Question
What type of radiation pattern is created by a single-turn, terminated loop such as a pennant antenna?
Answer Options
- A) Cardioid
- B) Bidirectional
- C) Omnidirectional
- D) Hyperbolic
Correct Answer: A
Explanation
A single-turn, terminated loop, such as a K9AY loop or a pennant antenna, is a small receiving antenna that is terminated at one end with a resistance (similar to a Beverage antenna). This termination creates a directional pattern that is highly desirable for nulling out noise and local interference.
This termination converts the loop into a traveling wave structure. The resulting radiation pattern is a Cardioid (heart-shaped) pattern, featuring a deep null pointing toward the direction of the terminating resistor and maximum sensitivity in the opposite direction. This makes it a popular receiving antenna on the LF and HF bands.
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