Barracuda Legend Kit Problems

[Impulse]

or do you mean like a half wave rectified 'ringing'?

[Impulse]

If you have an under damped coil it will ring

when you say ring do you mean an audible tone from the coil?

[Impulse]

The damping resistor is 329.3 ohm

[Impulse]

ok i have just taken the pot off the board and it seems fine starts at 0.3 ohm upto 19.83K ohm.

[Old cart]

It is also possible that the damping resistor ( the one across the coil) is bad or the wrong value. Check this with your dmm. You can test inside just keep the coil away from metal. If you have an under damped coil it will ring and can cause these problems. Under damping is caused by the damping resistor being too high of value or a poor solder joint. They also can fail open due to too much current.

[Old cart]

Sounds like you may have a bad delay pot. Try unsoldering it and with your dmm in resistance mode and it between the center terminal and one of the outside thermals. The resistance should vary smoothly as you vary the setting from end to end. If it jumps the pot should be changed.

[Impulse]

Ok i the coil has been wrapped in insulation tape and i have even stood in the middle of my garden with it beeping for no reason. When i turn the delay pot all the way to one end i get a click (end of the pot) then if i slowly turn the pot i get a BEEP (to signify the start of adjustment?) then after that i get a random BEEP then nothing and again a random BEEP then nothing for the rest of the adjustment.

[Old cart]

It could be a couple of things. Electrical interference, coil windings moving, sampling set too early. Sampling clock jitter or a noisy op amp. I would not pot the coil but you can tape the windings.
BTW that looks like a better scope.

[Impulse]

no the cable is taped to a length of wood! that’s what i do not understand, even if i leave it alone when the wind gusts the board BEEPS! (so close to throwing it over the fence at this point) I’m lost as to what to do with it now i even looked at off the shelf (££££) detectors i will set the coil in resin so it cannot move EVER again and i am going to buy one of these,

http://www.ebay.co.uk/itm/Hantek-6022BE-PC-Based-USB-Digital-Storag-Oscilloscope-2-Channels-20MHz-48MSa-s-/121754238316?hash=item1c591e3d6c:g:EigAAOSwyQtV39Im

so i can set the delay to the exact point where it is supposed to be rather than guessing.

[Old cart]

Is the cable still moving? I would not think the wind could case such an effect unless you have metal dust blowing in the air!��

[Impulse]

hey guys ok i thought i had solved the movement issue but i havent i took it all outside and the wind sets it off! any movement left right up down or twist or even a gust of wind! i dont understand what is happening?

[Impulse]

ok i have sorted the coil movement issue it was the coil cable movement causing the response issue yay something simple to fix!

[Impulse]

I have the setup on floor at the moment as that was the only area i could find in the house that was out of the way, i will move to the garden once it stops raining. Even if i pick the coil up and move it i get a response the any small movement is enough to set it off.

[Old cart]

Hey guys I have just made a coil 24 wraps 0.5mm mono loop I have it all connected and I can get it to pick up my gold ring at 20 cm if I move the coil I get a detection tone so how do I shield the coil to stop this? Here's a pic of what I have so far
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Do you have the coil sitting on the floor? There are often metal bars in the floor so moving the coil can cause a tone. Put the coil on a wooden bench with no nails or screws or a cardboard box with no staples and try the test again. If the coils gets near any metal it can overload the circuit and ruin the response. You must perform all adjustments with the coil at least 40cm away from any metal. Even farther is better. Just moving the coil slowly, even it is not shielded, will not generally cause a response.

[Impulse]

Hey guys I have just made a coil 24 wraps 0.5mm mono loop I have it all connected and I can get it to pick up my gold ring at 20 cm if I move the coil I get a detection tone so how do I shield the coil to stop this? Here's a pic of what I have so far