05361029 is referenced by 98 patents and cites 26 patents.

An improved locator system is provided which simultaneously couples a number of different frequency signals to a number of concealed underground conductive lines, for the purpose of locating and distinguishing between the underground lines. The locator system includes a transmitter which generates the different frequency signals for coupling to the underground lines. A receiver is also provided that detects the different frequency signals and distinguishes between the underground lines. The locator system further provides an arrangement for operating at virtually any frequency within the locating band, and for preselecting an operating frequency that avoids interference from extraneous signals.

Title
System for locating multiple concealed underground objects
Application Number
539616
Publication Number
5361029
Application Date
June 22, 1992
Publication Date
November 1, 1994
Inventor
Lester R Querry
Reston
VA, US
Alan J Rider
Reston
VA, US
Agent
Richards Medlock & Andrews
Assignee
The Charles Machine Works
OK, US
IPC
H04B 1/02
G01R 19/00
G01V 3/165
G01V 3/11
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