geof_junk Posted February 27, 2021 Share Posted February 27, 2021 So I thought I would throw a spanner into the discussion. Here goes. We have heard of the double D coils what about a triple D coil. Well that outside my knowledge but let look at a quad D coil the oldest ground balancing coil. Have a look at these links.....LINK....https://www.phys.k-state.edu/reu2011/nnorvell/Metal_Detector_Research.html and more detail.....LINK....http://41.67.20.41/bitstream/handle/123456789/18621/Metal%20Detector.pdf?sequence=1&isAllowed=y Are we on topic. _________________ Regards Geof. geof_junk Contributor Plus Number of posts : 794Location : Gippsland AustraliaRegistration date : 2008-11-11 Link to comment Share on other sites More sharing options...
Cascade Steven Posted February 28, 2021 Share Posted February 28, 2021 Geof: Interesting question and interesting first article. I personally have never read of anyone making a 4-D coil so I am curious if such a configuration has been investigated and if so what were the results? I was unable to access the second link. Thanks for posting an intellectually stimulating question. Link to comment Share on other sites More sharing options...
geof_junk Posted February 28, 2021 Author Share Posted February 28, 2021 1 hour ago, Cascade Steven said: Geof: Interesting question and interesting first article. I personally have never read of anyone making a 4-D coil so I am curious if such a configuration has been investigated and if so what were the results? I was unable to access the second link. Thanks for posting an intellectually stimulating question. The site has some problems...... It was a good write up on coils in the preamble I got ¾ of the way though it. I will try and get on it again when the site get back up as it had a lot of technical details in it over 40 pages. The site error listed below. This site can’t be reached 41.67.20.41 took too long to respond. Link to comment Share on other sites More sharing options...
Off Grid Posted February 28, 2021 Share Posted February 28, 2021 My first post here, coil-related, so I hope it's not too off topic. Two more spanners... First off I hunt residual gold mostly, not transported alluvial stuff and until I started nugget hunting a lot two years back I always thought that the term "gold patch" was just that, a term. To my surprise I've found that nuggets cluster really tightly. Although the district is a few square miles patches are no more than a hundred square yards with a whole lot of nothing between patches. So I tend to visit a patch multiple times. 1st pass-discovery, 2nd pass- move all the rocks, 3rd pass buy a PI and try again! Question 1 Is there a really thorough article somewhere on using no-motion mode? Both Garret and Fisher kinda cough and shuffle their feet on the subject saying it's best left to experienced users. Well, thanks guys that's real helpful! Question 2 (Full disclosure - I was an exploration geologist for many years and came up against EM systems) Has anybody ever used a relatively large, fixed transmitter loop and a roving receiver for nuggets in known patches where the soil profile is way, way thicker than even a GPZ's range. It's a standard technique in metals exploration and the large tranmitter and the ability to put more current through it would seem a no-brainer to get more depth in great patches that have been hammered? BTW I really enjoy this site and the discussions on it. Thanks. 4 Link to comment Share on other sites More sharing options...
geof_junk Posted February 28, 2021 Author Share Posted February 28, 2021 The PDF file of the second link in first post.http://41.67.20.41/bitstream/handle/123456789/18621/Metal Detector.pdf?sequence=1&isAllowed=y Metal Detector Second link.pdf 2 Link to comment Share on other sites More sharing options...
Steve Herschbach Posted February 28, 2021 Share Posted February 28, 2021 Question 1 Is there a really thorough article somewhere on using no-motion mode? Both Garret and Fisher kinda cough and shuffle their feet on the subject saying it's best left to experienced users. Well, thanks guys that's real helpful! None that I have seen. There would not be much to write about. Non-motion mode simply lacks an SAT function, so you have to be on top on the manual tuning. That’s it in a nutshell. Question 2 (Full disclosure - I was an exploration geologist for many years and came up against EM systems) Has anybody ever used a relatively large, fixed transmitter loop and a roving receiver for nuggets in known patches where the soil profile is way, way thicker than even a GPZ's range. It's a standard technique in metals exploration and the large tranmitter and the ability to put more current through it would seem a no-brainer to get more depth in great patches that have been hammered? Tow Coils Max Depth 1 Link to comment Share on other sites More sharing options...
Off Grid Posted March 1, 2021 Share Posted March 1, 2021 Steve Thanks for the links. I liked the tow coil post. Basically an airborne system flying at zero feet! My ground is too rugged for that but I recall that an early base metal EM system had the operator wearing a 5-6 foot coil like a giant hula hoop. One for the back-burner.... Next trip I'll blow the dust off my GB Mk1 for which I have a 14" aftermarket coil, pay attention to ground balance and give no-motion a shot over a hammered patch. 1 Link to comment Share on other sites More sharing options...
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