Before cable and satellite antennas, there were mast-style antennas. Across the countryside you can still see these antennas, but with the introduction and switch to digital TV transmission from analog, there has been a switch to high definition antennas. These antennas can be much smaller and some come equipped with their own built-in rotors. The NEC sets standards for installing these antennas. In article 810, it discusses materials used to construct antennas, lead-in wires, wire splicing, and how to properly support wires.
Antennas are used to transmit and receive electromagnetic waves. When a wave is received by a TV antenna, a current is produced in the antenna, it travels through the lead-in wires and is received in the TV’s receiver in which the signal is transposed into reception. Likewise, if you are transmitting a signal from an audio antenna, the antenna sends the signal out to other antennas.
When installed on antenna towers, the towers must be supported with support rods and/or guide wires. Antennas must be protected from lighting strikes by grounding the antennas by attaching a ground clamp to the antenna, running a ground cable to a ground rod, and driving the 8’ ground rod into the ground. This will protect the antenna, its components, and devices attached to antenna wiring connections from lightning damage.
Safety warning! When erecting or taking down an antenna, keep clear of overhead power lines and other obstacles. Antennas should always be kept a safe distance from any live wires. Antenna towers should always be assembled with the appropriate bolts and nuts to connect the antenna sections securely.
If you plan to climb your tower, you want no movement as you reach the top. And while we are on the subject, if you do plan to climb, please use a safety harness that is rated for your weight. These fall-arrestor harnesses are commonly used by construction workers and provide a life-saving safety net if you slip and fall. Instead of hitting the ground, the safety harness has a strap with quick clips that attaches to the harness and a secure attachment like a rung of the tower. If you fall, the strap, much like a bungee strap, stretches out and springs back to soften the fall. Better yet, it breaks the fall and saves you from hitting the ground!
TV antennas are at the mercy of reception and signal strength. The reception can be interfered with by tree limbs, buildings, and extreme weather conditions including rain, snow and fog. The quality of the picture depends on the quality and size of the antenna that you install. Along with these, you can boost the signal with the use of preamps that are mounted up near the antenna and an amplifier that is placed near your TV set.
Now comes the question that I often receive, “Will my old antenna, that I used for the analog signal, work to receive the new digital signal?” The answer is yes it will. However, you need to understand that digital signals don’t travel as far as analog signals. I know this from first-hand experience. Although I can receive HDTV channels that are crystal clear, the downfall is that the picture gets choppy at times and often loses connection all together on certain channels. Once again, an amplifier can help somewhat, but the real answer is to buy an antenna that is rated for the mileage distance from the channels that you are trying to receive. Some of these antennas are able to receive a signal up to 90 miles away.