large coil for minelab

[serhatsehri]

Hi all forum;
How do I make a 1x1 meter coil for Minelab gp 3500?
Best Regards

[mario]

I may be wrong, but I don't think you can make a coil this size for the 3500 without modifications.

Can some one else answer? I would like to know myself.

[serhatsehri]

large coil link

this coil
http://www.ebay.com/itm/Minelab-cust...67811361777186

[mario]

No where in the item description does it state the coil size -if anything, a reference is made to a 11" coil.

The auction is for 1 coil (excluding the housing).

[IBGold]

It should be no problem building a Mono 1 meter X 1 meter coil for the 3500 you just need the right wire and shielding I have built very successful 28" Mono coils and use them with both my 2000M and 3500M with success.

You will need a good LCR meter to get it right try for arround 300UH and .4ohms including coax you will probably need a wire either Litz or tinned wire with strands of .2mm or smaller as a starter I would try 34 or 36 strands of .2mm start at 12 turns and check inductance if too high remove a turn test again repeat until you get the inductance where you want it when winding use wood or plastic for your former and try not to have any metal close to the windings as it will upset the inductance readings my 28" x 18" Mono has 14 turns Yours should have around 10 turns I guess, Have fun.

Regards, Ian.

[homefire]

Look at the second photo.



Follow the links.

http://www.carboncoils.com/

[takhslambos]

do you think is posibole to made one squere 1,5x1,5 metre coil for the minelab gpx 4000???like the lorenz deepmax squere coil....(sealed inside a pvc pipe frame????)

[takhslambos]

the coil cable must be 6 metres long........it is posibole????? i like to buy a coil cable like that and placed to my minelab gpx 4000......imaging the depth.....

[takhslambos]

Look at the second photo.



Follow the links.

http://www.carboncoils.com/

how big is this coil cable??is 1x1x1x1 metre????(4 metres long??)

[homefire]

Don't know. I seen one they said was 48 inches across.

It's all in that link.

They also sell Coil Cable by the meter.

[6666]

From their site

[mario]

Thank you for sharing that with us Ian.

I didn't think we could reach the low resistance number for such a big coil. I've had issues finding Litz thick enough to even approach 18".

Anyway, those are some big coils on woody's site. But I don't see many people prospecting for very long with coils that heavy.

Have their been field tests? I doubt they're sensitive to the small stuff, but I'm curious to know about how deep they go.

Can the Minelabs finally pass Gary's horde test with these large coils?

[IBGold]

Hi Mario,

I have a 300uh coil I am working on for a project we are working on with Tinkerer and Group that uses commercial Litz wire and has a resistance way below .3 ohms in the TX coil but as I say it is for a special project and the wire is not light it is not a Minelab coil usually the Litz we use for the Minelab bigger coils is hand made by Stefan.

Regards, Ian.

[serhatsehri]

hi ıb gold

Hi Mario,

I have a 300uh coil I am working on for a project we are working on with Tinkerer and Group that uses commercial Litz wire and has a resistance way below .3 ohms in the TX coil but as I say it is for a special project and the wire is not light it is not a Minelab coil usually the Litz we use for the Minelab bigger coils is hand made by Stefan.

Regards, Ian.

my coil 290 uh and resistansce .56 ohms but how is shilding method.

[mario]

my coil 290 uh and resistansce .56 ohms but how is shilding method.

Figure that one out, and you can put the coil companies out of business. Their proprietary shielding method essentially explains 90% of why their coils are so good.

If you do a document search, you will find a very informative article written by Carl for the Hammer head. Read it, and afterwards, you can try experimenting yourself.

Unfortunately, you will not be able to use the scotch 24 shielding tape mentioned in his document. I have found this tape to be too thick, and if you use it, you will lose too much sensitivity.

The key lies in the material used for shielding. It has to be a very poor conductor, out of material that won't be picked up by the detector.

Check out your local crafts store and try different materials. I'm sure you will come across something useful.

Also, 290uH is not enough, you probably want to be as close to 300uH, not under.