Cobra 1000GTL 40-Channel Citizens Band Solid State 2-Way Radio Base Station With Separate Speaker Cabinet

INSTRUCTION MANUAL

for Cobra 1000GTL
40-Channel
Citizens Band Solid State
2-Way Radio
Base Station With
Separate Speaker Cabinet

Cobra Communications Product Group
DYNASCAN CORPORATION
6460 W. Cortland Street
Chicago, Illinois 60635

WARNING - TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.

THE CB STORY

The Citizens Band lies between the shortwave broadcast and 10-meter amateur radio bands, and was established by law in 1949. The Class D two-way communications service was opened in 1959. (CB also includes a Class A business band and Class C remote control frequencies.) Acquiring the Class D license requires no detailed technical or Morse-code knowledge that is required for a "Ham" license.

Although the FCC has eliminated the requirement for the $4.00 CB license fee, a license is still required. Filing procedure remains unchanged. One license can be good for any number of sets used by a given family or business. Once you receive your Class D license for your equipment, anyone may use it.

For example, though the equipment must be licensed to someone over 18 years of age, a child can use the equipment to talk to another child, or an employee can use the equipment as part of his or her routine services. However, final responsibility of legal operation rests with the CB licensee.

NOTE
FCC regulations permit only "transmissions" (one party to another) rather than "broadcasts" (to a wide audience). Thus, advertising is not allowed on CB channels because it is broadcasting.

HAVE A GOOD DAY TODAY AND A BETTER DAY TOMORROW!

Section I Introduction

FREQUENCY RANGE

The COBRA 1000GTL provides high level trouble-free performance in the Citizens Radio Service which is comprised of the following frequency assignments:

To obtain maximum performance from your COBRA 1000GTL, please read carefully the following descriptions and operation instructions.

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

WARNING

1. Operation of this equipment requires a valid Station License issued by the Federal Communications Commission. Do not transmit with your equipment until you have received your License or complied with procedures explained on FCC Temporary License Form 555-B. A copy of FCC Application Form 505, FCC Temporary License Form 555-B, and Part 95 of the Commission Rules, are packed with this combination transceiver for your convenience.
2. You are required to complete FCC License Application Form 505 and submit it to the FCC, Gettysburg, Pa. 17362, in order to receive your license.
3. You are required to read and understand Part 95 of the FCC Rules and Regulations, before operating your station. FCC Rules require you to always have on hand a current copy of Part 95 of the FCC Rules, as part of your Station Records.
4. All transmitter adjustments other than those supplied by the manufacturer as front panel operating controls, must be made by, or under the supervision of, the holder of an FCC-issued 1st or 2nd Class Radio Operator License.
5. Replacement or substitution of crystals, transistors, regular diodes or other part of a unique nature, with parts other than those recommended by Dynascan, may cause violation of the technical regulations of Part 95 of the FCC Rules, or violation of the Type Acceptance requirements of Part 2 of the Rules.

Section II Specifications

GENERAL

• Channels: 40.
• Frequency Range: 26.965 to 27.405 MHz.
• Frequency Control: Phase Locked Loop (PLL) synthesizer.
• Frequency Tolerance: ±540 Hz Typical.
• Operating Temperature Range: -30°C to +50°C.
• Microphone: Plug-in type; 600Ω dynamic.
• Power Source: 120V AC nominal. 13.8 V DC nominal. (Positive or negative ground).
• Power Consumption (120V AC): Transmit: AM full mod., 60 watts. Receive: Squelched, 20 watts. Full audio, 40 watts.
• Current Drain (13.8V DC): Transmit: AM full mod., 2A DC (nominal). Receive: Full audio output, 1A DC (nominal). No signal, 0.4A DC (nominal).
• Size: 5-3/4"H x 15"W x 13-3/8"D.
• Weight: 10 pounds.
• Antenna Connector: UHF, SO239.
• Semiconductors: 5 integrated circuits, 3 FETs, 28 transistors, 33 diodes and 2 LEDs.
• Meter 1: Illuminated; indicates relative power output and received signal strength.
• Meter 2: Illuminated, indicates standing wave ratio and level of modulation.

