One antenna can be used for the radio range and standard broadcast bands in light aircraft because the ranges are too close together.

One antenna can be used for the radio range and standard broadcast bands in light aircraft because the ranges are too close together.

• A. The ranges are too close together
• B. The bands are identical
• C. The aircraft has dual-band transceiver
• D. It is illegal

Answer: (A)

The key idea is that when two frequency ranges sit close in frequency, a single antenna can be designed to cover both if it’s broadband enough. In this situation, the air–band used for aviation communications and the standard broadcast FM band are near each other, so a radiator with a wide enough bandwidth and proper impedance matching can operate efficiently across both ranges. That reduces the need for multiple antennas on a light aircraft, which saves weight and space while still delivering acceptable performance in both bands. If the bands were far apart, the antenna would struggle to perform well on both without special designs or using separate antennas. The other options don’t provide the practical reason for sharing an antenna: the bands aren’t identical, the hardware being dual-band doesn’t by itself justify a single antenna, and legality isn’t the basis for sharing an antenna.

The key idea is that when two frequency ranges sit close in frequency, a single antenna can be designed to cover both if it’s broadband enough. In this situation, the air–band used for aviation communications and the standard broadcast FM band are near each other, so a radiator with a wide enough bandwidth and proper impedance matching can operate efficiently across both ranges. That reduces the need for multiple antennas on a light aircraft, which saves weight and space while still delivering acceptable performance in both bands.

If the bands were far apart, the antenna would struggle to perform well on both without special designs or using separate antennas. The other options don’t provide the practical reason for sharing an antenna: the bands aren’t identical, the hardware being dual-band doesn’t by itself justify a single antenna, and legality isn’t the basis for sharing an antenna.