The ultimate, optimum & all around bestus.

[Tilladude]

OK dudes and dudettes it's late, my grey cells are tired and I've tried a couple of searches and bombed, so I'll ask the what I'm sure has benn asked before.

What is the ultimate, optimum, bestus coil (inductance and so on) for a PI detector?

I await the expected flood of answers with trembling antipseration.

Dennis

[Tilladude]

Hey guys I'm building a new PI detector and I need some help on coils. I was told that the coils for this unit were as follows: 230mm / 43 trns .5mm wire // 460mm / 23trns .5mm wire and 1M sqr with 8 trns of 1mm wire. Now using Gary's calculator I come up with: 230mm coil = 995 uH / 460mm = 588 uH and the sqr coil is approx 155 uH.

Now that is a very wide range of inductances, two of which it seems to me are way off the mark, what thinks you?

Dennis

[mikebg]

To dude Tilla

Dennis,
There is no universal coil suitable for all purposes!
Most dudes do not know in advance what the targets they would need to seek. To be ready to present various targets and work in different ground properties, they use different dimensions and electrical data coils. The PI metal detectors work better with induction balanced coils. That means you should calculate TX coil having low timeconstant and RX coil having maximum turns. What is your circuit diagram?

[Tilladude]

Mike,

The unit is DBP2010 and the lead person is a fellow from the Netherlands name of Cornelius. I got up with him through the TH forum.

Dennis

[Carl-NC]

Hi Dennis,

The optimum PI coil inductance depends on what you are looking for. Most general purpose PI detectors run 250-300uH. If I wanted a sub-grain nugget detector, I would consider a 100uH. If I wanted to look for 100kg meteorites, I would consider 1mH.

Your parameters at glance appear incompatible. I would expect the 1m coil to have ~400uH, and the 230cm coil to be over 1mH. This is off my head, not a calculator.

- Carl

[Carl-NC]

I get:

230cm = 1.47mH
460cm = 0.95mH
1m = 315uH

[Tilladude]

Carl,

I agree, I jumble wound a 255mm with 42 turns and came up with 1.37 mH, that's why I asked the question. I'm including the schematic for both the main board and the module for you to peruse if you wish and make a suggestion if'n you feelso inclined.

Dennis

PS: sorry they're so big.