Section III Installation

LOCATION

Prior to beginning operation of the transceiver, a basic installation must be prepared. Installation of the transceiver itself is a rather simple procedure.

In selecting the location for the unit, two basic factors must be considered.

1. Access to a 120V, 60 Hz power source.
2. The location must be convenient for running the antenna lead-in cable if an outside antenna installation is proposed.

BASE STATION ANTENNA

Since the maximum allowable power output of the transmitter is limited by the FCC, the antenna is the most 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.

The recommended method of antenna tuning is to use an in-line watt-meter or VSWR bridge to adjust the antenna tuning for minimum reflected power on channel 21.

The radio may be used with any type of 50-ohm base station antenna. A ground plane vertical antenna will provide the most uniform horizontal coverage. This type of antenna is best suited for communication with a mobile unit. For point-to-point operation where both stations are fixed, a directional beam will usually increase communicating range since this type of antenna concentrates transmitted energy in one direction. The beam antenna also allows the receiver to "listen" in only one direction thus reducing interfering signals.

Antenna height is an important factor when maximum range is desired. Keep the antenna clear of surrounding structures or foliage. FCC regulations for base station antenna height are:

1. Omni-directional antennas may not be higher than 60 feet above the ground when using a tower, mast or pole, and no higher than 20 feet above an existing structure.
2. Beam antennas may not be higher than 20 feet above the ground when using a tower, mast, pole, or an existing structure.

These are only general regulations applicable to most but not all parts of the nation. Locations near airports and some military installations are subject to different rules; therefore, it is best to contact your nearest Federal Communications Commission office for information regarding your specific area.

MOBILE OPERATION/EMERGENCY POWER OPERATION

It is possible to operate the COBRA 1000GTL from an external 13.8 V DC power supply for emergency power conditions or from an automobile battery for mobile operation. The COBRA 1000GTL is supplied with a polarized plug for operation on an external DC supply.

The negative lead is black.
The positive lead is red and has an in-line fuse holder as an integral part of the positive lead.

AC-DC switch on rear panel-use "AC" for 120 volt operation and "DC" for battery operation.

PUBLIC ADDRESS

An external 8-ohm, 4-watt speaker may be connected to the PA speaker jack located on the rear panel when the transceiver is used as a public address system. The speaker should be directed away from the microphone to prevent acoustic feed-back. Physical separation or isolation of the microphone and speaker must be used when operating the PA at high-output levels.

REMOTE SPEAKER

The external speaker jack (SP1 and SP2) are located on the rear panel. An external speaker should have 8 ohms impedance and be able to handle at least 4 watts. Use one jack for speaker supplied with 1000GTL. The other speaker is available for use of optional speaker CA-2000 (available through your authorized COBRA DEALER.)

ALTERNATE MICROPHONES AND INSTALLATION

For best results, the user should select a low-impedance dynamic type microphone or a transistorized microphone. Transistorized type microphones have a low output impedance characteristic. The microphones must be provided with a four-lead cable. The audio conductor and its shielded lead comprise two of the leads. The third lead is for transmit/receive control and the fourth lead is the speaker return lead which disables the speaker during transmit. The microphone should provide the functions shown in schematic below.

4-Wire Mic Cable

If the microphone to be used is provided with pre-cut leads, they must be revised as follows:

1. Cut leads so that they extend 7/16" beyond the plastic insulating jacket of the microphone cable.
2. All leads should be cut to the same length. Strip the ends of each wire 1/8" and tin the exposed wire.

Before beginning the actual wiring, read carefully the circuit and wiring information provided with the microphone you select. Use the minimum head required in soldering the connections. Keep the exposed wire lengths to a minimum to avoid shorting when the microphone plug is reassembled.

