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manual cobra 2000 gtl, Manuais, Projetos, Pesquisas de Cultura

manual de rádio cobra 2000 gtl ,radioamadorismo

Tipologia: Manuais, Projetos, Pesquisas

2017

Compartilhado em 12/07/2017

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Baixe manual cobra 2000 gtl e outras Manuais, Projetos, Pesquisas em PDF para Cultura, somente na Docsity! Cobra Cobra Communications Product Group DYNASCAN CORPORATION 6500 W. Cortland Street Chicago, Illinois 60635 480-236-9001A O DYNASCAN CORP,, 1983 Printed in: the Philippines UTDS0151328 obra Cobra 2000GTL 40-Channel Solid State Citizens Band SSB/AM Two-Way Radio Base Station With Separate Speaker Cabinet Cobra Communications Product Group DYNASCAN CORPORATION 6500 We. Cortland Street Chicago, lilinois 60635 INSTRUCTION MANUAL for Cobra 2000GTL 40-Channel Citizens Band Solid State SSB/AM Two-Way Radio Base Station With Separate Speaker Cabinet 4 Sê. Cobra Communications Product Group DYNASCAN CORPORATION 6500 W. Cortland Street Chicago, Illinois 60635 WARNING — TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE. Section 1 Specifications GENERAL Channels Frequency Range Frequency Control Frequency Tolerance Operating Temperature Range Microphone Power Source Power Consumption (120 AC) Current Drain (13.8V DC) Size Weight Antenna Connector Semiconductors Meter 1 Meter 2 40. 26.965 to 27.405 MHz. Phase Locked Loop (PLI) synthesizer. *+130 Hz Typical -30C to +50, Plug-in type; 60092 dynamic. 120V AC nominal. 13.8V DC nominal. (Positive or negative ground). Transmit: AM full mod., 65 watts. SSB 70 watts. Receive: Squelched, 30 watts. Full audio, 40 watts. Transmit: AM and SSB, 2.24 DC (nominal). Receive: — Full audio output, 1.14 DC (nominal). No signal, (0.654 DC (nominal) SH) x 15º(W) x 4-7/16"(D) 19% pounds. (including speaker) UF, S0239. 18 integrated circuíts, 6 FETs, 76 transistors, 93 diodes, 12 LEDs and 1 SCR. Hluminated; indicates relative power output and received signal strength. Iluminated, indicates standing wave ratio and level of modulation. TRANSMITTER Power Output Modulation Intermedualtion Distortion SSB Carrier Suppression Unwanted Sidehand Frequency Response Output Impedance SSB Tilter Output Indicators RECEIVER Sensitivity Selectivity Image Rejection IF Frequeney Adjacent-Channel Rejection AM and SSB RF Gain Control Automatic Gain Control (AGO) Squelch ANI AM. 4 watts. SSB, 12 watts, PEP. AM, high-and low-level Class B. SSB: 3rd and Sth order, more than -25dB. 7th and 9th order, more than -35dB. -5S dB Nominal -SO dB Nominal. AM and SSB: 300 to 2500 Hz. 50 ohms, unbalanced. 7.8 MHz, crystal lattice type: Meters show relative RF output power, per- centage of modulalion and SWR. “ON THE AIR” Transmit Indicator. SSB: 0.25 uV for 10 dB (S+NY/N at greater than lé-walt of audio output AM: 0.5 uV for 10dB (S+N)/ at greater than att of audio output. AM: 6 dB 63 KHz, 50 dB 29 KHz. SSB: 6 dB 7.1 KHz, 60 dB €2,3 KHz. More than 65 dB. AM: 7.8 MHz Ist IF, 455 KHz 2nd IF SSB: 7.8 MHz 60 dR AM & 70 dB SSB. 40 dB adjustable for optimum signal reception Less than 10 dB change in audio output for inputs from 10 to 100,000 microvolts. Adjustable; Lhreshold less than 0.5 uV. Switchable. Noise Blanker RE type, effective on AM and SSB. Voice Lock Range 41.5 KHz. coarse 500 Hz fine RE Gain Control Adjustable for optimum signal reception Audio Output Power 4 watis into 8 ohm. Frequency Response 300 to 2500 Hz. Distortion Less lhan 10% at 3 watts output. Separate Speaker 8 ohms. External Speaker (not supplied) 4 — 8 ohms. Indicators “Receive” indicator. Meter shows receive signal strength. Headphone Output 8 ohm impedance, 10 mW output. AUX Output 100K ohm impedance, approx. 300 mW output. PA SYSTEM Power output 4 watts into extemal speaker External speaker for PA 4 & ohms. (not supplied) CLOCK/COUNTER Clock Uses 60 Hz power line reference. May be used to sound alamm or tum on radiv. Counter Displays transmit and receive frequency. Section Ill 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, three basic factors must be considered. 1. Access to a 120V, 60 Hz power source. 2. The location must be convenient for running the antenna leadiin cable if an outside antenna installation is proposed. 3. ACDC switch on rear paneluse “AC” for 120 volt operation and “DC” for battery operation. BASE STATION ANTENNA Since the maximum allowable power output of the transmitter is limited by the FCC, the antenna is the most important factor aflecting 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 the built in SWR meter 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 aliows 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 sume military installations are subject to different rules; therefore, it is best to contact your nearest Federal Communica- tions Commission office for information regarding your specific area. MOBILE OPERATION/EMERGENCY POWER OPERATION Ir is possible to operate the COBRA 2000GTL from an external 13.8V DC power supply for emergency power conditions or from an automobile battery for mobile operation. The COBRA 2000GTL 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 inline 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 fecd-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 (SPI 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 2000GTL. The other speaker is available for use of optional speaker CA-2000 (available through your authorized COBRA DEALER.) Section IV Operation CONTROLS AND INDICATORS There are 25 controls, 2 meters, £ indicators and 3 jacks on the front panel of your COBRA 2000GTL. A. CONTROL FUNCTIONS 1. POWER SWITCH. Press in to tum on radio. Press in knob all the way and release to tum off radio. 