I've never heard of this unit Jim, it's incredible to think of how far technology has come when it applies to detectors.
Many other blogs and articles talk about the first metal detector being invented by Alexander Graham Bell. In 1881, he used one in an attempt to locate and remove a bullet from President James Garfield’s back after he was shot by Charles J. Guiteau. The attempt to locate and retrieve the bullet was a failure however, as the metal springs of the bed he lay upon interfered with the crude metal detector. Sadly, the President would soon perish from an infection that set in from attempts to retrieve the bullet. Not from the gunshot itself, which was later deemed non-fatal.
It was not until roughly four decades later that metal detecting would take a huge leap forward in the 1920’s. German immigrant and inventor Gerhard Fischer was granted the first US patent for a metal detector in 1925, based off of radio direction finding. He shared the idea with Albert Einstein who was so impressed, that he predicted the worldwide use of metal detectors after seeing Fischer’s idea.
