Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 7) (First Revision) which is identical with IEC 60153-4 : 2017 ‘Hollow metallic waveguides - Part 4: Relevant specifications for circular waveguides’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on recommendation of the Wires, Cables, Waveguides and Accessories Sectional Committee and approval of the Electronics and Information Technology Division Council.

This standard was first published in 1981 and was mainly based on IEC Pub 153-4 (1973) and JSS 53005. The first revision of this standard has been undertaken to align it with the latest version of IEC 60153-4 : 2017.

The text of IEC Standard may be approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.