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Aviation History
1957
1957 - 1698.PDF
786 FLIGHT Portable Airborne D/F Good Performance from Marine Equipment DURING a recent two-hour flight between Croydon andHum, the Homer transistorized receiver and Heron D/F.aerial were successfully tried in Flight's Gemini. Now being produced by Brooks and Gatehouse, Ltd., of Lymington,Hants, the Homer and Heron are completely portable and require neither mounting brackets nor external power supply. In theGemini, which has a wooden airframe, good bearings and very accurate homing were obtained on Epsom and Dunsfold ranges,the marine beacon at St. Catherine's Point (I.o.W.), Southampton Water N.D.B., and Hum range. Brookman's Park beacon andChatham range had previously been received adequately from an extremely unfavourable location on the eighth-storey flat roof ofour London offices. The Homer receiver weighs 5.5 lb, measures 8inx4Jx21in,contains seven germanium transistors and will operate with ear- phones for 500 hours on its pack of four Mallory RM-522 dry cells.Being primarily designed for yachtsmen, the radio is contained in a hermetically sealed aluminium case and all shafts are also sealed.Controls are provided for waveband selection, tuning with a pre- cision-calibrated dial, broadcast/navigation (B.F.O.) selector andvolume control. Leads six feet long are provided to connect with the aerial and earphones. Frequency is from 150 kc/s to 1,550kc/s, a coverage which encompasses marine and aeronautical beacons and ranges, Consol, and medium- and long-wave broad-casts. The sensitivity provides for taking bearings at distances at least equal to the listed ranges of the beacons. The price of the receiver, earphones and D/F. aerial is £62 10scomplete. The cost of the Sestrel Junior compass adaptation, which is a new one, has not yet been fixed, but will be approxim-ately £5. The Heron aerial is a ferrite rod unit some 3iin tall which, withthe little Sestrel Junior compass fitted on top of it, can be very comfortably held in the hand for taking bearings. Operating pro-cedure is to tune the receiver to the listed frequency of the beacon or range required, tune the aerial unit to the same frequency, listenfor the identifying Morse signal from the transmitter, and then rotate the aerial until the extremely sharp aural null shows thedirection in which the transmitter lies. The D/F. magnetic bearing is read directly from the Sestrel compass. If a sense aerial is installed in the aircraft, a "to-from" indica-tion can also be obtained; if not, a turn through 90 deg and subsequent observation of the direction of magnetic bearingchange will quickly give such an indication. A bearing from an- other beacon would also resolve ambiguity. We found the aural null very sharp at ranges of about 20 n.m.,and compass bearings could be easily read down to a few degrees. We homed by turning until the rod aerial, which was held con-tinuously in the null position, lay along the fore-and-aft axis of the aircraft, and then "following" it to the transmitter. The As, Ns andequi-signal legs of range stations were very clearly received and used in the normal way. Of the soft rubber, sound-excluding typemade by S. G. Brown, Ltd., for tank crews, the earphones are extremely comfortable and light. During the trial run in the Gemini we flew exactly over the The Homer receiver (right) and Heron D/F aerial (centre), together with the lightweight earphones at left, are here compared for size with a normal pencil. The receiver is battery-operated and transistorized. range stations at Epsom and Dunsfold without at first realizingit, but the 90 deg turn technique gave a quick and definite indication of sense in a matter of 30 sec or so. Homing directly overheadDunsfold we noticed the station passage very clearly by a broaden- ing of the null and by the fact that the bearings caused us to rotatethe aerial through 180 deg. Flying at 4,000ft above about two- eighths cloud we easily found the actual masts of the range stationby banking sharply at the right moment and looking about below the aircraft. From the Portsmouth area we homed on the Southampton Waterbeacon and managed, at just over 1,000ft, to fly round it in tight circles with the aerial pointing at a constant angle to port. Lookingover the port wing we were able to identify the white mast along- side some buildings on which we concluded the aerial must bemounted. Using the hand-held aerial and compass at 2,000ft we obtained a bearing of 280 deg from Beaulieu to Hurn range; thecorrect bearing was 279 deg. We managed quite comfortably to hold Heron and control column in one hand and made our wayacross country from beacon to beacon without difficulty. The weak St. Catherine's Point beacon we received at 35 miles. The caution and intelligence required when using any A.D.F.equipment would have to be applied to the use of Heron and Homer. But although this equipment would probably not beaccepted as an aid for I.M.C. airways flying, its efficiency, com- plete portability, light weight and low price make it ideal as aneffective aid to general navigation for private owners and club pilots. One installation with a sense aerial has already been madein a Chipmunk and is reported to be giving satisfactory results. For aircraft with V.H.F. radio, the Homer signals can be fed intothe standard V.H.F. earphones through a mixer box. The Homer's own volume control would allow navigation signals to be fadedout when not required. The two units are robustly built for use in fishing vessels andyachts and will withstand even complete immersion in water for long periods. They should therefore stand up well to the generalwear and tear of fight aircraft work. We found tuning, sensing and homing very simple and very accurate for cross-country flying.During sea crossings, or in limited visibility, Heron and Homer- should prove an invaluable aid. THE INDUSTRY'S DILEMMA (continued from page 781) "The ttrrd alternative is nationa'ization. Unless the industry isprepared to act quickly it is a sitting target for nationalization, but I can only state that in my humble opinion it would be a mostghastly alternative." Lord Weeks went on to say that if, as he was advocating, theindustry must get on quickly with some form of rationalization, equally obviously it could not do so entirely on its own: HerMajesty's Government would have to play ball as well:— "First, by really doing something about Transport Commandinstead of paying annual lip-service to it. We must build up the Command not only as an R.A.F. movements policy, but also as anational acceptance of the need to have Government support for British aviation; the Government should say now that they willorder for Transport Command batches of the new airliners which are to be brought out. One of the vital requirements to deter orsuppress limited war is a strong Transport Command. "Secondly, by encouraging the independents to purchase newaircraft, by giving them worthwhile contracts with a reasonable future and security. I regard this as one of the most importantrecommendations of the Thomas Committee. The independents must be able to buy the right kind of aeroplane and, in addition,the Government could lease machines to them. "Thirdly, by realizing that the aircraft industry cannot existwithout adequate monies spent on research and development; and by recognizing that the far-reaching effect of such researchand development is of the greatest importance throughout the whole engineering industry of this country from the point ofview of fatigue, metallurgical arid many allied problems. "I will sum up," said Lord Weeks, "with two broad recom-mendations: First, someone, or some body, should try to reorien- tate the duties and organization of the Services and their supply-Second, someone or somebody should try to create a focus for the control of the aircraft problem, especially the civil one. Thesetwo points are necessarily very much interlocked; and that success can be achieved only by co-operation between Her Majesty sGovernment, the industry and the operators adds to the difficulties.
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