Southern Cross's Radio

Radio Record, Volume II, Issue 42, 3 May 1929, Page 3

Southern Cross's Radio

Detailed Description ' THE following description of the radio apparatus of the Southern Cross was written by Mr. Ray Allsop, the well-known Sydney expert, when Kingsford Smith and his comrades were missing and when their fate was unknown. The receiver and transmitter of the Southern Cross was made so that it could stand a good shock. In. the event of a bumpy landing, or even a forced landing, it was not likely to have been damaged. That portion of the *plane containing the radio instrunents would have had to have been very badly damaged, indeed, in order to put the instruments out of commission. It would have had to be a very big shock to break the filaments or valves, and, in any case, spares were carried. In the event of a forced landing the generators, which are air-driven, would have ceased to deliver "juice." This would hbuve meant that McWilliams would have had to rig a transinitter with a receiving tube with the batteries off his receiver. As the batteries carried were of the lightest and lowest capacity obtainable, the life of the transmitter would have been very short, and he would, therefore, not be able to transmit for very long, even supposing the ’plane to have descended and the receiving valves to be undamaged.

We worked on the Southern Cross with great hopes-and now what has happened? 'The:success of the Southern Cross in past flights made us optimistic. We replaced the original receiver with a locally-manufactured one, with wavelength ranging from 10 to 2500 metres. We had expected to hear this on the way to England. The aerial used in conjunction with the receiver was approximately 300ft. long, a separate aerial being used from the transmitting aerial. (The receiving aerial was later lost). The interchangeable coils provided for the various wave bands from the 10-2500 metres, a special cut-out arrangement being. provided on the condenser to bring in the short-wave band. Receiving Morse signals in aeroplanes is difficult, owing to the interference caused by the magnetos on the engines, six of these being. on the Southern Cross-two on each engine. To overcome this difficulty the set was provided with transformers peaked to 1000 cycles. The set complete weighed approximately 8lb.,.the whole being mounted in an aluminium container. The .com‘plete receiver was slung on rubbers into the framework provided on. the. ‘plane, to carry the radio apparatus.