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Things You'll Need
Instructions
Calculate the center point of the 11-meter band by finding the average of the minimum and maximum wavelengths assigned to 11 meters. The 11-meter band ranges from 26.96 MHz to 27.41 MHz, so add 26.96 and 27.41, then divide by 2. The result is the frequency center point. The center point is 27.185MHz -- 26.96 plus 27.41 equals 54.37, and 54.37 divided by 2 = 27.185.
Divide 468 by the center point value, 27.185, to ascertain the correct length for an 11-meter dipole antenna. For example, 468 divided by 27.185 equals 17.215, so an 11-meter dipole antenna has a total length of 17.215 feet.
Round the value obtained in Step 2 to 17.5 feet, or 17 feet 6 inches. Measure and cut a length of single strand copper wire to that length.
Fold the wire in half, and cut it. The result is two wires, each of them measuring one-half of the total length. Half of 17 feet 6 inches is 8 feet 9 inches.
Strip the final 1/4-inch of insulation from one end of each wire, if it is insulated. Ensure that the final 1/4-inch of wire is clean and free from corrosion. Rub it with fine emery cloth until the metal gleams.
Loosen the screws on two terminals within a plastic terminal block. Insert the prepared ends of the two wires into the holes. Align the wires and block to form a single straight line, and then tighten the screws to hold the wires in place.
Attach the wires and terminal block to a suitable frame, such as an attic joist, a long plastic pipe or a wooden plank. Secure them with self adhesive tape so they can be moved and adjusted during the fine tuning process. The ends of the dipole wires may be bent out of line to loop back on themselves if necessary.
Connect the antenna cable from your tuner to the terminal block, using the same two terminals to which the dipole arms are connected. Use 75-ohm or 50-ohm cable depending upon your radio tuner setup.