Advanced Qualification · A-007 Feedlines and matching · A-007-005-011
You want to convert a surplus parabolic dish for amateur radio use, the gain of this antenna depends on:
- A the focal length of the antenna
- B the material composition of the dish
- C the diameter of the antenna in wavelengths
- D the polarization of the feed device illuminating it
Correct answer: C — the diameter of the antenna in wavelengths. From the official ISED question bank, verified word for word.
Why
A parabolic dish acts like a mirror that gathers radio waves, and its ability to concentrate those waves into a tight beam depends on how wide the dish is compared to the wavelength you are using. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.