Latest articles from Office Supplies (http://www.office-supplies.co.za) http://www.office-supplies.co.za 2012-02-10T02:51:03+01:00 text/html 2009-01-01T12:19:55+01:00 http://www.office-supplies.co.za http://www.office-supplies.co.za/metal-detectors-with-vlf-a22.html The VLF technology is based on a two coil principle, where the transmitter coil is being used to send an electrical impulse in a very low frequency through the coil, emitting a signal, which is being picked up by the second coil, the receiver coil, where the wire of the coil is being used as an antenna to pick up the reflected frequencies from objects which are located anywhere in the ground.