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yes I have left a gap of 1 inch...I will try to explain abit more detail when the object lets say a silver coin when waved in front of the coil at the further limits of its detection where the sound is very faint and when the sensitivity is turned to maximum the sound is oscilating and its sound pulsey ...when the sensitivity is turned down just a little bit from the maximum mark the sensitivity drops dramatically....so either the machine is working harder to drive this coil or not hard enough im not sure,I am thinking it is the damping resistor that needs changing but i am not sure what value resistor to use...what do you guys suggest
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It will be very difficult to arrive at any conclusions without comparing oscilloscope pictures from before and after the modification.Originally posted by Micheal View PostComment
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Maybe you do not measure at the same position of the multimetr switch (on the same scale instrument) before and after, or maybe your multimeter battery dropped between two measurement (cause you do not switch off it).Originally posted by Micheal View Post.the garrett xl 500 8inch coil is not sheilded and measures 1.2 ohms... ...On completion I then measured the ohms and it has now dropped to 1.0 ohms ...so it has dropped by 0.2ohms ,t
Lower PI coil resistancy is ok for many reason (it is related to: better Q, faster response, lower parasitic C, stronger signal etc.) nothing bad.
Without the oscilloscope you will very difficult to determine the true value of damping resistor.
The right value of resistor was selected at time, when the return pulse voltage drops as soon as possible and as much as possible linear, rather than in some shape of curve.
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looks like I have hit a brick wall again ...I think I will just return it back to originalComment
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