Magnum on steroids!

[Ruben2000]

Hello friends!!
I was able to make it reject the ferrite, now what I see is that it doesn't have a greater range, when I raise the sensitivity pot it starts to screech.
It detects a 1 cent dollar coin at 18 centimeters and a 23.5mm diameter coin with a thickness of 1.44mm made of brass it detects it at 22cm.

[Ruben2000]

I need your help friends!!
I installed the coils according to the image that I uploaded previously about the configuration of the coils and I have not been able to make it reject the ferrite.

[Ruben2000]

Hello friends!!
I made the 12 inch double D coils with the following measurements.
TX1= 36 turns of 0.45 (25AWG), 742uH, 2.9Ohm.
TX2= 1 turn of 0.45(25AWG).
RX= 92 turns of 0.25(30AWG), 5.471mH, 22.6Ohm.

[Ruben2000]

?C?mo va a cablear el interruptor spdt para cambiar entre 8 y 18 khz? Una versi?n que he visto usa un interruptor dpdt y cambia completamente los condensadores 470 y 100 dentro y fuera. El otro deja ambos capacitores conectados a tierra -5v y simplemente intercambia el cable de transmisi?n activo entre los dos..

Hi Willtran!!If I do it at two frequencies I would place it this way.

[Wiltran]

How are you going to wire the spdt switch in order to switch between 8 and 18 khz? One version Ive seen uses a dpdt switch, and completely switches both 470 and 100 capacitors in and out. The other leaves both capacitors grounded -5v and just swaps the hot tx lead between the two..

[Ruben2000]

Next time, before soldering take some ultra-fine steel wool and polish the copper bright. It will make soldering much easier. If soldering will be done over several days then spray a light coat of clear paint to keep the copper from oxidizing. The soldering iron will burn right through the clear coat. A light coat of furniture wax might also do the trick.

Thank you very much Carl-NC for good advice, I'll keep it in mind for the next one.

[Carl-NC]

Next time, before soldering take some ultra-fine steel wool and polish the copper bright. It will make soldering much easier. If soldering will be done over several days then spray a light coat of clear paint to keep the copper from oxidizing. The soldering iron will burn right through the clear coat. A light coat of furniture wax might also do the trick.

[Ruben2000]

Here are the others.

[Ruben2000]

Hello friends here I share the photos of my PCB, I'm not that good at soldering but I defend myself there; I have used most of the second components but I had to make sure they were good.
Any query or help let me know, it would help me too.

[Ruben2000]

Yes, I am referring to that section of the TX coil or maybe I just use TX(3-5).
But anyway I'm going to try; the important thing is to take into account the inductance of the coils.
I have only gotten one model for the 10x12 inch elliptical coil. If someone wants to share another model, especially double D, I would appreciate it.
Here I share the form of the 10x12-inch elliptical coil for those who wish, only that at the time of printing they do it in real size; is a contribution from Nikko10.

[Carl-NC]

What is the purpose of TX(2-3)? [I think you mean TX(2-5)]

[Ruben2000]

Sorry I had to make a correction.
According to this.

[Ruben2000]

Hello friends!!!
I would like to know if I can configure my homemade coil in this way.

[ivconic]

Thank you very much teacher Ivconic for the encouragement.
I would like to consult you about your Magnum TH PCB. In the photo you posted I see that you placed a tantalum on C45, the SENSITIVITY cable is lost through the PCB or I can't see it well; you added a capacitor on pin 4 of U8 with the emitter of Q4.
I only ask about the capacitor that you added, it helps in something because in the schematic it is not appreciated.
Later I will ask about the construction of the coils.

It's been a while since then and I am not able to remember each little tiny detail, since I haven't done anything similar for long time.
I guess I put tantalum capacitor there because I had it at that moment in front of me on the bench.
To the right side there is finished and ready pcb, to the left is unfinished one, many things are missing.
About coils, I think i posted coil specs. It is important to try to replicate the coil specs as closest as possible.

[Ruben2000]

Thank you very much teacher Ivconic for the encouragement.
I would like to consult you about your Magnum TH PCB. In the photo you posted I see that you placed a tantalum on C45, the SENSITIVITY cable is lost through the PCB or I can't see it well; you added a capacitor on pin 4 of U8 with the emitter of Q4.
I only ask about the capacitor that you added, it helps in something because in the schematic it is not appreciated.
Later I will ask about the construction of the coils.