Basic Qualification · B-006 Feedlines and antenna systems · B-006-008-010
Some antennas are constructed with traps. What is a trap?
- A A hollow metal can
- B A coil and capacitor in parallel
- C A large wire-wound resistor
- D A coil wrapped around a ferrite rod
Correct answer: B — A coil and capacitor in parallel. From the official ISED question bank, verified word for word.
Why
A trap is a coil and capacitor in parallel because this combination blocks specific radio frequencies while letting others pass, allowing one antenna to work on multiple bands. 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.