2 boxxxx :)

[mikebg]

Did you mean coil like this?

No, like this:

[WM6]

No, like this:

Thanks. I suppose that only reason to divide windings layer in 7 sections is to reach better structural strength?

Here some comments from web about RONKA EM:

"The electromagnetic survey was made using a RONKA EM
electromagnetic unit. This instrument utilizes the United States
Very Low Frequency transmitting stations for its signal. The
VLF stations set up a series of concentric horizontal magnetic
fields about their vertical antennae and when their magnetic
fields encounter conductive bodies in the ground, secondary
magnetic fields are set up which radiate from these bodies.

The RONKA EM measures the vertical components of these secondary
fields by means of two coils.
For this survey signals from the station located at
Cutler, Maine, were used. Two readings, the In-Phase and the
quadrature were measured at each station."

[mikebg]

Thanks. I suppose that only reason to divide windings layer in 7 sections is to reach better structural strength?

Not. The winding in sections reduces stray capacitance at multilayer winding. In this case are formed 7 tank circuits, but having very high resonance frequencies.

[WM6]

The winding in sections reduces stray capacitance at multilayer winding.

How many layer you provide? More than 5?

In this case are formed 7 tank circuits, but having very high resonance frequencies.

"7 tank circuits"? By stray capacitance or by added real capacitance?

Can you represent this graphically by electrical symbols? It is not clear to me what you mean.

[mikebg]

How many layer you provide? More than 5?
"7 tank circuits"? By stray capacitance or by added real capacitance?

Can you represent this graphically by electrical symbols? It is not clear to me what you mean.

By stray capacitance only.
This can be represented not only graphically, but by a formula. The 7 sections of ferrite antenna form 7 coils with its own stray capacitance. Note that capacitances are connected in series, ie the total capacitance is 7 times smaller.
The inductance depends on square of turns number. If we reduce turns number 7 times, inductance diminishes 7 x 7 = 49 or near 50 times. So the tanks formed in the equivalent circuit has so high resonance frequencies, that they acts as a pure inductance.

[mikebg]

Geonics EM34-3

Geonics EM34-3 is TWO BOX system for measurement of terrain conductivity.
The intercoil spacing is measured electronically so that the receiver operator simply reads a meter to accurately set the coils to the correct spacing, which can be 10, 20 or 40 meters so as to directly vary the effective depth of exploration given by a table.
To measure terrain conductivity, the transmitter operator stops at the measured station; the receiver operator moves the receiver coil backwards or forwards until his meter indicates correct intercoil spacing and he reads the terrain conductivity from a second meter. The procedure takes 10 to 20 seconds.
The coils are normally carried with their planes vertical as shown in the picture (horizontal dipole mode) cince in this configuration, the measurement is relatively insensitive to misalignment of the coils.

[mikebg]

Exploration depths

In the event that the greater depth of penetration is desired, the two coils are horizontal (vertical dipole mode). At this configuration more care must be taken with intercoil alignment. Because of the relatively short intercoil spacing, correct alignment is usually not difficult to achieve. Table below shows exploration depths at various intercoil spacings.

[kt315]

interesting construction of two-box...

[GOLDENSKULL]

Hi kt315,

This is very nice two-box design ...
what about it's schematic and more information... ?

[steaua581]

2 Boxx

I though to post a youtube field test wich has been done with some two box detectors Gemini 3 and TM 808.Some of you migt have seen this test some not...
What do you think about the depht capability of TM 808?..To me looks impresive....is it beter then Delta Pulse?
Regards
Marius

Video 1) http://www.youtube.com/watch?v=RYzyG39fx1k

Video 2) http://www.youtube.com/watch?v=AGjB4...layer_embedded

Video 3) http://www.youtube.com/watch?v=67Y4Y...layer_embedded

[kt315]

Hi kt315,

This is very nice two-box design ...
what about it's schematic and more information... ?

I read it was done on a base of schematic Two-box of Andrej Schedrin. the books in Russian.

[Alexismex]

Hello Forum,
I have test from many years ago.... the geminis and tm 808 , but it is good to see the videos because here you can see very well the poor...very poor capability of ground penetration of this two box ..... NOT a comparative with a PI detector ...because to catch a helmet at 1,3 meters it is very easy for a PI ....with a 8 inch mono coil....very easy and ... in a more strong mineralized that i see in the video.
Alexis.

[steaua581]

Two Boxxx

What is the comparation of a target wich is detected in air with for example a PI Delta Pulse ...lets say a helmet at 1 meter in air...what will be the distance you will detect it in the ground? Will be tht same 1 Meter ? The distance will diminish by how much ?...
I have build a Delta Pulse ..everything works well but i am getting poor distance meaby the coils i am using must be more sensitive i am working on that...
Regards
Marius

[rajesh]

RX coils are close and parallel in .392 uf which means more depth. See the difference

[Hisoka]

Gary's ca3035

I really thank you Gary(chemelec) for ca3035 circuit I have been looking for it for long time.


you seem to be forgot the 1uf capacitor which connected to headphones and the earth



I tried to connect them in the circuit you made as shown in the attachment:




please check it



And can I really use it with the transmitter circuit made by Charles D. Rakes:






And I can not see this project on your website, please give me it's name