Metal Detecting Terminology 101
If you are just entering the fantastic hobby of metal detecting - there is a decent chance that confusion has landed in your lap once or twice. With all of the terminology and definitions thrown about the forums and websites, it is a wonder that anybody makes it from novice to veteran status.
Ground balancing? Sure, I can go outside and stand on one foot.
Sensitivity? I’m a pretty tough guy.
Threshold? I have one on every door in my house.
The way some veterans throw around terms like they are common household names, it’s easy to see how somebody who is not well versed in the hobby can become frustrated and confused.
I am here to help! Today’s blog will be centered on the “most common” terms that new hobbyists can expect to run across while they absorb knowledge. I won’t be covering the simple stuff like “batteries” or “arm cuffs” as I feel anybody can figure those terms out. This will be based on the more complicated terms that are tossed around.
While it would be easy to write an essay on each term - I will try to explain it in layman terms and keep each one short and to the point. In no particular order...let’s get started!
Ground Balancing:
The Earth is the largest target a metal detector can come across. If detectors had no way of canceling out the ground beneath our feet - the metal detector would sound off like the whole planet was a target worth digging. Nobody has a shovel that large, so this is where ground balancing comes into play.
Ground balancing “cancels out” the minerals (salt and iron for example) so that the detector can actually see the good targets underneath. Many entry level detectors have the ground balance setting preset to a common level, and it can never be adjusted. The more expensive detectors can be adjusted manually for the varying soil conditions our planet provides.
Discrimination (Disc):
Just like it sounds, this is the metal detector's ability to reject - eliminate - discriminate undesired targets. It is based on the conductivity of metals. A low conductor like iron is the first thing that will disappear as you raise the disc level. Next to be discriminated out would be mid-conductors like foil, nickels, aluminum pull tabs, and zinc pennies. BE CAREFUL! Gold is a mid-conductor and falls within the ranges mentioned above. It will be eliminated from detection if you discriminate most trashy mid conductors. Next on the scale are high conductors such as copper and silver. Most detectors do not allow you to discriminate out the high conductors, and the discrimination level stops just below clad dimes and above zinc.
The red box shows the conductivity scale. This is where discrimination and notching occur.
Notch:
Discrimination works by eliminating targets from left to right on the conductivity scale mentioned above. Notch is the ability to remove targets anywhere on that scale - while leaving the others alone. For example: You can run 0 disc where all targets are available for detection - and then notch out pull tabs that lay in the middle of the conductivity scale. Some detectors allow you to notch multiple targets in or out. So you could have iron and foil in...then nickels out...then pull tabs in...then zincs out. Like the disc setting - most detectors do not allow you to notch out high conductors, just low and mid conductors. However, a small percentage do allow notching across the entire range of targets.
Threshold:
This is the audible hum that many detectors produce while in All-Metal mode. It is basically the mosquito-like buzzing you hear. The threshold is the level where that hum barely starts to become audible. Also - if a target is strong enough to break the threshold - it produces an audible response you can hear. A beep or a “zip zip” sound.
If threshold is set to 0, or even a negative setting, you don’t hear than hum and many smaller targets can be missed. If set to a positive number, you start to hear that hum increase in strength (not volume). Set it too high, and again smaller targets will be missed since they cannot be heard over the hum/buzz sound.
Sensitivity:
This is the ability of your detector to increase or decrease the signal produced. The higher you crank the sensitivity - the deeper you go in good soil conditions. In some bad soils, it can have the “headlights in fog” effect where too much sensitivity will pick up too much ground mineralization. Lower can be better in bad soil. To keep things simple, the higher the sensitivity setting, the further out you can reach your targets. Setting this too high can produce chatter (random beeps) and make the detector unstable.
Gain:
This is the ability of the detector to amplify the audible power of signals. In the audio (and electronic) world it is measured in decibels (dB). So as you crank this up - the louder the signal of targets will sound as they cross the threshold. This is often confused with sensitivity as many detectors have a gain or sensitivity setting that ramps up when the other does.
In layman terms - gain makes the audible signal louder (more amplified). Sensitivity makes the signal stronger (shallow targets vs deep targets).
Separation:
Just like it sounds - this is your detector's ability to separate targets that are very close to each other. For example: A dime laying 1-2 inches away from another dime. Or a dime laying 1-2 inches from a nail.
The closer objects get to each other - the harder time a detector has telling one object from another. If it cannot separate the targets, you will get a single beep where two targets sound like a single target. If it CAN separate the targets, you will get two distinct beeps telling you both targets are there. The closer the targets - the harder it is for a detector to separate them.
Masking or Unmasking:
Just like a Halloween mask hiding your face, some targets can be masked by targets above them. If you have a dime at 4 inches deep with a nail directly above it at 2 inches deep - this is called masking. Your detector's ability to see that dime under the nail is it’s unmasking ability. It can remove the Halloween mask (the nail) and see the face underneath (the dime). The larger the mask, the harder it is for the detector to see the face underneath.
Recovery Speed:
This is how fast the detector can pick up a target, then reset itself in time to pick up the next target. So if you had 4 dimes laying out at 6 inches apart each - how fast can you sweep your coil over all 4 dimes before you miss one and only get 3 or 2 or 1 beeps.
A fast recovery speed means you can sweep the search faster while still hearing all 4 beeps, while a slow recovery speed means you need to slow your coil sweep to hear all 4 beeps.
Hopefully this helps you to understand all of these crazy terms people throw around in this hobby
That is all for this blog! TheHunterGT signing off - I will see you on the next blog!