Television at Earls Court 1955 

15 May 2017 tbs.pm/12270

A PRE-VIEW OF SOME OF THE EXHIBITS

From Practical Television for September 1955

Owing to the fact that all manufacturers have not released details of their exhibits at the time of going to press, it is not possible to give a fully detailed account of all that might be seen and the following pre-view therefore deals only with those items which have been announced. As in previous years, many manufacturers hold back “secrets” until the day of opening, and although one or two rumours have been heard it does not appear that there will be anything outstanding or surprising. As is to be expected, however, the accent will this year be on the forthcoming I.T.A. transmissions, and the major part of the Show will be devoted to television aerials, tuners and converters to enable users of existing receivers to tune in to the new frequencies. As has already been stated in these pages, a new aerial is essential, but the manufacturers have found ways of adapting existing aerials, whether indoor or outdoor models, and a number of “add-on” elements will be seen which may be clipped to different types of aerial so that either Band I or Band III signals may be tuned — with a single aerial feeder.

Experiments which have been carried out during the past few months have shown that best results are obtained with a multi-element aerial, in order to preserve sufficient bandwidth, and four- and five-element arrays, with the dipole folded, are now becoming a common sight in many parts of London. Small units, incorporating the printed circuit technique, will also be seen, and these are intended for inclusion either at the aerial end or at the receiver end, to enable a single lead to be used.

Tuners

In addition to many special Band III tuners, produced by practically every set maker, there will also be a number of “12-channel units” or similar tuners, designed to replace existing tuning units, or to be added to existing receivers. These provide a selection of any of the Band I channels and one or more of the Band III channels. An example of these is seen on the next page, and is an H.M.V. product. This sells at 6 guineas and is a 14-point tuner, designed for the H.M.V. “Highlight” receivers. An important point with many of these tuners is that they are intended to replace existing R.F. stages, and therefore valves have to be removed from the receiver. Special plugs are then inserted in the empty valveholders, and in some cases the valves themselves are inserted in the tuner. In other cases different valves have to be employed. As the I.F. is now being standardised in TV receivers, these types of tuner are only useful where that I.F. is used, and this precludes their use in quite a large number of receivers. A simpler type of unit is intended to be included between the aerial and the receiver, and calls for no modifications in the receiver itself. In fact in some cases it may not even be necessary to remove the back of the cabinet. The units in such cases are self-contained, with their own power unit and switch, and in most cases the two aerial leads are plugged into the unit, and a lead is joined from the unit to the receiver in place of the original aerial lead. Against the switching in some cases permits the receiver to be left in the “on” position, whilst in other cases both the unit and the receiver will have to be separately switched. The control on the new unit then selects either the Band I or the Band III station. Under the test conditions which have been the only source of experiment so far, very little trouble appears to have been experienced from “patterns” due to the two transmissions becoming mixed in the converter, but whether or not this will hold good when the transmitter finally starts up on full power is not certain.

Tubes

Among the tubes to be seen will be some truly “outsize” models, but the popularity of these large surfaces is in doubt. In order to keep down the overall size of cabinets a marked increase in the number of rectangular tubes appears to be the trend. The metal cone appears to be on the way out, or at least has not increased in popularity. The aluminised surface is now the most popular, due no doubt to the brighter picture which results, but no details have been received of any change in screen colours, and projection receivers appear to remain in the same proportion as last year. It is doubtful to say what is the most popular size of picture, but it would appear to be now either 14in. or 16in., these two sizes appearing to be more or less equally popular.

General Design

With the inclusion of the rectangular tube, and the consequent overall reduction in size, the general appearance of the receiver has been changed somewhat, and a much neater cabinet results. From the illustrations of the three table models seen on these pages, it will be noticed that the general trend is to a two-knob layout, with very little depth below the tube. Volume and Brilliancy appear to be the most popular controls for panel use, and band switches and other subsidiary controls are placed on the sides.

There is also a growing tendency to replace the cabinet fronts by cloth and fancy materials in order to fit in with modern contemporary furnishings. This tendency has, in fact, been carried into some of the console designs, where also in the radio and loud-speaker cabinets a large sheet of cloth forms the front of the design.

There is a growing tendency to revert to the one-time popular multi-knob for the controls where two or more knobs are arranged concentrically, and whilst this does make for a neat appearance on the panel front, it is not always convenient. Much depends upon the knob shape and size, but it is very easy to turn two knobs together and thus upset the setting of one when adjusting the other. One or two firms appear to favour the edgewise control which again, whilst making for neatness of appearance, may not be the ideal form for older people or those who want something easy and robust.

The Pilot 13 Channel Turret Tuner.

Reproduction of Sound

Again we are surprised to note that of the designs of which we have so far been notified, no manufacturer has gone in for the “hi-fidelity” on the sound side. In view of the high quality which can be obtained from television, we would have expected some manufacturer to have made some attempt to do justice to it, by fitting at least a 12in. speaker, and making some attempt to use the lower part of a console cabinet as a properly-designed speaker enclosure. The market for hi-fidelity tuners and amplifiers on the sound side is now quite large, and quite a lot of money is spent by enthusiasts on speakers and speaker enclosures, and we would have thought one or two makers would have found it worth while to produce a “hi-fidelity” television receiver, where the quality of reproduction was in keeping with that now available from records and F.M. radio. It might be argued that many enthusiasts now own hi-fidelity loudspeakers and are fully equipped on the radio and gramophone side and that the existing equipment may be used with the radio receiver. But it is essential to reproduce the sound from the area of the tube in order to retain the illusion of realism, and although it is possible in many eases to take the output from the sound detector to a quality amplifier, in most commercial receivers very little attempt is made to develop the best from the sound channel and an 8in. speaker appears to be the more or less general rule.

This aerial array by Labgear is intended for mounting on an existing Band I aerial mast.

F.M. and Television

With further reference to the question of quality of reproduction on television receivers, as this issue goes to press we learn that at least one firm, McMichael’s, will be showing a combined television and F.M. receiver. This takes the form of a 17in. receiver and includes in its console a standard AM/FM receiver. Each uses its own separate valves and components, and separate speakers. No details are yet available, however, concerning the amplification problem, and we do not know whether this does in fact utilise a single high-fidelity amplifier for the two units. If the reference to “separate” indicates that each set (television and radio) is complete, this still does not come within the category mentioned earlier, where really high quality is provided for the television section. Incidentally whilst dealing with the McMichael products it is interesting to note that they have made a departure in the design of the line output design — a frequent source of trouble. A special form of generator has been developed by McMichael’s in which the heat is kept to a minimum, and the resultant assembly is claimed to be safer and more reliable than many other high-voltage generators now in use. This feature is exclusive to the McMichael receivers.

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