Difficulty: Easy
Correct Answer: A-3, B-2, C-1, D-4
Explanation:
Introduction / Context:
This matching question checks foundational antenna knowledge: common feed impedances, pattern features, perfect-match indicators, and standard frequency bands used in radio and TV systems. Knowing these “textbook” facts helps when selecting antennas and reading measurement instruments such as SWR meters.
Given Data / Assumptions:
Concept / Approach:
Map each antenna/term to the best-known property: loop antennas have a sharp broadside null; folded dipole is about 300 Ω; SWR of 1 corresponds to a flat-line indication on an SWR meter (no standing waves); VHF spans 30–300 MHz. These pairings are standard across antenna references and exam syllabi.
Step-by-Step Solution:
Verification / Alternative check:
Cross-check with standard antenna texts: folded dipole impedance ≈ 300 Ω; SWR = 1.0 means reflection coefficient 0; VHF is 30–300 MHz; small loops present deep broadside nulls useful for direction finding.
Why Other Options Are Wrong:
Assigning 300 Ω to the loop or calling VHF outside 30–300 MHz contradicts accepted definitions. SWR = 1 cannot correspond to any non-flat standing-wave display.
Common Pitfalls:
Confusing broadside lobes with broadside nulls for small loops; mixing up UHF (300–3000 MHz) with VHF.
Final Answer:
A-3, B-2, C-1, D-4.
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