15" Deus Coil.

[Henrikras]

If some one ever should start a 15" Deus coil project, I've got the it now..
TX - 10.2 mH / 19 ohm and resonans with a 15nf= 12.7 khz. One turn is 92.5 cm - 115 turns with AWG 0.35 mm wire.
RX - 15.9 mH / 48 ohm and resonans with a 15nf= 10.2 khz. Ond turn is 92.5 cm - 140 turns with SWG 0.25 mm wire.
The 15" Shell came from Georgi. http://www.geotech1.com/forums/showt...ighlight=Shell

Henrik.

[Henrikras]

Coil ready to the first outdoor test...

Hi all.
My 15" coil project just got the outside shielding and before any more will Be done, I need to test it at my testbed outside. Same shielding like my DB 7" coil and my DB 5.5x7" eliptical coil; shielding with low resistance of graphite spray. At the lab everything seem to work nicely.. Airtest depth allso good.
The weight until now 875 gram.. Not bad with this Big coil.
It will Properly not Be easy to find a field with allmust no iron, were this Big coil could Be usefull (If it will work), but it gave me some more exsperience to make coils and I needed that.
Henrik.

[greylourie]

Looks good. Is the wire for shielding temporary on top ? Or are you going to cover it more when everything is tested ?

[Henrikras]

The drain wires is not temporary.. No no they stay there. After test and Maybee more graphite a solid paint outside.
It isn't a perfect solution and properly it will Be damage, but this is a test coil. If it will Be a good coil I can Allways make a new with a better solution.
Working with shielding in test mode inside the search coil isn't easy - Thats why I choose this way to do it! Easy to add some more graphite, and go out and do a new test or sand If it got to much.
Henrik.

[bernte_one]

hello henrik

i wait for the next video you post with the 15" coil

[Henrikras]

Smile to you . Just been out and I could see that wet grass is a problem. Now I'm painting more graphite, this time with a brush and my mixture.
Need to let it Dry up and then a new test this evening or tomorrow will Be done.
Here is the video I made.. http://www.youtube.com/watch?v=lzUZErcqHbQ&sns=em

If this coil ever will end usefull, a test with depth will Be done..
Henrik

[bernte_one]

i wish you succes

i looking for an old used 22cm coil under 150€
then i would slaughter the electronics out

but at the momentary prices this is an expensive experiment

[Henrikras]

150 € old used !!!! That sounds exspensive.
Tell us what your plans are, Maybee somebody got something !

[Skippy]

The going rate for a used 9 inch / 22cm Deus coil here in the U.K is about 160 Pounds Sterling = 190 Euro = 270 US Dollars, see this eBay example:
http://www.ebay.co.uk/itm/XP-Deus-9-...t_Equipment_ET

[golfnut]

A lot of coils dont work well in wet grass if the sheild material can touch the ground.

If you try with more graphite and it is still bad, dry it up and try a poly bag over it and see if then ok in order to test.




How to you test the Rx coil frequency?

Is it possible the Rx is tuned closer to the Tx with this version?

Steve

[Henrikras]

I learn just what you said about the touching the grass / ground.. A isolated lay works better.
This way here I got the coil to work... First make the TX perfect by getting the resonans - see scope and get high amplitude like the Stock coil at all 11 khz and 17 khz, close to the Inductance the Stock coil got. Using a capacity 15 nf and getting the same resonans like the Stock coil, that was 10.2 khz at this 15" coil. Found out the my meter only was a guidens. After the TX is ready and in the Shell, then work with RX.
First step is to Wind the RX a little higher than the 15.9 mH the Stock coil got, ( lower resonans that the Stock coil) with some 2 + 1 turns extra to finetune
Then work with the sharpe and the turns in the Shell, finding a good Null at 11 khz and 17 khz, testing the ID's all the way from low to high ID's and its ready. I got a good feeling what to do If some is off.. This 15" coil I got fast to work.
All 3 coils I made is Very close to the Stock coil Inductance and resonans...
I know that you said before, try to change the RX, just a test, but If I go lower the ID drops out of number, and to high I can't get the same sharpe like the TX.. There is so many thinks with the Deus I need to hit perfect, Otherwise something wouldn't work.
The problem all the time is shielding..... Allso with this 15" coil. I got a Very low resistance now -100-300 ohm, but still some chattering.
now I gone a paint it with some lak, to get the graphite isolated to the touch like grass or ground. Hope that will work.
I made a air test before the shielding was made, so I can say how much lose I got, when its finish.
A Very good idea how to paint the graphite in a thin lay, is the next work I need to find out. This brush painting is a mess, it not easy to make nice, it not easy to get the same lay all over.. I hate this job. Spray is perfect, but to expensive.
Henrik.

[muddy fingers]

Hi Hendrik, Two things you could maybe try; Can you get a coil cover for the coil you made and then bind black tape all round it to completely seal it. Secondly, you could try just rubbing powered graphite over the coil surface evenly with your finger and then sealing it with a light silicone or very dilute resin spray or water colour varnish in a spray form if the layer of graphite is sealed inside the coil. If you get some small 2" X 2" flat pieces of plastic material ( the same thing the coil is made from) you could more easily experiment with different ways to easily apply the graphite. One thing that might work as well is to make up a mixture of graphite and washing up liquid. This can be painted onto plastic evenly and easily and then when dry it can be sealed with a spray. If you experiment on the small cut up pieces of flat coil plastic first then the whole process won't be so stressful as it is if you are working directly onto the coil itself and things don't work out as you had hoped. (I've got a big tin of graphite powder so I may be able to carry out a few experiments myself that may help- I am an oil painter so I know a lot about painting techniques if not electronics!)

[Henrikras]

Thanks Muddy fingers..
If you some day could do a test with your idea and mixture it would Be great.
There is two issues that we need. 1. The graphite powder shall Dry up, so a touch with you finger wouldn't give you a Black finger.
2. The surface must still Be graphite to get connection with the next lay, so we can add / paint more, If its need lower resistance or the mixture just are thin and need more than one lay.
My last try to avoid the paint ended with dust after it dryed up, was like this ; acetone / graphite powder / alcohol and 1% spray paint.
That gave me a okay results...
Still need to exsperiment some more.
Henrik.

[Qiaozhi]

Henrik - Are you painting the shield onto the outside of the coil shell?

[Henrikras]

Yes Qiaozhi - this is an exsperiment. At my 7" coil I first made some Sheilding inside, but had to paint much outside allso. That coil ended perfect (in my newbie World) - same was done with my little eliptical coil... Out and inside. I let the drain wire come out by a small 1mm hole and back inside again.
This 15" coil I've only got graphite outside... (And drain wires only outside) It was my plan to learn what different shielding will do, Thats why only outside. Its impossible to work with shielding inside, when the coil is closed and that was nesasary with this Big coil, it was to sensitive without filled up with resin. I got a lot of foam to lower the weight.
Did you follow our work with the Deus Stock coil... XP had allso made some kind of a shielding outside!
Outside shielding isn't to recommend at all.. Its Very difficult to make it solid and touch will make false signals.. If I got something right in this World.
Ps. I not afraid of making a fool of me.. Learning by doing, together will all your help is my way to get results.
Henrik