🔍 Key Concepts

• ILS marker beacons: purpose and how they transmit signals to aircraft • Typical antenna patterns for marker beacons (directional vs. omnidirectional) • Common antenna types used for VHF/UHF navigation aids (dipole, loop, phased array)

💭 Think About

• Think about whether a ground-based marker beacon for ILS needs to aim a narrow beam or cover aircraft flying along the approach path overhead. • Consider which antenna types are usually simple, robust, and suitable for fixed-frequency navigation beacons near 75 MHz. • Ask yourself: is the marker beacon primarily a transmitting device or a receiving device in normal ILS operation, and how does that affect antenna choice?

✅ Before You Answer

• Verify what frequency band (~75 MHz) ILS marker beacons operate on and which antenna types match that band well. • Check whether a marker beacon is expected to produce a narrow directional lobe or a broad, essentially vertical/omnidirectional field under the aircraft. • Confirm whether terms like "reception antenna" fit the role of the marker beacon installation on the ground.