Full explanation of Side Scan Sonar

		Quote:			Posted by goldnboy
	A MAD is the same as a magnetometer.

Almost the same. In theory, they operate by detecting fluctuations in the earth's magnetic field and that's where the similarity ends. From there, it's a matter of scale. A MAD works from an airplane or a ship or even in combination by computer link. They are capable of detecting very large objects from many thousands of meters from the target. Finding a roving submarine is a typical application. A magnetometer is normally used within a few meters of a target - typically less that 100 meters. It's used for finding metal objects in the ground. All metal objects deflect the earth's magnetic field, even the non-ferrous metals out there. The degree of deflection will vary based on the internal flux density of the magnetic field in which it exists.

Of course, this is a divergence from the topic of Side Scan Sonar. If we carry this any futher, we should begin a new topic so this discussion won't be lost in the background noise.

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		Quote:			Posted by xavier
	Or is it dragged on the sea floor and you are looking for an object protruding out of the sand

As I understand it, it is deployed a bit above the sea floor (after all, you don't want to snag it)....but just to be sure I "googled" it. 

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All of the side scanning sonars I have ever seen are boat centric. You really need a reference point to chart things and a boat is as good as it gets. Having the sonar free wheeling in the ocean would mean that a full navigation system as well as sonar would have to be in the towed unit.

As for MAD,they tow them airborne behind airplanes normally. Look up the P3 Orion and see how they are outfitted. Go on. Google one. You know you want to. Newer MAD system used disposable deployed buoys which coordinate their detected patters into one signal for analysis. Beyond hobby use, I'm afraid.

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		Quote:			Posted by xavier
	Sure sounds like the unit that they use to detect illegal mining too me mate

There are units for land use that are comprised of sensors placed in an array over a known grid. Anomalies are detected and analyzed by a computer system designed for that purpose.

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Xavier,

I know this is an old post, but if you are still interested in a home built Sidescan Sonar, check this site out. I think you might be able to get the plans from this guy.

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Carl

Posted on: October 18, 2014, 09:01:19 pm

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		Quote:			Posted by golddustcarl
	Xavier, I know this is an old post, but if you are still interested in a home built Sidescan Sonar, check this site out. I think you might be able to get the plans from this guy. You are not allowed to view links. Please Register or Login http://www.mbtelectronics.com/side-scan-sonar.php Carl

I just checked. The plans can be downloaded for free at the bottom of the page. The document contains everything you need to know to build one. It is well documented with photos, charts, parts list, circuit diagrams, even a red-neck way to carve the tow fish. examples, etc.
Carl

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A bad day at gold prospecting or metal detecting is better than a good day at work.