Target ID Discrimination: A Guide to Finding Hidden Treasures with Your Metal Detector
Target ID Discrimination: A Guide to Detecting and Identifying Metal Targets
Metal detecting is an exciting hobby that has been around for centuries. It involves using a metal detector to locate buried metal objects such as coins, jewelry, relics, and other treasures. However, one of the biggest challenges that metal detectorists face is identifying what they have detected. This process is called target identification (ID).
Target ID discrimination refers to the ability of a metal detector to distinguish between different types of metals based on their conductivity or magnetic properties. Discrimination can be adjusted on most detectors by adjusting sensitivity levels or selecting specific modes.
Why Is Target ID Important?
Proper target identification can save time and effort while detecting. For example, imagine digging up every signal you get while hunting in a heavily littered area like a park or beach. You would quickly become exhausted and discouraged if all you found were bottle caps and pull tabs.
Knowing how your detector responds to different targets will help you ignore unwanted signals and focus on valuable finds like gold rings or silver coins. Additionally, some areas may have local laws prohibiting removing certain items from public spaces (e.g., artifacts). Proper target ID helps prevent accidental removal of prohibited items.
Types of Metal Targets
Before we dive into target ID discrimination techniques let’s briefly discuss the common types of metallic targets:
1) Copper-based alloys – These are metals with low electrical conductivity such as aluminum foil, pull-tabs from beverage cans, modern zinc pennies minted after 1982 (95% copper-plated zinc), nails with large heads made from steel coated with brass or copper plating.
2) Ferrous metals – These include iron objects such as rusted bolts, nails without coating/plating.
3) Nickel/Lead alloys – Most common examples are old nickel pennies (1942-1964), lead fishing sinkers.
4) Silver/Copper alloys – Targets include silver dimes, quarters and half dollars minted before 1965 (90% silver), pre-1982 copper pennies, brass objects.
5) Gold – This is the most valuable target for most detectorists. Gold jewelry can be found in various karats (purity levels), with 14K being the most common.
Target ID Discrimination Techniques
1) Conductivity-Based Discrimination:
Conductivity-based discrimination refers to a detector’s ability to distinguish between different metals based on their conductivity. Metals that conduct electricity well are considered high-conductive while those that do not are low-conductive. Detectors use this principle by emitting an electromagnetic field which induces eddy currents into a metal object causing it to emit its own magnetic field, which is then detected by the coil of the detector.
A metal’s conductivity value determines how quickly it will react to changes in the electromagnetic field generated by your detector. High conductive metals will produce a strong signal and respond quickly while low conductive metals will have a weaker signal and slower response time.
To adjust for conductivity-based discrimination, detectors typically offer users options such as Notch Filtering or Tone ID. These features allow you to filter out unwanted targets based on their conductivity value while allowing others to remain unfiltered.
For instance, you might choose to notch out all signals from low-conductive targets (e.g., pull-tabs or bottle caps). By doing so, you can focus only on high-conductive targets like coins and rings without getting distracted by false readings from junk items.
2) Target Depth Discrimination:
Another important aspect of target ID discrimination is detecting depth information about metallic objects buried underground. The depth at which an object lies affects how much energy it takes for your detector’s electromagnetic field to penetrate through soil layers and reach that target. As a result, deeper targets may generate weaker signals than shallow ones because they reflect less radiation back towards the coil when hit with an electromagnetic pulse.
To adjust for depth discrimination, detectors typically offer users options such as Sensitivity and Ground Balance. These features allow you to fine-tune your detector’s response based on soil mineralization or the specific type of ground you’re searching in.
For instance, if you’re hunting in highly-mineralized soil like saltwater beaches, you might need to reduce sensitivity levels to avoid false signals generated by sand minerals that can trick your detector into detecting a target at a greater depth than it actually is.
3) Target Size Discrimination:
The size of the metallic object detected can also affect its signal strength and response time. Larger targets will generate stronger signals than smaller ones due to their larger surface area exposed to the electromagnetic field emitted by your detector.
To adjust for size discrimination, detectors typically offer users options such as Discrimination modes or Target Volume Adjustments. These features allow you to ignore small objects while focusing on larger items with potentially higher value.
For instance, if you’re searching for large gold nuggets in Australia’s Goldfields region where smaller gold flakes are abundant but less valuable, then setting your metal detector’s Discrimination mode high enough may help filter out unwanted flakes.
4) Audio-Based Discrimination:
Audio-based discrimination refers to the use of sound cues produced by a metal detector when it detects different types of metals. Depending on how advanced your machine is; audio cues can be simple beep tones or more complex sounds that indicate both target type and relative depth information.
Many detectors now have multiple audio tones which make them very useful when discriminating against certain metals while letting others come through unfiltered. For example: gold jewelry produces a unique “low tone” when detected whereas iron objects produce a distinct “high-pitched tone”.
Conclusion
In conclusion, proper target ID discrimination is crucial for every serious metal detecting enthusiast who wants to maximize their finds while avoiding frustration from digging up junk targets repeatedly. Knowing what type of metal you’re detecting, and its conductivity, depth, size and audio response can help you focus on high-value targets that are worth your time and effort. Discrimination features on many detectors allow for customization settings to be adjusted so that users can filter out unwanted signals while letting the good ones come through unfiltered. With practice, using these techniques will become second nature allowing you to make more finds in less time.