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Coil Info/Counterfeits

SEARCH COIL BASICS and General Info

The searchcoil is a vital part of your metal detector. It is the flat, typically circular disk, which generates a magnetic field and senses metallic targets in the surrounding environment. It is located at the end of the stem and is connected to the control housing via a cable normally wound around the stem. The size and depth of the magnetic field is determined by the shape and size of the searchcoil. Understanding the purposes behind the various sizes and shapes of searchcoils will empower you with the ability to choose the best searchcoil for each application.

HOW SEARCH COILS WORK

Searchcoils generally consist of two internal sets of coiled wires, a Transmit Coil (TX) and a Receive Coil (RX). Mono coils can be different in that one coil acts as both the TX and the RX. When the detector is turned on, the TX coil generates a magnetic field in the surrounding space. When a metallic object is within this generated magnetic field, it will create a distortion in the magnetic field. The RX coil will sense this distortion and send a signal to the control housing. A searchcoil’s detection pattern is determined by the combination of the TX’s generated field pattern and the RX’s sensing field pattern. 

SEARCH COIL DEPTH

The detection depth of a searchcoil, as a rule-of-thumb, will be approximately equal to its diameter, for a coin-sized object. However, as a searchcoil’s size increases and its field pattern becomes larger, the field pattern becomes less concentrated and begins to miss small objects. For a coin-sized object, this effect becomes noticeable when using searchcoils larger than about 15" in diameter. Since the field generated by a large searchcoil is larger, deeper and less concentrated than a small searchcoil, it is the best choice when hunting for targets that are usually large and deeply buried, such as caches or relics.

SIZES & SHAPES

There are a variety of searchcoil sizes and shapes. The correct one to use depends on the environment it will be used in as well as the targets being sought. A change in any one of these variables may require a different searchcoil. Generally, searchcoils are circular or elliptical in shape. An elliptical searchcoil is more maneuverable than a circular searchcoil and its narrow width actually provides greater coverage than a circular coil due to its elongated length. However, a circular searchcoil has slightly more detection depth and sensitivity in non-mineralized soil, so it is still the most commonly used shape. Searchcoils also come in a 2-box configuration, which are used for detecting deeply buried targets. Searchcoils range in diameter from a few inches to several feet. Those less than 6" in diameter are generally considered small, 6-11" in diameter are considered medium and over 11" are considered large. As noted earlier, there is a direct relationship between the size of a magnetic field and the size of a coil. The bigger the coil, the larger the magnetic field. Therefore, larger searchcoils generally detect deeper than smaller searchcoils.

Small Search Coils

Because the magnetic field of a small searchcoil is concentrated within a small volume, it is the best choice for hunting in areas with a lot of metal debris. This allows you to maneuver through and around trash to locate good targets, especially when searching in tight places where large searchcoils cannot go. In addition, because of their concentrated detection field, small searchcoils are the best for detecting very small objects. However, a small searchcoil provides less coverage per sweep; more scans will be required to cover a search area.

Medium Search Coils

For general-purpose hunting, which typically includes coins and coin-sized targets, a medium sized searchcoil (8 - 9") is the best choice. Because a medium sized searchcoil provides the best combination of magnetic field concentration, detection depth and capability to detect the greatest range of target sizes within the detection area, it is standard with most detectors. In addition, it’s lightweight and easy to maneuver.

Large Search Coils

Large searchcoils generate wider and deeper magnetic fields than small coils and consequently provide greater depth and coverage. This means that scanning a search area requires fewer sweeps with a large searchcoil than with a smaller coil. This larger scan area, however, can become a problem in trashy areas where the searchcoil is detecting several targets at once.

In addition to searchcoil sizes and shapes, there are also a variety of searchcoil configurations available, with each proving to be the best choice depending on hunting applications and ground conditions. The configuration of a searchcoil refers to the arrangement of the TX and RX coils within the searchcoil shell. There are basically five configurations: Concentric, Mono, Imaging, Double-D and 2-box.

Concentric Coils

The concentric configuration consists of a TX coil and RX coil which are usually circular and arranged as shown at left. The advantage of this configuration is that both the TX and RX coils are wound as large as possible within a given searchcoil diameter. This provides the largest possible detection field and greatest detection depth, making the concentric coil potentially the most sensitive configuration available. In addition, concentric coils also provide the most symmetrical detection field, allowing ease in pinpointing and consistency in target identification. For these reasons, they are the most commonly used searchcoil and will provide the best overall performance in most environments. Unfortunately, this configuration is the most susceptible to interference from ground minerals, which results in substantial loss of performance when used over heavily mineralized ground. 

Mono Coils

A mono-coil is available only on Pulse Induction detectors and is a variation of the concentric configuration. The mono-coil can be manufactured with the TX and RX coils located together or as a single coil acting as both TX and RX. The detection and performance characteristics of the mono are essentially the same as the concentric in that it provides the maximum possible sensitivity, but suffers some performance in mineralized ground. 

Imaging Coils

An Imaging searchcoil is an enhanced version of the concentric configuration that features an additional RX coil. This extra coil provides the detector with additional target information necessary for true target-depth perception and true target-sizing capabilities. With this additional sizing information, the detector can more fully characterize a target and for the first time distinguish between trash and good targets of the same conductivity (e.g. a quarter vs. a soda can). Only Garrett’s GTI series offers this technology; no other detector in the world has this capability

Double-D Coils
The Double-D configuration is designed to significantly reduce ground interference and, thereby, recover the performance lost by a
concentric coil over mineralized soil. With the Double-D, it is the arrangement of the TX and RX coils that produce a canceling effect of ground signals.
 
