with a damaged
antenna cable. This can damage the radio.
You must purchase an antenna to operate this radio. 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, Uniden
strongly recommends 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, but
itsefficiency is less than that of a full quarter-wave whip antenna
Connecting the Power Cords
Uniden recommends 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.
As an alternative, the power cord may be connected to an available terminal on
the fuse block or to a point in the wiring harness. However, take care 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 ground
system vehicle.
Ground Information
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
For negative ground systems, 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.
USING YOUR PC78LTXFM
TURN PC78LTXFM ON/OFF
Turn the VOLUME knob clockwise until the unit turns on and the display
backlight turns on.
Turn the VOLUME knob counter-clockwise to turn the unit off.
CB MODE
Be sure that the power source, antenna, and microphone are properly connected before proceeding.
-
Turn the unit on. Set the volume to a comfortable level.
-
Set switch to CB.
-
Select AM or FM.
-
Turn the CH knob to select a CB channel.
-
Adjust HI CUT as needed.
-
Set noise limitations switch to NB/ANL.
-
Adjust squelch.
● Adjust SQUELCH knob fully clockwise so only strong signals can get through.
● Adjust SQUELCH knob fully counter-clockwise until you hear a hiss. Everything gets through – noise, weak signals, and strong signals.
● Slowly adjust SQUELCH knob back clockwise until the hiss stops. Only clearer signals get through.
Set SQUELCH only when the radio is not receiving a strong signal. -
Press and hold PTT and check the multifunction meter. It will show the RF output power.
-
Adjust RF GAIN knob set RF Gain sensitivity. Normally, the knob is turned clockwise to maximum.
-
Set the brightness (BRT or DIM).
-
Set meter switch to S/RF.
PA MODE
Using the PA mode requires an optional speaker.
- Switch to PA.
- Press and hold PTT to speak.
- Release when finished.
To prevent acoustic feedback, separate the microphone from the speaker when operating the PA at high output levels.
If you are in PA mode but not pressing PTT, the radio receives CB transmissions and transmits them through the PA speaker. You cannot respond to the transmission.
HI CUT
The Hi Cut function reduces high frequencies and minimizes white noise. Turn the HI CUT knob clockwise to reduce higher frequencies.
TO TRANSMIT/RECEIVE
Perform a voltage Standing Wave Ratio (SWR) measurement prior to using the transmitter. An 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.
- Select a channel.
- Adjust MIC GAIN.
- When the channel is clear, press the microphone PTT and speak.
- Release PTT when you are finished speaking to listen for the response.
MULTI-FUNCTION METER
SWR Meter: Measures the standing wave ratio (SWR) of the antenna. Use this
meter to check the antenna system or to adjust your antenna to the proper
length.
To Measure SWR:
- Set the meter switch to CAL.
- Press and hold microphone PTT switch (Transmit).
- Calibrate meter with SWR CAL knob by adjusting the needle to the ▼ mark.
- Move the meter switch to the SWR position while pressing the microphone PTT switch.
- Release the PTT switch.
A reading less than two is acceptable. Higher readings indicate a problem in the antenna system. Problems may be caused by humidity, vibration, a mistuned antenna, or corrosion. Check both ends of the coaxial cable connector. Also check for damage to the cable or antenna. Tune the antenna according to the instructions that came with the antenna. RF Meter: Measures RF Output Power for transmitter. To use, set the meter switch at S/RF. Press microphone PTT switch to read transmitting power.
S-Meter: Measures incoming signal strength. To use, set 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:
- Check the Standing Wave Ratio (SWR). See page 12.
- Be sure all electrical connections are tight.
- Inspect antenna coaxial cable for wear or breaks in shielding.
- Be sure all screws and mounting hardware are tight.
MAINTENANCE
The PC78LTXFM 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:
- Press ends of the fuse holder together. Twist to open.
- Carefully separate the two pieces.
- Remove the fuse and inspect. If blown, replace with the same type fuse. Use only the fuse specified for your PC78LTXFM. Failure to do so may void your warranty
TROUBLESHOOTING
In the event of system malfunction, perform the following procedures:
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/PA to CB.
Check VOLUME and SQUELCH. Check antenna.
Check antenna connection.
Adjust RF Gain.
Poor Reception| Be sure that the transmitting and receiving radios match (AM- AM or FM-FM).
Check VOL and SQ.
Be sure antenna SWR is normal. Adjust RF Gain.
No Transmission| Set CB/PA switch to CB.
Check microphone connection. Adjust MIC Gain.
Low Transmission| Be sure antenna SWR is normal. Adjust MIC Gain.
Calibration does not move the meter needle to the left side| Adjust the
antenna length. Check all antenna connections.
