A rooftop fixture is a device that is installed on the roof of a building. The most common rooftop fixtures are a DISH, VANE, and epi. A DISH is a curved reflector used to collect or focus waves, such as those used in satellite communications. A VANE is a flat metal plate attached to a spindle that is used to measure wind direction. An epi is a type of antenna that is used to transmit or receive radio signals.