A
Anonymous
Guest
Hi Eric, there is an article from J.A.Corbyn in Wireless World, March & April 1980, describing a PI with an TX and two noise cancelation RX-coils (900mm diameter!) with much theoretical stuff. The noise of the earth magnetic field is measured and there is also a sofisticated analog ground rejection cirquit, overcoming magnetic viscosity effects. This way he comes to a gain up to 5000 and claims to detect a 50mm piece of brass at 750mm distance! Do you have this article? Besides the unpractical size, do you have further comments? regards Walter