Advanced Qualification · A-007 Feedlines and matching · A-007-007-007

For long distance propagation, the vertical radiation angle of the energy from the antenna should be:

1. A more than 30 degrees but less than 45 degrees
2. B less than 30 degrees
3. C more than 45 degrees but less than 90 degrees
4. D 90 degrees

Correct answer: B — less than 30 degrees. From the official ISED question bank, verified word for word.

Why

For long distance communication, radio waves must bounce off the upper atmosphere to reach faraway stations, which works best when the signal leaves the antenna at a low angle, specifically less than 30 degrees. 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.

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