VLF stands for Extremely Low Frequency and is similar know-how Employed in detectors developed for coins, jewelry, and relics. VLF detectors broadcast at frequencies measured in kilohertz ranging from 3 kHz to 70 kHz. Here i will discuss five explanations why you might pick a VLF around a PI A http://lkf.phorum.pl/viewtopic.php?p=53151&sid=ee41a2acd54159409d5e7f82544d229b#53151