For deep search

[darov922]

ok the thread for my concept will continue here:

www.geotech1.com/forums/showthread.php?26887-HammerHead-II-rev-D-SMD-specialized-in-prospecting-for-gold

Dario

[waltr]

hi walt... i have finished my pcb and i am going to start assembling the components, do you recommend i make a new thread to show the development and discussions of the HH2 SMD?

Dario

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Yes, I think a thread just for this version of schematic, PCB, build and testing plus mods are worth while.

[MartinB]

hi walt... i have finished my pcb and i am going to start assembling the components, do you recommend i make a new thread to show the development and discussions of the HH2 SMD?

Dario

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I will be very interested to see how this detector performs

[darov922]

hi walt... i have finished my pcb and i am going to start assembling the components, do you recommend i make a new thread to show the development and discussions of the HH2 SMD?

Dario

[waltr]

Wow, I've never tried anything like that.
I think you need to try all three options.
Will be interested in how they work.

[darov922]

First of all I want to thank you for your disposition Walt, thanks for helping me with your knowledge. From what I've been reading the coil in the next post... I think they call this coil 3DSS and it seems to be the geometry with the lowest capacitance for the TX:
https://www.geotech1.com/forums/show...-PI-coil/page5 post #111

Now, in the Rx coil, neither the capacitance nor the speed is important, which is why I have been thinking of introducing a second winding to the 3DSS coil for the Rx, without adding capacitance between the two windings.

The first option is to wind the Rx coil "inside" the Tx coil in a flat spiral winding. The second option is to wind two enamelled copper wires together with the Tx AWG 26 cable, which make the interlacing, but the two pieces of wire are connected in series, resulting in a double transformation ratio.
The last option that occurs to me is to wind the 3DSS coil and separately place the Rx coil "on top" in a single vertical layer of wire as if it were a speaker coil (voice coil) I think that both coils had a coupling area minimum. Tell me what you think of these three ideas, which do you think would be the one with the best characteristics to hunt gold? Thanks in advance to everyone who can help and contribute to this thread.

Darius

[waltr]

Do you mean a receiver coil that is induction balanced?
That is what I did with my HH2. I have two coils, one is a 10" DD that is good for covering more ground (wider sweep path) and an 8" concentric that is more sensitive to smaller objects but is not as deep and only about a 4" wide sweep path.

As to number of turns, it is a trade off between greater sensitivity and more noise.
Also, the RX does couple to the TX coils and adds C. However, if properly induction balanced some speed (shorter delay) can be obtained.

[darov922]

Thanks Walt for your advice. I decided on Carl's HH2 circuit. Right now I am making a PCB for SMD components. As my search is oriented to small gold nuggets I am thinking of using the spider coil to reduce the TC to a minimum. I guess I have to modify the firmware... (I have seen at least three versions for this detector, but for now I am focused on the hardware, I still don't know which will be the best version to start with). Regarding the coil... do you think it's a good idea to add a second coiling to the spider coil with more turns to increase the sensitivity? I didn't find anything about it in the forum, but I would like to know how to place the second winding so that it doesn't affect the capacitance of the TX coil...

[waltr]

I hope you use a microprocessor to do the timing. This makes experimenting very easy.
I used a PIC processor and only needed to change the code to add GB pulses.
Do note that I used pots as inputs to the PIC's ADCs to make timing adjustments.

[darov922]

Good ground balance will help but only on mineralized ground. Individual chunks of iron or other metals will still trip a PI detector.
Ground balance may work on rocks with high iron ore component. My GB scheme does work on old bricks with high iron content and also on black sand on the Rhode Island, USA coast.

Walter. Thank you very much for your recommendation... I have read many of your comments related to HH2 that will help me a lot in the set-up.

[darov922]

You need a PI detector that has ground balance. Such designs have been discussed in various threads, start with this one:

https://www.geotech1.com/forums/showthread.php?24251-My-take-on-the-HH2

Someone (I can't remember now) also posted a fairly simple PI-GB design, you'll have do some searching.

An eminence has answered my message! I am very grateful for directing me... I love the design of the hammer head. I will build my version and post the results I got with this detector.

[waltr]

Good ground balance will help but only on mineralized ground. Individual chunks of iron or other metals will still trip a PI detector.
Ground balance may work on rocks with high iron ore component. My GB scheme does work on old bricks with high iron content and also on black sand on the Rhode Island, USA coast.

[Carl-NC]

You need a PI detector that has ground balance. Such designs have been discussed in various threads, start with this one:

https://www.geotech1.com/forums/showthread.php?24251-My-take-on-the-HH2

Someone (I can't remember now) also posted a fairly simple PI-GB design, you'll have do some searching.

[darov922]

Depende del tama?o de la pepita..........

exact! where I live there are many nuggets under stones in the rivers... I have been following this thread with the purpose of knowing a good PI detector that can detect a 1 gram nugget buried at 20cm... I have VLF detectors, but the The river is full of stones with a high content of iron or other metals that drive my detectors crazy. I have programmers and I work in electronics... which PI detector do you recommend?

[Stevedbk]

like if it said 4m down there?s a nugget, well who is going to bother?

Depends on the size of the nugget..........