Federation to the End of the Second World War (continued)

Australian contribution to research was stimulated when a Royal Commission on wireless with wide terms of reference, included in its recommendation in 1927

that a special appropriation, sufficiently large to enable the present problems in radio to be thoroughly investigated should be made available to the Council for Scientific and Industrial Research.

This gave rise to the establishment of the Radio Research Board in the same year, with representation from the University of Sydney, the P.M.G. Department, the Defence Department, the University of Melbourne and CSIR. Early studies, under the aegis of the RRB, of the transmission of radio waves along the ground and in the upper atmosphere provided a sound basis for the initial planning of the Australian Broadcasting Service. Intensive studies of the fundamental mechanism in the ionosphere followed and the RRB developed an ongoing role in stimulating fundamental radio research within universities and encouragement of post-graduate research. Evans,[19] in a well researched publication, has set out the detailed attainments, controversies and characteristics of those associated with the RRB over the period 1926 to 1945.

As has been noted earlier, the first task of the newly established PMG Research Laboratories related to the use of vacuum tube amplifiers on long trunk circuits to improve the quality of communications. A number of these amplifiers were installed and proved reasonably satisfactory and indeed, Adelaide and Perth still relied on a single VF amplified circuit in 1939. The major contribution which vacuum tubes were to make to trunk line technology in Australia with its great distances, lay, however, in the carrier technology which was then developing overseas, particularly by the AT&T Company in the USA. In 1925, the first 3 channel system in Australia, using equipment supplied by AT&T, was installed between Sydney and Melbourne and operated in the frequency band to 30 KHz providing 3 KHz channels. Further systems were soon installed on the Sydney-Brisbane, Sydney-Adelaide and Melbourne-Adelaide routes after upgrading of open wire pairs by re-transposing to single extra types.

As an indication of the rate of development, the Sydney-Maitland route was transposed in 1928, after investigation by AT&T engineers, to enable eight 3 channel systems to be installed. By 1936, after re-transposing had been carried out on an alternative route through Wisemans Ferry, the two routes carried a total of fourteen three channel systems, working to 30 kHz, a programme carrier system working 34 to 42.5 kHz and a telegraph carrier working to 10 kHz. In 1939, further growth was met by installation of separate go and return, 24 pairs in 12 quads, 40 Ib. conductor, special carrier type star quad cable in accordance with BPO specification 598. Table 4 (from reference[20] by C. J. Griffiths who, with W. H. Walker, played an important role in the development of external plant engineering,) shows the twenty-year estimate of circuit development made in 1938, an estimate which events were to prove quite inadequate. In planning the cables, the Australian engineers developed specifications in the form of requirements to be met, rather than detailing a particular system or systems, establishing a practice which was to be the basis for seeking Australian communication equipment in the decades ahead.

Table 4 Sydney-Newcastle-Maitland Cable -circuit development

Note 1:

Including one special broad band channel for the existing Type B, O. W. telegraph carrier system

Note 2:

D. C. omnibus telegraph circuits

Note 3:

D. C. telegraph circuits

Note 4:

Except where otherwise referred to, telegraph development figures refer to voice-frequency telegraph systems

Australian Academy of Technological Sciences and Engineering