RADIATION POWER OF A TRANSMITTER The expression in meters-amperes (effective height h in meters, intensity at the antinode in amperes) of the radiating power of a radio-transmitter seems to be no longer of value in the case of complex aerials generally used for short waves and especially in the case of multiple aerials. On the other hand, the measure of the field due to radiation of the aerial could not supply any indication of the effect at a distance from a station, since such measurement would have to be taken at a distance which would be a function of the length of the wave employed. Lastly, as regards aerials with radiation directed in a vertical plane (aerial excited in harmonics), the measure of the field in the horizontal plane would be without significance. It therefore seems that the technical information regarding the descriptive list of short-wave stations might be limited to the following points: Frequency and wave-length; System of transmission; Power of transmitter to be followed [optionally] by approximate indication of output; Short description of the aerial; Name of private management, if need be. More detailed information as to each short-wave post might further be sent by the administration concerned to the Bureau at Berne, which would communicate it to such administrations as so desired. 18 FRENCH PROPOSAL CONCERNING TOPIC 5a OF THE PROGRAM STANDARDIZATION OF FREQUENCY-METERS 1 Fixed stations with a power higher than 20 kilowatts must be equipped with two wave-meters with a first-class certificate.2 One of these certificates must not be more than nine months old. 1 See definition given in Proposal 15, pp. 142-43. 2 See post, p. 146. Fixed stations of power from 1 to 20 kilowatts should have a wavemeter with a certificate of calibration, first class, not more than nine months old. The frequency of transmission of mobile stations will be verified. as often as possible by the inspection service on which they are dependent. 19 FRENCH PROPOSAL CONCERNING TOPIC 5b OF THE PROGRAM INTERNATIONAL CHECKING OF FREQUENCIES A permanent international frequency-measurement service shall be organized by the International Bureau of Weights and Measures. This service will coordinate the frequency-measuring done in the different central laboratories, by organizing the comparison of results obtained both as regards the determination of frequencies of an absolute value and as regards the calibration of wave-meters. From these comparisons it will deduce the coefficients of correction to be made in the standards of frequency of each laboratory. It will also standardize wave-meters for those countries which have no central laboratories and which make a demand to that effect. By central laboratories are meant: (1) The national laboratories of different countries; (2) Certain individual laboratories which have made a special effort to attain a high degree of accuracy in frequency measurement. The central laboratories will calibrate wave-meters sent to them and will issue calibration certificates. These will be specified as first class, if the relative error throughout the scale is less than roo (two ten-thousandths) under fixed conditions. The International Bureau of Weights and Measures will draw up a list of central laboratories entitled to deliver calibration certificates, first class. 20 FRENCH PROPOSAL CONCERNING TOPIC 6a OF THE PROGRAM STABILITY OF WAVES The emission-frequency of a tube-station may be maintained constant by various methods falling under three groups: (a) Specially designed master oscillator; (b) Master oscillator stabilized by a mechanical oscillator (quartz, tuning-fork or magneto-striction); (c) Master oscillator with frequency-regulator. The frequency of an alternator is provided for by mechanical or electric regulators. Constancy of temperature, which is essential in most cases, is maintained by a thermostat, working continuously or noncontinuously. 21 FRENCH PROPOSAL CONCERNING TOPIC 6b OF THE PROGRAM TOLERANCES The absolute irregularity to be tolerated must increase with the frequency, but less rapidly than the frequency, because it is desired to obtain a relative variation which is smaller at high frequencies. The following formula is proposed: i = A√f Where i=absolute irregularity tolerated in cycles per second; f=basic frequency in cycles per second; A coefficient to be fixed, which might be of the nature of 1 unity. 22 FRENCH PROPOSAL CONCERNING TOPIC 7 OF THE PROGRAM WIDTH OF A FREQUENCY-BAND The following empirical formulae are proposed: a-Telegraphy: L=B (i+m) telegraphy in pure continuous waves; L= width of band occupied in cycles per second; = B coefficient to be fixed; this should be larger than 2, in order to take account of the rounding out of the characteristic of the filter. B-Simplex telephony and broadcasting: L=B (i+2 P) L, i, B same significance as under a; P=maximum audible frequency transmitted, i. e., adopting the figures accepted by the C. C. I. Telephone; 1 P=3,000 for speeches; 1 P=5,000 for music of good quality and sounds perfectly expressed; P=10,000 for music perfectly produced. y-Multiplex: The width of band occupied will be determined by adding up the widths L mentioned above, counting the telegraphic channels as waves modulated, with the frequency m=1,000, and telephonic channels as commercial telephony, with P=2,400 c/s (C. C. I., Berlin, 1929). &-Picture transmission: P will again be taken as =2,400 c/s (C. C. I., Berlin, 1929), this value corresponding to the minimum speed of transmission by wire for commercial purposes. 23 FRENCH PROPOSAL CONCERNING TOPIC 8a OF THE PROGRAM SEPARATION BETWEEN TWO SUCCESSIVE FREQUENCIES Widths L, and L2 of the bands occupied by the two transmissions will be calculated by the above formulae, and the minimum distance between the two carrier waves will be determined by the formula: However, a smaller distance may be admitted, if the conditions of Article 5 of the Washington Conference are fulfilled. 24 FRENCH PROPOSAL CONCERNING TOPIC 8b OF THE PROGRAM DISTANCE BETWEEN THE FREQUENCY OF A STATION OF A GIVEN SERVICE AND THE EDGE OF THE BAND ASSIGNED TO THAT SERVICE The introduction of factor B in the formulae in the proposals concerning Topic 7 establishes such a zone of protection. 25 FRENCH PROPOSAL CONCERNING TOPIC 9 OF THE PROGRAM ELIMINATION OF NON ESSENTIAL TRANSMISSIONS By "nonessential transmission" may be meant: Harmonics; The compensation wave in telegraphy, when it is not effectively used concurrently with the working wave; One of the side bands and the carrier service in the case of modulated telegraphy or telephony; Transmissions made during the period of variable régime, in particular at the beginning and end of signals; Transmissions due to oscillating circuits other than the circuit of the antenna; Sub-harmonics due to relaxation, etc. The elimination of these nonessential transmissions would considerably increase the number of carrier frequencies which might work effectively at the same time within the band of frequencies allotted to a particular service. The means to be employed could not, however, form the subject of general regulations. 26 FRENCH PROPOSALS CONCERNING TOPIC 10 OF THE PROGRAM STUDIES TO BE MADE ON VARIOUS PHENOMENA RESPECTIVE TASKS OF THE C. C. I. RADIO AND THE U. R. S. I. The organization of special inquiries to be undertaken, by international agreement, as to the above phenomena, is among the duties of the U. R. S. I., whose members are perfectly equipped in their laboratories to undertake the work necessary for these inquiries. But the transmissions on which this work should be based can generally be carried out only by powerful stations in regular operation; the assistance of these should be obtained and organized by a permanent organization of the Radiotelegraph Union. Further the U. R. S. I. should place itself as far as it could at the disposal of the C. C. I. Radio for any inquiry which the latter might ask it to undertake. FIRST PROPOSAL Special Transmissions for Collective Experiments Programs for special transmission with a view to certain inquiries which might be proposed by the C. C. I. Radio would be drawn up |