gpx5000 coil

[jinbiao]

Hello everyone, I have a gpx5000, now only a single channel coil, can not achieve the iron drain function. I want to make a concentric coil or DD coil, who can provide data or link, thank you!

[Tim]

Minelab DD coil specs.

[jinbiao]

Minelab DD coil specs.

Thank you for your reply. I would also like to ask if the damping resistance is needed.

[Tim]

If you were to build the DD to these specs the current damping resistor should be correct. I am presuming it is on the mainboard though. If it is in the connector or coil you would have to experiment using a temporary variable damper consisting of a 10k pot seriesed with 200R and paralleled with 2k. To give a range of 181-1672 ohms.

[jinbiao]

If you were to build the DD to these specs the current damping resistor should be correct. I am presuming it is on the mainboard though. If it is in the connector or coil you would have to experiment using a temporary variable damper consisting of a 10k pot seriesed with 200R and paralleled with 2k. To give a range of 181-1672 ohms.

Thank

[6666]

A typical ML type DD has the RX damping R inside the coil
not my pictures

[Tim]

Thanks for that 6666. I did pull my Commander DD apart a few years ago, but cannot remember if there was an R in there. As I use it on my Surfpro, I will try removing the on-board damper at some stage.
Can you answer, do the inductances on the jpg above look correct? I am presuming they are measured with the R removed??

[6666]

Thanks for that 6666. I did pull my Commander DD apart a few years ago, but cannot remember if there was an R in there. As I use it on my Surfpro, I will try removing the on-board damper at some stage.
Can you answer, do the inductances on the jpg above look correct? I am presuming they are measured with the R removed??

The TX inductance remains constant at about 300uH .4 ohm, the RX inductance vary's a bit between ML model and manufacture, but my own 11" GP series RX measures 410uH
from some of the measured rx inductance figures removing the internal R add a few uH like about 10-20uH

[Nandor]

Thank you for sharing these pics. Very informative, it's interesting to me that the Tx is a Litz wire with isolation, expensive coil and it's so simple.
I don't know these machines, is it a PI configuration?

[6666]

Yes , they are DD for PI machines.

[jinbiao]

Recently, I made a DD detector for the GPX5000.
TX: 300UH
RX: 450UH
It is normal to exclude iron now. But no mono coil is stable, I want to know if the pulse detector's DD probe needs to be adjusted to zero. Thank you!

[Wahyu]

A typical ML type DD has the RX damping R inside the coil
not my pictures
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[ATTACH]42465[/ATTACH]

special coax? i see coax use litz red wire

[dbanner]

Recently, I made a DD detector for the GPX5000.
TX: 300UH
RX: 450UH
It is normal to exclude iron now. But no mono coil is stable, I want to know if the pulse detector's DD probe needs to be adjusted to zero. Thank you!

You mean should the TX and RX be balanced? Is that what you're asking?

[jinbiao]

yes

[refref]

gpx 18 inç mono ohmic What is the value?

What is the output damping resistance?