Dummy load

A dummy load is a kind of "fake antenna" used for testing things such as the output power and transmit frequencies of a radio transmitter or transceiver without radiating a signal, this is important as it allows operators to safely test, for example, wether a specific radio will allow transmission on a heavily guarded band such as airband.

They usually consist of a 50 ohm resistor, screened (wrapped with wire like a faraday cage) inside of a metal canister or other container, dummy loads can get hot in operation as the resistor converts almost if not all the RF energy into heat energy in the IR band, thus a dummy load can be technically seen as a kind of upconverter.

Dummy loads are required as transmitting without an antenna will still radiate a signal and can cause serious damage to the radio.