April 1993 Grinding Frequency capture
Grinding sound recorded 1993 April.                     Sensor underground
Unknown reception

VLF test receiver
April 2, 1993           HUM Capture
February 1993          HUM Capture
2 print outs of odd foot prints. Experimental VLF Receiver
10/30/08
October 1992
Computer Sound cards are not created equal.
You may or may not play back these samples.
Raw ambient magnetic flux in work room. Sensor test. Orientation
1989/1991
1989/1991
1989/1991
1989/1991
1989/1991
1989/1991
1989/1991
1989/1991
1989/1991
1989/1991