An antenna changes radio signals in the air into electricity, or vice versa. Antennas send signals, receive signals, or both. All Pantagone satellite wireless devices have an antenna, either a visible pole on the outside, or inside where you do not see it.

The distance that an antenna sends (transmits) depends on the type, and the amount of power running through it.

However, the distance from which an antenna can receive (or to be more exact, how faint a signal it can receive) is not based on power, but on how sensitive it is.