Middle Marker

(See also Compass Locator, Glideslope, Instrument Landing System, Localizer, Outer Marker) A marker beacon that defines a point along the glideslope of an Instrument Landing System (ILS) normally located at or near the point of decision height (ILS Category I). It is keyed to transmit alternate dots and dashes, with the alternate dots and dashes keyed at the rate of 95 dot/dash combinations per minute on a 1300 Hz tone, which is received aurally and visually by compatible airborne equipment. (FAA4)