Antennas and propagation – Match each item to its best association List I A. Sky wave B. Antenna feed C. Reflector (in arrays such as Yagi–Uda) D. Rhombic antenna List II Parasitic element used to direct the main lobe Delta match (common feed technique) Long-wire antenna (traveling-wave type) Ionosphere (medium enabling long-distance propagation) Choose the correct mapping.

Introduction / Context:
This match connects propagation terminology and common antenna structures/feeds. These associations are standard in amateur radio, broadcast, and HF communication practice.

Given Data / Assumptions:

• Sky-wave propagation relies on ionospheric refraction/reflection.
• Delta match is a classic feed/impedance-matching method.
• Reflectors are parasitic elements used with directors to steer beams.
• Rhombic antennas are long-wire, traveling-wave antennas for HF with high gain and directivity.

Concept / Approach:

Map each item to its natural association: sky wave ↔ ionosphere; antenna feed ↔ delta match; reflector ↔ parasitic element; rhombic ↔ long-wire/traveling-wave antenna.

Step-by-Step Solution:

Verification / Alternative check:

Antenna handbooks and licensing guides illustrate these pairings repeatedly.

Why Other Options Are Wrong:

Associating “sky wave” with parasitic elements confuses propagation with array geometry; calling a rhombic anything but a long-wire is incorrect.

Common Pitfalls:

Mixing feed techniques (delta match, gamma match) with parasitic element roles; confusing ground wave vs. sky wave.

Final Answer:

A-4, B-2, C-1, D-3.