TX/RX 3 coil design - How to wind?

[scs]

Have coils electrostatic shielding ?

[geoscash1]

D's done, on to TX

Well, finally working on mine. Got the 2 D's wound, temporarily zip tied. Now to wind the TX coil then the process of putting it all together. The 2 RX D's are right at 190uH individually, 20 turns 24awg. I think I will make the TX around 300uH unless someone knows a better inductance to start with. I'm using 600v teflon 7 strand 24awg for all 3 coils since it is what I have on hand. I shaped them more "football shaped" based on a drawing I saw from Eric foster so hope it works right. Per the drawing, Coil "A" is supposed to be the best way to shape the D portion of the coil. Guess we will see... Will try to get the TX done today and see if I can get some testing done.

Do the TX and RX coils need to match as far as inductance or should the TX be less inductance than the RX coils? I think I read somewhere the TX can be half what the RX coils are but cannot find that info anymore.


RX Coils


Best way to form D's (A being best)


MPP used for testing


inside

[eclipse]

Have coils electrostatic shielding ?

Sasho hellowww! From the picture it seems that there's no shielding.

[geoscash1]

coils wound

Coils are wound, TX - 280uH, RX1 - 182uH/RX2 - 183uH (combined measure 364uH)

The D's were wound on the same jig, same direction, one is flipped.



Now just need to figure out how to connect everything....

[scs]

I make discriminating detector with dd coil.Coil was with shield.

[eclipse]

I make discriminating detector with dd coil.Coil was with shield.

Sasho, your TR detector became very popular in Iran from what I can see as activity in the forum there, despite not able to read one persian word.
Congratulations on your genius and ingenuity.

I will also build it one day. Cheers!

Sorry for the off topic!

[geoscash1]

coil connections to mpp

Would this be the correct way to connect the DOD type of coil to the MPP? See sketch below, added diagram on upper & lower right.

[6666]

Sasho, your TR detector became very popular in Iran from what I can see as activity in the forum there, despite not able to read one persian word.
Congratulations on your genius and ingenuity.

I will also build it one day. Cheers!

Sorry for the off topic!

Could you please provide a link to the forum you are quoting thanks

[scs]

One working idea -dd coil,pulse oscillator400hz,resiver level in transmission is discrimination ,signal for metal is with sample.Very good depth with perfect discrimination.

[geoscash1]

Could you please provide a link to the forum you are quoting thanks

One working idea -dd coil,pulse oscillator400hz,resiver level in transmission is discrimination ,signal for metal is with sample.Very good depth with perfect discrimination.

Does this all have something to do with DOD OOO coils?

[geoscash1]

Ok, tried a multitude of different connections, and found that the only way to get all 3 coils working was to flip flop one of the D's.

They are both wound the same direction but one is just turned over. Wired to a 5 pin plug, used 200R damping resistors for both Receive sides and a 390R on the transmit. Not working to bad for first test without fine tuning. It is detecting the US nickel at 13 inches, faint at 14 and the 14k ring at 10 inches, faint at 11.

Each D half is 182/183uH with the transmit coil at 280uH.

Not to sure why it is reacting opposite to gold nuggets but once it just starts detecting my 1.2 gram nugget, then it sort of nulls or goes silent until raising the target nugget back away from the coil again.

[geoscash1]

I make discriminating detector with dd coil.Coil was with shield.

Can you post the link or more info please. 6666 asked as well, hopin to see some more info please.