Build concentric coil for IDX-PRO+VDI

[camel131]

Hallo all
I can't find any solution for my problem.

I have this (plastic -PS-) for coil form and I want to build concentric coil for IDX-PRO+VDI.
My main question is :
-numbers of turns tx ,rx and bucking coils I should use in these parameters (tx diameter-245mm, rx-115mm)
Now I can use wires : 0,15 and 0,7mm.
Maybe someone has already solved a similar problem?

[dfbowers]

As long as you can add shielding you will be OK. I have used George's sticky coil calulator with great success. You can find it under the coils section of the forum.
I can run the numbers for you..
Tx - 29 to 30 turns (about) for 580uH <- Get this to work first with a 1uF cap in Parallel at slightly BELOW desired frequency (6.59kHz). It will rise slightly when bucking coil is added.
Rx - 350 turns (about) for 35mH <- You will need a 33nF cap in parallel with this coil.
These numbers are ballpark and generally get you pretty close.

Bucking coil is a relationship of the area enclosed by the two circles. The best way to null is to add extra turns to start with - say 10 turns (which will be about 3 or 4 turns too many).

The ratio of your inside/outside area in each coil is about .21, so 30 turns X .21 is 6.3 turns for the bucking coil.
You can calculate that yourself here :
http://www.basic-mathematics.com/are...alculator.html

Start to remove bucking coil turns while checking your Rx signal with the Tx running. You will soon hit your null. You may then need to fine tune with smaller capacitors.
Wire size is OK.

[camel131]

Thanks dfbowers
In Your fast answer is given almost all I needed for build this coil.
For shielding this coil I plan to use graphite spray inside coil cover before aplying foam glue.

[dfbowers]

Thanks dfbowers
In Your fast answer is given almost all I needed for build this coil.
For shielding this coil I plan to use graphite spray inside coil cover before aplying foam glue.

Just a few side notes.. These coils seem to be very pickey. If you are just a little off on the tuning and you may not get the GB adjustment within range. Don't get frustrated though.. take your time and figure it out. I just finished my 4th coil for IDX - a 10" concentric almost as you are building, except mine is 254mm and the Rx coil is 127mm . It works just as good as a stock 9.5" coil and only cost $20.00 to build.
I will post up some pics and video of coil #4 soon.
Good luck!

Don

[camel131]

thx, thx ...
It's great to see additional pictures and video. Do not forget to add these images.
I, too, I can fit my plastic coil housing with dimensions such as your coil, there's so much space.
Now knowing that it works well, I can start to do. It is very good for beginer as I'am.

[dfbowers]

Here u go.. The latest 10" coil.

Don

http://www.youtube.com/watch?v=bVbGz...ature=youtu.be

[gurdal]

IDX-PRO + VDI 30 cm concentric coil values