Broadcasting (Oct 1931-Dec 1932)

Scientific Measurement of Station Coverage By C. M. JAN SKY, Jr. Accuracy Held Dependent Upon Engineering Field Study; Three Classes of Service in Relation to Reception MIRACULOUS inventions lacking for the determination of the number of listeners of any station, their sex, age and buying power, an engineering method of ascertaining station coverage stands out as the most accurate yet evolved. The scientific and mathematical formulae used as bases for this measurement are herewith explained in a convincing manner. The writer holds that coverage cannot be determined by mail response, power assignment, nor a house-to-house canvass and points out that it is not the location of a station that is important but the location of the night and day coverage areas. C. M. Jansky, Jr. which, when put in the studio of a broadcasting station, would show accurately the number of radio receiving sets which at that minute were tuned jj to the station. The only trouble is that no one has ever been able to invent a simple little "deevice" to fill this need, and furthermore — no one ever will. While speaking of miraculous inventions, it might be well to stretch the imagination a little further and ask for an indicator ';■ which will not only show the number of radio sets tuned to a station but also the number of listeners, their sex, age and buying power. Also, why not a simple machine which would automatically tell just how many radio listeners buy the product of the program spon | sor and just how much return the advertiser gets from a particular sponsored program. Then, and only then, would the radio station owner and the advertiser be truly satisfied. Now all of this sounds and is fantastic, yet the various factors which determine the value of radio advertising can be studied and the information thus secured, if accurate, can be of real value. However, to be of value the degree of accuracy must be known. The science of medicine made but little advance until by dissection doctors began the study of the parts which make up the human body. Similarly, accurate knowledge of the value of commercial broadcast programs is dependent upon knowledge of the parts which go to make up a commercial broadcast system. Classifying the System FIGURE I is a rather crude graphic representation of a complete commercial broadcast system. The first half of the diagram, composed of Parts I, II and III, is the radio communication system proper. The second half, composed of Parts IV, V and VI, deals with the radio listeners and their reaction to broadcast problems. A radio communication system consists of three parts:,(I) a transmitter installation, (II) a transmission medium which in broadcasting carries signals from the broadcast station outwardly in all directions from the transmitter to (III) all of the receiving sets which receive adequate signal for reception if those receiving sets are adjusted for that particular station. Consider each receiving set shown in part III to be multiplied by a factor of 100,000. Then of 600,000 receiving sets capable of receiving the program from the station (coverage), 400,000 are shown as actually tuned to it while 200,000 are either not in use or tuned to some other station. Of the 400,000 sets tuned to a particular program, 100,000 have four listeners each, 100,000 have one listener each and 100,000 have three listeners each, while 100,000 have two listeners each. The "audience" for this particular program is therefore 1,000,000. (The factor 100,000 times the number of circles shown in part IV.) Of these 1,000,000 listeners, 400,000 are shown as sometimes buying the product of the program sponsor. (The factor 100,000 times the number of circles shown in part V.) From these figures and other essential facts, the value of the pro gram to the sponsor can be determined. The complete commercial broadcast system as shown has certain inherent characteristics which must be given careful consideration in laying the plans for any investigation intended to determine the value of broadcasting. Some of these are: Inherent Characteristics 1. IN MOVING from left to right, that is from transmitter to buying listener, accurate facts become of greater importance in determining the value of the program. 2. However, in moving from left to right, accurate facts become more and more difficult of determination, (i.e. audience varies from day to day and hour to hour and can never be determined with the same accuracy as coverage. Coverage is harder to determine than power radiated.) 3. A knowledge of the parts of this system is basic to a knowledge of the whole (i.e. study of radio listeners who buy requires studies of audience. Studies of audience should be based on a knowledge of coverage, etc.) 4. Parts I, II and III, being parts of the radio communication system can be investigated only by study of the scientific phenomena of radio transmission and the engineering factors affecting radio receiving set design. In dealing with coverage, we are dealing with the scientific facts and principles which go to make up the radio communication system and only to a very limited extent with human reactions. On the other hand, study of the last three parts of this commercial system requires consideration of human reactions and human emotions as well as their cause and effect. That is to say, the complete commercial broadcast system naturally subdivides itself into two major divisions, the first dealing with the science of radio communication and the second with the reactions of human beings to the broadcast programs which they receive. Not only are the methods which must be applied to the study of the communication system radically different from those which must be applied to the division dealing with human reactions, but the facts with respect to the radio communication system, while exceedingly complex, are capable of much more exact determination than are facts concerning parts IV, V and VI of this system. 5. Because of the very nature of the system as a whole, consideration of the first three parts of this system is fundamental to consideration of the last three parts. In other words, consideration of where a station can be heard is fundamental to consideration of who listens to it and why in any well-organized course of procedure. Reception Conditions NOW DIRECT attention to Part III of Figure I, the last link in the radio communication system proper which is just ahead of those parts so complicated by the human reactions. Consider a single particular receiving location where the receiving set is adjusted for reception from a particular broadcast station. Consider first daytime conditions. These may be classified under one of three heads: 1. The listener can receive the station satisfactorily any day. 2. The listener can receive the station satisfactorily only on certain days but not satisfac (Continued on page 2 %) K&pto Communication Sy-o~TcTM Exsofxxjr&t T/aqHts/yr/rree OF ft GIVEN1 FbwEis ^dwtec F&OM •Station" \foLU£ OF SF&rJsOfZEO ptso&mtn TO (tOVS&TtSEK , The Power &9rirts of /? | Bl?OS?OCl9ST SrffTIOfiJ is hJoT THE lQcTUF>L FbWER &VOMTED Bf THE ST&T/oM The Fbwce ^iRC>iftrEO f/som O/Je STI9T/0?/ AWr BE FROM -5 TO IO TIMES TH/9T FROM ffA/OTHER OF THE Sf>me FbwER &?r//v<s The: 7ienrtsMissia>/ MEO/UM SOMETIMES CffLLEP THE ETHER &xxo receiving sets RECEIVING fiOEGUArc SieM9L 'COVEfZtfGE " The Coverage £>re<9 of CAfc srrmorJ be IO to 20 TIMES F)S great i9s that of another station of the same power. T f?ADIO L/STEHERS "fiuPIENCE " &>Dio Listeners who Buy THE propuctof the sponsor JANSKY ft BAILEY zr m jsr it jzt COMMEZCIfiL SYSTEM February 15, 1932 • BROADCASTING Page 11