A dummy load also known as a radio frequency termination, is a device used in place of an antenna to aid in testing a radio transmitter. It is a substitute for the antenna when transmitting into an antenna might create interference or is otherwise undesirable. If a transmitter is tested without a load, such as an antenna or a dummy load, the transmitter could be damaged. A dummy load absorbs the incoming signal from the transmitter and converts that energy into heat. Without a dummy load, the energy is reflected back to the transmitter, possibly damaging it.

Normally, a dummy load is a completely ohmic load used mainly in radio frequency electronics. The device takes the place of the antenna, where it dissipates all radio frequency power as heat. Do not touch the dummy load during or immediately after equipment operation for this reason. Some dummy loads like those used in high power microwave transmitters can glow cherry red to nearly white hot! The resistance of the dummy load matches the intended resistance of an antenna, typically 50 ohms.

The ideal dummy load provides a standing wave ratio (SWR) of 1:1 at the given impedance. There are also dummy loads for power supplies, also known as load banks.

See also

• antenna (radio)
• Electrical termination
• Electrical impedance
• Standing wave ratio

External links

• Bird Electronics - Power terminations and loads

Radio electronics

Ersatzlast