LOCALIZER

LOCALIZER

 

Localizer is a part of ILS that provides the pilot with horizontal guidance towards the airport runway center line.

Operating Frequency Band

  108 – 111.975 MHz

Modulation Frequency

  90 Hz and 150 Hz

DDM

  20% (90 Hz and 150 Hz) Nominal

  18% - 21% allowed for Cat. I and Cat. II

  19% - 21% allowed for  Cat. III

Voice Modulation

  Optional

Identification Signal

  1020 Hz with 5% - 15% Modulation

  keyed 2 – 3 Characters of International Morse Code (audio of 1020 Hz) e.g. I-CIA

Monitoring

  Automatic Monitoring System to designated control locations.

 

Localizer radiates two modulating signals 150Hz and 90Hz. It produce a predominance of 150Hz to the right of the runway centerline as seen by the aircraft and a predominance of 90Hz modulated RF to the left of runway centerline. At centerline the two modulated RF are equal.