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An antenna mast, often referred to simply as an antenna or an aerial, is used to pick up TV signals. It can also be used to pick up radio signals, both traditional broadcasting stations and amateur or “ham” radio. As the lifespan of an antenna mast is usually fairly long, it is worth taking the time to choose a good quality mast that suits your needs.
One of the most important variables to check in regards to an antenna mast is its gain. This is a figure, measured in decibels, which measures how sensitive a mast is and thus how well it can pick up broadcasts. The further away you are from the nearest broadcast tower, the bigger the gain you will need. In many cases the gain increases with the physical size of the antenna mast, but this isn’t a hard and fast rule.
Another variable to look for is the directivity, or power density. The better the directivity, the better the antenna mast will perform where there are buildings or hills between the mast and the broadcasting tower. One measure of directivity is the receiving angle: narrower is better. Another measure is the front-to-back ratio. The higher this is, the more the mast is able to pick up signals from the right direction without interference from other directions.
You may see retailers and installers advertising a digital TV mast. It’s important to remember that there is no such thing as a specific “digital TV mast” that has a fundamental difference from an ordinary antenna mast. The term is simply a way of explaining that the antenna mast in question is of high enough quality to ensure that digital channels can be received. This is important because digital reception is an all-or-nothing issue, unlike with analog reception where a poor signal can still be viewed, just with a fuzzy picture.
Even a good quality antenna mast will give poor results if you use low-quality cabling. You should install coaxial cable rather than the old-fashioned twinlead cable, which is distinguished by having two separate wires in it. Coaxial cable has built-in shielding, which makes it considerably less prone to interference and more resistant to damage from rain. You will usually find that the difference in quality between cheap and mid-price cable is significant, while the difference between mid-price and expensive cable is less noticeable.