More Speed

[dbanner]

A good layout/ bad layout design pcb can make an otherwise good circuit performance very poor.

[dbanner]

Flat spiral coil is best choice for coil. Don't waste your time building basket coil nonsense, of twisting some fat cable and soldering a ton of wires. Ask any expert on forum, multi strand wire insulated Teflon, in bundle coil is all you need.
Leave Litz Wire for fanboy who is fanatical about fast coil and Minelab has penchant for spending money
Making Litz Wire coil for surf Pi is like putting gold teeth in mouth of chimpanzee. It will still be a chimpanzee.
Completely unnecessary.

[dbanner]

Above I stated signal to noise ratio, I mean the higher the wanted signal is above the noise, the better. So higher signal to noise ratio the better.
Carl put all the maths on noise calculations here on forum for all to benefit.
Do use search engine, and read to enhance knowledge. You don't have to remember all the maths, but come away with good conceptualization of fundamental theoretical meaning so you understand what makes fast pi

[dbanner]

Noise can be a limiting factor in the design as it also gets amplified along with the wanted signal,it is important to keep in check.

[Andi68]

Thanks for the many suggestions dbanner and others

Also, I do not believe in basket coils.

If so, then I will try a cross wind coil.

And maybe test HF-Litze, if I get cheap which.

Otherwise, I have to do many experiments

[qute1]

Multiple strands of thin litz to get the resistance down works and the thin stuff is cheaper.

[green]

I'm thinking more speed is for detecting lower time constant targets. A set of test targets can be made with regular strength aluminum foil(kitchen, cooking foil). (TC=time constant) TC=1usec(16x16mm, 1layer), TC=2usec(16x32mm folded one time for 16x16mm, 2layers), TC=4usec(32x32mm folded two times for 16x16mm, 4layers), TC=8usec(32x64mm folded three times for 16x16mm,8 layers). Not sure the need to detect a target with a TC lower than 1usec. The test targets would have more area than a wanted low TC target but could be used to determine if the detector could detect low time constant targets.

[dbanner]

Ah but a fast pi is not only depending on early sampling. This is only for setting up the timing matrix to suit data acquired by testing of various elements of metals. It doesn't take into consideration the fact that metal targets are in the ground and some are alloyed. What is achievable with practical circuit, MOSFET,driver,preamp, noise etc.

[dbanner]

Pulse detector is never going to be able to compete with discrimination machine which compares phases of metals. Trying to get the holy grail you have to go to Hollywood Indiana Jones.

[dbanner]

However They do have niche for specific uses.

[Qiaozhi]

However They do have niche for specific uses.

By the way, did you know that you can go back and edit a previous post within a 30 minute window. You don't have to start a new post 3 minutes later. Unless of course you're just trying to get your post count as high as possible.

[dbanner]

Why would I need to do that?