Ideas Maybe a help..

[Henrikras]

Coil works isn't not Allways easy.
Made some small Tools to help me finetune - now its easy to change a little sharpe, finding the Null and the scope work.

By turning the Black wasser the distance will either Be more or less.

Henrik.

[Davor]

Interesting, but IMHO superglue works perfectly well and is much easier to come by.

[Henrikras]

You right Davor.... Only an idea Maybe other can use.
This coil is part of a new Deus project - and I need to get it tuned to 8 khz, 11 khz ,17 khz and take it in and out of the Shell many times, and the shielding will not Be painted in the Shell.... Thats why I needed some easy way to finetune.
Picture is showing my new plan with shielding - A wooden form to encapsulate the coils in some foam, then paint the graphite... And last down in Shell and close it with the Compound mass... Result Hopefully a lighter searchcoil and a bette shielding.
Time will tell.
Henrik

[satdaveuk]

Coil works isn't not Allways easy.
Made some small Tools to help me finetune - now its easy to change a little sharpe, finding the Null and the scope work.

By turning the Black wasser the distance will either Be more or less.

Henrik.

Very smart , thanks for sharing

[golfnut]

Is this a 6" too?

The foam may not be rigid enough to stop falsing.


PE Insulation foam board may be option? (strip the aluminium off) Knauff/Kingspan/celotex)

If you can get your coils in this, you could glass fibre the outside. ???

steve

[Henrikras]

No Steve this is a 15" Deus coil... Its a learning for fun project.
In a few days the NEW eliptical 5,5" x 7" Shell design from Donald Bowers will arrive and that will Be my no.1 project.
I'm still VERY happy with the 7" DB Deus coil.. It just perfect at the Heavy iron area.(found a lot with that little nice coil).
The idea to make a closed shield case with some kind of foam is difficult, (like all coil works), but I found out that paint with grahite inside a Shell is allmust impossible to make perfect with a brush.. Spray can be done, but to exspensive in the long run.. Thats why I'm trying some new ideas. Just got some Black solid and rigid foam (I think its this 45kg) http://www.lindeoglarsen.dk/files/sk..._and_60kg..pdf
Its my idea to cut place to the coils and close it with glue. Then do the shielding. Still only like test to see how it would work.
Its not easy to make a lightweight 15" coil, so that allso in my mind, using this material.
But Thanks with your proposals, its the same way I'm thinking.
Henrik.

[golfnut]

Yes I see - I wanted to use a strengthening tube across one of my coils to stop flex. Falsing.


I was going to use 5mm diam carbon tubing from model shop, or they do square section also - very stiff and light

This kind of thing

http://www.rcfoam.com/carbon-fiber-s...f68f916e55c4e3

good luck S

[Henrikras]

Good idea Steve, this Carboon tubes.. Less weight and makes the coil more stable.
I need to make the third try RX / TX to my 15" project.. Second try I broke this morning.
Henrik.

[Henrikras]

How would you do this ?
Skippy learned me to add 2 or 4 turns turns, Winding the coils. Like this 134 turns + 2 + 2 turns...
Then its easyer to find this enductance the coil should end at. But what would you do with those extra wires coming out in the end of the coil, If the total turns ends with 138 ? (All turns together)
1. cut the extra wires short and solder them nice and isolate them. 2 No Cutting, but tape them close to the other windings.
I would think that no.1 would Be the best, but I know that normal we prefer to avoid soldering close to the windings ! Or not.
Thanks. (Ps. Hope you understand my quenstretion, Otherwise I must post a picture)
Henrik..

[golfnut]

I have only seen this extra loose turns on a concentric not DD.

If the freq has to be bang on with caps which are pre selected, then I would make more than one coil.

The first as prototype, learn what you get, correct it.

Validate what you got.


Make the real coil incorporating your findings so it will be right.
Even then I would add say 2~3 extra turns, these can be teased out from the bindings one at a time in order to remeasure L value and frequency and hit the target.

(Tighter bindings lift the L value slightly)

I dont like having loops of active wire in any design. Steve

[Skippy]

The purpose of adding the extra isolated windings is you can add or subtract a few turns, or not use them at all, with the winding bundle tightly bound up, in its finished shape. You can even individually screen a winding, and still fine-tune it afterwards. So if you calculated (and used other experience, eg. a previous build) that you need 130 turns, wind it with (130T + 2T +2T). If you measure the 130T, and it is a little low, wire in one of the 2T, in the same direction, to get 132T, etc. If you have too much L, wire in the 2T in anti-phase, to give 130T - 2T = 128T.
Any unused extra turns can be left unconnected, with short (10mm) leads just long enough to connect to them if you have a change of plan etc. If you are planning on immersing the coil in conductive resin, it might be wise to paint/varnish the bare copper wire / solder-joints to insulate them, or bring them out of the way of the resin.
The L value of a coil varies with the (Turns squared), so you can easily calculate what changes to make to the total number of turns, based on how the main winding measures up.
For coils with lower number of turns, eg. TX coils, you could try, for example winding (35T + 2T +1T), so you can make any number from 32T to 38T.

[Henrikras]

Thanks... That was a good information. Okay anti-phase can allso Be made (130 -2 = 12.
Henrik.