I can now detect a penny [air testing] at 7.5 inches with a gain [sensitivity setting of 9] There was no advantage of moving it up to 11 or twelve. The same result happens using a dime. After using it in the field a few days ago, I have decided that my settings will now be notch and nine for gain. I plan to notch out only the soda cap. If I get the middle tone on those lower icons, whatever is buried needs to be investigated.
I changed R49 to 850K. In hindsight, it would have been better to have used 900K. I changed R50 to 201 ohms (measured with Heath IM-2215). I also "in-circuit" bridged resistor with my schematic I.D. ER-1, but in the end I did not change the value of that emitter resistor. You will note that all original resistors installed have covered the board printing. Resistor values were determined by bridging the resistors with my Eico Model 1140, then removing and measuring the both of them while in parallel. Individually, they all produced a change in sensitivity with "in-circuit" bridging.
My other two detectors cannot compete with this one. I worked with the other GC and the Bounty Hunter using the same method, but there wasn't enough gain to warrant making changes.
Well, I guess I am unable to upload my diagram and photos. I would need help with that since all I get is an error.
Linkback: You are not allowed to view links.
Please Register or Login
http://www.thunting.com/smf/index.php/topic,71443.msg331454.html#msg331454
|
|
Logged
|
|
