Basic Qualification · B-006 Feedlines and antenna systems · B-006-001-004
Why can coaxial cables of different diameters have the same characteristic impedance?
- A Their characteristic impedance depends on operating frequency
- B Their characteristic impedance depends on the ratio of conductor diameters
- C Characteristic impedance is independent of line diameter
- D Characteristic impedance is set by the choice of conducting material
Correct answer: B — Their characteristic impedance depends on the ratio of conductor diameters. From the official ISED question bank, verified word for word.
Why
Coaxial cable acts like a transmission line where the resistance to signal flow, called characteristic impedance, is determined by the physical relationship between the inner wire and the outer shield. The full explanation — and one for every question — is in Pro.
Practise this section
Getting the signal out: antennas, feedlines, SWR, baluns, matching, and why antenna length depends on frequency.