Radio broadcast .. (1922-30)

Ml immmiHi A Discussion of the Manufacturer's Production Problem SETTING RADIO STANDARDS ANEW RADIO set is being made. It may be a marvelous achievement or just another radio set. It may be in great demand or unheard of. Just what technical details will make this new set what it will be? Why will it work the way it does and not like some other make of radio receiving set? The determination of how good a radio receiver should be, and the maintenance of that degree of "goodness" is one of the most fascinating problems connected with the radio industry. It is a curious balance between human discernment and the laws of probability. It involves a conflict be- tween individual temperaments and en- gineering preciseness. And perhaps most of all, it is a problem in economics from the viewpoint of the manufacturer. The setting of a standard of performance is a fundamental problem to which a cor- rect answer must be obtained by any manufacturer hoping to stay in the radio business. It is surprising to note the in- definiteness with which this problem is viewed by a great many manufacturers, and it is significant that the most success- ful producers are those who have ap- proached the problem in a logical manner. The following discussion presents one possible approach, and considers some of the factors involved. Not a great many figures are included, and then only for illustration, as quantitative values are of interest only in specific cases. The relative standards of performance are so varied by market and manufacturing conditions as to make the correct choice a matter of company policy rather than the sole answer to what is the best type radio set to make. Relative Standards By relative standard is meant a hypothetical receiver, comparable to previous or competitive models, whose performance capabilities are guessed at as a function of develop- ment possibility, cost, and cus- tomer demand. It may be an ex- pensively engineered, high priced, refined, beautifully operating re- ceiver, appealing to the tastes of those who can afford such details. It may cost but little, serving to give those less favored in worldly goods some of the joys and static of radio reception. In either case, the operational characteristics have a relative standard about which level the policy of the manufactur- ing company tends to keep the manufactured article. The com- pany policy, and as a conse- quence, the relative standard, is influenced by the time and cost of development, the cost of produc- tion and materials, and the sales demands. A brand new company would hardly be justified in build- ing the finest and most expensive radio set its first year; the time needed for development alone would prevent such a move. Nor does this mean that the older companies will all tend to go toward higher price and finer By KENNETH W. JARVIS Chief Engineer, Sterling Manufacturing Company operating receivers. The trend might more nearly be toward that price and per- formance compromise which would give the manufacturer the greatest profit. As production increased year after year and more money could be spent in develop- Production engineers are faced with a two-fold problem; to build a certain number of units per day, and to determine which of those units will be shipped and which will be scrapped. Mr. Jarvis in this article discusses the problem of the engi- neers who must set performance limits on radio receivers and com- ponent parts; he discusses from a practical standpoint what the pass- ing and rejection limits should be, the relation between performance and cost, and other factors which are no less vital to a successful radio manufacturer than the careful labo- ratory design of the apparatus. — THE EDITOR ment, the relative standards of that manufacturer might increase. Long ex- perience in manufacturing, refinement in methods of production, and fabrication of materials tend to raise the relative stand- ards. Changing customer demands react in changing the performance standards. b 5 10 s 83 I I I I I 1 I I I I I VARIATION IN RECEIVER SENSITIVITY VS. CONDENSER TOLERANCE 234 ± MMFD. TOLERANCE \Fig. 1 A lower price demand may result in a lowered standard, and conversely. These facts merely mean that to occupy a place in the radio field a manufacturer must choose his relative standard as based on these facts; and for each manufacturer and his particular conditions, a receiver design with a definite relative standard is, advisable. Absolute Standards By absolute standard is meant a stand- ard working model, which is copied for production as nearly exact as economically possible. It represents, crystalized into facts, the fancies of the relative standard. This standard is established and built in three steps. First, the details required are added to the relative standard by the management of the design division. Usu- ally this means the individual highest in the organization interested in the radio receiver. In the case of a radio receiver manufacturing company this is customa- rily the president. For more diverse con- cerns, it may be the vice president or manager of the radio division. These de- tails may cover the suggested size, appear- ance, manner of construction, sensitivity, selectivity, fidelity, output, number and manner of controls, type of circuit, maxi- mum possible cost, date for production, number to be built, and those extras which may serve to make the product more marketable. Meetings between the execu- tive, engineering, production, and sales departments serve to resolve difficulties and effect compromises. As a result an absolute standard (still on paper) is evolved which the engineering department believes can be con- structed in the time available and at the cost specified, and which the production department can build. This is the first step. As a second step, the engineer- ing department takes these ideas and builds a model which conforms as close as possible to the proposed absolute standard. This model must represent previous develop- ment work and the experience of the engineers in charge. Newly proposed additions must be de- veloped so far as possible in the time available. General develop- ment work, applying previousK determined factors, must be carried on with this specific receiver in view. When engineering principles are applied to produce a desired performance in a physical model, cost studies must be made to show whether the method of application is the cheapest and whether the result justifies the cost. As a result of this work and study, a receiver is evolved approximating the characteristics desired for the ab- solute standard. Unfortunately, due to human limitations, it is seldom possible for the engineering department to realize all of the " ideals of the first chosen absolute standard. A compromise is effected, sometimes bitterly, for com- petition is keen, but a second stage 108 • DECEM BER 1929 •