Question T7C03
From subelement T7 - T7C
What does a dummy load consist of?
Why is this correct?
A dummy load consists of a non-inductive resistor mounted on a heat sink because it must convert RF power to heat without radiating signals. The resistor provides a 50-ohm load matching typical transmitter output impedance, while being non-inductive prevents unwanted reactance that could distort measurements. The heat sink dissipates the converted power safely. Options A and C describe unrelated equipment, while D incorrectly suggests reactance when pure resistance is needed.
Memory tip
Look for 'non-inductive resistor + heat sink' combinations in test equipment questions. This pairing appears whenever you need to safely convert electrical power to heat without affecting circuit behavior - the resistor does the work, the heat sink handles the consequences.
Learn more
In practical station operation, dummy loads are essential for transmitter testing and antenna tuner adjustment without interfering with other stations. Commercial dummy loads often include cooling fans for high-power operation and may incorporate directional couplers for power measurement. The non-inductive design ensures accurate impedance matching across amateur frequency privileges, making SWR measurements meaningful during equipment setup and maintenance procedures.
Think about it
Why do you think a dummy load needs to be specifically non-inductive rather than just any 50-ohm resistor?