5/25/2023 0 Comments 11 meter dooble bazooka![]() The end wires are soldered to the shorted coax ends, run to insulators at the end of the antenna, and the soldered joints are sealed against the weather. At each of the two ends of the coax forming the center of the antenna, the coax is stripped back and the center conductor and shield are shorted together and soldered. It goes without saying: seal the feed-point to prevent water from getting in. ![]() To attach the feed-line, solder the two exposed feed-line conductors to the two pieces of the separated exposed shield of the dipole center. On the feed-line strip off about 3 inches of outer insulation, separate the shield from the center conductor, and strip about 1 inches of the insulation from the center conductor. Leave the center conductor with its insulation exposed. Do not cut the dielectric or the center conductor. Cut the shield in the center and separate it into two parts. At the center of the coax dipole, remove about 3 inches of the plastic covering, exposing the shield. The feed-point of the double bazooka is unique. To increase the bandwidth some builders use shorted ladder-line in place of the number 12 wire, which makes the end pieces to be electrically larger. The length of each of the end wires is found by dividing 67.5 by the frequency in MHz. The coax forms the center part of the double bazooka and a piece of number 12 wire on each end completes the antenna. To find the length of coax needed, divide 325 by the frequency in MHz. The center of the antenna is made from RG-58 coax. Other users say it is quieter than a regular dipole. ![]() 300 Ohm Twin Lead with the ends shorted is an option for even greater bandwidth. The larger the wire, the wider the bandwidth. The End Wire Size can range from 16 AWG to 12 AWG. The double bazooka will not transmit its second harmonic, and its users say it does not need a balun. The measurements below are for building a Double Bazooka Near Vertical Incident Skywave (NVIS) Antenna. have shown the double bazooka is only slightly more broad-banded than a regular dipole, probably due to the use of a large conductor (coax) for the center part of the antenna. The double bazooka is claimed by its users to be broad-banded, a quality especially interesting for those hams operating on 75/80 meters.
0 Comments
Leave a Reply. |