Cobra 19DXII User Manual

HOW TO USE YOUR

40 CHANNEL

CITIZENS BAND

2-WAY MOBILE RADIO

Model 19 DX

Nothing comes close to a Cobra™

6500 WEST CORTLAND STREET CHICAGO, IL 60707 USA

Serial No. Date of Purchase Dealer Name

Keep this manual for detailed information about your Cobra CB Radio System.

SAVE YOUR SALES RECEIPT, THE CARTON AND “PACKING” FOR POSSIBLE FUTURE USE.

If You Think You Need Service,

please contact your local dealer.

The Cobra®line of quality products includes:

CB radios

microTALK

radios

Radar/Laser Detectors

GPS

Safety Alert

Traffic Warning Systems

Accessories

HighGear

™

Accessories

CITIZENS BAND

2-WAY MOBILE RADIO

HOW TO USE YOUR

40 CHANNEL

Introduction

Frequency Range........................................................................................2

Specifications ..................................................................................................3

Installation

Location ......................................................................................................4

Mounting and Connections ..................................................................4-5

CB Antenna ................................................................................................6

Ignition Noise Interference ......................................................................7

Operation

Controls and Indicators....................................................................8-9-10

Operating Procedure to Receive ............................................................11

Operating Procedure to Transmit ..........................................................11

Maintenance and Adjustment ....................................................................12

Appendix

Ten Code....................................................................................................13

A Few Rules That Should Be Obeyed ..................................................14

How Your CB Can Serve You ................................................................14

Use Channel 9 for Emergency Messages Only....................................15

Model 19 DX

Frequency Range

Your COBRA CB radio provides high-level, trouble-free performance over the following frequency assignments:

Channel Channel Frequency Channel Channel Frequency

in MHz in MHz

1 26.965 21 27.215 2 26.975 22 27.225 3 26.985 23 27.255 4 27.005 24 27.235 5 27.015 25 27.245 6 27.025 26 27.265 7 27.035 27 27.275 8 27.055 28 27.285

9 27.065 29 27.295 10 27.075 30 27.305 11 27.085 31 27.315 12 27.105 32 27.325 13 27.115 33 27.335 14 27.125 34 27.345 15 27.135 35 27.355 16 27.155 36 27.365 17 27.165 37 27.375 18 27.175 38 27.385 19 27.185 39 27.395 20 27.205 40 27.405

These frequencies are generated and accurately controlled by a phase lock hoop (PLL) circuit, comprised of the latest state-of-the-art integrated circuit technology, ensuring high reliability and excellent frequency stability on the above channels.

To obtain maximum performance please read carefully the descriptions and operating instructions in this manual.

Introduction

GENERAL

Channels 40. Frequency Range 26.965 to 27.405 MHz. Frequency Control Phase-Locked Loop (PLL) synthesizer. Frequency Tolerance 0.005%. Operating Temp. Range -22

F to +122°F (-30°C to +50°C). Microphone Plug-in type; Electret condenser. Input Voltage 13.8V DC nom. (negative ground). Current Drain Transmit: AM full mod., 1.5A (maximum).

Receive: (Squelched, 0.115A, full audio output 1.0A (nominal).

Size 6-5/8”D x 4-9/16”W x 1-13/16”H

(165mm x 116 mm x 44 mm.) We ight 3 lbs., 4 oz. (1.0 kg.). Antenna Connector UHF, SO-239. Semiconductors 22 transistors, 17 diodes, 3 integrated

circuits, 7 LEDs. Meter Indicates relative power output and

received signal strength.

TRANSMITTER

Power Output 4 watts. Modulation High- and low-level Class B amplitude. Frequency 300 to 3000 Hz. Output Impedance 50 ohms, unbalanced. Output Protection Output transistors protected against

mismatch up to 20:1.

RECEIVER

Sensitivity Less than 1µV for 10dB(S + N)/N. Selectivity 6 dB @ 7 KHz, 55dB @ 15 KHz. Image Rejection 60 dB typical. Adjacent CH. Rejection 50 dB, typical. IF Frequencies Double conversion, 1st: 10.695 MHz.

