Underwater coil sled design

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What detector are you think of here?

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Have you even been reading my answers to your previous questions? The designer of the Delta Pulse probably hasn't tried to use that CAT5/CAT6 trick because it DOES NOT WORK. At all. You will get SOME return, but depths of 18 inches maximum for a 1 meter coil is a dismal result, not acceptable. You will be wasting your time, effort and money on a dream, not reality. NOBODY has ever built a coil that big using CAT5/CAT6 cable successfully.

If you insist on building one anyway, here is the answer to your latest folly. As to buoyancy, strive for neutral, not weighted. Use concrete latex repair patch and fill some PVC with it. There's no metal in it. The stuff you want can be found at Home Depot or any hardware store as concrete repair patch.

I still believe your best option is to rent an underwater camera. At 25 ft, a camera with a light will be far better that trying to decipher what you "hear" for your target return. Also consider sonar with 3D mapping. You can rent these things at a far smaller expense than building a coil.

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Too bad about the viewing with a camera. That would have been the easiest route.

I suggest you try to build your control mechanism in miniature before you proceed. You need to be able to put the coil into a plane (depth level) and keep it from going all haywire, left, right and center. If you know what I mean. You'll need both elevation control and yaw control underwater so your coil doesn't try to drag down your boat. Willy Bayout, one of our regulars here, has a Proton Magnetometer project going on right now where he describes his control mechanism for his magnetometer. See if you can find the thread because he lists his personal web site in each of them where he describes the entire design from start to current status.

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I still think that a floating coil will do the job for such a large object, OK put it this way my MDX280 will detect an aluminium door frame at 1.5m and that's with a 280mm coil with a 500mm x 500mm coil I did the same door frame at about 3.2m I did not try a 1000 x 1000mm coil as I did not have a reason to do so but am quite sure that it will perform well for such a large object. (Possibly up to 6m)

All the best Xavier

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Xavier

		Quote:			Posted by xavier
	I still think that a floating coil will do the job for such a large object, OK put it this way my MDX280 will detect an aluminium door frame at 1.5m and that's with a 280mm coil with a 500mm x 500mm coil I did the same door frame at about 3.2m I did not try a 1000 x 1000mm coil as I did not have a reason to do so but am quite sure that it will perform well for such a large object. (Possibly up to 6m)

The detector he is using will not provide enough power to drive such a large coil. His results in air will be disappointing but the results in water will be abysmal. That's the nature of the beast. Bigger coil? Needs much more power than a small box can provide. He'll get some detecting but for optimum, he needs to increase the power and radically alter the timing.

By now, you surely know why that is.

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