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Aviation History
1957
1957 - 0498.PDF
500 FLIGHT, 12 April 1957 Automatic Direction Finding . amplifier, I.F. amplifier, control unit, quadrantal error corrector and abearing indicator. " ;i Type AD. 7092 Marconi's Wireless Telegraph Company, Ltd. Address on page 499.COMPRISING a receiver, receiver-controller, dual sense amplifier, and servo amplifiers for the sense amplifier and R.M.I., Marconi'sAD.7092 is fitted in the Viscount and many other types. The aerial system is a motor-driven recessed iron-cored loop with a separate senseaerial (normally provided by the aircraft manufacturer) or another type (1268) is contained in a streamlined housing; quadrantal and field-alignment error-correction is automatically applied by the mechanism in the loop. There is a single screw adjustment for the amplitude ofcorrection. The current consumption is 4.5 A at 28 V D.C. for a single installation of the self-contained H.T. power unit, valve heaters andauxiliaries; and 0.4 A at 115 V, 400 c/s, for remote-control systems. The total weight is about 45 lb. : Automatic Direction Finder CMA-301 Aviation Department, Canadian Marconi Co., Montreal, Canada.THE CMA-301 A.D.F. was designed to meet C.A.A. and Canadian Department of Transport requirements and ARINC standards. It issuitable for use in modern high-performance aircraft and weighs 30 lb complete. The flat, ferrite-core aerial can be suppressed below theaircraft skin. The sense aerial is specially designed to meet high-speed aircraft requirements and has a special coupling unit to reduce cablecapacitance and increase signal/noise ratio. Accurate tuning and good frequency stability are provided by a precision electrical servo tuningsystem and temperature compensating components. ARINC form factor and interconnection standards are used. The loop can rotatethrough 175 deg in approximately four seconds. Operators in Canada, the U.S.A., South Africa, Pakistan, and West Germany have adoptedthe CMA-301. Either 28 V D.C. or all-A.C. versions are available. A typical radio magnetic indicator, in this case the Bendix MN-58C. The needles can serve A.D.F. and V.O.R. D.F.A.-70 System Bendix Aviation Corp., Baltimore 4, Maryland, U.S.A.THIS Bendix A.D.F. provides (manually or automatically) visual in- dications of the direction of a transmitting station, aural reception ofradio range and other course-orientated navigational aids and Consol reception. The components comprise a double-conversion superheterodyne re-ceiver (a "static-blanker" unit for the receiver is being developed for Bendix by the Lightning and Transients Research Institute, Minne-apolis), a flush-mounted automatic loop aerial, an electrically-operated remote-control unit, and a radio-magnetic indicator (described onpage 497). The L.P.A.-70B flush loop antenna has four ferritic collector barswhich concentrate the received energy into a small loop coil; the whole can be mounted in an ellipsoidal cut out. Compensation up to 21 degcan be obtained with either ferrite or aluminium bars. An alternative loop is the MN-60B which is an iron-core, electro-statically shielded unit hermetically sealed in a glass dome covered with a streamlined anti-static housing. This projects about six inchesfrom the fuselage skin. DF-201 Automatic Direction Finder System Collins Radio Company, Cedar Rapids, Iowa. THE DF-201 functions as an automatic or manual direction finder andprovides amplitude-modulated or continuous wave reception, range re- ception and Consol reception. It comprises a control unit, receiver,and loop antenna. It is claimed that printed circuits, silicon diodes, dry-disc rectifiers and transistors add to the reliability of the system. The control unit embodies a veeder-counter frequency indicationwhich is easy to read. The tuning circuitry in the remote control box is operated by three frequency-selecting knobs with an arrangementof resistors to provide voltages which are linearly proportioned to frequency over the four bands. The advantage claimed for this arrange-ment is that the problem of change in slope of the tuning curve with band change is solved electrically. The 137A-1 loop aerial is electrically and mechanically interchange-able with a flush-mounted type. Quadrantal error