Voodoo Main Discussion

[Qiaozhi]

Am i wrong to assume these would be perfect coils for Voodoo detector... PROVIDING that coil is cut open and those TX tuning caps are stripped out?

I didn't know there were tuning caps in the White's coils. I thought the DFX was wideband. If true, at least the TX cap will need to be removed.

I want answer on this; if we omit (usually noisy) NE555 and connect directly RC3 to R61 ; we'll have probably simpler audio, but 100% synchronized and totally noise free, right?

This might work, but the audio tone will then be 1kHz instead of 430Hz.

Second; i fully understand why LT1054 is chosen instead 7660. All the arguments truthful and mentioned in the book.
But generally 2 main are ; sync frequency and input voltage. If i decide to supply my detector with anything less than 12v, or put 7812 to keep it there, than second argument goes away and only first one, the sync frequency stays unsolved.
Is there any way to properly sync the 7660 with ~1kHz and less?
I am forcing this question for simple reason, LT1054 is harder to obtain and some 5x more expensive than 7660.

In the past I've experienced some issues when trying to synchronize a 7660 directly from the TX oscillator, but recently I was able to sync a 7660 to a 1000pps TX even when the pulse width was 50us. The previous problems may have been with pulse rates below 1000pps. I cannot be certain, so it might be worth trying.
You should use a 7660A though, and not a basic 7660 as it only has a max input voltage of 10V.

[ivconic]

White's Spectrum
Rx 1,2 36mH 123 ohms
Tx 4,5 540uH 1.4 ohms

White's DFX concentric
Rx 1,2 13.8mH 36 ohms
Tx 4,5 540uH 2.7 ohms

White's DFX DD
Rx 1,2 14.2mH 55 ohms
Tx 4,5 680uH 3.5 ohms

Am i wrong to assume these would be perfect coils for Voodoo detector... PROVIDING that coil is cut open and those TX tuning caps are stripped out?
...
Still reading a book. Close to the end. Impressed with the idea but more important with materialization of the idea.
Of course nothing is perfect and always can be improved further.
Morphology of this detector allows precisely that; easiness of further improvements.
I want answer on this; if we omit (usually noisy) NE555 and connect directly RC3 to R61 ; we'll have probably simpler audio, but 100% synchronized and totally noise free, right?
Not to mention affect on power consumption too, which will be somewhat lower. But at this particular moment i am focused only on S/N.
Second; i fully understand why LT1054 is chosen instead 7660. All the arguments truthful and mentioned in the book.
But generally 2 main are ; sync frequency and input voltage. If i decide to supply my detector with anything less than 12v, or put 7812 to keep it there, than second argument goes away and only first one, the sync frequency stays unsolved.
Is there any way to properly sync the 7660 with ~1kHz and less?
I am forcing this question for simple reason, LT1054 is harder to obtain and some 5x more expensive than 7660.

[lamoiz]

Hi Lamoiz, which coil is this one?

hi surf; it is a 175/46 litz wire coil that I use on my mpp beach.It measures 31 cm. this test is on the voodoo

[surfdetector]

350 uh well damper with litz threads .. it works hard.
[ATTACH]54003[/ATTACH]

Hi Lamoiz, which coil is this one?

[lamoiz]

350 uh well damper with litz threads .. it works hard.

[Matt_Rowe]

Sent you a PM

Pmed you back, thank you,

[ivconic]

Reading a book...
thoroughly and meticulously done... nothing less i expected from George.
My hat down to this!
...
Preparing order, component lists, tomorrow will place order to local supplier.

[ivconic]

Finally arrived...

[surfdetector]

Hi surfdetector,
I am at the preamp stage of the voodoo tonight i will progress.

I tested the Voodoo preamp with a 300 uh 30 awg flat planar coil I knew was pretty fast.
Just trying to get a idea of the Pi front end portion of the voodoos capability.
the following shot is with a Maxim 412, I also tried a 4562, it was faster but it wasn't as clean.

[ATTACH]53973[/ATTACH]

I have only tested the dual d on the Mpp but I took off my preamp and went to stock except for a 4562 amp.
this shot is of the coil balanced on a signal gen it worked pretty well but further testing and playing with the Rx coil I was able to get a little better performance bringing the nugget into play.
This coil is pretty forgiving I can even stack the rx right on top of the inner tx.
I don't know what to even call it it could be considered everything from a omega to a concentric and dual d. All depending where you put the Rx coil.
I'm building two larger size Rx d coils to see what happens to the depth and sensitivity of this coil where the trade off is.

[ATTACH]53974[/ATTACH]


Thanks again for the great job on your videos.

Thanks for the images. I do like the 4562 as well. You are doing good work with the coils.

[TH'r]

no, i have to watch my money because of my chemo and bills right now, i had to retire because of this disease. so only have SSI

Sent you a PM

[MartinB]

no, i have to watch my money because of my chemo and bills right now, i had to retire because of this disease. so only have SSI

Hi Matt
Don't quite know how to do this, but if you can get your address to me, I will purchase a copy and post it on to you. Sounds like you have a lot going on at present.

[6666]

RE Concentric coils
I re read the Dave Emery tutorial on how he makes his coils, and I noticed that he nobbles his TX coil with a 22 ohm resistor, anybody tried this ?
I put a 22 ohm resistor in a sim, and it knocks the fly back voltage from about 700 volts down to about 220 volts so will effect performance somewhat
but helps the nulling I guess.
Did a search on the forum to see if there was any chatter about this 22 ohm resistor and found some old info on vlf coils that dont have internal caps that may be usefull
and will post here for reference.
Coil pinouts

Winding, followed by pins (pos,neg), followed by inductance, and finally DC resistance.

