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21-869 10M Ham/CB Base Antenna Your RadioShack 10M Ham/CB Base Antenna provides excellent reception of amateur radio, CB, and commercial radio signals. The antenna can handle up to 2000 watts of transmit power. Your antenna’s features include: Electrical Half-Wave Design — provides high gain. Note: To improve your antenna’s gain, you can connect an optional ground plane kit (available through your local RadioShack store) to your antenna. Three Easy-to-Assemble Sections — help you quickly and easily assemble the antenna. Dual Tuning Rings — help you quickly set the antenna for optimum performance over a wide range of frequencies. Ultraviolet Inhibitor — the antenna’s UV-protected housing is made of impact- resistant fiberglass, making the exterior resistant to weathering and color change. Strong Internal Construction — prevents the antenna’s internal wires from rattling, for maximum strength. IMPORTANT SAFETY PRECAUTIONS Many do-it-yourself and professional antenna installers are injured or killed each year by electric shock. Many power wires are within 20 to 25 feet of the ground and could easily be touched by an assembled antenna or cable. Touching the overhead wires with any part of the antenna is the same as touching the wires with your bare hand. Contacting an electrical wire almost always results in a very serious shock. To avoid electric shock, please read and follow these important safety precautions: • Be sure to select an antenna site well away from all overhead wires. • Do not try to guess which overhead wires carry high voltage. Check with the power company. • If you notice anything making contact with the overhead wires, call the power company to have it removed. • Do not run the antenna’s cable over power wires. • Get help from a qualified professional when removing the old antenna, especially if you have any doubt about clearing overhead wires. • Never install an antenna by yourself. Be sure to have at least two people available for help. • Never install an antenna on a windy day. © 1999 Tandy Corporation. All Rights Reserved. RadioShack is a registered trademark used by Tandy Corporation. 21-869.fm Page 2 Wednesday, October 13, 1999 11:50 AM BEFORE YOU BEGIN When deciding on an antenna’s location, consider these points: • The antenna should be as high as possible on the building. • The antenna and its cable should be as far as possible from sources of electrical noise such as appliances or other radios. • The antenna should be vertical for the best performance. Always use 50-ohm coaxial cable, such as RG-58 or RG-8, to connect the antenna to your radio. For lengths over 50 feet, use RG-8 low-loss dielectric coaxial cable. Your local RadioShack store carries a wide variety of coaxial antenna cable and connectors. Warning: When you install an outdoor antenna, use extreme caution. If the antenna starts to fall, let it go! It could contact overhead power lines. If the antenna touches the power line, contact with the antenna, mast, cable, or guy wires can cause electrocution and death. Call the power company to remove the antenna. Do not attempt to remove it yourself! Cautions: • Do not run the cable over sharp edges or moving parts that might damage it. • Do not run the cable next to power cables or other antenna cables. Coaxial Cable Installation Precautions • Do not install coaxial cable where it will have a pulling tension of greater than 50 pounds. Leave no tension on the cable after installing it. • Use only round-headed staples. Any clamps or securing devices used with coaxial cable should grip the cable evenly about the circumference without crushing the cable. Flat staples can damage coaxial cable. • Do not expose coaxial cable to a temperature greater than 176°F (80°C). Keep the cable away from heating vents and water heaters. • Do not install coaxial cable where it will be crushed, stuffed, wedged, or pinched. • The cable’s jacket withstands most outdoor environments. However, you must seal connections and splices to prevent moisture from entering them. 2 21-869.fm Page 3 Wednesday, October 13, 1999 11:50 AM PREPARATION Pre-Tuning the Antenna Your antenna is preset to use 27.205 MHz (the middle of the CB band) for the lowest SWR. If you are using your antenna with a CB radio, you do not have to pre-tune it. See “Assembling and Mounting the Antenna” on Page 3. Before you assemble and mount the antenna, you must determine the frequency range you will be using with it. If you are not using CB frequencies, you must either trim the antenna’s top element to match the range you are using or use an antenna tuner (not supplied) to electrically trim the antenna. Caution: To avoid damaging the antenna, do not trim the antenna’s middle or bottom elements. If you are using your antenna with an amateur radio and want to trim the antenna’s top element to pre-tune it, follow these steps. 1. Use the following chart to determine how much you need to trim off of the top element (if any). For example, to p...