Basic Qualification · B-006 Feedlines and antenna systems · B-006-011-001
What design feature allows a single Yagi antenna to function on the 20-metre, 15-metre and 10-metre bands?
- AElement traps
- BLarge diameter elements
- CMultiple reflector elements
- DT-match feed circuit
Correct answer: A — Element traps. From the official ISED question bank, verified word for word.
Why
Element traps act like electronic switches inside the antenna rods, blocking certain frequencies so the antenna changes its effective length for each band. The full explanation — and one for every question — is in Pro.
Practise this section
Feedlines and antenna systems is section B-006 of the Basic exam: Getting the signal out: antennas, feedlines, SWR, baluns, matching, and why antenna length depends on frequency.
Drill B-006 — free, no account