What is a dummy load?

A dummy load is a piece of test equipment that can be used in place of an antenna when testing out a transmitter. They consist of either a single or multiple resistors that absorb the RF power out of the transmitter. Cooling is provided either through fins on the dummy load acting as a heat sink, or through the use of a dielectric oil bath. The amount of RF that can be put into a dummy load is dependent on the wattage of the resistors being used. Likewise the amount of resistance value needs to be properly calculated in order to achieve 50Ω.