Antennas rely on height and surface area to ensure maximum transmission and reception strength. One way to ensure both parameters are met is to extend the antenna using a telescoping mast. Amateur radio operators and anyone living further from television signals have long recognized the need for antennas stretching into the sky for maximum range.
Telescoping antenna masts are large steel versions of the telescoping antennas found on portable radios and older car stereos. Aligned vertically, these antennas move straight up and down, rather than "folding" like tilt-over crank-style masts. These antennas are held in place by a series of guy wires, with normally four wires per segment. Although the actual antenna feed lines and guy wires normally require detachment if the antenna is routinely extended, this process takes minutes and is a small encumbrance in most cases. Segments are locked in place by rotating them to a locked position, or using cotter pins.
Evaluating the Space
The first step when installing or extending any telescoping antenna is to evaluate its surroundings. In most areas, antennas and wires may not extend across public streets or approach within 8 feet of power lines. Telescoping masts may be extended by hand crank, 12 volt actuator or air compressor. Inspect the area for possible obstructions, such as tree branches, power lines and structural overhangs. Check your wiring to ensure it's not tangled or twisted, to avoiding when the mast is fully extended. You'll need to take into account the total size of the antenna you plan to attach to the mast when evaluating its surroundings, not just the mast itself.
In most cases, antenna masts exceeding 10 feet require steel guy wires. Even if the foot of the unit it encased in a concrete base, using guy wires keeps you code-compliant and eliminates mast and wire damage from excessive swaying as wind catches the antenna. Grounding is also a consideration for any antenna, both to bleed off the inevitable static charge buildup on the mast and array, as well as shunting lightning strikes to ground. Antenna grounds should be 8 gauge, attached to a cold water pipe or 6 foot metal rod hammered into the ground. You can also ground the signal coaxial cables into a ground block, further protecting downstream electronics from damage.
Your choice of antenna mast is dependent on the range you require and your surroundings. Antenna signals suffer from multipath, a phenomenon that negatively affects signals by causing the array to receive the same signal from several directions. This problem occurs as these signals bounce off of buildings, trees and surrounding terrain. People who live in valleys, heavily wooded and urban environments want to extend the mast beyond these obstructions. Most telescoping masts range from 10 to 50 feet in total height, allowing you to select the right height to maximize signal and reduce annoying reflections.
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