SPECIFICATIONS
GENERAL
Channels: 40
CB Frequency Range: 26.965 – 27.405 MHz
Frequency Control : PLL synthesizer Antenna Impedance 50 ohms
Power Input : 13.8VDC
Current Drain:
TX:
AM Full Modulation: 2.1A (max)
FM – 1.6A (max) RX : At no signal: 400mA
Operating Temperature: -22°F to 140°F (-30°C to 60°C) Size (W x D x H):
7-9/32 in. x 7-51/64 in. x 2-13/64 in.
(without knobs and jacks)
Weight: 3 lb with microphone
Antenna Connector: UHF, SO-239
TRANSMITTER
Power Output: 4 watts
Emission Type: AM/FM Hum and Noise
AM:
FM:
46dB
38dB
Frequency Tolerance ± 0.003%
Spurious Harmonics Emission -70 dBc
Output Impedance: 50 ohm, unbalanced
RECEIVER
Sensitivity
AM at 10 dB (S+N)/N:
FM at 12dB SINAD :-111dBm
-120dBm
Maximum Sensitivity (AM): -113dBm Squelch Threshold -117dBm
Squech Tight: -47dBm
Signal Meter S-9 : -67dBm
Audio Output Power (max): 5 watts
Audio Output (10% Dist.): 4.5 watts
Image Rejection: 80 dB typical
Adjacent CH Rejection: 60 dB typical
Internal Speaker Impedance: 16 ohms Antenna Impedance 50 ohms
RF Gain Control: Adjustable for optimum signal reception
Noise Blanker: RF type
Squelch Sensitivity: Threshold -117dBm Tight -47dBm
Frequency Response @6dB Down 1kHz, 0dB Reference: 200 to 3000 H Internal
Speaker Impedence: 16 ohms
PUBLIC ADDRESS SYSTEM
Audio Output (10% Dist.): 4 Watts
External Speaker for PA Speaker (not supplied): 8 ohms when CB/PA
switch is PA. The PA also monitors the receiver; separate jack provided.
Specifications shown are typical and subject to change without notice.
RADIO CODE DEFINITIONS
10-CODES
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 | 10-34 | Trouble at this station |
10-2 | Receiving well | 10-35 | Confidential information |
10-3 | Stop transmitting | 10-36 | Correct time is |
10-4 | OK, message received | 10-37 | Wrecker needed at |
10-5 | Relay message | 10-38 | Ambulance needed at |
10-6 | Busy, stand by | 10-39 | Your message is delivered |
10-7 | Out of service, leaving air | 10-41 | Please turn to channel |
10-8 | In service, subject to call | 10-42 | Traffic accident at |
10-9 | Repeat message | 10-43 | Traffic tie up at |
10-10 | Transmission completed, standing by | 10-44 | I have a message for you |
10-11 | Talking too rapidly | 10-45 | All units within range please report |
10-12 | Visitors present | 10-50 | Break channel |
10-13 | Advise Weather/ Road conditions | 10-60 | What is next message number |
10-16 | Make pickup at | 10-62 | Unable to copy, use phone |
10-17 | Urgent business | 10-63 | Net directed to |
10-18 | Anything for us? | 10-64 | Net clear |
10-19 | Nothing for you, return to base | 10-65 | Awaiting your next message/ |
assignment
10-20| My location is| 10-67| All units comply
10-21| Call by telephone| 10-70| Fire at
10-22| Report in person to| 10-71| Proceed with transmission in sequence
10-23| Stand by| 10-77| Negative contact
10-24| Completed last assignment| 10-81| Reserve hotel room for
10-25| Can you contact| 10-82| Reserve room for
10-26| Disregard last information| 10-84| My telephone number is
10-27| I am moving to channel| 10-85| My address is
10-28| Identify your station| 10-91| Talk closer to microphone
10-29| Time is up for contact| 10-93| Check my frequency on this channel
10-30| Does not conform to FCC rules| 10-94| Please give me a long count
10-32| I will give you a radio check| 10-99| Mission completed, all units
secure
10-33| EMERGENCY TRAFFIC| 10-200| Police needed at
If you do not get satisfactory results after performing the above checks, visit www.uniden.com for further information.
FCC PART 15
Changes or modifications not expressly approved by the party responsible for
compliance could void the user’s 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.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against harmful
interference in a residential installation.
This equipment generates, uses, and can radiate radio frequency energy, and if
not installed and used in accordance with the instructions, may cause harmful
interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment
does cause harmful interference to radio or television reception, which can be
determined by turning the equipment off and on, the user is encouraged to try
to correct the interference by one or more of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
FCC 20 CM STATEMENT
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with a minimum distance of 20cm between the radio and your body. This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter.
ONE-YEAR EXTENDED WARRANTY
Important: Evidence of original purchase is required for warranty service.
WARRANTOR: UNIDEN AMERICA CORPORATION (“Uniden”)
ELEMENTS OF WARRANTY: Uniden warrants, for one year, 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 one year 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, towarrantor at:
Uniden America Corporation C/O Saddle Creek
743 Henrietta Creek Road, Suite 100 Roanoke, TX 76262
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