A single beam TV receive-only antenna uses what primary physical shape to focus the signal?

A single beam TV receive-only antenna uses what primary physical shape to focus the signal?

• A. Has a parabolic shape that reflects the downlink signal from all locations on the dish surface onto a central focal point
• B. Is a flat dish
• C. Uses a horn antenna
• D. Is a circular flat reflector

Answer: (A)

A parabolic reflector is used because its shape focuses energy from a distant source onto a single point. When radio waves arrive from the satellite along near-parallel paths, each point on the parabolic surface reflects a ray toward a common focal point on the dish axis. Placing the feed horn or LNB at that focal point captures the concentrated signal, giving the high gain and narrow beam needed for satellite TV reception. A flat dish wouldn’t bring all the rays to a single spot, so it wouldn’t provide the same focusing and gain. A horn antenna is the feed that sits at the focus, not the dish shape itself, and a circular flat reflector wouldn’t produce the required focus either.

A parabolic reflector is used because its shape focuses energy from a distant source onto a single point. When radio waves arrive from the satellite along near-parallel paths, each point on the parabolic surface reflects a ray toward a common focal point on the dish axis. Placing the feed horn or LNB at that focal point captures the concentrated signal, giving the high gain and narrow beam needed for satellite TV reception. A flat dish wouldn’t bring all the rays to a single spot, so it wouldn’t provide the same focusing and gain. A horn antenna is the feed that sits at the focus, not the dish shape itself, and a circular flat reflector wouldn’t produce the required focus either.