Introduction The fields of an infinite line source in the presence of a conducting half-space have been examined by Wait and Spies (1971). In any real communication link using a current-carrying cable for the transmitting antenna, the cable is of finite length. Here we examine the fields of a finite length cable carrying a constant current in the presence of a homogeneous conducting half-space. The constant current assumption is valid at sufficiently low frequencies when an insulated cable is grounded at the end points (Wait, 1952; Sunde, 1968). Here we examine both surface and buried cables since both downlink and uplink communication links are of interest. Also, we examine both frequency and time solutions since either CW or pulsed communications may be used. Finally, it is necessary to include both magnetic and electric field solutions since reception could be with either loops or dipoles. Since the finite cable solution is more complicated than both the infinite line source and the short dipole solutions, we explore under what conditions a cable appears to be either infinitely long or very short. Some special cases, such as- the low frequency limit, permit analytical solutions which exhibit the dependence on various parameters, such as cable length, quite clearly. Frequency Domain Subsurface Fields The geometry of a line source of length 2[l] located on a conducting half-space with the observer in the half-space is shown in Figure 1.Â
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The Coal Mine Health and Safety Act of 1969, passed by Congress in the wake of the disaster at Farmington, West Virginia, led to an extensive study by...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
An approximate solution to the electromagnetic boundary value problem consisting of a horizontal cylindrical conductor buried in a lossy half-space an...
1973 | 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 i...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
A portable, multichannel battery-operated mine-permissible measurement system was developed to measure the rms magnetic-field noise spectrum in the fr...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The attention of this group was focussed on four through-the-earth communication systems that are presently of high interest to the U.S. Bureau of Min...
1973 | 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...
1973 | 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 Bur...
1973 | 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 allo...
1973 | 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 i...
1973 | 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 t...
1973 | 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 con...
1973 | 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 s...
1973 | 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 magnet...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
A system for measuring amplitude probability distributions (APD’s) of electromagnetic noise in coal mines is described and typical APD’s from an u...
1973 | 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 docume...
1973 | 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...
1973 | 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, Bu...
1973 | 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 b...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
Noise processing experiments with ELF (3 to 300 Hz) atmospheric noise and signals in the 40 to 80 Hz range are described. The primary purpose of the e...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
The Coal Mine Health and Safety Act of 1969, passed by Congress in the wake of the disaster at Farmington, West Virginia, led to an extensive study by...
1973 | Proceedings of Thru-the-Earth Electromagnetics, August 15-17,1973, Colorado School of Mines
Description:
An approximate solution to the electromagnetic boundary value problem consisting of a horizontal cylindrical conductor buried in a lossy half-space an...
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