field test unit no 001 "model T"

[Doug2]

Oh stop promoting your Chinese loving website Doug. Only you and your 3 blokes who worship you believe your talk.

I would have thought that consumers would jump at the opportunity to buy high quality coils that could be much less expensive than present commercial offerings. And isn't it the case that the current Australian Liberal government is hoping to conclude a free trade agreement with China this year?

[robby_h]

Moodz said on AEGPF "I would expect to sell an 18 inch for whatever the market will pay"

Perhaps Doug should rename AEGPF to "The Count Your Chickens Before The Eggs Have Hatched Forum"?

[Doug2]

"The Count Your Chickens Before The Eggs Have Hatched Forum"?

Reminds me of a certain companies legal firm!!!!!!!!!!

[Aziz]

It will be an outperformer, when shielded of course! No other coil will go deeper. Even ML's won't go deeper.
So the very smart question is, why will it be an outperformer?
Robby_H?
UFox?
PJ?
Candy?
Any ideas?
^sif

[Paul99]

It will be an outperformer, when shielded of course! No other coil will go deeper. Even ML's won't go deeper.
So the very smart question is, why will it be an outperformer?
Robby_H?
UFox?
PJ?
Candy?
Any ideas?
^sif

Well Aziz, contrary to what DougAEGPoof and a few others would like everyone to believe, basket weave coil windings do not result in the ultimate performer. however, why don't you give us all a laugh and attempt to explain the science behind why they should be the ultimate coil on a PI.

[Paul99]

Reminds me of a certain companies legal firm!!!!!!!!!!

Reminds me of the regularly seen claims made on a forum in fairyland where every detector being developed is going to better Minelab. 15 years of history demonstrates that Minelab are safe.

[moodz]

green = mosfet tx gate white = post first amp

yum yum

[Doug2]

Well Aziz, contrary to what DougAEGPoof and a few others would like everyone to believe, basket weave coil windings do not result in the ultimate performer. however, why don't you give us all a laugh and attempt to explain the science behind why they should be the ultimate coil on a PI.

You are wrong! Basket weave coils or spider wound coils for a start are more efficient antenna's than bundle wound coils of the same diam!! That's why they are used in the best crystal sets!!!!!! The best mono I ever tested on a ML was a hand made litz spider wound mono coil which left any commercial mono coil of the same diameter for dead as far a sensitivity and depth! The only downside was the coil was probably more sensitive to EMI. The lower capacitance also results in a higher Q!

[PATCHES JUNIOR]

You are wrong! Basket weave coils or spider wound coils for a start are more efficient antenna's than bundle wound coils of the same diam!! That's why they are used in the best crystal sets!!!!!! The best mono I ever tested on a ML was a hand made litz spider wound mono coil which left any commercial mono coil of the same diameter for dead as far a sensitivity and depth! The only downside was the coil was probably more sensitive to EMI. The lower capacitance also results in a higher Q!

Thanks for the great info Doug. The next detector I get that has a crystal radio built into it I will have to get one of these coils. Have to have the best coil to listen to music while detecting.

[Doug2]

Thanks for the great info Doug. The next detector I get that has a crystal radio built into it I will have to get one of these coils. Have to have the best coil to listen to music while detecting.

But do you agree with me that spider wound metal detector coils are more efficient antenna's (Rx) and have a higher Q,lower interwinding capacitance and that these factors make for a better detector coil for sensitivity, efficiency and depth capability and may allow for earlier sampling?

[Paul99]

You are wrong! Basket weave coils or spider wound coils for a start are more efficient antenna's than bundle wound coils of the same diam!! That's why they are used in the best crystal sets!!!!!! The best mono I ever tested on a ML was a hand made litz spider wound mono coil which left any commercial mono coil of the same diameter for dead as far a sensitivity and depth! The only downside was the coil was probably more sensitive to EMI. The lower capacitance also results in a higher Q!

You certainly are a clown Doug. If basket wound coils are that good then every detector manufacturer who wants an edge would be using them. So tell me Doug, are you that stupid that you don't believe that others have made spider or basket wound coils and done extensive measurement?

[PATCHES JUNIOR]

You certainly are a clown Doug. If basket wound coils are that good then every detector manufacturer who wants an edge would be using them. So tell me Doug, are you that stupid that you don't believe that others have made spider or basket wound coils and done extensive measurement?

Let Doug talk Moodz into building a bunch of these coils. Maybe then Moodz will figure out the truth about Doug and run as far away as he can.

[moodz]

You certainly are a clown Doug. If basket wound coils are that good then every detector manufacturer who wants an edge would be using them. So tell me Doug, are you that stupid that you don't believe that others have made spider or basket wound coils and done extensive measurement?

Actually if you knew your subject Peter ( AKA P99 ) .... there has been alot of research into basket weave coils and litz wire. The main reason you dont see them in commercial coils is manufacturing difficulty coupled with mechanical stability and bulk of the windings. However the use of basket weave in a resin matrix overcomes these difficulties and the basket weave actually reinforces the resin addition to the other benefits. The resin also prevents the windings moving relative to each other which causes instability when the coil is knocked.

Basket weave and litz resolve the issues below ...

• Skin effect: The resistance of a wire to high frequency current is higher than its resistance to direct current because of skin effect. Radio frequency alternating current does not penetrate far into the body of a conductor but travels along its surface. Therefore, in a solid wire, most of the cross sectional area of the wire is not used to conduct the current, which is in a narrow annulus on the surface. This effect increases the resistance of the wire in the coil, which may already have a relatively high resistance due to its length and small diameter.
• Proximity effect: Another similar effect that also increases the resistance of the wire at high frequencies is proximity effect, which occurs in parallel wires that lie close to each other. The individual magnetic field of adjacent turns induces eddy currents in the wire of the coil, which causes the current in the conductor to be concentrated in a thin strip on the side near the adjacent wire. Like skin effect, this reduces the effective cross-sectional area of the wire conducting current, increasing its resistance.
• Parasitic capacitance: The capacitance between individual wire turns of the coil, called parasitic capacitance, does not cause energy losses but can change the behavior of the coil. Each turn of the coil is at a slightly different potential, so the electric field between neighboring turns stores charge on the wire, so the coil acts as if it has a capacitor in parallel with it. At a high enough frequency this capacitance can resonate with the inductance of the coil forming a tuned circuit, causing the coil to become self-resonant.

[6666]

Thanks for the pictures of your coil Moodz

[moodz]

Very nice cool coil there Moodz, I especially like the sleek look, but more importantly, no shield to get in the way of all those shy "holey minelab" evading nuggets.

Thanks Kev .. The shield is easily added but will use without to start with.