To wire the microphone cable to the plug provided, proceed as follows:

1. Remove the retaining screw.
2. Unscrew the housing from the pin receptacle body.
3. Loosen the two cable clamp retainer screws.
4. Feed the microphone cable through the housing, knurled ring and washer as shown.
5. The wires must now be soldered to the pins as indicated in the above wiring tables. If a vise or clamping tool is available it should be used to hold the pin receptacle body during the soldering operation, so that both hands are free to perform the soldering. If a vise or clamping tool is not available, the pin receptacle body can be held in a stationary position by inserting it into the microphone jack of the front panel. The numbers of the pins of the microphone plug are shown, as viewed from the back of the plug. Before soldering the wire to the pins, pre-tin the wire receptacle of each pin of the plug.

Be sure that the housing and the knurled ring of Fig. 2 are pushed back onto the microphone cable before starting to solder. If the washer is not captive to the pin receptacle body, make sure that it is placed on the threaded portion of the pin receptacle body before soldering.

If the microphone jack is used to hold the pin receptacle during the soldering operation, best results are obtained when the connections to pins 1 and 4 are made first and then the connections to pins 2 and 3. Use a minimum amount of solder and be careful to prevent excessive solder accumulation on pins, which could cause a short between the pin and the microphone plug housing.

6. When all soldering connections to the pins of the microphone plug are complete, push the knurled ring and the housing forward and screw the housing onto the threaded portion of the pin receptacle body. Note the location of the screw clearance hole in the plug housing with respect to the threaded hole in the pin receptacle body. When the housing is completely threaded into the pin receptacle body, a final fraction of a turn either clockwise or counterclockwise may be required to align the screw hole with the threaded hole in the pin receptacle body. When these are aligned, the retaining screw is then screwed into place to secure the housing to the pin receptacle body.
7. The two cable clamp retainer screws should now be tightened to secure the housing to the microphone cord. If the cutting directions have been carefully followed, the cable clamp should secure to the insulating jacket of the microphone cable.
8. Upon completion of the microphone plug wiring, connect and secure the microphone plug in the transceiver.

MIKE

Diagram showing microphone cable preparation and wiring.

Section IV Operation

CONTROLS AND INDICATORS

There are 18 controls, 2 meters, 4 indicators and 3 jacks on the front panel of your COBRA 1000GTL.

