Keyhole effect

Explanation Keyhole Effect:

The keyhole effect in antenna rotors refers to the limitation where an antenna, particularly when tracking satellites or other moving objects, experiences reduced or insufficient tracking coverage in specific angular regions. This issue arises when the rotation of the antenna system, typically in azimuth and elevation, encounters difficulty in maintaining continuous alignment, especially as the object nears the zenith (the point directly overhead). The term “keyhole” refers to the small viewing window through which the object can be effectively tracked before the rotor reaches its mechanical or operational limits, creating an incomplete tracking range.

To mitigate the keyhole effect, X/Y rotors are often employed. These systems use two independent axes of motion—one for azimuth (horizontal rotation) and the other for elevation (vertical tilt). Unlike traditional azimuth-elevation (Az-El) systems, which struggle near the zenith due to mechanical limitations (where both azimuth and elevation rotors must move rapidly in unison), X/Y systems avoid this singularity. In an X/Y configuration, one axis handles elevation independently, reducing rapid movement near zenith and providing smoother, more accurate tracking of objects throughout their trajectory.

This dual-axis method enhances coverage and eliminates the blind spots typically associated with keyhole effects, especially for tracking low-Earth orbit (LEO) satellites that require precision tracking across a wide range of angular positions. By using X/Y rotors, operators can ensure continuous and reliable alignment across the full sky without significant gaps or loss of signal due to mechanical limitations.

RF HAMDESIGN offer 3 model X/Y rotors:
SPX-01-X/Y = light duty rotor / max 1.2Meter RF HAMDESIGN mesh dish
SPX-02-X/Y = medium duty rotor / max 1.5Meter RF HAMDESIGN mesh dish
SPX-05/XY = Heavy duty rotor / max 3.0Meter RF HAMDESIGN mesh dish

RF HAMDESIGN B.V.
www.rfhamdesign.com