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ok i just ordered a sniffer xr71 pcb board and parts.this will be my first build.i would like to build a coil for it i have searched on the forums for the how to but could not find any. is tehre anyone here that could walk me through this?i've been reading all i can about building coils and want it to work out for me.but there are some many differant types that i dont have a clue about where to start...i know i want about a 13inch coil.concentric/DD/eliptical.im not sure about it will be used mainly relic hunting and some beach hunting.i am open on building 2 or 3 coils for each hunting area.i would like to start on this project before the board and all gets here just to get a jump on things.so i need to know whats a good wire/size of wire and i guess all that i need to build a coil.i appreciate everyones help in advance p.s is there a factory coil that will work for me
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Hi,
it is tough to predict exact number of turns to similar coil.
For 13" coil you can use wire #25 awg for a start, and make 27 turns on 13" former. Constrain windings good using some yarn (wrap it around wire windings and constrain) .
Would be good if you have previously finished detector to check with that coil before yarn wrapped around wire, so to be able easily to increase or decrease (more probable situation) number of turns for few windings.
It is desirable to also apply Faraday cage on that coil, simply because XR71 could be run on higher pulse rate, so cage can help to overcome instability issues caused by ground conditions (mineralization...etc..etc) so as interferences and surrounding hums.
Now...most common Faraday cage is Al foil wrapped tightly over wire windings and than contact made between Al foil and one of coil ends, by using ~5" long naked (uncoated or resin removed) also pretty tightly wrapped around Al foil, to make good electrical contact.
Another way (could be better) is to use graphite spay and spray good coil along its surface, except leaving small narrow gap somewhere on coil. Gap should be no more than 1/3" wide.
Before spraying first ensure also few turns of naked wire over coil, so later when spray applied to make good contact with it.
Naked wire is logically connected to one of coil ends (the one that goes to + pole at pcb)..
Hopefully this can help...
Regards!
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yes it helps some it gives me somewhere to start.but i have never built a coil or a detector, so some of the terms are confusing to me.but i will try my best.thank you if there is anyone else that has some helpful in put. im open to allComment
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also i forgot to ask what would be easier for me to make a concentric/a DD/ or a eliptical coil? i am a begginer thanks for your help
P.S. i talked to a guy that replaced the wire going from his coil to the detector to a heavy red one and he said it as the best there was.does anyone know of this wire/cable and a good supplier for coil building material? thanks againComment
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is this worth using or not?Cole-Flex SPT12 CFX11353 Teflon Spiral Wrap.or is the same thingComment
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has anyone used this wire before?is it any good?? silver and ofhc solid wire 26awgComment
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