Many people are drawn to purchase an “amplified antenna.” However, the reality is that most times an amplifier will only help if there is a very long cable from the antenna to the TV or if multiple TV sets are connected. If using an indoor antenna — an amplifier is probably not needed and can actually make reception worse. With an outdoor antenna or attic antenna - an amplifier may help if the coax cable is over 30 feet in length or if you’re connecting multiple TV sets.
The three main types of amplifiers are preamplifiers, inline amplifiers, and distribution amplifiers (also known as powered splitters).
A preamplifier comes in two parts. One part is the amplifier itself that gets connected to the antenna with a short 3- to 5-foot cable and the other part is the power inserter that gets connected somewhere inside. This makes it so that you do not have to run electricity up to where the antenna is located.
About Inline Amplifiers
An inline amplifier requires a nearby outlet for power. In most cases, one will only improve reception if there’s a long cable after the antenna or if splitters are needed to connect multiple TV sets.
About Distribution Amplifiers
A distribution amplifier, also known as a powered splitter, is an inline amplifier and splitter in one. This prevents signal loss that you would usually get with a regular unpowered splitter. Some models can be powered remotely through one of the coaxial cables that already go to one of your TV sets. This is convenient if there’s no power source near where the coax cables in your home are located — such as outside in a junction box.