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Originally posted by baum7154
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NICE WORK, you should do a build plan of your coil design, i've been trying to produce a coil like that for my pi for over a year! -
OOOO I see. It is great ArtWork! Build with love!Originally posted by baum7154 View Post
For coil build plan please check a PDF file in the attachment. It is basket coil is for another Russian PI detector "Koschey-5I/IM" but it should fits Chance too.Comment
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Originally posted by Waikiki_Sweep View Post
Yes the paper in your attachment was the basis for my own redesign...kudos to the original!Comment
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Thanks!...I have more pictures of the coil build that I will post in the COILS forum under the title of CHANCE PI COIL/SPIDERCOIL tonight or tomorrow.Originally posted by sinclairuser View PostComment
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All photos and descriptions have been posted in COILS forum/CHANCE PI COIL on the spider coil build, and in the TECH forum/CHANCE PI BUILD on the overall CHANCE build.
DanComment
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[QUOTE=Waikiki_Sweep;183214]Also Minelab detectors using that same patent and technology which Chance MD tried are good to report beer caps and other questionable iron as ferric.
So I still have doubts about may-be better results are connected with use of separated balanced RX/TX coils in those detectors instead of monocoil in Chance.
Or they just processing data more accurately.
I am so jumpy about that beer caps because mingy local government and greedy hotel corporations have removed trash cans from my beach recently.
So now tourists sitting on the beach drinking beer and shooting that beer caps to the water in biblical proportions.
There must be some of your bottle cap shooters here too. Yesterday I was out on the dredge piles and got lots of hits but two were very strong and indicatedon the GOLD end of the scale. One was a broken off aluminum pull tab and the other on a crown cap, now on display in my collection
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Reporting broken off aluminum pull tab as gold is a legit result! Just OK!
Beer cap as gold is confusing but do not worry. You can find same failure for several very good metal detectors starting with popular Fisher CZ series.
Anyway your results with chance are amazing!!!!
There is your coil cooking receipt revealed:
insulated stranded wire = fast coil
basket shape = fast coil
insulated stranded wire X basket shape = SUPER fast coilComment
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Here in Oz we are also plagued by the New alloy's they are making beer bottle caps from, the alloy is very conductive and gives confusing results, you just have to dig them.Comment
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Originally posted by Waikiki_Sweep View PostReporting broken off aluminum pull tab as gold is a legit result! Just OK!
Beer cap as gold is confusing but do not worry. You can find same failure for several very good metal detectors starting with popular Fisher CZ series.
Anyway your results with chance are amazing!!!!
There is your coil cooking receipt revealed:
insulated stranded wire = fast coil
basket shape = fast coil
insulated stranded wire X basket shape = SUPER fast coil
Yes you have the gist of what I have done! However there are a few more nuances to the coil.
1. Eliminate the coax by using a continuation of the coil wire to make a twisted pair feed line. This eliminates a lot of capacitance and there is no lead or tin from solder in the field of the coil.
2. Use the smallest stranded gauge wire with at least 600 volt (thick) PTFE AKA Teflon insulation to minimize capacitance. This coil was wound with 26AWG silver plated 600 volt teflon insulated wire. I am looking for some 28 AWG 600 volt teflon wire now. The earlier coil wound with 23 AWG solid conductor with thinner Teflon wire had much more capacitance. I know that the silver plating is a no-no due to eddy currents but as the wire gauge gets smaller it gets diminished.
3. Do not flood the coil with any insulating resin. I used rod and sheet polyethylene foam to fill out the profile as in the pictures posted. Then 2 layers minimum of fiberglass woven mat and resin for armor to protect the coil.
4. I did not do a shield on this coil, just tied the wire lead from outermost windings to ground. Done this way I believe the geometry of this coil does provide a degree of self shielding but it may not be enough in some situations. No problem! The additional shield, if needed, can be applied directly to the fiberglass shell in the form of a painted on mixture of graphite and varnish with a protective layer of fiberglass over that and a connection back to the ground end of the feed should do the trick. I would make the shield coating measure in the range of 2k at one inch separation of the probes. By the way, I have seen comments on testing a shield by putting your hand on the coil and monitoring to see if the detector reacts to your hand (no rings or jewelry). This detector with the self-shielded coil does not react to this hand test which indicates an adequate amount of shielding if I understand the test.
5. For the CHANCE PI detector you do not have to use the prescribed 400uh coil and in fact, if you seek small gold, a fast/low capacitance coil in the range of 300uh to 350uh with an optimized damping resistor is the way to go. The coil in the photos posted is 334uh and about 2.0 ohms with an 1150ohm damping resistor. Feed line is 33 inches long…shorter is better.
6. Coil slots in the coil form must be wider than the form material is thick. This will insure that the wires cross in the slots at about the optimum 90 degrees to each other minimizing capacitance. Slots made as narrow saw slits will put the wires parallel to each other as they pass through increasing capacitance.
This mono-coil recipe should work for just about any PI detector designed for finding small gold…not just CHANCE PI. The coil I use was derived by making a 40 turn/486uh coil and making measurements, removing 1 turn at a time, while testing sensitivity to small gold targets using the CHANCE PI detector. In this case 32 turns was best.
Happy Hunting
DanComment
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Originally posted by 6666 View Post
Yes I think the geometry of the crown cap is bad enough of a challenge without a change to other alloys!Comment
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vidio of chance
hi exe bec the vidio dont upload the youtube and dont upload in this site but if evryone need to see send email to me than i send the vidio toComment
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Originally posted by Waikiki_Sweep View PostReporting broken off aluminum pull tab as gold is a legit result! Just OK!
Beer cap as gold is confusing but do not worry. You can find same failure for several very good metal detectors starting with popular Fisher CZ series.
Anyway your results with chance are amazing!!!!
There is your coil cooking receipt revealed:
insulated stranded wire = fast coil
basket shape = fast coil
insulated stranded wire X basket shape = SUPER fast coil
PS. Thank you for your kind words!
DanComment
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hi see this link for vidio of chance
http://www.uplooder.net/cgi-bin/dl.c...a831b3061ae166
or
http://uplod.ir/ml00240d98or/chance_...bardia.3gp.htmComment
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Hi what about your idea for my chanceComment
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