21LTDST.MANUAL.REV.QX 9/25/98 10:59 AM Page 13

Operation (Cont.)

B. Press-To-Talk Microphone

Both the receiver and transmitter are controlled by the Press-to-Talk switch on the microphone. Press the switch and the transmitter is activated; release the switch to receive. When transmitting, hold the microphone two inches from the mouth and speak clearly in a normal voice. The microphone provided with your radio is a detachable low-impedance dynamic type.

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C. Rear Panel

1. PUBLIC ADDRESS: An external 8-ohm 4.0 watt PA speaker may be con- nected to the PA Speaker Jack when this unit 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 micro- phone and speaker must be employed when operating the PA at high output levels.

2. EXTERNAL SPEAKER: The External Speaker Jack is used for remote receiver monitoring. The external speaker should have 8-ohm impedance and be rated to handle at least 4.0 watts. When the external speaker is plugged in, the internal speaker is automatically disconnected.

3. ANTENNA CONNECTOR: This SO-239 connector permits connection of the transmission line cable PL-259 connector to the transceiver.

4. POWER. This jack permits connection of the DC power to the transceiver. A power cord with polarized plug is supplied with the radio. The polar- ized plug ensures that the power will always be connected properly.

Operation (Cont.)

Operating Procedure to Receive

1. Be sure that the power cord, antenna and microphone are connected to the proper connectors before proceeding further. The PA/CB should be in the CB position.

2. Turn the radio ON by rotating the VOLUME CONTROL clockwise.

3. Set the RF GAIN CONTROLfully clockwise.

4. Set DELTA-TUNE CONTROL to center(click-stop) position.

5. Rotate SQUELCH CONTROL counterclockwise until incoming signal is heard. 6. Set the CHANNEL SELECTOR Switch to the desired channel.

7. Set VOLUME CONTROL to a comfortable listening level.

8. Engage the SoundTracker system by depressing the button labeled ST.

Listen to the background noise from the speaker. Turn the SQUELCH CON- TROL slowly clockwise until the noise JUST disappears (no signal should be present). Leave the control at this setting. The squelch is now properly adjust- ed. The receiver will remain quiet until a signal is actually received. Do not advance the control too far, or some of the weaker signals will not be heard. The revolutionary SoundTracker system allows you to reduce unwanted background noise (static) and increase the signal for better reception.

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Cobra Electronics 21 LTD operating instructions Press-To-Talk Microphone, Rear Panel, Operating Procedure to Receive
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21 LTD specifications

Cobra Electronics 21 LTD is a versatile Citizen Band (CB) radio designed for seamless communication in a wide array of environments, making it a staple for truck drivers, outdoor enthusiasts, and hobbyists alike. Known for its reliability and quality, the 21 LTD combines advanced technology with user-friendly features, ensuring clear and efficient communication.

One of the standout features of the Cobra 21 LTD is its compact design, which makes it easy to install in trucks, cars, and even boats. Despite its small size, it accommodates a comprehensive 40-channel system, allowing users to select from various frequencies, ensuring they can find optimal communication channels regardless of their location.

Equipped with a powerful, built-in noise-canceling microphone, the 21 LTD is adept at minimizing background noise, producing crystal-clear audio even in noisy environments. This feature is particularly beneficial for truck drivers traversing busy highways, ensuring that both transmitted and received messages maintain high quality. Additionally, the radio boasts Automatic Noise Limiting (ANL) technology, which further enhances sound quality by reducing static and interference.

The Cobra Electronics 21 LTD also includes a front-firing speaker for improved audio clarity and a large, easy-to-read analog gauge for channel selection and signal strength monitoring. This design enhances operational convenience, allowing users to stay focused on the road while effortlessly adjusting settings.

Another notable characteristic is the inclusion of a PA (Public Address) feature, which enables users to connect an external speaker. This is especially useful for communicating with larger groups or providing instructions at job sites. Furthermore, the radio features a built-in SWR (Standing Wave Ratio) meter, an essential tool for ensuring proper antenna alignment and optimizing signal performance.

In terms of durability, the Cobra 21 LTD is designed to endure the rigors of outdoor use, featuring a robust construction that can withstand vibrations and varying weather conditions. With an easy installation process and compatibility with various microphones and accessories, this radio is perfect for both seasoned CB users and newcomers.

In conclusion, the Cobra Electronics 21 LTD is a powerful and reliable CB radio that boasts numerous user-friendly features, advanced technologies, and rugged characteristics. Whether for long hauls, outdoor adventures, or casual communication, the 21 LTD stands out as a top choice for those who value quality and convenience.
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