摘要:

It is well known that radiogoniometers of accepted design possess inherent errors due to the coupling between the search-coil and the field-coil windings, and that the magnitude of these errors increases with an increase of this coupling. In practical design it has therefore been usual to effect a compromise between the tightness of the coupling and the permissible errors.A special study of the subject has therefore been made with the object of analysing the causes of these errors and of introducing modifications which, while providing a tighter degree of coupling to the search coil, will at the same time reduce the magnitude of the instrumental errors.A preliminary examination of the various existing types of radiogoniometer shows that the errors are not uniformly “octantal” in form, and that the value of the maximum error is not necessarily directly proportional to the tightness of the coupling.Several methods of measuring the instrumental errors are described, and further information regarding the causes of apparently non-symmetrical errors is recorded. These are shown to be due to the vector addition of a number of separate errors all harmonically related in frequency but differing in phase relationship.A final summary, in tabulated form, shows the more important results obtained at various stages during the development of a new design of radiogoniometer which is evolved and shown to be at least 6 db better in signal/noise ratio than any existing design, while at the same time possessing a maximum instrumental error of less than ±½°.

DOI:10.1049/ji-3-2.1947.0014

出版商:IEE    

年代:1947

数据来源: IET

摘要:

This paper solves the problem of a circular coil of any radius with its plane parallel to two infinite and perfectly conducting planes separated by any distance. It is shown that if the distance between the planes is less than half a wavelength, then the output of work from the coil is zero; this corresponds to the well-known “cut off property” of the more conventional form of wave guide. The radiation resistance per unit arc of a single-turn coil is found to fluctuate, according to the radius of the coil, between zero and twice the resistance per unit length of a straight wire between the same planes. Equation (12) of the paper gives an exact expression for the field when the sheets are close together, and thus gives the absolute calibration for an “attenuator” of this form: also the parameters are calculated for a current transformer consisting of a pair of concentric circles between metal sheets. The solution is attempted for a single turn surrounding a metal tube (such as a steel mast): this succeeds formally and a numerical solution in any particular case is feasible. It may thus be said to have solved the two extreme cases of a circular girdle round a biconical metal sheet, a problem whose general solution remains very cumbersome so far.A particular form of solution of great practical interest is a coil enclosed in a cylindrical screening-can with closed ends. This solution turns out to be simple, and by its help the extensive experimental work of Mr. A. G. Bogle can now be completed analytically and extended to cover the change of high-frequency resistance of a coil due to enclosing it in a screen.

DOI:10.1049/ji-3-2.1947.0015

出版商:IEE    

年代:1947

数据来源: IET