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Can anyone help with the final touches to my home grown coils please?
Parameters I am using are: 980 square mono; 38 strands of magnet wire 0.2mm dia; 9 turns; 2 layers of insulation between turns; 32 meters of 38 strand wire; 0.44dc ohms (coil); 297 uh inductance; coil capacity 0.400nf; coax capacity 0.180nf; coil to shield capacity 0.385nf; coil and coax capacity 0.46nf; coil and coax 0.55dc ohms; 2 layers of spiral wrap (poly); 1 turn of Stefans shield 20mm; 1 turn of Stefans shield 15mm; 6-7 rolls teflon tape (plumbers); 2 meters heat shrink (coax) and a 5pin plug to suit minelab.
It's certainly homegrown even down to the coax, I can ground balance okay, but when waving the coil around 1 meter off ground it sounds off.
I can put on a 14inch coil tech coil and it is quite and ground balances okay. The tests I do are 1/2 km from any powerlines.
To get the length of coax required for the coil, I plug in a heavy coax to my GP3000 which is connected to 800mm of hardline coax; which consists of 2 x 800mm lengths of 1/2 inch copper pipe, with holes drilled and tapped every 25mm. To obtain the length of coax for any coil I can tap the coil into whichever length gives me the best depth on a given target. From this I have found the coaxes are a lot longer than minelab and coil tech's etc. However, if I miss the right length either long or short, it will reduce the depth that it detects at, hence there seems to be an exact length for the coax to be to get the maximum depth from the coil.
I don't really know much about this, but 1/4 wavelengths for fitting coaxes to antenna in HF radio work seems to fit the bill, maybe a noise bridge could be used instead?
Any help on what would be an ideal capacity for coil, coax and coil and coax together? Where to get a Q meter from and how are they used? How do I get a quieter coil? Would be appreciated
My coil detects a coke can at 1600mm; the detectors I use are a GP3000 and GPX4000, I have made 6 coils which all ground balance and detect gold but need to be quieter.
Can anyone help please?
Parameters I am using are: 980 square mono; 38 strands of magnet wire 0.2mm dia; 9 turns; 2 layers of insulation between turns; 32 meters of 38 strand wire; 0.44dc ohms (coil); 297 uh inductance; coil capacity 0.400nf; coax capacity 0.180nf; coil to shield capacity 0.385nf; coil and coax capacity 0.46nf; coil and coax 0.55dc ohms; 2 layers of spiral wrap (poly); 1 turn of Stefans shield 20mm; 1 turn of Stefans shield 15mm; 6-7 rolls teflon tape (plumbers); 2 meters heat shrink (coax) and a 5pin plug to suit minelab.
It's certainly homegrown even down to the coax, I can ground balance okay, but when waving the coil around 1 meter off ground it sounds off.
I can put on a 14inch coil tech coil and it is quite and ground balances okay. The tests I do are 1/2 km from any powerlines.
To get the length of coax required for the coil, I plug in a heavy coax to my GP3000 which is connected to 800mm of hardline coax; which consists of 2 x 800mm lengths of 1/2 inch copper pipe, with holes drilled and tapped every 25mm. To obtain the length of coax for any coil I can tap the coil into whichever length gives me the best depth on a given target. From this I have found the coaxes are a lot longer than minelab and coil tech's etc. However, if I miss the right length either long or short, it will reduce the depth that it detects at, hence there seems to be an exact length for the coax to be to get the maximum depth from the coil.
I don't really know much about this, but 1/4 wavelengths for fitting coaxes to antenna in HF radio work seems to fit the bill, maybe a noise bridge could be used instead?
Any help on what would be an ideal capacity for coil, coax and coil and coax together? Where to get a Q meter from and how are they used? How do I get a quieter coil? Would be appreciated
My coil detects a coke can at 1600mm; the detectors I use are a GP3000 and GPX4000, I have made 6 coils which all ground balance and detect gold but need to be quieter.
Can anyone help please?