2nd: 455 KHz.

Automatic Gain Control Less than 10dB change in audio output for

(AGC) inputs from 10 to 50,000µV. Squelch Adjustable; threshold less than 1µV. Audio Output Power 3 watts. Frequency Response 300-3000 Hz. Distortion Less than 10% @ 3 watts @ 1000 Hz. Built-in Speaker 8 ohms, round. External Speaker 8 ohms; disables internal speaker when

(Not Supplied) connected.

PA SYSTEM

Power Output 4 watts into external speaker. External Speaker for PA 8 ohms; a separate jack is provided.

(Not Supplied)

(Specifications subject to change without notice.)

Specifications

Location

Plan the location of the transceiver and microphone bracket before starting the installation. Select a location that is convenient for operation and does not interfere with the driver or passengers in the vehicle. In automobiles, the transceiver is usually mounted to the underneath of the dash panel, with the microphone bracket beside it.

Mounting Connection

The transceiver is held in the universal mounting bracket by two thumb screws, permitting adjustment at the most convenient angle.

A universal mounting bracket is supplied along with self tapping screws and star washers. The mounting must be mechanically strong and also provide a good electrical connection to the chassis of the vehicle. To mount the transceiver:

1. Determine the most convenient location in your vehicle. Hold the

COBRA radio with mounting bracket in the exact location desired. If nothing will interfere with mounting it in the desired position, remove the mounting bracket and use it as a template to mark the location for the mounting screws.

2. Drill necessary holes and secure mounting bracket in location.

Installation

3. Connect the antenna cable plug to the standard receptacle on the

unit. Most CB antennas are terminated with a type PL-259 plug which mates with the receptacle marked “ANT.”

4. Connect the red lead of DC power cord to +13.8VDC. In

automobile installations, +13.8VDC is usually obtained from the accessory contact in the fuse box. This prevents the set being left on accidentally and also permits operating the unit without the vehicle’s engine running.

Before installing the CB radio, visually check the vehicle battery connections to determine which battery terminal, positive or negative (positive is the larger of the two) is grounded to the engine block (or chassis).

5. Connect the black lead to the negative side of the automobile.

This is usually the chassis of the car. Any convenient location with good electrical contact (remove paint) may be used.

6. Mount the microphone bracket on right side of the transceiver, or

near it using two screws supplied. When mounting in an automobile, place the bracket under the dash so the microphone is readily accessible.

Installation (Cont.)

CB Antenna

Since the maximum allowable power output of the transmitter is limited by the FCC, the antenna is one important factor affecting transmission distance. Only a properly matched antenna system will allow maximum power transfer from the 50-ohm transmission line to the radiating element. In mobile installations (cars, trucks, boats, etc.), an antenna system that is non-directional should be used.

Avertically polarized, quarter-wavelength whip antenna provides the most reliable operation and greatest range. The shorter, loaded-type whip antennas are more attractive, compact and adequate for applications where the maximum possible distance is not required. Also, the loaded whips do not present the problems of height imposed by a full quarter-wavelength whip.

Mobile whip antennas utilize the metal body of the vehicle as a ground plane. When mounted at a corner of the vehicle they are slightly directional, in the direction of the body of the vehicle. For all practical purposes, however, the radiation pattern is nondirectional. The slight directional characteristic will be observed only at extreme distances. A standard antenna connector (type SO-239) is provided on the transceiver for easy connection to a standard PL 259 cable termination. Cobra loaded-type antenna models ATW-500, AT-55, ATW-1000 and ATW-400 are highly recommended for most installations. Consult your Cobra dealer for further details.

When installed in a boat, the transceiver will not operate at maximum efficiency without a ground plate, unless the vessel has a steel hull. Before installing the transceiver in a boat, consult your dealer for information regarding an adequate grounding system and prevention of electrolysis between fittings in the hull and water.

