After removing the outer jacket, start bunching the shield down the coax from the end. We have talked to stations over 40 miles away using this antenna up about 30 feet high, running a mobile rig for a base.įor a quickie CB antenna, a vertical dipole (1/2) wave can be made right from the coax itself You take your coax and very carefully, without nicking the braided shield, strip 102 inches of the outer insulation jacket off one end. It should be lower than 2, and ideally lower than 1.5 or 1.3.Ī ¼ wave ground plane CB antenna made from wire can be suspended from a tree. If you are short on room for such a radial system, you can use 104″ (radials) and 102″ (driven elements) pieces of aluminum tubing, or suspend the wires on PVC pipe, bamboo, or 1″ x 2″‘ wooden sticks. They can be attached to anywhere convenient trees, a fence, house, etc. Rope or nylon cord is then tied to the insulators and used to hold the radials out. The radials slope down at about a 45 degree angle in different directions, and are tied to the insulators. Remember that the inner conductor and outer braid of the coax must not touch each other, nor can the radials come in contact with the driven element. The wires must be exactly 264 cm (104′) long (¼ wavelength). The braided wire which forms the outside conductor of the coax is soldered to all four radial wires. This is called the ground plane of the antenna. On this CB Antenna, the four radial wires are used as the ground. A mobile CB antenna uses the car body as the ground. Coat this connection with sealer or cover it with tape to protect it from corrosion.Īll vertical antennas need to be grounded in some way. The inside conductor of the coax is connected to the aluminum pipe by means of a screw into the bottom of the pipe. Rope, enough to guy the ground radial, depending on the height of the antenna The driven element receives the transmit energy from the rig.ġ04″ (264 cm.) piece of aluminum pipe or conduitĤ08″ (10.22 m.) of 16 gauge wire This CB antenna consists of a driven element and four radial wires that act as a ground. You will need an SWR meter to check out the Antenna after building it. You can make an one out of readily-available parts that will work as well or better than some commercially-made CB Antennas. However, you might want to try your hand at making an antenna. Commercially-made CB antennas are usually easy to put up and maintain. Because of this competitive market, companies are always trying to put out a better product for a cheaper price. There are lots of CB antennas out on the market today, all kinds of different shapes and sizes. A car with one installed on the roof usually will still fit into a residential garage. It’s about 20″ tall with a sealed phasing coil in the center, and offers increased gain over a little 611 spike.
You can spot these antennas easily by a single yard-long whip and a gray or stainless steel loading coil at the base.įor UHF operation at 400-500 MHz, a popular mobile CB Antenna is the collinear halfwave-over-halfwave whip. Why send half your signal into the sky when it can do more good down close to the horizon? You can spot a VHF or UHF collinear high-gain antenna by the loading coils in the center of the whip.įor VHF operation, a 5/8-wavelength CB antenna offers a low take-off angle and may achieve increased gain of approximately 3dB over a conventional 18″ spike on the roof.
On VHF and UHF mobile radio bands, the whips are so short that they may be phased vertically in a collinear array to achieve increased gain on transmit and receive. Because it has no loading coils, it will offer unity gain without loss whereas you might expect a loss of 1 to 2dB from a loaded CB antenna. Mount the whip as high on your vehicle as possible. You may purchase these stainless steel or fiberglass whips at any CB Radio store. The easiest way to get the strongest signal out on Citizens Band is to use an unloaded whip CB antenna. The best performance will be to the front and rear of the vehicle, with slight nulls to each side of the vehicle. Mount the antennas on either side of your vehicle. Make sure that each side of your co-phased coaxial cable feed lines are identical in length, down to a fraction of an inch, but be sure to avoid a precise half-wavelength on 11 meters for your phasing harness. You can purchase “co-phase” coaxial cable assemblies, or make your own using a coaxial cable T-connector and two equal lengths of RG8AU coax. You might also consider a phased two CB antenna system to give an additional 3dB of gain.
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