A. CONTROL FUNCTIONS

1. OFF/ON VOLUME: Turn clockwise to apply power to the unit and to set the desired listening level.
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 the control should be adjusted only to the point where the receiver background noise or ambient background noise is eliminated. Turn fully counterclockwise then slowly clockwise until receiver noise disappears. Any signal to be received must now be slightly stronger than the average received 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. DYNAMIKE PLUS: Adjusts the microphone gain in the transmit and PA modes. This controls the gain to the extent that full talk power is available several inches away from the microphone. In the public address (PA) mode the control functions as the volume control.
4. RF GAIN: Adjust as required to optimize the signal. This control is used primarily to optimize reception in strong signal areas. Gain is reduced by counterclockwise rotation of the control.
5. SWR CAL CONTROL: In order for you to achieve maximum radiated power and the longest range, it is important that your antenna be in good condition, properly adjusted and matched to your transceiver. The built-in SWR (standing wave ratio) meter lets you easily measure your antenna condition. To operate this function, connect your antenna to the transceiver antenna output connector. Select a channel near the middle of the band such as 21, or the channel you plan to use most frequently. Turn the power on and set the meter function switch to the CAL position. Press and hold the microphone push-to-talk button; using the SWR CAL control, adjust the meter to read the CAL position indicated on the meter face. Then, without releasing tae microphone button, switch the meter function switch to the SWR position and read the SWR indicated. The lower the figure, the better, with 1 being ideal. Generally speaking, readings up to 3 are acceptable, but over 3 indicates that you are losing radiated power and antenna adjustment may be advisable.
6. DELTA TUNE: For normal operation set the control to the center position. This feature has several uses and can greatly enhance receiver operation. First, if a received signal is slightly off frequency, the Delta-Tune control can be operated as required to optimize the received signal level. The effectiveness of the Delta-Tune feature under these conditions can be observed either by listening for a more readable signal at the speaker or by noting the S-meter reading when the Delta-Tune control is operated. Another effective application of this control is in eliminating adjacent channel interference. If it is verified that an exceptionally high level signal from an adjacent channel is creating interference on the channel being used, the Delta-Tune can be used to minimize or eliminate the interference. Operate the control as required to obtain minimum adjacent channel interference.
7. TONE: This control is used to shape the audio response to the operators preference. Base is increased by counterclockwise rotation and treble is increased by clockwise rotation.
8. CHANNEL SELECTOR: This switch selects any one of the forty Citizens Band channels desired. The selected channel appears on the LED readout directly above the Channel Selector knob. Channel 9 has been reserved by the FCC for emergency communications involving the immediate safety of life of individuals or immediate protection ofproperty. Channel 9 may also be used to render assistance to a motorist.
9. SPEAKER SWITCH (SP1/SP1+2/SP2): Use this switch to select either or both speakers.
10. OFF/ANL SWITCH: In the ANL position, the noise reduction circuits of the Automatic Noise Limiter are activated.
11. OFF/NB SWITCH: When the switch is placed in the NB position the RF noise blanker is activated. The RF noise blanker is very effective for repetitive impulse noise such as ignition interference.
12. PA/CB SWITCH: Selects the mode of operation. In the CB position, the PA function is disabled and the unit will transmit and receive on the selected frequency. The PA function should not be used unless a PA speaker is connected. To use this PA feature, a speaker having a voice coil impedance of 8 ohms and a power handling capability of at least four watts should be used. This speaker must be plugged into the PA SPKR jack at the rear of the transceiver. Be sure that there is physical separation between the microphone and the speaker itself. If the speaker is located close to the microphone, acoustic feedback will result when the public address system is operated at high volume. Some experimentation will determine the minimum amount of isolation required for a given sound level from the public address system. NOTE: PA volume is controlled by adjusting the DYNAMIKE PLUS CONTROL to the desired volume.
13. SWR/SWR CAL/%-MOD SWITCH: In the %-MOD position, the MOD meter is activated. When in the SWR or SWR CAL positions the SWR meter is activated.
14. PRESS-TO-TALK MICROPHONE: The receiver and transmitter are controlled by the press-to-talk switch on the microphone. Press the switch and the transmitter is activated; release switch to receive. When transmitting, hold the microphone two inches from the mouth and speak clearly in a normal "voice". The radios come complete with a low-impedance 500-ohm dynamic microphone. For installation instructions on other microphones, See, "ALTERNATE MICROPHONES AND INSTALLATION."
15. PHONES: For your individual listening with head phones.
16. RECORD OUTPUT: Both transmit and received messages may be recorded from this output.
17. SEPARATE SPEAKER CABINET: Allows you to set speaker in the most convenient location.

B. INDICATOR FUNCTIONS

• S-METER: Indicates relative strength of the incoming signal.
• RF METER: Indicates RF output power.
• MODULATION METER: Indicates the percent modulation. NOTE: The SWR/SWR CAL/%-MOD switch must be in the %-MOD position to read modulation.
• SWR METER: Measures the ratio of standing wave voltage of the antenna system. Used to properly adjust the length of the antenna, and to monitor the quality of the coaxial cable and all RF electrical connections. If there is any degradation whatsoever in any of the above, due to humidity, salt spray, vibration or corrosion. the SWR meter reading will rise, thereby indicating that a problem exists. To calibrate, switch to the "SWR CAL" position. Transmit by pressing the mike switch, and adjust the SWR control to the "CAL" mark on the meter. Then switch to "SWR" position for the SWR measurement.
• CHANNEL INDICATOR: The selected channel appears on the LED readout directly above the channel selector knob.
• RECEIVE INDICATOR: Lit while in the receive mode.
• ON THE AIR: Lit while in the transmit mode.

