Voodoo Main Discussion

[MartyJ1963]

@6666,,,,Thanks a lot. I thought I could but as always, it's safer to ask and make certain! I've plenty 1n4004 and 1n4007 so I'll use the 007. Thanks again, Regards, Marty.

[MartyJ1963]

Hiya Lamoiz,,,Yes, I was wrong thinking there wasn't a Bucking coil but Qiaozhi corrected me. I still have to find out how to calculate the amount of turns needed for the bucking coil of the small coil I'd like to try first. I had some recent success making an Omega coil for my IGSL,,it works quite good but I'm still experimenting with it at the moment. Regards, Marty

[6666]

Hi all,,On the 'Battery charger' PCB, Am I able to use either a 1n4004 or 1n4007 diode in place of the 1n4001 please? Totally out of 4001's. Thanks, Marty

Hi Marty, YES.
The in4001 is only a 50 volt device where the 04 0r 07 are a higher voltage rated replacement, buy the 07 so you dont have to worry about it again

[lamoiz]

@Lamoiz,,,I don't think the Voodoo coil has a ' Bucking' coil. I believe it just consists of an outer loop, the TX, and the inner loop, which is just the RX. The TX Coil has a parallel Damping resistor and the RX Coil has a parallel Capacitor. Someone can correct me if I'm wrong or mistaken,,,Regards, Marty.

good evening Marty,
if there is a canceling coil, otherwise it will be impossible to null the rx coil. I have already made several concentric coils, the development is not easy, even with the calculation, trust me. the double d solution is easy to do, so is the omega. but if this is the only way to make a coil for the voodoo, then it will have to be done. however, I am going to do a 30cm omega and a super d with two rx. I don't think I will say anything more on the forum, because when I ask questions I have no answer .. so ..

[MartyJ1963]

Hi all,,On the 'Battery charger' PCB, Am I able to use either a 1n4004 or 1n4007 diode in place of the 1n4001 please? Totally out of 4001's. Thanks, Marty

[MartyJ1963]

Thanks guys,,,I already have that document but I will definitely give it a good 'Re-read' again. I hopefully want to start building on Friday, after my house repairs are out of the way. Thanks, Regards, Marty.

[lamoiz]

As you see from Chapter 6, all the coils were of the concentric type except one. The exception was the Fisher F75 DD coil, which had a slight disadvantage when the detector was switched into PI mode.

but in disc mode (hybrid) the f75 was good or bad too?

[Qiaozhi]

Do this detector hybrid vlf and pi like continuous mode hybrid or it can also work with a single coil ? If we use a concentric probe with two coils then it should work always as a hybrid am I right?

You can switch between a standard PI mode and a Hybrid mode. A concentric coil will work in both modes. If you fit a mono coil it will only work in PI mode.
This is all explained in the book.

[Orbit]

Do this detector hybrid vlf and pi like continuous mode hybrid or it can also work with a single coil ? If we use a concentric probe with two coils then it should work always as a hybrid am I right?

[Qiaozhi]

Thanks Qiaozhi. Regarding the 'Small' coil in your book I.E:- Outer loop= 7"@306uh and Inner loop=3"@467uh,,,How would I calculate the amount of turns for the Bucking coil please? This is the first coil I'd like to attempt to make for my Voodoo build. Regards, Marty.

The document linked to by 6666 describes the process of building a concentric coil very well.

[eclipse]

The book is very good read. I have ordered a set of 5 boards for try out.

[6666]

Thanks Qiaozhi. Regarding the 'Small' coil in your book I.E:- Outer loop= 7"@306uh and Inner loop=3"@467uh,,,How would I calculate the amount of turns for the Bucking coil please? This is the first coil I'd like to attempt to make for my Voodoo build. Regards, Marty.

hi Marty check out this doco, has some good info and may help https://www.geotech1.com/cgi-bin/pag...anar/index.dat

[MartyJ1963]

Thanks Qiaozhi. Regarding the 'Small' coil in your book I.E:- Outer loop= 7"@306uh and Inner loop=3"@467uh,,,How would I calculate the amount of turns for the Bucking coil please? This is the first coil I'd like to attempt to make for my Voodoo build. Regards, Marty.

[Qiaozhi]

Thanks Qiaozhi for those answers. So these concentrics then have no bucking coil, is that right?

Wrong.
The concentric coil type requires a nulling (bucking) loop to cancel the TX signal in the RX loop.

[MartyJ1963]

Thanks Qiaozhi for those answers. So these concentrics then have no bucking coil, is that right? @6666,,Glad you sorted him out, he's a good frend of mine and great bloke,,,I know his good wife Bridgitte bought him the book for a Xmas pressy and he's worried now that when she wraps it up in Xmas paper he won't be allowed to read it until Xmas day!,,LOL.. I sent him a Felezjoo pcb to have a play with,,,he's going to let me know how it handles with our highly mineralized 'Aussie' soil,,,It'll be great to see what yours and Trev's results are using the Voodoo on Aussie soil too,,,Hope your book comes soon, Regards, Marty.