Double loop receiver-transmitter combination

• US 4,163,977 A
• Filed: 12/21/1977
• Issued: 08/07/1979
• Est. Priority Date: 12/21/1977
• Status: Expired due to Term

• Current Assignee: Jurgen K. Polstorff
• Original Assignee: Jurgen K. Polstorff
• Inventors: Polstorff, Jurgen K.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/862,905
• Time in Patent Office: 594 Days
• Field of Search: 343/112 D, 343/112 R, 343/719, 340/551, 325/28, 325/371
• US Class Current: 342/459
• CPC Class Codes: G01S 3/14 Systems for determining direction or deviation from predetermined direction aerial arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00; combinations of different interacting aerial units for giving a desired directional characteristic H01Q21/29; aerials or aerial systems providing at least two radiation patterns H01Q25/00
• CPC Class Codes: G01V 3/104 using several coupled or uncoupled coils G01V3/101 takes precedence

Abstract

A double loop receiver used in conjunction with a transmitter broadcasting at low frequencies as a vertical magnetic dipole. The two loops are connected with their planes parallel in a resonant circuit, thereby cancelling atmospherics generated by distant thunderstorms and allowing the receiver to receive only the signal produced by the near transmitter. The loops are rotated around a horizontal axis perpendicular to the connecting line between the loops until a maximum signal is obtained. The direction of the connecting line is varied until the maximum signal shows the gradient and the direction to the transmitter. By noting the position of the loops and the loop angles with respect to the horizontal, the position of a transmitter buried in the ground can be determined. This system has particular utility in locating lost miners buried in a cave-in. Additionally, the double loop receiver concept can be used to detect subsurface ore deposits.

Claims

1. A communication link comprising:

(a) a transmitter buried beneath the surface of the earth, said transmitter producing a magnetic field having vertical dipoles; and

(b) a receiver upon the surface of the earth for receiving the signals produced by said transmitter including an identical double loop antenna connected in a resonant circuit, said double loop antenna rotatable around a horizontal axis perpendicular to the connecting line between said loops, said magnetic field produced by said transmitter reaching both of said loops at substantially the same time, whereby opposing atmospheric noise emf'"'"'s are eliminated and an optimum signal/noise ratio is produced.

2. A communication link in accordance with claim 1 further including a central loop and a varometer in said receiver.

3. A communication link in accordance with claim 1 further including a capacitor connected between said loops.

4. A communication link in accordance with claim 1 wherein said transmitter generates frequencies in the range of 100-10,000 Hz.

5. A method of locating subsurface individuals equipped with a magnetic field generating transmitter through the use of a surface receiver employing an antenna having two identical loops, comprising the steps of:

(a) activating the transmitter;

(b) tilting the two identical loops around a horizontal axis perpendicular to the line connecting the two loops until a maximum signal is obtained;

(c) rotating the two identical loops in a plane parallel to the earth'"'"'s surface until a maximum signal is obtained;

(d) moving the double loops in a straight line towards the transmitter as determined by said rotating step;

(e) tilting the angle of said double loops at each new location with respect to the horizon for maximum signal until the loops are normal to the surface of the earth;

(f) rotating the double loops 90°

;

(g) moving the double loops in a straight line in the new direction; and

(h) tilting the angle of said double loops for each new position with respect to the horizon for maximum signal until the loops are normal to the surface of the earth.

6. A method of locating subsurface individuals in accordance with claim 5 further including the step of estimating the depth of the transmitter and its distance from the receiver and then separating the two loops by a distance of either half as great as the depth of the transmitter or 10-20% of the estimated distance between the transmitter and the receiver before rotating the two identical loops in a plane parallel to the earth'"'"'s surface before tilting the two identical loops around a horizontal axis perpendicular to the line connecting the two loops.