C. OPERATING PROCEDURE TO RECEIVE

1. Place the PA/CB switch in the CB position.
2. Turn the set ON by rotating the VOLUME control clockwise, until a click is heard.
3. Adjust the VOLUME for a comfortable listening level.
4. Set the Channel selector switch to the desired channel.
5. Rotate the RF GAIN fully clockwise.
6. Set the DELTA TUNE control to the center position.
7. Adjust SQUELCH control as previously described.

D. OPERATING PROCEDURE TO TRANSMIT

1. Select the desired channel of transmission.
2. Rotate the DYNAMIKE PLUS control fully clockwise.
3. If the channel is clear, depress the push-to-talk switch on the microphone and speak in a normal voice.

The S-RF meter will indicate relative power output and the modulation meter will indicate percentage of modulation as you speak into the microphone.

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.

E. LED CLOCK

1. Located on the left hand side of LED clock are the AM & PM indicators. These LED indicators will show the correct reading for AM & PM.
2. The flashing colon indicates seconds.
3. Flashing clock numbers will indicate an AC power Interruption.

For the proper procedure to set your LED clock there are the following features:

TIME ADJUST - 3 Switches (Clock) DYNALERT - 2 Switches (Alarm)

Follow the instructions as listed below:

TIME ADJUST (Clock)

• Fast Switch: Depressing this switch causes the time to advance rapidly. This will set the clock for AM or PM. Use this switch till approx. 2 minutes before correct time and then use slow switch.
• Slow Switch: Depressing this switch causes the clock to advance slowly to correct time.
• Hold Switch: Depressing this switch causes the clock to hold setting until released. This allows setting the clock to the exact seconds.

DYNALERT (Alarm)

• Set Switch: Depressing this switch enables you to set the alarm time. Set alarm time by following time adjust procedure. Release switch after alarm time is set.
• Alarm Switch: Depressing this switch causes the alarm to sound at a preselected time. Release the switch to shut the alarm off.

NOTE: SET and ALARM switches are released by depressing them slightly and then allowing them to release.

Section V Maintenance and Adjustment

The COBRA 1000GTL transceiver is designed specifically for use as a base station and may also be used in mobile installations. The use of all solid state circuitry results in light weight and high reliability. Should a failure occur, replace parts only with identical parts. Do not substitute. Refer to the schematic diagram and parts list.

NOTE
If the performance described in the OPERATION and MAINTENANCE AND ADJUSTMENT section is not obtained, review the operating instructions to insure that proper procedures were followed. If a problem still exists, refer to WARRANTY SERVICE INSTRUCTIONS on the last page of this manual.

FCC WARNING
Federal law requires that adjustment of the radio frequency section of this transceiver may not be made by a Citizens Band operator. Only a United States licensed First or Second Class commercial license holder may tune the transmitter section of this transceiver, per FCC part 95 section 95.97 d .

Section VI Appendix

Citizens Band radio operators have largely adopted the "10-code" for standard questions and answers. Its use permits faster communications and better understanding in noisy areas. The following table lists some of the more common codes and their meanings.

10 CODE

A FEW RULES THAT SHOULD BE OBEYED

1. You must identify your official licensed call sign at the beginning and end of every conversation.
2. You are not allowed to carry on a conversation with another station for more than five minutes at a time without taking a one-minute break, to give others a chance to use the channel.
3. You are not allowed to blast others off the air by over-powering them with illegally amplified transmitter power, or illegally high antennas.
4. You can't use CB to promote illegal activities.
5. You are not allowed to use profanity.
6. You may not play music in your CB.
7. You may not use your CB to sell merchandise or professional services.

HOW YOUR CB CAN SERVE YOU

• Warn of traffic tie ups ahead.
• Provide weather and road information.
• Provide help fast in event of emergency or breakdown.
• Suggest good spots to eat and sleep.
• Make long trips more interesting, and help keep you awake.
• Provide direct contact with your office or home.
• Make friends for you as you travel.
• Provide "local information" to find your destination.
• Help law enforcement officers by reporting drunk and reckless drivers.

