Homemade 12" Whites Coil

Hello Critterhunter and Everyone . These two attachments may be enough to get you started . Remember these are rough estimates and this search coil project was never completed . You will need some test equipment . The values still do not seem right . What I would do is buy a ton of wire and make more turns than is posted till you get the proper DC resistance . What I am trying to say is the calculations are correct for a 12 inch coil in respect to the wire gauge but the inductance values are wrong for a Quantum search coil [36 mh receive and 540 uh for transmit is correct] . There are enough numbers here now to get you started !!! Thats why nothing is posted on the internet because somebody started this project [same idea as you] but never finished it  !!! If you shop around , the wire is not expensive in big quantities and you can use the left over wire for more search coils if you want , or if you build other metal detectors .
HH........Regards........Eugene

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		Quote:			Posted by critterhunter
	Thanks for posting that. Good info to investigate. I'm wondering...what size double D coils have you built and for what machines? Did you find pinpointing to be impossible without a hand held pinpointer? We all know the stock Explorer DD 10.5" coil is a nightmare to pinpoint with. The machine is almost unusable unless you have a hand held probe to use with it. Which reminds me...anybody have any plans for a hand held pinpointer that is better than the Whites Bullseye? A friend uses the new Garretts pinpointer and it's real nice, but I'm not willing to pay $60 to $80 or so for one of those. I have no trouble pinpointing with the stock 9.5" coil on the QXT using VCO but that's not to say that a larger coil or a double D won't give me some problems.

Hello . Yes I have made some different DD coils for Tesoro and my Whites XLT . And pin-pointing is not as bad as everyone thinks . It just takes a little practice and you have to slow down on your sweep speed . When you go fast the target ID/depth is not accurate untill you slow down . I just use a composite trowel and brass probe . Dig your first targets very slow and remember the exact position of the coil in respect to the target you find . And after a while you will be "Right on the Money" every time . There are some pin-ponter schematics posted here . A pin-pointer is very helpfull and will speed up your target recovery time .
HH...........Regards.......Eugene

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		Quote:			Posted by critterhunter
	I'm still here. Just been busy with other projects. Again, do you still need an oscilloscope to tune a double D coil? What makes it easier to tune a double D versus a concentric? And, do you have a link to a double D building how-to?

Hello Critterhunter . You can use a inexpensive DVM/millivolt-ohmmeter for DD coil nulling . An oscilloscope is very helpful for concentric search coil / Metal Detector circuit building . There are some good tips on other forums with photos . Just do a google search . I will try to be back here late tonight to post some more on this subject , and others are welcome to post here too !!!
HH........ ......Eugene

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i also would like some info on a 12in or 14in DD coil for the whites blue and gray model detectors if someone could help me out.thank you

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thanks 

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