Advanced Qualification · A-007 Feedlines and matching · A-007-008-003
What factors determine the radiation resistance of an antenna?
- AIt is a physical constant and is the same for all antennas
- BAntenna location with respect to nearby objects and the conductors length/diameter ratio
- CTransmission line length and antenna
- DSunspot activity and time of day
Correct answer: B — Antenna location with respect to nearby objects and the conductors length/diameter ratio. From the official ISED question bank, verified word for word.
Why
Radiation resistance changes because an antenna's environment and shape alter how it radiates energy; nearby objects like buildings or trees reflect signals back, while the ratio of a wire's length to its thickness shifts the electrical balance. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and matching is section A-007 of the Advanced exam: Feedlines and matching at the advanced level: transmission line theory, impedance transformation, stubs and matching networks.
Drill A-007 — free, no account