agreement between the administrative authorities of the several countries involved. Approximate optimum communicating distance-Miles Ship transmitting (land station re- Land station transmitting freceiving) frequency positions quency positions The separation between adjacent assignments should take account of the width of a telephone station-band" at that frequency. The following table shows the number of standard station-bands required for a telephone station band at frequencies between 1,500 and 23,000 kc. DUTCH EAST INDIAN PROPOSAL CONCERNING TOPIC 1 OF THE PROGRAM ORGANIZATION OF THE C. C. I. RADIO The Dutch East Indies Administration wishes to recommend that Article 6 of the draft rules proposed by the Netherland Administration (Proposal 2) should be completed by the following: The administration preparing the work of the Committee for the next meeting shall draw up as quickly as possible a provisional program, with the help of the documents handed over by the administration previously dealing with the Committee's work (Article 1), the reports of the reporters (Article 2) and the correspondence with those taking part in the next meeting (Article 3). This provisional program will be distributed fourteen months at latest after the last meeting. If those taking part desire changes or amendments in the provisional program, they must send their requests to the administration dealing with the work four months at latest before the beginning of the next meeting. The final program will be fixed by the administration dealing with the work and will be sent through the International Bureau of the Telegraph Union to those taking part, three months at latest before the beginning of the next meeting. The Dutch East Indies Administration also desires to recommend that the last sentence of Article 2 should be modified as follows: The whole of these questions must be placed on the agenda for the next meeting. and that this article should be completed as follows: The Advisory Committee also decides who among those taking part at the next conference shall introduce the proposals. All these introductions shall be sent to the administration dealing with the work of the Committee three months at latest before the beginning of the next meeting. 69 DUTCH EAST INDIAN STATEMENT CONCERNING TOPIC 2 OF THE PROGRAM POWER OF A TRANSMITTER In order to get an idea of what this problem involves, we must first consider what happens through all the process of wireless from the beginning to the end (from the transmitter to the receiver). A transmitting-station may be defined as a whole, with many different parts, producing a certain quantity of energy and furnishing that energy to the surrounding dielectric. The energy spreads and is propagated in this dielectric as far as the receiving-station, where a small part is captured. That part of the transmitting-station which produces the high-frequency energy may be defined as a transformer of energy of low frequency or of no frequency (continuous current) into high-frequency energy. Beside this transformer is the antenna as means of transmission. The whole of a transmitting-station may be understood as: (a) Means of producing at a certain point (the receiving antenna) a certain amount of energy. (b) Means of supplying to the surrounding dielectric a certain amount of energy. 118275-30-20 A distinction must be made owing to the fact that the percentage of energy under (b) which reaches the receiving-station-in a cer tain case is quite different in the case of very high frequencies (short waves) and of high frequencies (long waves). Empirical formulae which give this percentage for long waves are of no use for short waves, the means of propagation being quite different in the two cases. From the beginning to the end-from the transmitter to the receiver the following forms of energy may be distinguished: 1. The total energy supplied from the electric main to the whole installation. 2. The low-frequency energy supplied to the transformer. 3. The high-frequency energy supplied by the transformer. 4. The energy supplied to the antenna. 5. The energy supplied by the antenna to the dielectric. 6. The energy captured by the receiver. These forms of energy will be considered successively. As to 1 There is no doubt concerning this form of energy. As to 2 This energy is different for different types of transmitters: (a) High-frequency alternating transmitter. The low-frequency energy supplied to the motor. (b) Arc transmitter. The energy supplied to the arc, including the magnets. (c) Spark transmitter, supplied by current of musical frequency. The energy supplied to the transformer. Supplied by continuous current: the energy supplied by the source of continuous current (accumulators, generator). (d) Tube transmitter. The total energy supplied at the last stage of the tubes, including the energy supplied to the filaments, the grids and the plates. The tube transmitter constructed as high-frequency amplifier is a limited relative transformer, but the last stage may always be regarded as a quantitative transformer. If the last stage contains also a doubling of frequency, the transformation is quantitative and qualitative. The three forms of energy-filament, grid, plate-produce highfrequency energy. As to 3 This form of energy, although in theory very well defined, is difficult to measure in practice. (a) Alternating high-frequency transmitter with transformations of frequency after the alternator. By this energy is then meant energy supplied after the last transformation. Alternating high-frequency transmitter without transformation after the alternator. The energy supplied to the outlet terminals of the alternator. (b) Arc transmitter. With direct or indirect coupling to the antenna, the energy measured directly after the arc. (c) Spark transmitter. The energy supplied by the spark. For all these cases this form of energy is very difficult to measure only for: (d) Tube transmitter. The conditions of measurement are easier. In several cases the energy absorbed by the plate may be measured-with a cooled plate this is only a measure of the heat of the water or oil; with a non-cooled plate this energy may be measured by photometric methods. The measurement of the energy supplied to the tube presents no difficulty. From its two quantities the high-frequency energy produced by the lamp may be deduced. As to 4 This energy can only be measured indirectly. There are, in the case of long waves, different methods of measuring the resistance of the antenna as a whole or partially, which are fairly accurate. When the resistance of the antenna is known, and also the current at the base of the antenna, the energy in the antenna may be calculated (=12R). In the case of short waves, this simple method is no longer possible. We can only measure the energy supplied to the antenna when a system of feeders is used in which stationary waves are suppressed. It will, however, always be possible, in any short-wave transmitter, to measure the energy at the output by means of a system of feeders with an absorbing resistance at the end instead of an antenna-an artificial antenna, so to speak. For small and medium tubes this energy may be directly measured in an artificial antenna, by using an ordinary large incandescent lamp. As to 5 It is only possible to obtain information as to this form of energy by field measurements. In order to obtain a complete picture, field measurements must be made also in the space around the antenna; this is very difficult, if not impossible. In certain cases it is possible to calculate this energy approximately. As to 6 The energy supplied to the receiver by the surrounding dielectric may be calculated by empirical formulae, which are only applicable for long waves. In these formulae there are, beside the frequency, two factors of the transmitting antenna, namely, the current at the base of the antenna and the effective height of the antenna. The first factor may be measured directly by means of an amperemeter at the base of the antenna, the second factor is only measurable indirectly. The product of the two, expressed in meter-amperes, gives only an idea of the radiated power and no direct information as to the energy radiated. This product, expressed in meter-amperes in the Berne Terminology, is referred to in the Washington 1927 Regulations. According to Article 13, Paragraph 4 (e), of the Regulations, mention must be made of the normal radiated power expressed in meter-amperes, or, lacking this, the height of the antenna and intensity of the current at the base of the antenna. This information gives no idea of the energy actually radiated, but only of the influence of the transmitter at a distance. Moreover, for short waves this information is of no value; the empirical formulae mentioned above no longer apply; the propagation of these short waves follows quite different laws. The information in the nomenclature has the purpose not only of giving an idea of the power of a transmitter at a distance, but also an idea of the transmitter properly so-called, as a technical object, which is, in the case of short waves, the principal purpose. It therefore seems very desirable to give in the nomenclature, besides meter-amperes, all possible information as to energy; for instance, the energy referred to under numbers 2, 3, and 4, and also a short, but clear description of the kind of antenna used. With such information it is possible to obtain an idea of the transmitter and its possibilities. 70 DUTCH EAST INDIAN STATEMENT CONCERNING TOPIC 3 OF THE PROGRAM CLASSIFICATION OF WAVES The Dutch East Indies Administration recommends that: Extra short waves should be waves from 0 to 10 meters. |