Which of the following describes a log-periodic antenna?
Element length and spacing vary logarithmically along the boom✓Correct answer
Impedance varies periodically as a function of frequency
Gain varies logarithmically as a function of frequency
SWR varies periodically as a function of boom length
Explanation
The name comes from the geometry: each element's length and its spacing from the next differ from the previous one by a constant ratio, a geometric or logarithmic progression along the boom, which is why performance repeats with the logarithm of frequency.