Question T4A02
From subelement T4 - T4A
Which of the following should be considered when selecting an accessory SWR meter?
Why is this correct?
Frequency range and power level are the critical specifications when selecting an SWR meter. Each meter is designed for specific frequency ranges and maximum power levels. Using a meter outside its specified frequency range produces erroneous readings, while exceeding the power rating can damage the meter. Distance from antenna and modulation type don't affect meter selection.
Memory tip
Look for the specifications label or manual when choosing test equipment. Most amateur radio measurement devices have clearly marked frequency ranges (like 'HF/VHF' or specific MHz ranges) and power limits (like '200W max'). This pattern applies to all RF test equipment selection.
Learn more
SWR meters function by sampling forward and reflected RF power through directional couplers or bridge circuits. These circuits are frequency-sensitive and have power limitations based on their internal components. In practical operation, you'll install the meter in your feed line between transmitter and antenna, where it must handle your full transmit power while providing accurate measurements across your operating frequencies. Modern transceivers often include built-in SWR measurement capabilities.
Think about it
Why do you think frequency range matters more for SWR meter accuracy than the physical distance between the meter and your antenna?