Which statement about DME antenna placement and reception is correct?

Which statement about DME antenna placement and reception is correct?

• A. Unobstructed line of sight is important for reception
• B. Proximity to the engine improves reception
• C. Height provides no effect
• D. The antenna location is irrelevant

Answer: (A)

DME reception depends on a clear, direct radio path between the aircraft’s antenna and the ground station. UHF signals used by DME are readily blocked or degraded by obstructions, including the aircraft’s own structure, so an unobstructed line of sight is essential for reliable reception and accurate range measurements. Elevating the antenna helps maintain that clear path by reducing shielding from the airframe and terrain, which is why height does have a positive effect. Proximity to the engine isn’t beneficial because metal and large structures can block or reflect the signal, and the antenna’s location is not irrelevant—it should be placed where it can see the ground station with minimal obstruction.

DME reception depends on a clear, direct radio path between the aircraft’s antenna and the ground station. UHF signals used by DME are readily blocked or degraded by obstructions, including the aircraft’s own structure, so an unobstructed line of sight is essential for reliable reception and accurate range measurements. Elevating the antenna helps maintain that clear path by reducing shielding from the airframe and terrain, which is why height does have a positive effect. Proximity to the engine isn’t beneficial because metal and large structures can block or reflect the signal, and the antenna’s location is not irrelevant—it should be placed where it can see the ground station with minimal obstruction.