What carrier frequency does a marker beacon use?

What carrier frequency does a marker beacon use?

• A. 75 MHz
• B. 150 MHz
• C. 300 MHz
• D. 400 MHz

Answer: (A)

A marker beacon operates at a carrier frequency of 75 MHz. This frequency is specifically designated for the purpose of providing precise position information to pilots during the approach phase of flight, usually in conjunction with Instrument Landing Systems (ILS). Marker beacons transmit signals that indicate the aircraft's proximity to specific points along the approach, such as the outer marker, middle marker, and inner marker. The choice of 75 MHz is important because this frequency is part of the VHF band that is suitable for aviation applications and provides reliable signal propagation characteristics. In contrast, the other frequencies listed—150 MHz, 300 MHz, and 400 MHz—are used for different aviation purposes or other communications and do not align with the specified operational band for marker beacons. Thus, the use of 75 MHz is both standard practice and essential for accurate airborne navigation and positioning.

A marker beacon operates at a carrier frequency of 75 MHz. This frequency is specifically designated for the purpose of providing precise position information to pilots during the approach phase of flight, usually in conjunction with Instrument Landing Systems (ILS). Marker beacons transmit signals that indicate the aircraft's proximity to specific points along the approach, such as the outer marker, middle marker, and inner marker.

The choice of 75 MHz is important because this frequency is part of the VHF band that is suitable for aviation applications and provides reliable signal propagation characteristics. In contrast, the other frequencies listed—150 MHz, 300 MHz, and 400 MHz—are used for different aviation purposes or other communications and do not align with the specified operational band for marker beacons. Thus, the use of 75 MHz is both standard practice and essential for accurate airborne navigation and positioning.