Critterhunter
New member
Now, don't get me wrong. I want to know I'm using a machine that gets as much raw depth as any other, and one machine can be better than another in that ability due to how well they compensate for ground minerals. That's why I use a machine that has the best ground mineral ignoring capabilities I can find.
But, setting aside how well the machine can ignore the minerals in the ground as a non-issue and no longer a problem with the right machine, there are limits to the physics of VLF detector technology in terms of the depth and size of the detection field. Once that is maxed out (depth in terms of being able to ignore ground minerals, which it has been for the most part on some machines) you can't get any deeper unless you go to a bigger coil due to the laws of physics that govern the traits of the generated magnetic fields the coils can generate. Sure, some machines got less depth due to how they handled the ground signal than others, but on some machines that's no longer a limiting issue. And that doesn't affect the physical size of the magnetic field the coil is putting out, but rather how well the detector can process and ignore the ground signal while reporting the target found within.
Once you've resolved the effects of ground mineralization in processing the signal (which certain machines do better at than others), there is no other way to "see" deeper unless you use a bigger coil to generate a bigger detection field. Well, there is one exception to that rule...You can provide more voltage to the TX winding in the coil to generate a bigger field but that has it's drawbacks. I know on one machine there was an aftermarket amp designed to feed more voltage to the coil but for many people it showed less depth due to the ground "glare" created by the stronger detection field with the higher voltage it used. That's why most machines have a static TX power setting that can't be changed, because the strength of that field has already been maxed to where anything beyond would actually cost you depth. Sensitivity control only adjusts the gain or amplification of the received signal from the RX coil (received signal), and doesn't affect the transmitted signal into the ground. Really if a machine is very good at ignoring the ground signal the only pratical way to increase depth is by increasing coil size. That has it's limits too, as a bigger coil can see too much ground matrix and actually wash away or degrade the target signal that is mixed in with it.
Beyond that, separation ability also follows the laws of physics. A detection field can't see around corners. Nor can it go past a shallower trash signal that it's also lighting up to see a deeper coin signal near it. The field warps or bends and stops with the first peice of metal it hits. Recovery speed can be an issue for those who like to swing faster, but if you swing slow enough it's a non-issue for slow recovery machines. Where unmasking or separation ability really matters is in just how sharp the detection field is that the coil is generating so you can "light up" one signal and not the target next to it.
No amount of cramming electronics into a machine can change these depth or separation limits in the laws of physics. Sure, if the machine can't handle ground minerals as well as some others then that will cost you depth. But if it does well at ignoring the ground minerals then it's limited by the share size of the detection field based on coil size. There is a point where you reach a glass ceiling, and no amount of electronics can do anything better with the limits of what the physical size of the detection field can reach.
Having some programming features are nice but there comes a point when handy features become a tacky boondoggle. All I really care about is raw depth and the sharpness of the detection field (which is why I use a SEF 12x10 with it's super tight left/right compressed field). All the rest of the stuff doesn't really matter for performance. They are just fancy flashy features designed to get you to shell out more cash. I just want the raw power in the ground and I'll let my eyes and ears do the rest, which are your best discriminating tools. I don't even prefer machines that have a highly software processed VDI or audio report because that puts you further away from the true nature of the original signal. I want the raw data to see and hear and go from there.
But, setting aside how well the machine can ignore the minerals in the ground as a non-issue and no longer a problem with the right machine, there are limits to the physics of VLF detector technology in terms of the depth and size of the detection field. Once that is maxed out (depth in terms of being able to ignore ground minerals, which it has been for the most part on some machines) you can't get any deeper unless you go to a bigger coil due to the laws of physics that govern the traits of the generated magnetic fields the coils can generate. Sure, some machines got less depth due to how they handled the ground signal than others, but on some machines that's no longer a limiting issue. And that doesn't affect the physical size of the magnetic field the coil is putting out, but rather how well the detector can process and ignore the ground signal while reporting the target found within.
Once you've resolved the effects of ground mineralization in processing the signal (which certain machines do better at than others), there is no other way to "see" deeper unless you use a bigger coil to generate a bigger detection field. Well, there is one exception to that rule...You can provide more voltage to the TX winding in the coil to generate a bigger field but that has it's drawbacks. I know on one machine there was an aftermarket amp designed to feed more voltage to the coil but for many people it showed less depth due to the ground "glare" created by the stronger detection field with the higher voltage it used. That's why most machines have a static TX power setting that can't be changed, because the strength of that field has already been maxed to where anything beyond would actually cost you depth. Sensitivity control only adjusts the gain or amplification of the received signal from the RX coil (received signal), and doesn't affect the transmitted signal into the ground. Really if a machine is very good at ignoring the ground signal the only pratical way to increase depth is by increasing coil size. That has it's limits too, as a bigger coil can see too much ground matrix and actually wash away or degrade the target signal that is mixed in with it.
Beyond that, separation ability also follows the laws of physics. A detection field can't see around corners. Nor can it go past a shallower trash signal that it's also lighting up to see a deeper coin signal near it. The field warps or bends and stops with the first peice of metal it hits. Recovery speed can be an issue for those who like to swing faster, but if you swing slow enough it's a non-issue for slow recovery machines. Where unmasking or separation ability really matters is in just how sharp the detection field is that the coil is generating so you can "light up" one signal and not the target next to it.
No amount of cramming electronics into a machine can change these depth or separation limits in the laws of physics. Sure, if the machine can't handle ground minerals as well as some others then that will cost you depth. But if it does well at ignoring the ground minerals then it's limited by the share size of the detection field based on coil size. There is a point where you reach a glass ceiling, and no amount of electronics can do anything better with the limits of what the physical size of the detection field can reach.
Having some programming features are nice but there comes a point when handy features become a tacky boondoggle. All I really care about is raw depth and the sharpness of the detection field (which is why I use a SEF 12x10 with it's super tight left/right compressed field). All the rest of the stuff doesn't really matter for performance. They are just fancy flashy features designed to get you to shell out more cash. I just want the raw power in the ground and I'll let my eyes and ears do the rest, which are your best discriminating tools. I don't even prefer machines that have a highly software processed VDI or audio report because that puts you further away from the true nature of the original signal. I want the raw data to see and hear and go from there.