Final answer:
The Localizer operates in the Very High Frequency (VHF) band from 108 to 112 MHz with a channel width of about 150 kHz. It emits a continuous directional signal strong enough to be received by aircraft navigation systems for runway alignment.
Step-by-step explanation:
The Localizer, a component of the Instrument Landing System (ILS), operates within the radio-wave portion of the electromagnetic spectrum, specifically in the frequency band known as Very High Frequency (VHF). The frequency spectrum utilized by Localizers typically ranges from 108 to 112 MHz. These frequencies are chosen because they are less susceptible to being absorbed by common building materials and thus provide a reliable signal for aircraft navigation during landing.
The Localizer provides horizontal guidance to aircraft approaching a runway. It transmits a directional radio signal that an aircraft's avionics can use to align with the centerline of the runway. The channel width, or the frequency difference between the clear signal and the sidebands, is usually about 150 kHz. The strength of the Localizer signal is sufficient for detection by onboard aircraft receivers, which are designed to be highly sensitive to this frequency range. The signal is continuous, assisting pilots during their approach until landing.