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How to Install an 11-Meter Antenna for an Amateur Tower

Citizens Band or CB radio reached its heyday in the 1970s, leaving an abundance of surplus 11-meter CB equipment available for recycling. Of particular interest to amateur radio operators are 27-megahertz yagi beam CB antennas, which can easily be converted for the 28-megahertz (10-meter) ham radio band. Convert an old CB antenna for amateur radio use and install it on your existing amateur radio antenna tower to save yourself hundreds of dollars while recycling some useless aluminum into a useful and highly directional 10-meter antenna fully capable of worldwide wireless radio communications.

Things You'll Need

11-meter yagi beam CB antenna
Mounting hardware
Amateur radio antenna tower
Television antenna rotator
Rotator control box and wire
Coaxial cable
Antenna analyzer
Penetrating oil spray
Medium- or fine-grit sandpaper
Screwdrivers
Pliers
Hacksaw

Instructions

- 1
  Obtain an 11-meter (27 megahertz) CB antenna and any mounting hardware, such as U-bolts and antenna mast sections, that come with it. Give all surfaces a thorough cleaning and a light sanding to remove any oxidation. Spray hardware, screws and bolts with penetrating oil to free them for adjustments.
- 2
  Install the antenna on a mast section about 10 feet above the ground for testing and adjusting. Attach the coaxial cable transmission line to the antenna and to your antenna analyzer. Set the band switch of your analyzer to the setting for 25 to 30 megahertz. Dial the tuning knob to determine the existing resonant frequency of your antenna. The Standing Wave Ratio (SWR) should be about 1:1 near 27 megahertz.
- 3
  Loosen the screws and slide the sliding adjustable clamp toward the boom in increments and check for the resonant frequency on your antenna analyzer if your antenna has a gamma match section. If the resonant frequency goes up, continue adjusting the clamp until you reach your desired center frequency in the 10-meter (28 megahertz) amateur radio band.
- 4
  Shorten the antenna's elements in 1-inch increments with a hacksaw until resonance is achieved if your antenna does not have a gamma match section or if you cannot attain the desired resonant frequency. The center-driven element for a 10-meter yagi should be about 15 1/2 to 16 1/2 feet long depending on other variables such as desired center frequency, tube diameter and element spacing.
- 5
  Shorten the parasitic elements. Shorten the director element (shortest element at front end of antenna) by cutting it symmetrically so that it is about 95 percent of the length of the center-driven element. Shorten the reflector element (longest element at back end of antenna) so that it is about 110 percent of the length of the driven element. Readjust the gamma match for resonance on your desired center operating frequency.
- 6
  Install your newly converted 10-meter antenna on its mast and antenna tower using the appropriate hardware and a rotator motor. A 10-meter antenna is small enough and light enough that an inexpensive television rotator and control box will work. Make sure all hardware is secure and make a final test for resonance over the 10-meter band. Attach the coaxial cable to your radio transmitter or transceiver.

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