Published Resources Details
Journal Article
- Title
- A field intensity set
- In
- Journal of the Institution of Engineers, Australia
- Imprint
- vol. 5, no. 1, Jan 1933, pp. 6-13
- Description
This paper, No. 433, originated in the Sydney Division of The Institution.
[Authors Alfred Leonard Green, MSc, a non-member and Herbert Boyne Wood BSc BE StudIEAust were both involved with radio research at the Council for Scientific and Industrial Research.]
- Abstract
Following the Kennelly-Heaviside layer investigations at Jervis Bay, distant 140 km. from the sending station, it became desirable to continue the work at much shorter distances from the transmitter, of the order of 20 km. This called for short investigation of sky wave and ground wave field-intensities, for which apparatus was developed.
The paper describes a field-intensity set for both ground and sky waves. The development of a vacuum-tube millivoltmeter enabled the components of the artificial signal injection apparatus to be calibrated directly; the accuracy of the complete assembly therefore depends only on the precise measurement of the geometrical dimensions of the loop aerial, and on the calibration of the millivoltmeter. The use of a substantially linear vacuum-tube voltmeter, following the amplifier in the receiver, greatly facilitated the measurement of low field-intensities.
A few results are given of practical tests with the apparatus in measuring field-intensities of both ground and sky waves, from which the conclusion is drawn that a suitable set of conditions for subsequent Kennelly-Heaviside layer studies is the combination of a distance between sender and receiver of about 25 km., with a transmission frequency of about 1,500 kilocycles.