Amateur ExtraE9C10
Which of the following describes a Zepp antenna?
B
Answer
Antennas and transmission lines
Type
A
A horizontal array capable of quickly changing the direction of maximum radiation by changing phasing lines
B
An end-fed half-wavelength dipole
C
An omni-directional antenna commonly used for satellite communications
D
A vertical array capable of quickly changing the direction of maximum radiation by changing phasing lines
Answer Notes
A Zepp antenna is historically named for its original use trailing behind Zeppelin airships in the early days of radio. It is essentially an end-fed half-wavelength dipole antenna.
To feed a half-wave wire at its end where the impedance is extremely high, it traditionally uses a quarter-wave open-wire matching section. One side of the feedline connects directly to the radiator, while the other side simply ends in an insulator, balancing the system.
It is entirely a simple wire-based HF design, making the distractors about horizontal or vertical phased arrays and omnidirectional satellite antennas completely incorrect.
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