Mechanical Polarizer

A mechanical polarizer discriminates among linear or circular polarization formats by virtue of a physical motion. The original method to select between linearly polarized C-band signals was simply rotating the entire feed and low noise amplifier assembly. While this method is still occasionally used, more efficient techniques are employed today. Polarity is usually selected by rotating a small, lightweight metal probe that is housed in the circular waveguide in the throat of a feed between horizontal and vertical polarity orientations. A servo or dc motor accurately controls its position. Most satellite receivers available today have built-in controls for interfacing with one or both types of mechanical polarizers. Such devices are commonly employed in North America but are becoming rare in Europe where V/H switched or ferrite polarizers are more common. Mechanical devices suffer from the limitations of having moving parts that wear out and potentially seize in wet climates where freezing occurs.

A polarizer that is controlled by electrical pulses from the receiver.