32 cm DD Coil

[Geo]

Hi All. I Needed a coil for the ClassicIII so i made one 32cm DD .
So i ordered a coil housing from Mdetectors (without cover:confused: )
Transmitter coil has 90 turns 0.4mm wire (5mH).
Receiver coil has 110 turns 0.2mm wire (6.2mH).
After a good balance the coil working fine . So i post here some photos for everyone who interesting to build one.

[Geo]

Some photos yet. Photos from scope are before and after coil balance.
After balance the out of RX coil is about 5mv. The board inside the coil is to sold the coil leads.

[Qiaozhi]

I've just looked at http://www.mdetectors.com and these coil housings are really inexpensive.
In your experience - how reliable is this company? It looks like they're based in Bulgaria.
Do you also know if this is a secure site for ordering with a credit card?

[Geo]

I've just looked at http://www.mdetectors.com and these coil housings are really inexpensive.
In your experience - how reliable is this company? It looks like they're based in Bulgaria.
Do you also know if this is a secure site for ordering with a credit card?

Hi Qiaozhi. There is a company who check the authorising of credit card so i believe that it is a secure site (yes it is a Bulgarian company). The coil housings are very cheap but the transport is high. I paid 14.33 Euro for 3 housings and 32.56 Euro for transport. Never mind. Delivery was very fast. All was ok .

[Qiaozhi]

Hi Qiaozhi. There is a company who check the authorising of credit card so i believe that it is a secure site (yes it is a Bulgarian company). The coil housings are very cheap but the transport is high. I paid 14.33 Euro for 3 housings and 32.56 Euro for transport. Never mind. Delivery was very fast. All was ok .

Thanks Geo,

Wherever you try to buy these coil housing you always pay extra money.
I bought some from Hays Electronics, but got caught for Customs and Excise Duty, plus a big shipping charge.

[Geo]

Hi Qiaozhi.
I bought 2 DD housing coils and 1 concentric oval 36x22 cm. The concentric has two pieces (housing and cover) but the DD have not cover so are open from the down side (ground). From Bulgaria i had not any problem with Custom.

[Hush]

sesitivity

Hello Geo!

Your coil looks fantastic. Did you made some tests with it? Please share your
experience with as. I am thinking to make classic III, and I need to know which coil is better - DD or spider? Please answer me!
Almost forget- lucky I own Fisher spider coil 20 cm, Ivconic sad it can be used on it. Ivconic thanks !
So long muchachos! Best wishes to all of you!!!!!

[Geo]

Hi Hush. First time that i made the shield (it was from foil pieces) the coil was very good. But slowly-slowly i had a bad connection at foil pieces and i had unstable operation. Now i try to make a new shield with 3M tape as Reg told me. The turns that i constructed the coil are ok. If you have a Fisher spider coil try with it and later try to make a bigger one. Spider coil has better sensitivity but DD is better for wide scan. Only you know what is better for you.
Bye