Coil for a DIY detector

[Marauder]

In the interest of science(yeah science) i'd lie to remove one of the variable from my soon to be DIY PI detector. Namely the coil.

So does anyone have any advice as to a good coil for a PI detector? The DIY detector that i'll most likely be building is the Surf PI 1.2 which I think was based on the Whites Surfmaster Pro. Not sure what type of coil it runs, but i've heard PI detectors work better with monoloop coils.

Thoughts?

 

[AtomRat]

Hello again

From what I remember on the 'tube.. mono coils work great for them. There is a website and some guys done all the testing you want to do. If I could find it, it would help you lots..googles not showing it though

He tried and modified..many diy kits and coils

A help for google is that he covered the coil for protection using plastic plates. It could even be on PA forum
.ijust can't remember

 

[kleinman98]

In the interest of science(yeah science) i'd lie to remove one of the variable from my soon to be DIY PI detector. Namely the coil.

So does anyone have any advice as to a good coil for a PI detector? The DIY detector that i'll most likely be building is the Surf PI 1.2 which I think was based on the Whites Surfmaster Pro. Not sure what type of coil it runs, but i've heard PI detectors work better with monoloop coils.

Thoughts?

I have built the SM Pro PI and built my own coil and it is easy if you follow online instructions. Coil inductance is around 300uh.

 

[SteelPat]

I would look at building a coil first. No point in spending good money on a coil if you find the kit doesnt perform as you would like.

There are some very good instructions on this link as well as little theory to help you understand the basics of coil design for a PI machine. I have built a coil as described and it works fine. There are other methods but this is a good start.

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=/projects/fastcoils/index.dat

 

[Marauder]

Had a read of that coil article and it sounds easy to do but hard to get perfect. Not sure.

Would like to get a nice coil cover, but haven't found an 8" one with the top bit and brackets yet.

 

[SteelPat]

I have made a few coils and bought quite a few shells. Most come from Bulgaria but I have bought a few from a guy in the USA. You can look them up on Ebay.

Some finished coils look pretty good (some a little rough) but they do generally tend to be a little heavier than commercial ones as I have been using heavier Litz wire.

I also have a pretty good method of shielding using graphite that works very well (better than the aluminium or copper wrap) so if you want to build a coil let me know and I will give you the shielding method I use.

 

[Marauder]

http://www.ebay.com.au/itm/Detector-Coils-/111796868637

What do you guys reckon about these? 2X for $50 seems pretty good

 

[AtomRat]

Probably do the job if its not an issue matchinh coil to electronics like resistance or impedence whatever..

 

[Marauder]

bid placed. probably cheaper than the wire to make two of them!

 

[Nuggetbuster]

http://www.ebay.com.au/itm/Detector-Coils-/111796868637

What do you guys reckon about these? 2X for $50 seems pretty good

You know the old saying

 

[SteelPat]

One thing you have to be careful of is that not all mono coils have the same inductance. They can vary quite widely. You need to look at the specs of the coil and then look at what the kit needs. It will make a big difference in performance if they are not matched - A higher inductance will also mean a larger flyback voltage which can destroy a TX FET if its not designed for it. Too low an inductance will possibly mean a higher coil current (dependent on coil resistance as well) which again could cause issues.

 

[Marauder]

Is that saying "there are no stupid questions, just stupid people"?

hmm that's a good point on the physical characteristics.

Will probably need to modify the board to suit the coil.

 

[Marauder]

OK so I got the coils!

Now all i got to do is wait for them to arrive, and figure out how to work out their physical properties. I imagine that they will have the same pin out on the coil as the standard minelab ones?

 

[SteelPat]

They are for Minelab GPX series so I would assume so but its pretty easy to put a meter on them and see which pins are used.