What does a typical RF dummy load consist of?

A typical RF dummy load is designed to mimic a perfect, well-tuned antenna system. Since modern amateur radio equipment is standardized to a 50-ohm impedance, the dummy load is built around a 50-ohm resistor. It is critical that this resistor is "non-inductive." If a standard wire-wound (inductive) resistor were used, its reactance would change wildly at different radio frequencies, ruining the 50-ohm match and causing severe reflected power. Finally, because a dummy load prevents RF energy from radiating into the air, all that transmitter power must be dissipated safely. The non-inductive resistor converts the RF energy directly into heat, which is why it must be securely mounted on a heat sink to prevent it from burning up.