Which antenna device eliminates precipitation effects on the radar indicator and is used to filter signal?

• A. Antenna switch
• B. Circulator
• C. Polarizer
• D. Air compressor

Answer: (C)

Controlling polarization is a key way to filter the radar signal and reduce clutter from precipitation. A polarizer changes the polarization state of the transmitted and received wave, often converting linear polarization to circular. Rain and other precipitation scatter energy in ways that can create unwanted, depolarized reflections, which show up as clutter on the radar display. By filtering to a specific polarization component, the polarizer suppresses much of that stray energy, making the true signal cleaner and easier to interpret.

The other devices don’t perform this filtering role. An antenna switch simply selects which antenna or feed to use. A circulator helps separate the transmitter and receiver paths to protect them, but it isn’t used to filter precipitation clutter. An air compressor has no relevance to RF signal processing.