Advantages For N.Z. In F.M. Broadcasting

Press, Volume CVIII, Issue 31835, 13 November 1968, Page 20

Advantages For N.Z. In F.M. Broadcasting

(Specially written for “The Press” by

B. S. FURBY, M.N.Z.E,I.)

Comment in Parliament during debates on the Broadcasting Authority Bill touched briefly on the fact that channels in the broadcast band are not unlimited, and interference between stations could increase if more broadcasting stations are licensed.

Correct: there are a few more than 50 channels in the present broadcast band, and already there are 46 N.Z.B.C. stations, one private station and one unlicensed. The Post Office apparently intends to accommodate new channels by halving the existing ones, a solution which reduces the quality of the transmissions.

This is, however, only a partial solution. There are more than 200 Australian stations, not to mention others in the South Pacific in Fiji, Tonga, etc. Many are easily received in New Zealand, and most are a source of interference to the listener who tunes off his local Station in search of variety. The agreement under which certain Australian stations reduce power every evening to avoid interfering with New Zealand programmes is again only partially satisfactory, as is the palliative whereby New Zealand stations periodically increase power. This helps temporarily until the Australians are driven to do the same, when it all begins again.

Hi-fi Enthusiasm In any case, medium wave broadcasting is incapable of providing the technical quality which has inspired so much interest in home installations for high fidelity (hifi). This enthusiasm has been encouraged not only by the L.P. record and tape recorder, but also the way such equipment has reduced in price since the war, thanks to engineering improvements. Medium - wave broadcasting eannot transmit the range of musical notes needed for high-quality reproduction, and is always subject to background noise and interference.

Had the Parliamentarians, however, fully studied all the evidence submitted their committee on the Broadcasting Authority Act, they would have been informed on how New Zealand could have a better service, offering broadcasting free of interference and noise, and transmitting the full range of music frequencies with stereo as well. This was covered in the sub-

missions of the New Zealand Electronics Institute, the only local learned society exclusively devoted to electronics with membership ranging over the whole electronics profession. The experts in electronics had drawn attention to VHF (Very High Frequency), FM (Frequency Modulation) broadcasting, a system widely used in the United States, Canada, the United Kingdom, Europe and Japan. Television viewers in New Zealand who have noticed the high quality of the television sound transmissions, and their freedom from noise and static, are probably not aware that these are because television sound uses the FM system. This is its only broadcasting use in New Zealand so far. This is because FM broadcasting has been discouraged by the N.Z.B.C. until the country was completely covered by the present broadcasting system: with 47 stations, this day may be considered as having come.

V.H.F. Necessary There are technical reasons why FM transmissions must be in the VHF (or higher) bands, and the system cannot be used on the present medium wave broadcast band. Like television, FM transmissions are therefore limited to “line of sight" reception distances from the transmitting aerial. While this would reduce possibilities of interference, FM has a further inherent feature in this respect: “capture effect.” Where two transmissions on the same channel overlap, the stronger “captures” the receiver and excludes the weaker. However, the use of the VHF bands carry another bonus: the transmissions can be made reasonably directional. Because of New Zealand’s peen-

liar geography, close to half the power so expensively converted to radio broadcast transmissions on the broadcast band at present is radiated over uninhabited ocean. The difficulties of making broadcast aerials directional make this present waste economically acceptable. One argument for opening up the VHF band reserved in New Zealand for FM broadcasting is that by licensing any future private broadcasting stations on it, the work the N.Z.B.C. (and its predecessors) did in establishing broadcasting in New Zealand entitles it to have the medium wave band preserved for it exclusively. Future private stations would not then cash in on the N.Z.B.C.’s pioneer work, but would have to work to attract listeners to the new medium. Furthermore, FM would offer great technical possibilities, in the nature of a challenge with stereo and the ultimate in technical quality. Against this, is that the N.Z.B.C. has not taken any new step in broadcasting of itself. Shortwave broadcasting, television and other innovations were all pioneered in this country by private individuals or organisations to the point where they became sufficiently successful to arouse public interest and force Government action.

F. M. Receivers The refusal of the Post Office to approve experimental licences for FM broadcasting can perhaps be interpreted as a determination not to let bureaucratic inertia be stampeded again. Ordinary broadcast receivers cannot receive FM transmissions, but there are many receivers in the country which can. Immigrants bring radios which, having been niade for European services have both the medium wave broadcast band and the VHF FM band, and can receive both. Similarly many of the larger Japanese transistor portables which have found their way into the country are made to receive both types of transmissions. The New Zealand radio industry is

quite capable of building FM receivers, including small transistor portables.

However, if FM broadcasting began here the “television landslide” would hardly be likely to be reepated. The present broadcasting system would continue for many years yet, first because many listeners (especially, according to overseas experience, the teen-agers who saturate themselves with “pop” noise) would not appreciate FM quality until they became educated to prefer it. Second, country listeners remote from populated areas could continue to have service from the distance - covering medium wave transmissions.

Overseas Networks In the United States and Canada, there are now over 1500 FM stations (many retransmit on FM the programmes they broadcast on medium wave). The United Kingdom introduced FM about 13 years ago, and now has a network of nearly 200 stations. Western Germany, forbidden medium wave broadcasting after the war turned to FM and Germans have shown little interest in their restored medium wave services. Japan has a large FM network. Australia attempted FM experiments before television dominated the broadcasting scene, but these experiments, with sporadic and unpublished transmissions had little hope of arousing interest. Now interest is reviving and attempt to found

an effective service are under, way.

New Zealand is doing noth-• ing, and both the N.Z.B.C. ■ and the Post Office appear to discourage mention of FM let alone issuing a licence. When broadcasting channels are in short supply, and subject to interference, Parliament has approved a ball aimed at creating more sources of interference. When the electronics industrj is discovering an export potential for some of its products, it needs the security of a good home market on which to base its exporting. With

overseas experience proving a resurgence in high quality records and tapes (television having been assimilated after a few years) FM broadcasting—offering stereo—comes into its own. New Zealand electronic engineers and industry can offer the country a technically better broadcasting service now. Perhaps the Broadcasting Authority Act may give pottential broadcasters who are looking for a way of improving a service to the public the opportunity to give New Zealand a technically superI ior broadcasting system.