Final answer:
The ILS Localizer operates at a frequency of 108 to 111.95 MHz, with a signal width of about 5 degrees and a typical range of 18 nautical miles. It emits a continuous, strong signal for reliable reception within its service area and unlike a lighthouse beam, it does not turn off at intervals.
Step-by-step explanation:
Characteristics of ILS Localizer
The Instrument Landing System (ILS) Localizer provides lateral guidance to aircraft for precision approach and landing. The localizer operates on a frequency of 108 to 111.95 MHz, which is just above the commercial FM radio band. The frequency is modulated by two directional patterns - one modulated at 90 Hz and the other at 150 Hz. The standard width of the localizer's signal coverage is about 5 degrees, which translates to around 700 feet (210 meters) at the threshold of a typical runway from a distance of 10 nautical miles.
The range varies depending on several factors like altitude and weather, but typically, the service volume of the localizer is 18 nautical miles from the antenna for aircraft at a height of up to 4500 feet. The localizer signal is sufficiently strong and is designed to be reliably received within its service volume but is not intended for detection by ground-based radio telescopes.
The signal emitted by an ILS is continuous when the system is operational. It does not shut off at intervals, unlike the intermittent beam of a lighthouse.