Hybrid Bipolar Detector

[Detectorist#1]

Hi all DIY enthusiasts,
Happy New Year! This is my present for the new year. This project uses truncated bipolar half-sine TX signals. For ground balancing is used the signal from the last 10us of TX-ON time. As result, no reduction of the sensitivity of the detector in GB mode and no "targets-hole" in this mode. Further, I will post detailed time-diagrams for more easy repeating of this construction from DIY people. For bipolar supply (+/-7.4V) 4xLipo accus 3.7V 650mAh are used. In next days, I will post the scheme of the Power Board with the charging parts.
Attached is the scheme of the detector.

[Op04]

Thank you Detectorist#1 !!!

[Op04]

Hi Detectorist#1 what is the purpose C19 ? Thanks

[Detectorist#1]

Hi Op04,
C19 with the inductance of the transmitting coil form a series LC circuit to generate a sinusoidal type of current in the transmitting coil.

[Op04]

Hi Op04,
C19 with the inductance of the transmitting coil form a series LC circuit to generate a sinusoidal type of current in the transmitting coil.

Thank you for your explanation... so the cap need in 1000V rated? Or perhaps 1500V ?

[Detectorist#1]

Hi Op04,
No, the big voltage is on the coil (+/-440V). On the C19 the voltage is less than 25V in all time.

[karakus]

Thanks Detectorist#1, I can now build a working detector. I have a GPX 11-inch D-D coil, and its specifications match yours. Can I use it? I'm a bit of a novice when it comes to PCBs, I hope someone can help.

[Op04]

Hi Op04,
No, the big voltage is on the coil (+/-440V). On the C19 the voltage is less than 25V in all time.

I stil have a lot to learn...thank you Sir

[Detectorist#1]

Hi karakus,
Please, measure the inductance and resistance of the TX and RX GPX 11inch DD coil and post here this information. It is important to use a search sensor with close (not very different) inductances of TX and RX coils for reliable "IRON CHECK" mode for this project and to follow recommendations described in Garrett ATX detector's user manual how to proceed in "IRON CHECK" mode.

[Laith]

I hope we see it in test

[sayan1345]

Thank you Detectorist#1

[sura]

Thank you Detectorist#1

[Detectorist#1]

Hi sura,
Good question. This solution gives more flexibility for the possible levels of the signal in the Ground Balance channel. Resistor trimmer RT5 gives a possibility to reduce the level of the signal and the two resistors R50 and R56 gives a possibility to increase the level of the signal by changing of the values of these two resistors.

[sura]

Thank you !!!

[Op04]

Hi Op04,
C19 with the inductance of the transmitting coil form a series LC circuit to generate a sinusoidal type of current in the transmitting coil.

Dear Detectorist#1,

How does 2.2uf came up? Is it like VLF we count C19 to freq desired or just to make it sinusodial? What happen if I put C with jumper so it became pure PI since that I can make sure at how many ampere turns I want, in my view I want it get minimum 1A coil blast after tx off, so to make it PI transmit is it possible with the rest demods and integrators?