In layman’s terms: Antenna gain refers to the ability of antenna to focus scattered RF (radio frequency) waves into a narrower, useful plane, thus increasing signal strength. Antenna gain is expressed in decibels (dB), and a higher gain antenna will make use of weaker signals more efficiently than a lower gain antenna, all else being same conditions. In more specific terms, a person who living at the outer reaches of his local networks’ broadcast range will get better reception using a high-gain antenna than a low-gain model.
The Antennas design dictates how efficient and is in gathering the wavelengths it is designed to receive. High gain antennas makes use of extra elements to pull in wayward RF (radio frequency) waves, focusing the radiation into a stream along a “flattened” trajectory. In a rough analogy, consider a magnifying glass that focuses scattered sunlight into a beam, greatly strengthening the beam’s power. Elements play the same role and the ability to focus scattered RF (radio frequency) waves results in a gain in signal strength, or antenna gain.
The one who have trouble receiving over-the-air (OTA) broadcasts can possibly benefit from a high gain antenna. Regional topography can scattering RF waves or reduce broadcast range by blocking. Online tools such as those found at TV Fool help people conduct research that can be useful when it comes to choosing the right antenna. An interactive map displays regional broadcasts, signal strength , and distance. Adjusting antenna height can cause results to recalculate, and then see if raising the antenna would result in better reception. Tools also indicate whether or not the antenna gain will make a difference.
You might wonder, If the antenna gain provides better reception, why not just use a high gain antenna no matter what? The answer is twofold. A high gain antenna will be more expensive than a low gain model, so you can save some money if you don’t need it. Also the higher the gain, the more important is to point the antenna exactly towards the station you want to receive. If it is only a few degrees off, it cannot pick up the signal at all. Therefore, it’s better to buy an antenna that can accommodate a broader angle of reception so that pointing it to an exact spot isn't so crucial if antenna gain is not required.
Aside from gain, height and range, some antennas also are made to withstand extreme weather. It is a good investment for those in harsh climates. Mounting masts are not always included but can be purchased separately along with cabling.
The claim is often made that free-to-air, local HDTV broadcasts come in clearer over roof antennas than through cable or satellite boxes, but your experience could vary. A roof antenna does provide a backup solution for receiving local channels if cable or satellite services are interrupted.
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