DOI:10.1049/ji-3-1.1942.0008

出版商:IEE    

年代:1942

数据来源: IET

摘要:

The paper covers vertical aerials and is divided into an Introduction and six other sections. In Section (2), low aerials are considered in relation to approximate formulae for radiation resistance and for terminal reactance, whilst the importance of the earth system is also examined. In Section (3), van der Pol's analysis for the radiation resistance (Rr) of vertical aerials, of all heights, is discussed, and various curves are given forRrvalues likely to be met with in practice. The effect of retardation of current is dealt with briefly, and curves for modifiedRrvalues are given. Vertical polar diagrams are next considered, in Section (4), while in Section (6) the knowledge thus gained is applied to determine the optimum height of anti-fading aerials. Technical details of anti-fading aerial design are discussed. Section (5) deals with feed current, and to a great extent bridges Sections (4) and (6). In Section (7), terminal values are considered, while two groups of curves are given for computing terminal resistance and terminal reactance.Appendix 1 outlines the calculation of field strength and of radiation resistance. Appendix 2 is a discussion of the distribution of current along an aerial, and gives a résumé of Dr. Bohm's analysis for feed current. Appendix 3 contains particulars of two new aerials, and gives notes relative to an observed variation of measurements.

DOI:10.1049/ji-3-1.1942.0009

出版商:IEE    

年代:1942

数据来源: IET

摘要:

The paper deals with the development of time bases of various types employing hard and soft valves both for general and for special-purpose applications. Since thedevelopmentof time bases is considered it follows that several instruments mentioned herein have been described elsewhere, but the purpose of the paper is to elucidate the principles involved in the wide variety of known time base circuits, rather than to attempt a detailed description of the actual instruments.Except for a few special remarks the application of the time-base potentials and currents to the cathode-ray tube is not discussed, and for this reason the electromagnetic time bases which have been evolved for television purposes are, in general, omitted from the paper. For similar reasons time bases which are solely applicable to high-voltage cathode-ray tubes are not considered.Several devices which are not generally known are described, and the technique of producing and controlling pulses is also considered since this has become of prime importance in many time base applications.The results of a recent investigation into some peculiarities of the gas-discharge triode are presented in the form of an Appendix.

DOI:10.1049/ji-3-1.1942.0011

出版商:IEE    

年代:1942

数据来源: IET