compensation is provided electrically bv means of crescent-shaped ferritic correctorsmounted in the field of the loop. A main frame gives support for the loop-rotating mechanism and correctors, which are enclosed in asealed cover. Bearing information is displayed on a radio magnetic indicator. Components of the crystal-tuned Marconi AD-712 include (left to right) the extremely thin, fixed loop, quadrantal error corrector, receiver and control panel. ADF-100 Lear Inc., 3171 S. Bundy Drive, Los Angeles 34, California. WEIGHING only 18.5 lb, ADF-100 has printed circuits and tran- sistors, thus reducing the normal power consumption to only 10 per cent of that normally required. Virtually no warm-up time is required. ADF-12 Lear Inc. THIS set can reasonably claim to be one of the lightest made: it weighsaltogether 17.3 lb. Power requirements are 3.3 A at 28 V or 5.7 A at 14 V. The components of the system are a controller (with ADF/ANTswitch, 3-band selector switch, tuner, sloped scale and test button); an amplifier suitable for 12 or 24 V power supply; and a ferro-dynamicloop which is electrically driven. Error compensation is performed electrically and the loop is hermetically sealed. Audio A.D.F. presenta-tion can be provided through a loudspeaker mounted in the cockpit or through headphones. Type 21 Automatic Direction Finder Aircraft Radio Corporation, Boonton, New Jersey.THE small, lightweight Type 21 A.D.F. consists of six components whose total weight is only 19 lb. These are the receiver and mounting;power unit; loop; control unit; indicator; and loop housing. The loop for this A.D.F. is contained within a sealed glass dome which projects21in from the fuselage skin; a flush loop may be produced when provision is made for it in new designs of aircraft. A problem of siting an A.D.F. loop is that—no matter where it ismounted—it will be located in a distorted magnetic field. Type 21 A.D.F. therefore has 14 error-correcting screws (which allow correc-tions of up to 25 degrees) and the housing has anti-static properties. Crank tuning is provided, 29 turns of the handle covering each band.There is an audio-level and R.F. sensitivity control and, in the "ANT" position, the receiver may be used for reception of standard four-course L.F. ranges if A.D.F. is not required. Two versions of the indicator are manufactured; IN-12 and IN-13. The latter is used fordual A.D.F. installations. Radio Compasses RC 230 and RC 231 THE RC 230 (single-frequency) and RC 231 (two-frequency) direction finders are made in France for light aircraft and fighters. They are used in conjunction with a flush loop antenna. The RC 231 is to be installed in the Morane-Saulnier M.S.760 Paris. Radio Direction Finder RDF-1A Aircraft Specialty Lines, Savage Industries, 10,200 North 19th Avenue, Phoenix, Arizona. THIS is a much simplified light-aircraft D.F. unit using its own receivercoupled with a shock-mounted dynamotor power unit and amplifier. The receiver has a tuned R.F. stage giving high selectivity. Thereceiver/tuner is instrument panel-mounted and covers the standard broadcast and L.F./M.F. navigation frequency bands. A voice filtercuts out range signals between 200 and 450 kc/s to improve voice reception. The direction indicating element is a fixed ferrite rod aerialwhich, under a plastic streamlined housing, projects about 2in from the aircraft skin. Cockpit presentation is in the form of heading error-signals on a left/right needle instrument. In some aircraft the loop can be positioned inside the cabin. Total cost, ex works, is advertised as$395. If the receiver is tuned with due care, good homing indications will be given at ranges in the region of 60 miles, but there is no clearindication of station passage. Needle sensitivity is adjustable by turn- ing a knob which initially selects either the sense aerial or the directionalaerial. The RDF-1A is an improvement on several earlier devices of thiskind in which the needle indicator and ferrite "loop" were coupled to standard aircraft M.F. receivers. RDF-1A weighs approximately 15 lb. It is not considered entirely adequate for I.M.C. operations. Left, the Canadian Marconi CMA-301 control panel and (right) that of the British Marconi AD.7092C.
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