Extensive measurements have been made of the field distribution about a vertical antenna operating at 29 megacycles over sea water. With the help of a small, nonrigid airship observations were made at various altitudes which permitted the plotting of the space characteristic and the determination of the attenuation as dependent on altitude. The experimental results are compared with field intensities computed for the given physical conditions from the theoretical expressions of Sommerfeld and Strutt. Of interest is the manner in which the field is attenuated in the immediate vicinity of the ground plane and the marked effect on the general intensity distribution of the effective height of the antenna above ground.Details are given of the design of the apparatus required for carrying out the measurements.
In recent years it has become increasingly difficult to correlate readings of volume level made by various groups because of differences in the characteristics and calibrations of the volume indicators used. This paper describes a joint development by the Columbia Broadcasting System, National Broadcasting Company, and Bell Telephone Laboratories which resulted in agreement upon, and standardization in the respective broadcast and Bell System plants, of: a new copper‐oxide rectifier type of volume indicator having prescribed dynamic and electrical characteristics: a new reference level based on the calibration of the new instrument with a single frequency power of one milliwatt; and a new terminology, the readings being described in “vu.” It is hoped that other users of volume indicators will join in the adoption of these new standards.
The paper gives in considerable detail the technical data and considerations on which was based the choice of the characteristics of the new volume indicator and the other features of the new standards. Particular attention is paid to the technical data supporting the decision to make the new volume indicator approximately an r‐m‐s rather than a peak‐reading type of instrument.
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