Airborne receivers and test gear for instrument landing systems
14 June 1952
The ILS-2 system [see Abstr. 1950B03078 is summarized and the problem of sensitivity of airborne equipment is discussed. The localizer and glideslope receivers SR14/15 are provided with carrier, and audio-derived automatic volume controls respectively and monitor flags on the cross-pointer indicator give warning of deterioration in performance. Both receivers are double superheterodynes using wide band r.f. and first oscillator stages. Channel selection is effected by crystal switching. The teat equipment includes signal sourc6s for initial calibration and for field testing immediately before each flight.