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So I have this suspicion. I suspect that many metal detector companies deliberately limit the depth of their low end detectors by rejecting any signal it perceives as deeper than it's rated depth in order to make their better units more desirable. One thing I was wondering is if there would be any way to build a device between the coil and the control box that would adjust the feedback that the coil receives to always place signals in excess of the rated depth to what the control box would register as being slightly under the rated depth. My bh discovery 1100 for instance is rated at 6". If it automatically rejects signals in excess of 6" it would give me a reason to buy a 3300. If this is the case however than there should be some way of tricking it into thinking that objects of a greater depth are actually only 6" making it a much better cost effectiveness. just thinking
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To an extent you are correct, they don't make the low-end machines as sensitive as the high-end ones, in addition to giving them a lower feature count. But it's not just as simple as limiting the gain or changing software code. The whole machine is designed around the lower specification, so search-coils won't be so precisely nulled (hence they cost less), amplifier chips won't be so low noise (so they are cheaper), the search-coil housing may be simpler and less thermally stable (cheaper), capacitors may be polyester instead of polypropylene (cheaper) etc etc. So if you did hack a low-end machine by changing amplifier gain or such-like, you would expose all the other problems: drift, overloading, false-triggering, etc. -
I'm not so sure that it all comes down to lower quality components. I don't see how they would get significant savings buying a higher range of components for each model when some such as bounty hunter only have something like 10 different products. Though I don't have the other models to compare with, I suspect that some such as the discovery line may even use extremely similar if not identical mother boards with various features stunted or disabled in lower models.Originally posted by Skippy View PostComment
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Bear in mind if it's depth you are talking about, the target signal drops off very rapidly with distance from the coil (roughly inverse 5th - 6th power relationship), so if you made a machine with one-third the sensitivity, you're only talking 20% depth loss. But that lower gain makes things a lot easier for mass production, hence a cheaper detector.Comment
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Don't think so. Low end detectors often use short-cuts and simpler circuits, like half-wave demods instead of full-wave demods, or a lesser/cheaper ADC or micro.Originally posted by mashersmasher View PostComment
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Look at the Whites 6000Di schematic (do a search on here) find those 1% matched capacitors in the integrators then go look up the price difference between the STANDARD 10-20% toerance caps used in cheap detectors and the 1% ones Whites use. At LEAST 10-50X the price! There's part of what you have to understand right there
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Also try low noise amplifiers like any of the LT series, again not cheap. 1% metal film resistors as opposed to 5% cardon (noisy AND cheap) multilayer F4 (or better) based PCB's as opposed to single sided SRBP, it ALL adds up. If you do the maths or run you own business, you wil understand there are many more factors involved too. I have given you some very basic pointers though. Also be aware of the huge wastage companies like Whites must endure as they (used to) hand test each component for tolerance. ONLY the best get into their (top end) machines.
Remember, there are many ways to "skin a cat". The best ways are invariably the most expensive which is why Aston Martin cars cost more than Ford!Comment
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Fair enough. It was a theory that I had given some other products I have seen but in any case I guess it's understandable.Comment
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