The system, called electromagnetic subsurface profiling (ESP), consists of a mobile transmitter-receiver antenna unit, electronic signal processor, magnetic tape recorder, graph recorder and battery power source. The antenna unit measures 36 x 40 x 8 in. and weighs 35 lb. A cable connects this unit to the processing and recording instruments, which weigh 375 lb. and can be mounted in a small truck or boat, depending upon where the ESP unit is used. The equipment requires two men to operate. The ESP unit is effective to a depth of about 20 ft., operating on principles similar to that of conventional surface-to-air radar, except that the radar pulses, sent out by the antenna unit, are directed downward. A portion of these pulses are reflected back to the antenna as they strike objects and are recorded as function of time. The time scale is converted electronically to a depth scale. The location, depth and type of utility lines beneath a city intersection are determined by pulling the antenna unit along each leg of a grid laid out on the intersection. As the unit travels the grid line, the underground structures identify themselves because each structure has different electrical properties than the earth surrounding it. Using the equipment, a contractor can locate utility lines under a typical 40 x 50-ft. intersection in four hours compared to the two days required using the more traditional method of digging across one leg of the intersection and determing visually the type and location of structures. Cost of the unit is 26,500 dollars.

  • Availability:
  • Corporate Authors:

    McGraw-Hill, Incorporated

    330 West 42nd Street
    New York, NY  United States  10036
  • Publication Date: 1974-7-4

Media Info

  • Features: Photos;
  • Pagination: p. 26
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00260468
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Oct 11 1974 12:00AM