2. 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. 3. VOLUME. Turn clockwise ta set the desired listening level. 4, 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. Tum 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. O! E. FREQUENCY COUNTER/LED DIGITAL CLOCK 1. Located on right hand side of the counter/clock is the time and MHz indicator. This indicator identified the mode display. to Located on the left hand side of the counter/clock is the AM and PM indicators. 3. The flashing colon indicates seconds. For the proper procedure to set your LED clock, there are the following features: TIME SET - 3 switches (used to set time) DYNALERT - 3 switches (used to set alarm and radio) COUNTER/CLOCK - 3 switches (used to select display) Follow the instructions as listed below: TIME SET TIME SET SWITCH - Depress this switch with hour switch or minute switch for setting correct time. HOUR SWITCH - Depress this switch at the same time with time set switch to get correct hour setting. MINUTE SWITCH | - Depress this switch at the same time with time set switch to get correct minutes setting. DYNALERT SET SWITCH Depressing this switch first then following the time set procedure (do not depress time set switch) will set your alarm. After alarm is set release switch so the clock will function normally. ALARM SWITCH | - Depressing this switch causes the alarm to sound at a preselected time. Relcase switch to shut alarm off. Alarm will also go off automatically after one (1) minute if you choose not to release switch. RADIO SWITCH - Depressing the radio switch will cause the radio to tum on at the preselected time. Depress switch to tum the radio off. t6 COUNTER/TIME COUNTER SWITCH - Depressing this switch causes the receiver frequen- cy to be displayed in the receive mode and the transmitter frequency to be displayed in lhe transmit mode. AUTO SWITCH - Depressing this switch causes the time to be displayed in the receive mode and the trans- mitter frequency to be displayed in the transmit mode. TIME SWITCH - Depressing this switch causes the time to be displayed continuously. RECEIVING SSB SIGNALS There are three types of signals presently used for communications in the Citizens Band: AM, USB, and LSB. When the MODE switch on your unit is placed in the AM position, only standard duuble-sideband, full carrier signals will be detected. An SSB signal may be recognized while in the AM mode by its characteristic “Donald Duck” sound and the inability of the AM detector to produce an intelligible output. The USB and LSB modes will detect upper sideband and lower sideband respectively, and standard AM signals. SSB reception differs from standard AM reception in that the SSB receiver does not require a carrier or opposite sideband to produce an intelligible signal. A single-sideband transmitted signal consists only of the upper or the lower sideband and no carrier is transmitted. The elimination of the carrier from the AM signal helps to eliminate the biggest cause of whistles and tones heard on channels which make even moderately strong AM signals unreadable. Also, SSB takes only half of an AM channel, therefore two SSB conversations will fit into each channel, expanding the 40 AM channels to 80 SSB channels. The reduction in channel space required also helps in the receiver because only half of the noise and interference can be received with 100% of the SSB signal. An SSB signal may be received only when the listening receiver is functioning in the same mode. In other words, an upper sideband signal (USB) may be made intelligible onty if the receiver is functioning in the USB position. 