in the original schemes it's very instable because problem of stabilyty it's temperatur, but if you modified it work nice, i hunting with it from 1996 and it better deep than mxt. it is stable. problem of it is coil, it work with two coil concentric, but i think that it can worked with sef to increase sensibility and deep. serch shemes of the circuit and i post here
Posted on: July 08, 2014, 03:57:27 am
image 1 it 's the original schemes, images 2 it's modified schemes.
c3-c4 on the coil in the modified schemes it is only capacitor 22nf silver mica for stabilyty in temperatur, fet mpf 102 is 2n3819 for increase voltage on the circuit and for problem temperatur, ic is not lm 311 but ad 822 duble for amplifing signal and stabilyty in the temperatur, resistor 15 and capacitor c7 are 47ohm and 47uf tantalic for increase voltage in to the oscillator circuit.
in to the buffer is connected ua instrument to controller oscillator circuit, for this in the resistor r4 it is potenziometer 1,2 komh to controller sensibility and metal that circuit detected and deep of the metal.
into the ad 822 came 1v ac and stabilized with ic and diodes to 0.5v dc. into the oscilloscop circuit oscillator generaze wave half-sine that varies when the metal is detected
circuit it s not pi, it s not vlf but it is ibryd to pi and vlf, for this it can detected gold and have not disturb of the soil
Posted on: July 08, 2014, 04:14:35 am
i have found most roman coin with it in to sites where it is impossible work with vlf, or vlf deep is very small.
ua instrument is connected direct to oscillator for controller also performance of the metal..mxt have grab on the display this circuit have visual controller and i think that we can to be sure of the performance of it istant to istant, not than mxt where display dont speak if performance it is constant...
regards
Posted on: July 08, 2014, 04:25:07 am
with m6 for example we can not work on the grass becaus it sounds, it sounds also on the carbon if ot is into the soil, mxt and m6 dont work nice if soil is wet...this circuit work nice and deep increase if soil is wet....
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