This configuration is called DD because both
TX and RX coils are in the shape of a “D”. The
positive detection field of the DD runs beneath
the overlapping center section from front-to-back.
The remaining portion of the coil actually produces
negative (i.e. canceling) detection fields. It is this
canceling field that allows the DD coil to maintain
performance over mineralized ground.
Because of its small positive detection field, the
DD is inherently less sensitive than a concentric
searchcoil of the same size, over non-mineralized
ground. The Double-D will, however, significantly
outperform the concentric coil over mineralized
ground. For this reason, it is highly recommended
when hunting over mineralized ground commonly
found when prospecting and relic hunting.

Some Basic Trouble Solutions 

SYMPTOM SOLUTION

No power

1. Ensure batteries are installed in the correct position.
2. Replace all old batteries with all new batteries.


Erratic sounds or Target ID 
cursor movement

1. Ensure your searchcoil is securely connected and the coil is tightly wound around the stem 
2. Ensure you are not using the detector indoors or where excessive amounts of metal are found
3. Reduce your sensitivity setting
4. Determine if you are close to other metal detectors or other metal structures such as electrical power lines, wire fences, benches, etc.

(NOTE: Iron targets may cause erratic sounds or Target ID Cursor movement. You can identify iron targets in an All-Metal Mode)


Intermittent Signals

Intermittent signals typically mean you’ve probably found a deeply buried target or one that is positioned at a difficult angle for your detector to read. Increase the sensitivity on your detector and scan from different directions until the signal becomes more definite. In the case of multiple targets switch to the All-Metal Mode or press PINPOINT to precisely locate all targets.

 

(NOTE: Iron targets may cause Intermittent Signals. You can identify iron targets in an All-Metal Mode).


I'm not finding specific targets Ensure you are using the correct mode for the type of hunting you are doing. If you are hunting for coins, ensure you are in the COINS mode. You may also use the All-Metal mode, which detects all metal targets to ensure desired targets are present.

Target ID Cursor bounces

If your Target ID Cursor bounces erratically, chances are you’ve found a trash target. However, a Target ID Cursor may bounce if a good target (such as a coin) is not parallel to the searchcoil (e.g. on edge). It may also bounce if there is one or multiple "junk" targets laying next to the good target. Scan from different directions until your Target ID Cursor becomes more stable.

 


 

MAKE SURE IT’S MADE IN AMERICA!

These marks certify Garrett’s Made in USA quality inside and out.

Don’t be fooled by imposters. All Garrett products are designed, assembled, tested for quality control and shipped from the company headquarters in Garland, Texas, USA. Garrett’s ISO 9001 certified Quality Management System emblems are an outward reflection of the true quality within.

Garrett Metal Detectors has a long commitment to manufacturing its products in the United States and maintains its only manufacturing facility in Garland, Texas. Garrett does not manufacture or license for manufacture its detectors by any other company. With regard to components and accessories, the company makes every effort to obtain these from U.S. sources. In some cases due to competitiveness or availability our suppliers source globally and it is necessary to offer these items to meet the needs of our customers. All items are marked with the country of origin as required by U.S. law.
Garrett Quality Made in USA, ISO 9001 Certified

Look for the Garrett Made in USA seal
 

Garrett ISO 9001 Certified 

Garrett detectors are made in America under our 
strict ISO-9001 Quality Management System.

 

FACTS ABOUT COUNTERFEITING


Metal detector products from several manufacturers have been copied and manufactured by Chinese manufacturers. These are typically sold by Internet retailers. Garrett is most concerned about counterfeits, as our goal is to have satisfied customers who have not been tricked or cheated.

 

 

BEST WAYS TO AVOID COUNTERFEITS:

  • Protect your purchase by using PayPal or a credit card that helps protect you against fraud
    .
  • Look for country of origin stickers on the product. If it is a metal detector with the Garrett brand name and it is labeled “Made in China” or has no country of origin, it is a counterfeit. All Garrett hobby and security metal detectors have the Garrett Made in America seal either on the product itself, on the packaging, or both. Any “Garrett” product that is shipped from China is definitely a counterfeit.
     
  • Make certain that you are buying from an authorized Garrett dealer. Garrett has authorized distributors in countries around the world. To find the authorized Garrett Distributor in your country, visit www.garrett.com and click on Hobby Division. Then click on the upper row “Where to Buy” tab. For customers outside
    the United States, use the drop-down menu to select your country. Then click the “Find an International Dealer” tab to obtain contact information for the authorized Garrett Distributor(s) in your country.
     
  • Authentic Garrett products use proprietary digital technology which the counterfeiters have not been able to duplicate. The result is a look alike product that does not work very well if at all.
     
  • When ordering the product please be cautious of extremely low prices and inquire about the location from which the product will be shipped. If the price sounds too good to be true, it’s probably fake.
 

IF YOU HAVE PURCHASED A COUNTERFEIT:

  • The serial number of the unit you are planning to purchase or have purchased can be verified with Garrett for authenticity. Please email the number to Garrett’s Customer Service Department and request verification.
     
  • Unfortunately we have no immediate remedy other than to assure you that trademark laws as well as country of origin labeling laws have been violated.
     
  • We encourage you to file a complaint with the seller and the website on which the product was listed. Ask for your money back citing fraudulent country of origin marking and trademark infringement. We can supply official documentation showing Garrett trademark and country of origin information if requested.
     
  • You can also help Garrett take action against repeat offenders by emailing to us any of the following that you have available:

    Name of person and company selling the product

    Name of the website on which the product was listed

    A copy of the invoice showing company name and price of the product

    Return address on the shipping package

    Method of shipment

    Response to your complaint on by the seller and the listing website

Learn More About Garrett and how it all began, Take a trip back 50 years to see it all.. 

http://www.garrett.com/mediasite/history.aspx

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