This is a discussion of the application of the zonal harmonic series to problems involving dipole sources in the vicinity of spherical boundaries. The application of a formal zonal-harmonic series solution to directly obtain numerical results involves two distinct problems: namely, the convergence of the series solution and the accurate calculation of the special functions involved in the series solution. Some interesting techniques will be introduced which help to improve the convergence properties of the series solution.
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 92-94
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
Three -dimensional boundary value problems are difficult to solve. Indeed, while the separation of the scalar wave equation can be effected in 11 different coordinate systems, an analytic solution requires that the boundaries, both external and inter...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 86-91
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The perturbation of alternating electromagnetic fields by three-dimensional structures is considered. The general model is that of a semi-infinite conducting half -space which consists of regions of different conductivities. A numerical method is use...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 62-72
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The use of radio signals for underground communications was considered as early as the mid-1920's [1] - [4] . However, early experiments did not produce promising results with the type of equipment that was available then [5] . With advancements in s...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 168
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
An electromagnetic sounder developed for an archaeological application in Egypt has been successfully tested in a California dolomite mine. Chambers in the mine 100 to 130 feet from the surface gave intense, well-defined echoes consistent with an ave...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 130-139
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
To realize a radiowave communication along mine galleries a few kilometers long without repeater, we show that it is possible to use a coaxial cable bearing an important surface transfer impedance like a transmission line with an inductive coupling t...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 1-8
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
In 1969, new coal mine health and safety legislation was enacted in the United States. As a result of this legislation, the Department of Interior, Bureau of Mines has carried out communications research aimed at developing whole mine communications ...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 9-14
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
It is the purpose of this paper to review theoretical model concepts in through- the -earth transmission of electromagnetic waves. While the subject is very broad in its defined scope, we will be conscious of the specific applications to mine rescue ...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 169
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The present status of the National Bureau of Standards program is that many magnetic tapes of analog data have been recorded in four major mines. Each mine uses different types of equipment. In addition, some surface measurements of noise have been m...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 121-129
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
We present an electromagnetic method taken from the well known radiogoniometer that allows us to locate at the surface of the ground the vertical axis of a magnetic antenna transmitter buried at a depth h in the earth. The method and the equipment ac...
Emslie, Alfred G.; Lagace, Robert L.; Strong, Peter F.;
Conference Authors:
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 38-48
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
This paper is concerned with the theoretical study of UHF radio communication in coal mines, with particular reference to the rate of loss of signal strength along a tunnel, and from one tunnel to another around a comer. Of prime interest are the nat...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 20-33
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications system which will allow surviving miners to make their circumstances known to rescue teams. Various communications techniq...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 48-53
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
So far as the propagation of electromagnetic waves is concerned, an underground tunnel behaves like a pipe or hollowed waveguide. Waves propagate in this tunnel with a low attenuation only if their frequency is higher than a so-called critical freque...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 162-167
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
Explicit expressions are presented for the input admittance and effective height of several buried metal antennas, namely: (i) prolate spheroidal; (ii) spherical; (iii) oblate spheroidal; (iv) parallel plate; (v) parallel plate with protruding dielec...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 140-148
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
nvestigation into the expressions of the field produced by a loop over a conducting half space or in an infinite conducting half space are well documented. Reasonably complex descriptions of the effects of stratification also are reported. However, a...
Bannister, Peter R.; Williams, Frederick J.; Katan, J. Robert; Ball, John R.;
Conference Authors:
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 162-167
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
During the last week in March and the first week in April, 1973, the Naval Underwater Systems Center measured the 76 Hz magnetic field strength (in Wisconsin and Texas) produced by both the elevated and (newly installed) buried Wisconsin Test Facilit...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 54-61
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
Radio propagation measurements were conducted in a coal mine at UHF (200 to 1000 MHz) and VLF (1 to 50 kHz) to characterize the transmission loss of intra-mine paths. The basic experimental parameters included frequency, polarization, path orientatio...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 171-177
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The Location Group conversed in the Petroleum Room of the Green Center with the purpose of addressing the following list of topics in light of the Bureau of Mines' requirements for detecting and locating trapped miners by electromagnetic methods. The...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 81-85
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The feasibility of locating a buried vertical magnetic dipole source (horizontal loop) from surface measurements of the vertical and horizontal magnetic field components has been investigated by Wait (1971). , For sufficiently low frequencies, the ma...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 112-120
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
Considerable current interest is evident[l,2] in the use of transient electromagnetic methods for subsurface remote sensing. A transient method is discussed which uses a periodic video-type pulse containing a wide frequency range. A video pulse is us...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 92-94
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
Three -dimensional boundary value problems are difficult to solve. Indeed, while the separation of the scalar wave equation can be effected in 11 different coordinate systems, an analytic solution requires that the boundaries, both external and inter...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 86-91
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The perturbation of alternating electromagnetic fields by three-dimensional structures is considered. The general model is that of a semi-infinite conducting half -space which consists of regions of different conductivities. A numerical method is use...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 62-72
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The use of radio signals for underground communications was considered as early as the mid-1920's [1] - [4] . However, early experiments did not produce promising results with the type of equipment that was available then [5] . With advancements in s...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 168
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
An electromagnetic sounder developed for an archaeological application in Egypt has been successfully tested in a California dolomite mine. Chambers in the mine 100 to 130 feet from the surface gave intense, well-defined echoes consistent with an ave...
Thru-the-Earth-Electromagnetics Workshop (1973 : Colorado School of Mines)
Published Date:
1973
Source:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines, p. 130-139
Series:
Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
To realize a radiowave communication along mine galleries a few kilometers long without repeater, we show that it is possible to use a coaxial cable bearing an important surface transfer impedance like a transmission line with an inductive coupling t...
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