3-Way Combinations Antennas are available which allow operation of all three bands (AM-FM & CB), using a single antenna. However, use of this type of antenna usually results in less than normal transmit and receive range when compared to a standard-type “Single Band” antenna designed for CB only.

Installation (Cont.)

Ignition Noise Interference

Use of a mobile receiver at low signal levels is normally limited by the presence of electrical noise. The primary source of noise in automobile installations is from the alternator and ignition system in the vehicle. Under most operating conditions, when signal level is adequate, the background noise does not present a serious problem. Also, when extremely low level signals are being received, the transceiver may be operated with vehicle engine turned off. The unit requires very little current an therefore will not significantly discharge the vehicle battery.

Even though the COBRA radio has an automatic noise limiter, in some installations, ignition interference and other forms of automobile generated noise may be high enough to make good communications difficult. The electrical noise may come from several sources. Many possibilities exist and variations between vehicles require different solutions to reduce the noise. Consult your COBRA dealer or a 2-way radio technician for help in locating and correcting the source of severe noise.

Base Station Operation (Operation from 120VAC, House Current)

To operate your transceiver from your home or office, using the regular house current as the power source, you will require a 12VDC power pack that has been specially designed for the purpose. It is available as optional equipment from your COBRA dealer. It consists of a 120-volt, 60 Hz AC to 12-volt DC power converter with a 3A rating. Simply connect the red (+) and black (-) leads of the transceiver to the corresponding terminals of the power packs.

DO NOT ATTEMPT TO OPERATE THIS TRANSCEIVER BY CONNECTING DIRECTLY TO 120 VAC. SERIOUS DAMAGE WILL RESULT.

Temporary Mobile Operations

To operate your COBRA transceiver from a car on a temporary basis, you may want to purchase an optional cigar lighter adapter from your COBRA dealer. This adapter and a magnetic mount antenna allow you to quickly "install" your transceiver for temporary use.

Installation(Cont.)

Controls and Indicators

Refer to controls, indicators and connectors as illustrated below:

A. Front Panel

1. Off/On/Volume. Turn clockwise to turn power on and set the

desired listening volume.

2. Squelch. This control is used to cut off or eliminate receiver

background noise in the absence of an incoming signal. For maximum receiver sensitivity, it is desired that the control be adjusted only to the point where the receiver background noise or ambient background noise is eliminated. Adjust until the receiver noise disappears. This will require the incoming signal to be slightly stronger than the average receiver noise. Further clockwise rotation will increase the threshold level which a signal must overcome in order to be heard. Only strong signals will be heard at a maximum clockwise setting.

3. Microphone Connector. This front mounted, screw-on connector

allows for convenient removal of the microphone plug when storage is required. The microphone MUST be connected to the unit at all times when in use, for proper operation. The screw-on connection enhances the life of the microphone cord as well.

4. Channel 9/Normal Switch. Used for instant selection of

emergency channel 9 (CH 9 position). In NOR position, all 40 CB channels are selected by the UP/DOWN CHANNEL BUTTONS.

Operation

CB/PA Switch. Selects mode of operation. In the CB position, the PA

function is disabled and the unit will transmit and receive on the selected channel. The PA function should not be used unless a PA speaker is connected.

6. S-RF/Power Meter. Shows relative transmitter RF output power

and input signal strength when receiving. The five LED (Light Emitting Diode) segments glow to indicate receive or transmit activity.

7. TX Indicator LED. This indicator will light red when in the

transmit mode.

8. LED Channel Display. The selected operating channel will be

displayed here.

9. Channel Selector Switch. When turned, this knob is used to

select any one of the forty citizens band channels desired.

For a “RAPID” change of channels, depress and hold the desired button (up and down). This allows all 40 channels to be covered in about 6 seconds.

Other Operation Features

•Automatic Noise Limiter. This is a non-switchable feature that

is always on to reduce background noise.

Operation (Cont.)

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