White's Spectrum
Rx 1,2 36mH 123 ohms
Tx 4,5 540uH 1.4 ohms

White's 6B
Rx 1,2 16mH 35 ohms
Tx 4,5 1.7mH 7 ohms

White's DFX concentric
Rx 1,2 13.8mH 36 ohms
Tx 4,5 540uH 2.7 ohms

White's DFX DD
Rx 1,2 14.2mH 55 ohms
Tx 4,5 680uH 3.5 ohms

Tesoro concentric
Rx 3,4 6.2mH 22 ohms
Tx 1,5 5.7mH 22 ohms

Tesoro early Lobo DD
Rx 1,3 1.35mH 12 ohms
Tx 2,4 10mH 55 ohms

Fisher CZ
Rx 1,2 6.8mH 30 ohms
Tx 3,4 1mH 2.8 ohms

Most numbers are based on several coil measurements, including different size coils for a given coil type.

The White's 6B coils are really easy to find, and come in a huge range of sizes.

- Carl

Fisher 1210
Rx 6,48mH / 15,3 Ohm
Tx (1,64mH / 7,7Ohm) + (1,62mH / 7,5Ohm)

Fisher 1266
Rx 10-10,4mH / 38,2-39,3 Ohm
Tx 2,14-2,2mH / 4,7-4,9 Ohm

Fisher Quick Silver
Rx 6,69-6,7mH / 31-32Ohm
Tx 0,945-0,960mH / 3-3,1Ohm
Tesoro concentric
Tx 1,5 5.7mH 22 ohms
Rx 3,4 6.2mH 22 ohms
====
Tesoro early Lobo DD
Tx 2,4 10mH 55 ohms
Rx 1,3 1.35mH 12 ohms
====
Tesoro
Name TX-L TX-R (ohms) TX-fo TX wire RX-L RX-R (ohms) RX-fo RX wire
________________________________________
Brown 8" 5.59mH 21.2 --- --- 6.23mH 22.1 ---
---
Lobo 5x10 9.93mH 50.5 --- --- 1.33mH 10.97 --- ---
Lobo 8x15 10.52mH 62.8 --- --- 1.37mH 13.13 ---
========
Troy Shadow
Name TX-L TX-R (ohms) TX-fo TX wire RX-L RX-R (ohms) RX-fo RX wire
________________________________________
X2 S-9 9" 5.72mH 23.6 --- --- 6.25mH 25.2 --- ---
X5 7" 1.067mH 4.33 --- --- 6.53mH 32.2 --- ---
X5 9" 1.044mH 4.45 --- --- 6.50mH 32.7 ---
---
X5 1.1mH / selfrez = 255kHz 6.5mH / selfrez = 87kHz

[godigit1]

Hi, I am unclear if you are testing your DD on the Voodoo at this time or currently just on the MPP? I would like to see a scope shot of the pre-amp output if possible. Your experimentation is very interesting to follow.

Hi surfdetector,
I am at the preamp stage of the voodoo tonight i will progress.

I tested the Voodoo preamp with a 300 uh 30 awg flat planar coil I knew was pretty fast.
Just trying to get a idea of the Pi front end portion of the voodoos capability.
the following shot is with a Maxim 412, I also tried a 4562, it was faster but it wasn't as clean.



I have only tested the dual d on the Mpp but I took off my preamp and went to stock except for a 4562 amp.
this shot is of the coil balanced on a signal gen it worked pretty well but further testing and playing with the Rx coil I was able to get a little better performance bringing the nugget into play.
This coil is pretty forgiving I can even stack the rx right on top of the inner tx.
I don't know what to even call it it could be considered everything from a omega to a concentric and dual d. All depending where you put the Rx coil.
I'm building two larger size Rx d coils to see what happens to the depth and sensitivity of this coil where the trade off is.




Thanks again for the great job on your videos.

[ivconic]

Now bit more serious.
I think i discovered why previously i had problems to build the source with mikroC PRO for PIC.
It is not about the version at all.
My 6.6.3 version would work just alright as it works now.
But earlier i didn't install mikroProg Suite For PIC along with mikroC PRO for PIC.
Although i really don't need mikroProg Suite For PIC, since i don't have supported programmer for it.
I flash 18F45K22 with mikroBootloader v2.1.0.0.
When i start mikroProg Suite For PIC; it can't recognize the "Ready for PIC" dev board at all.
So i unistalled mikroProg Suite For PIC for that reason, no use from it.
But than mikroC PRO for PIC is not building the source!? Don't produce HEX file at all.
So today by very random and fortunate coincidence i again installed full package; mikroC PRO for PIC and mikroProg Suite For PIC.
And since than; mikroC PRO for PIC started to build and produce HEX files.
Those two are in separate folders. On skim look not having any mutual dependencies.
Yet... there must be something that mikroC PRO for PIC uses from mikroProg Suite For PIC...
otherwise i can't explain it different than that.
Previously it didn't work and today is working flawlessly on several attempts.

[ivconic]

Very funny.
But you've spelled "stolen" incorrectly. "Stollen" is a traditional German fruit bread that is eaten during Christmas.

Me?
Nooo!
I guess this is due incompatibility between 18F4520 and 18F45K22!
I'll have to obtain 18F4520 to straight this up!
BTW it makes sense.
When you put it in sentence properly than it says:
"It is traditional German fruit bread by Q !! "
But there is no place in 16 characters line for this.
...
All the troubles started because you didn't want to share with me you version of mikroC PRO for PIC!
Look what you have done!