摘要:

Measures are being taken to modernize, popularize, and speed up the Inland Telegraph Service. Instruments and machinery new to the Service have been introduced with unprecedented rapidity. Teleprinters, typewriters, copper-oxide rectifiers, rotary convertors, thermionic valves, voice-frequency signalling, and band conveyors, are the main features of the reorganized system. Each of these items- receives notice in the paper. Panel-mounted apparatus is a novel departure that has created considerable interest among telegraph engineers. In the circumstances it may be some time before technical literature giving a comprehensive account of the methods employed is available; the paper, therefore, describes the standard equipment in detail. A new class of technical officers for testing and maintenance duties has been created; the personnel is chosen from the general body of telegraph operators and receives training in an engineering school.A telegraph exchange service, “ The Telex,” has been made available to subscribers to the telephone service, for whom the necessary apparatus is installed on rental terms. The renters are able to transmit and receive printed communications in addition to the usual telephone facilities. They may also transmit messages to the Post Office, creating a new class of traffic designated “Printergrams.” We have telegrams, phonograms, and now printergrams. The supply of underground conductors is now more than adequate for the requirements of the public services, and channels of communication are offered to the public, on rental terms, for the purpose of private-wire circuits. The ascertained results of the reorganization, still far from complete, are in the direction of increased stability and accuracy. In addition, recent figures show an improvement in the financial position. In another direction there is evidence that the changes have not been entirely unfruitful as regards increased comfort and convenience of the army of workers who staff the telegraph instrument rooms of this country.

DOI:10.1049/jiee-1.1933.0031

出版商:IEE    

年代:1933

数据来源: IET

摘要:

In Part 1 of the paper is given a description of the phenomena observed when using a cathode-ray direction-finder on closed coils for examining received signals on frequencies of the order of 10 000 kilocycles persec. The two outstanding features are the systematic appearance of certaincyclic forms, and the large values obtained for the horizontally polarized electric components.The former are then examined in the light of the magnetoionic theory, and it is shown that the majority of them admit of simple explanation on this basis. The latter are chiefly of interest in raising the question of angle of incidence, which appears to be much less than is generally supposed; and Part 2 is devoted to a more detailed examination of the question.

DOI:10.1049/jiee-1.1933.0036

出版商:IEE    

年代:1933

数据来源: IET

摘要:

In a previous report dealing with the significance of contact phenomena in relation to measurements in dielectrics, the E.R.A. foreshadowed further work on a range of dielectrics, with a view to studying the effect of a.c. contact impedance with different types of electrodes.The present report gives an account of this work and leads to the conclusion that, for accurate determinations of power factor, permittivity, etc., flat metal electrodes should not be used. Both mercury and graphite give satisfactory results; consequently the choice between these two may be settled by considerations of convenience.The Director of the Electrical Research Association will be pleased to hear from investigators who have occasion to apply any of the proposals outlined herein.

DOI:10.1049/jiee-1.1933.0038

出版商:IEE    

年代:1933

数据来源: IET

摘要:

One of the most important problems in telephone interference at the present time is that of the dangerous voltages induced in communication circuits when an earth fault occurs on an adjacent high-tension transmission line with earthed neutral. Theoretical formulae have been developed which enable the coupling between the two circuits to be calculated, and measurements in the field have shown that, provided the resistivity of the earth is known, these formulae will enable an accurate forecast to be made of the induced voltage in the communication line, after steady fault con ditions have been established.The present paper examines the derivation of a mathematical expression for the coupling under the initial transient conditions. In order to see whether the variation between the initial and final values of the coupling is important, a number of practical cases have been worked out numerically for the first time. This has enabled curves to be drawn showing the induced voltage during the first few microseconds of a fault. The result of the investigation is to establish the sufficiency of the simpler steady-state methods of dealing with the problem for practical cases.

DOI:10.1049/jiee-1.1933.0039

出版商:IEE    

年代:1933

数据来源: IET

DOI:10.1049/jiee-1.1933.0040

出版商:IEE    

年代:1933

数据来源: IET