A relatively simple rooftop antenna is your key to free high-definition television. HD terrestrial signals broadcast from local affiliates not only issue the highest video quality from any television HD source but also offer Dolby Digital surround sound in most cases. However, you must choose the right HD antenna to suit your distance from and relationship to your local broadcasters. The Consumer Electronics Association provides a color-coded standard to point you in the right direction. Other factors to consider include amplification and mounting options.
Your geographic location relative to local affiliates matters when choosing the right HD antenna. If you're located more than 75 miles from the individual towers, you're considered to be in a fringe area. High-powered directional antennas help mitigate this by aiming the elements on the antenna directly at the broadcast tower cluster. If you have a few antennas around you, you'll need an omnidirectional unit. Although less powerful, you have a far better chance of receiving channels broadcasting around your location. Ironically, if you're close to the bulk of broadcast towers but have two or three behind or above you when viewed on a map, you'll encounter more reception problems than someone located further from all of them on average. In this case, you may wish to employ a motorized rotor to re-orient the antenna directly at problem broadcasters, rather than using an omnidirectional unit.
In addition to the distance and relationship to local broadcasters, you have other challenges when aiming an antenna. Large buildings and trees cause broadcast signals to bounce around, causing the signal to reach the antenna array at different times. This causes cancellation, manifesting itself through intermittent sporadic reception. Additionally, if you live in a valley or mountainous area, this same reflection causes similar problems. Multipath is mitigated in most cases by mounting a large antenna as high as is feasible, capturing as much of the broadcast as possible.
If you happen to be in a fringe area or are forced to mount your antenna 100 feet or more from your television tuner, a preamplifier may help. Preamps mount on the antenna mast close to the array, boosting the signal. At the other end, the amplifier receives this feed, often overcoming the losses incurred from these issues. Additionally, amplifiers help when splitting an antenna feed multiple times. In fact, the largest splitters are actually distribution amplifiers, mitigating the 3 decibel loss encountered per split. Note that boosting a signal unnecessarily overloads tuners, impairing or preventing images and possibly damaging hardware.
Depending on whether you live in a house, condo or apartment, you will encounter different antenna installation demands. Although housing associations can't prevent you from mounting an antenna, if you're in a condo you typically have to mount it on an area under your exclusive use. This means the roof directly over your head or on your deck. In such cases using mounting brackets in addition to the mast and hardware included with the antenna should prove adequate. In apartments you'll probably be forced to mount the unit in a concrete-filled bucket, or use a "pizza box" square-style directional antenna with a lower profile. If you have the real estate and have a home with aluminum siding, you'll want to move the antenna as far away from the structure as possible. Mounting the antenna to a pole sunk into the ground away from the building and other obstructions gives the array a clear line of sight, providing the best reception.
CEA Color Coding
With all of the seemingly daunting considerations you have when choosing an antenna, there's a key resource you can fall back on. Antennaweb.org is the official CEA website that enables you to plot your location on a virtual map. The site displays your location relative to local broadcasters, in addition to taking other data such as how high above ground level you plan to install the array. The site then recommends one to a few antenna options, each of which corresponds to a certain color. Matching this color to the color on an antenna's retail packaging helps you instantly locate the right one, leaving you or your installer to handle the trickier part of actually aiming the array.
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