What determines the depth when making a detector

[TheGreenBoy]

I do not belive the depth is purposly limited, it's just not in the scope of developement and improvements.

 

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[ScoTTT2]

all the detector manufactures have a engineering dept .. if the machines they built were actually capped, these guys would know that .. so would everyone else associated with the industry .. now with two major players closing their doors .. any, now unemployed engineer along with a friend from the marketing dept, would build and sell this great un-capped machine .. make themselves a bunch of money, shutting down the other major companies .. but it is here, in engineering, where the science is the limiting factor .. then there is the "how deep do you need to go to find a dime" or where is the deepest the metal actually is located at any given site .. this is where a fraction of an inch makes a difference .. if your machine can only find a dime at 10 inches, but the dimes are all at 11 inches, that is a huge difference .. to some people .. companies are now making machines for the sales, surely .. cutting corners on performance, but still workable as a hobby detector .. some in this category are much better than others .. this allows someone to get into the hobby for little money and see if they like detecting, and if so, they might stay loyal to their brand and buy a real good detector .. but these same companies also offer their "best, known" performance in a better, more costly machine .. those companies will also push to produce a better and better machine as the science and engineering allows .. but they do not limit what they can do, so as to make you buy something later on, that makes no business sense .. it is an individual's choice as to which detector is best for them .. some people don't want or have a need to push the limits of a detector .. then there are others who will always push the limits, wondering just what lies a fraction of an inch deeper.

 

[Terry Soloman]

...I have a couple Noktas I don't even use.

Could you send them to me? I'll pay shipping!

 

[dave_e]

It seems as though the laws of physics would be the major factor in depth and separation limits.

There's your answer.

 

[smokeythecat]

The FCC has had the ability to regulate frequencies on metal detectors since their inception in 1934. So, nothing new here.

 

[TheGreenBoy]

The fact is, we just like to go out on a fresh air, just anywhere, without any previous research, and leave ourselfes to the beeps while digging out our targets with as little effort as possible. Picking our targets by chance and statistics, finding something made from silver or even gold makes our day fullfiled. This is what the commercial hobby detector is tailored for, and it is unsurpassed king.
I am using my 4m detector on a regular basis, slightly deeper than a Nox, and i really wonder how many people would be interested in machine like this? What, not deep enough? Oh yeah, the ingeeners of the developement team just deliver what they are told to. And the metal detector manufacturer is not interested in a few excentric customers, but rather the wast majority of them, most hasn't have a clue of what would they need or want - and this is a domain of another department, to spread the proper religion as much as possible. It's called customer education.

 

[Terry Soloman]

Pulse Induction, and the power supplied to the coil. This is why PI machines are deeper than VLF machines, and Why Minelab continues to be the most used machine in goldfields, European artifact locations, and civil war relic sites. Radio Waves will always be limited, electro shock therapy is deep and satisfying!

 

[TheGreenBoy]

IGBT driven, high voltage, high current pulses. 800W/uS of polarization power.... Entirely different game.

 

[crashbandicoot]

Could you send them to me? I'll pay shipping!

With the exception of Terry,s comment here,this is still an unproductive line of argument,FCC limitation on power is not the same as a company deliberately capping the depth a detector will reach.As I understand it the reason for different coils is to achieve a particular result,as in the bigger the coil,more depth,more coverage per swing,a smaller coil gives better separation in trashy places and is easier to use in close quarters,no conspiracy there.But I like an argument as well as anybody,so have at it!

 

[Treasure_Hunter]

With the exception of Terry,s comment here,this is still an unproductive line of argument,FCC limitation on power is not the same as a company deliberately capping the depth a detector will reach.As I understand it the reason for different coils is to achieve a particular result,as in the bigger the coil,more depth,more coverage per swing,a smaller coil gives better separation in trashy places and is easier to use in close quarters,no conspiracy there.But I like an argument as well as anybody,so have at it!

True, and no manufacturer is limiting depth either.

 

[Terry Soloman]

With the exception of Terry,s comment here,this is still an unproductive line of argument,FCC limitation on power is not the same as a company deliberately capping the depth a detector will reach.As I understand it the reason for different coils is to achieve a particular result,as in the bigger the coil,more depth,more coverage per swing,a smaller coil gives better separation in trashy places and is easier to use in close quarters,no conspiracy there.But I like an argument as well as anybody,so have at it!

Think of your metal detector, operating at the frequency of your choice, as a manually dial-tuned radio. It transmits, and it receives, however to achieve both to its highest capabilities sending and receiving must be correctly "tuned" to defeat static from ground noise, magnetic anomalies, and minerals. The maximum power it can it can transmit is 96.4 of maximum power available, or about 5-watts.

This is where tuning your machine - by internal computer circuitry, and/or manually, fits into the equation hard. There is always static with a Very Low Frequency device. Analog tuning, and training your ears to hear SLIGHT breaks and WHISPERS is key to depth.

 

[FreeBirdTim]

Coil size has a lot to do with how deep a detector can go. I bought a sniper coil for my AT Pro to pick out the good stuff in iron infested cellar holes. Worked pretty good, but the maximum depth was probably 5" or so and it didn't cover ground very fast in the woods. My 8 1/2"x11" coil can detect a dime up to 10" down and it covers a lot of ground. I felt like the sniper coil was missing a little too much and slowing me down, so I eventually sold it.

But as I've stated before, the vast majority of coins are less than 8" down, so all this worrying about how deep your detector goes is wasted time.

 

[xaos]

okay...I can help on this (well perhaps)

basically, the detector sends out a signal at a frequency, (or perhaps several frequencies) .
The signal reflects, and the detector reads the reflection of the signal...

There are a few things at play here...(not in order of importance)
Signal frequency
Signal strength
Length of signal
Strength of the return
and of course, the speed of sound.

all of these factors (and more) are what a detector does, and balances depending on the myriad of things programmed in to the detector.

Lets say, for the topic at hand, depth. Depth is a function of several variables, but in my analysis signal length and frequency are the most able to expand or limit depth.

Balancing depth is difficult....you want deep, shallow, all? Signal length will get you deeper, but, if a target is shallow, the signal will be reflecting back to the detector before the signal is finished broadcasting. You can optimized this by adjusting the frequency (due to the speed of sound length of time),
buuuut...depending on the density of the matrix material...
Now the return signal is measuring the background reflection and the strength of the return signal....things being equal, a denser material will have a stronger return signal...

You balance your detector, given that all of this is relative, to minimize the matrix material, and show the relatively denser materials...

I hope that you can see why the balance between depth, frequency, and signal strength are important...

I could make this post last for days!

Suffice to say....keep in mind all of these factors...