INTRODUCTION
In the rapid growth of radio communication the appliances and methods used have undergone frequent and radical changes.
In this growth progress has been made largely by new inventions and applications, and comparatively little attention paid to refinements of measurement.
In consequence the methods and instruments of measurement peculiar to radio science have devel-oped slowly and have not yet been carried to a point where they are as accurate or as well standardized as some other electrical measurements.
This circular presents information regarding the more important instruments and measurements actually used in radio work.
The treatment is of interest to Government officers, radio engineers, and others.
Many of the matters dealt with are or have been under investigation in the laboratories of the Bureau of Standards and are not treated in previously existing publications.
No attempt is made in this circular to deal with the operation of apparatus in sending and receiving.
The Bureau’s publications on that and other radio subjects are listed in Appendix 2.
The Bureau will appreciate suggestions from those who use this publication for improvements or changes which would make it more useful in future editions.