Colonel Samuel S. Smith of the Missouri Highway Patrol called the number of drunken drivers, wrong-way drivers and speeders reported by CBers as "amazing." He said, that even the "Smokey Bear" warnings don't shake their beliefs that "the potential benefits of CB radio to law enforcement are so great that they far outweigh the disadvantages." In regards to CB radar warnings to other CBers, Colonel Smith said cheerfully that "We've overheard warnings being relayed to truckers long after our operations have been discontinued . . . so we actually receive a residual benefit from these warnings."

USE CHANNEL 9 FOR EMERGENCY MESSAGES ONLY

FCC gives the following examples of permitted and prohibited types of communications for use on Channel 9. These are guidelines and are not intended to be all-inclusive.

Permitted Example Message

• Yes "A tornado sighted six miles north of town."
• No "This is observation post number 10. No tornado sighted."
• Yes "I am out of gas on Interstate 95."
• No "I am out of gas in my driveway."
• Yes "There is a four-car collision at Exit 10 on the Beltway, send police and ambulance."
• No "Traffic is moving smoothly on the Beltway."
• Yes "Base to Unit 1, the Weather Bureau has just issued a thunderstorm warning. Bring the sailboat into port."
• No "Attention all motorists. The Weather Bureau advises that the snow tomorrow will accumulate 4 to 6 inches."
• Yes "There is a fire in the building on the corner of 6th and Main Streets."
• No "This is Halloween patrol unit number 3. Everything is quiet here."

WARRANTY SERVICE INSTRUCTIONS

1. Refer to the MAINTENANCE section of your Cobra instruction manual for adjustments that may be applicable.
2. If the above-mentioned procedures do not correct the problem you are experiencing with your unit, pack it securely (preferably in the original carton or double-packed). Enclose a letter describing the problem and include your name and address. Deliver to, or ship PREPAID (UPS preferred) to the nearest Cobra authorized service agency (see list enclosed with unit).

If your list of authorized Cobra service agencies has been misplaced, contact your local dealer for the name of your nearest service agency, or write to:

Service Department

Cobra Product Group
DYNASCAN CORPORATION
2815 West Irving Park Road
Chicago, Illinois 60618

LIMITED 90-DAY WARRANTY

DYNASCAN CORPORATION warrants to the original purchaser that its COBRA Citizens Band Radios, and the component parts thereof, will be free from defects in workmanship and materials for a period of ninety (90) days from the date of purchase.

DYNASCAN will, without charge, repair or replace, at its option, defective radios or component parts upon delivery to an authorized COBRA service contractor or the factory service department, accompanied by proof of the date of purchase in the form of a sales receipt.

To obtain warranty coverage, this CB radio must be registered by completing and mailing the enclosed warranty registration card to DYNASCAN Cobra Communications, P. O. Box 35148, Chicago, Illinois 60635 within five (5) days from the date of purchase.

Exclusions: This warranty does not apply in the event of misuse or abuse of the product or as a result of unauthorized alterations or repairs. It is void if the serial number is altered, defaced or removed.

As indicated in your product instruction booklet, certain COBRA models are suitable for dash board installation without modification of the dash. In other cases professional installation is recommended. In either event, DYNASCAN is not responsible for damages to the product or the automobile resulting from improper installation.

DYNASCAN shall not be liable for any consequential damages, including without limitation damages resulting from loss of use or cost of installation. Some states do not allow limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you.

This warranty gives you specific rights and you may also have other rights which vary from state to state.

For your convenience we suggest you contact your dealer, who may be authorized to make repairs or can refer you to the nearest service contractor. If warranty service cannot be obtained locally, please send the unit to Cobra Communications Service, 2815 West Irving Park Road, Chicago, Illinois 60618, properly packaged to avoid damage in shipment.

For future reference, jot down the serial number (shown on the FCC identification plate of your COBRA 1000GTL) below:

Cobra Communications Product Group
DYNASCAN CORPORATION
6460 W. Cortland Street
Chicago, Illinois 60635