17 If a lower sideband (LSB) signal is heard when the receiver is in the USB mode, no amount of tuning will make the signal intelligible. The reason for this may be understood if you consider that when modulation is applied to the transmitter's microphone in the USB mode, the transmitter's output frequency is increased whereas in the LSB mode the transmitter's output frequency is decreased. The result in listening to the receiver is that when the MODE switch is in the proper position (either USB or LSB), a true reproduction pf single tone of modulation will result, and if the tone is increased in frequency (such as a low-pitched whistle to a high-pitched whistle) you will hear the increase in the output tone of the receiver. If the incorrect made is selected, an increase in tone of a whistle applied to the transmitter will cause a decrease in the resultant tone from the receiver. Thus when a voice is used in place of a whistle or tone, in the proper listening mode the voice will be received correctly whereas in the incorrect mode, the voice will be translated backwards and canno! be made intelligible by the voice lock control. When listening to an AM transmission, a correct sideband is heard in either mode since both upper and lower sideband are received. Once the desired SSB mode has been selected, frequency adjustment may be necessary in order to make the incoming signal intelligible. the VOICE LOCK control allows the operator to vary frequency above and below the exact-center frequency of the received signal. If the sound of the incoming signal is high or low pitched, adjust the operation of the VOICE LOCK. Consider it as performing the same function as a phonograph speed control. When the speed is set too high, voices will be high-pilched and if set too low, voices will be low-pitched. Also, there is only one correct specd that will make a particular record produce the same sound that was recorded. If the record is played on a turntable that rotates in the wrong direction (opposite sideband) no amount of speed control (VOICE LOCK) will produce an intelligible sound An AM signal received while listening in ane of.the SSB modes will produce a steady tone (carrier) in addition to the intelligence, unless the SSB receiver is tuned to exactly the same frequency by the VOICE LOCK control. For simphicity it is recommended that the AM modes be used to listen to AM signals. Section V Maintenance and Adjustment The COBRA 2000GTL transceiver is designed spocifically for use as a base station and may also be used in mobile installation. The use of all solid state circuitry and light weight result in high reliability. Should a failure occur, however, replace parts onty with identical parts, Do not substitute. Refer to the schematic diagram and parts list. NOTE IC the performance described in the OPERATION and MAINTENANCE AND ADJUSTMENT sections is not obtained, review the operating instructions to insure thal proper procedures were followed. If a problem still exists, refer to WARRANTY SERVICE INSTRUCTIONS elsewhere in (his manual. - FCC WARNING All transmitter adjustments other than those provided on front panel by the manufacturer must be made by or under the supervisian of the holder of an FCC-issued gencral radio-telephone operator's license. 19 Section VI Appendix Citizens Band radio operators have largely adopted the “IO-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 Code Meaning Code Meaning 101 Recciving poorly 10-29 Time is up for contact 102 — Receiving well 103 Stop transmitting 10:30 Does not conform to FCC 104 OK, message received rules 105 — Relay message 10:32 Iwill give you a radio check 106 Busy, stand by 10:33 EMERGENCY TRAFFIC 107 Outof service, leaving air 10-34 Trouhle at this station 10.8 Inservice, subject to call 10:35 Confidential information 109 Repeat message 1036 — Correct time is 10-37 | Wrecker needed at 10-10 — Transmission completed, 10:38 — Ambulance needed at standing by 10:39 Your message delivered 10-11 Talking too rapidiy 10-12 Visitors present 10-81 Please tura to channel 10:13 Adyise Weather/Road 1042 Traffic accident at conditions 1043 Traffic Tic up at 10-16 Make pickupat 10-48 Lhave a message for you 10-17 Urgent business 10-45 Al units within range please 10-18 Anything for us? report 10-19 Nothing for you, return to base 10:50 Break channel 10:20 My location is 10.60 What is next message number? 10-21 Call by telephone 1062 - Unable to copy, use phone 10-22 Report in person to 1063 Net directed to 10-23 Stand by 10464 — Netclar 1024 — Completed last assignment 10465 — Awaiting your next 10:25 Can you contact message/assignment 10-26 — Disregard last information 10-67 Alt units comply 10:27 Yam moving to channel 10-28 — Identify your station 10:70 Fireat 20 10 CODE (Continued) Code Meaning Code Meaning 10:71 — Proceed with transmission in 1091 Talk closer to mike sequence 10:93 Check my frequency on this 10-77 — Negative contact channel 10.94 Please give me a long count 10-81 Reserve hotel room tor 10:99 Mission completed, all units 10:82 — Reserve room for secure 10-84 My telephone number is 1085 My addressis 10200 Police needed at A FEW RULES THAT SHOULD BE OBEYED 1. You are not allowed to carry on à conversalion 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. 2. You are not allowed to blast others off the air by over-powering them with illegally amplified transmitter power, or illegally high antennas. 3. You can'tuse CB to promote illegal activities. 4. You are not allowed to use profanity. 5. You may not play music in your CB. 6. You may not use your CB to sell merchandise or professional service. 2
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