- Are most metal detectors basically the same?
[Top
of page]
Metal detectors are like cars, they have many different
technologies, features, and performance characteristics for
their intended use. There are five basic types of metal
detectors:
- General Purpose-Coin/Relic/Treasure
Gold Prospecting
Underwater & Salt Beach
Cache Hunting/Deep Searching
Industrial & Security
Some metal detectors are designed specifically for one type of
searching. For example, gold prospecting detectors are
designed to be extremely sensitive to small pieces of gold.
General Purpose models are typically not designed to detect
metals as small as a grain of rice, however, offer far
superior trash metal rejection compared to prospecting models.
When purchasing a metal detector, it is important to consider
what type of metal detecting you will do most often, and
prioritize according to your typical usage.
How deep do metal detectors detect metals? [Top
of page]
The most frequently asked question and unfortunately the most
difficult to answer! Most general purpose models are factory
equipped to search for coin & jewelry sized metals at
depths of 8 to 12+ inches depending on metal size and alloy.
To significantly and consistently detect beyond 12 inches
requires larger accessory loops, and/or to give up attempts to
eliminate trash metals. The 15" loop responding to all
metal alloys can detect larger metal items (coin jars) at
depths up to four feet. However, sensitivity to single coins
is greater with smaller loops. White's TM 808 can detect 55
gallon drums at 16 feet, car-sized metals at 20 feet. However,
it is not likely to respond to individual coins or pieces of
jewelry.
Detection depth varies with many factors:
- The size, shape, exact metal alloy, and orientation of
the object in the ground. Objects of a greater surface are
detected at greater depths. For example a coin lying flat
exposes a greater surface area than a coin laying on its
side and will be detected at a greater depth.
- The size of the loop (search coil). Loops come in a wide
range of sizes and shapes- 4", 6", 8",
9.5", and 15". There are also differences in the
configuration of the coils inside the loop producing
different shape search patterns. The larger the loop, the
deeper it can detect larger metal items. However, it is
more difficult to use in trashy areas with less depth to
small metal items. Smaller loops provide better separation
in high trash and better sensitivity to small metals.
- Soil conditions and the amount of minerals in the soil.
The higher the soil mineralization, i.e. the presence of
magnetic and/or conductive properties, the more difficult
it is for a metal detector to cancel the interference
these soils produce. Detection depth is reduced in severe
grounds. Depth may increase or decrease with subtle
changes in the soil conditions, more noticeably with the
entry level models. Soil mineralization varies widely
around the country & around the world.
- The experience and skill of the operator. There's no
substitute for experience. Knowing how to operate your
detector and understanding the signals will significantly
increase depth.
- The metal detector used and the selection of settings,
particularly All Metal or Discrimination.
What types of things will a metal detector help me find? [Top
of page]
All metallic objects. Example: gold, silver, iron, nickel,
copper, brass, aluminum, tin, lead, bronze. Metal detectors
will not detect nonmetal items such as gemstones, diamonds,
pearls, bone, paper, or stone figures.
What is discrimination? [Top
of page]
Discrimination is the ability of a metal detector to tell the
difference between different types or alloys of metals. This
allows you to selectively dig up only those types of metals
likely to be of interest to them. There are audio
(speaker/headphone) types of discriminators and visual (meter,
LCD) types. Most higher end models have both types. The idea
is to increase the odds in favor of digging valuables, and
decrease the odds of digging trash.
Can a detector be set only to respond to gold? [Top
of page]
No. There are too many variables with exact alloys and sizes
to pin it down tightly enough to dig only one type of metal.
For example, a large piece of gold may read high on a display
or audio discrimination scale and a small piece of gold may
read low on that same scale. Gold with some copper, silver, or
platinum within its natural alloy will indicate differently.
And other metals with similar electrical characteristics may
read identically. Lead and aluminum are the most difficult
common trash metals to eliminate. Even with the most
sophisticated detectors available, expect to dig some trash.
But a good discriminator increases the odds in your favor.
What is operating frequency? [Top
of page]
Frequency in a metal detector is referred to in kHz. (kilo
hertz). It is the number of times the signal is transmitted
and received by the detector every second. For example a metal
detector operating at 6 kHz will transmit and received 6,000
times per second, and at 50 kHz 50,000 times per second.
As a rule, lower frequency detectors offer better sensitivity
to copper and silver and better overall detection depth and
trash rejection. Most general purpose models operate at lower
frequencies.
Higher frequency detectors are more sensitive to small metals
and natural gold. However, they have difficulties with
discrimination against nonferrous (not-of-iron) metals. Their
sensitivity to small metals makes them tedious to use around
trashy areas. Most gold prospecting detectors operate at
higher frequencies.
Are there any good places left to hunt? [Top
of page]
Nobody gets it all. Just because an area has been hunted
before doesn't mean a person with patience and a modern
detector can't still find the "good stuff" just
about anywhere. Spending time with research can still turn up
places which may never have been searched. Seasonal changes
such as storms, frost heaves, and erosion, can also renew
areas, particularly beaches.
What is the difference between "two filter"
Classics and the higher end "four filter" models? [Top
of page]
Two filter (Classic Series) and four filter (Pro, Quantum,
& XLT) are terms used to describe the amount of electronic
circuitry a metal detector uses to deal with both
discrimination and ground mineral elimination. A two filter
model will work great in low to medium ground minerals and
offer faster response between close together targets in trashy
areas. Two filter models are user friendly, lightweight, and
less expensive. Four filter models typically detect deeper in
mineralized ground, have superior audio discrimination and
depth, and offer more advanced features.
What will target ID displays or meters do for me? [Top
of page]
Many models have displays that indicate the likely
identification of the metal detected. This is in addition to
the audio discriminator. Once an audio signal of interest is
heard the display will give a second, independent, opinion
about whether the target is a good target, or trash. You dig
less trash with an ID display.
ID displays are a very accurate measure of a targets
"electrical phase". Unfortunately, many different
metals have the same electrical phase. The Target ID will
increase your odds of digging good alloys and decrease your
odds of digging trash alloys. If, in a given area, a
particular indication consistently turns out to be trash, such
indications in that area are likely to continue to be trash
and can be ignored.
I want to go metal detecting with friends and family. Will
more than one detector interfere with each other? [Top
of page]
Yes. Like models operating on the same frequency will
interfere with each other if operated within 100 feet. To
search with a partner nearby, at least one of the instruments
requires the frequency shifting feature. The ClassicXLT® IDX,
Quantum II, Quantum XT, Goldmaster 4/b, and Spectrum XLTXLT®
all have this feature.
What about all these different sized loops? Do I need
accessory loops? [Top of page]
The standard equipment loop is ideal for all-around searching.
A person may want to use a smaller loop for extreme trash
(lots of close-together targets). A person may want to use a
larger size for increased depth. Larger loops 15", are
recommended for larger targets (jars of coins) at extreme
depths. Remember, with a 15" loop, sensitivity to coin
sized targets decreases.
What about a carrying case for my metal detector? [Top
of page]
For everyday use, the gun style detector bags are recommended.
The detector and accessories can be installed and removed
easily, without taking the detector apart. Shock-proof cases
are intended for more serious storage and travel.
Do I need headphones? [Top of
page]
Headphones will increase battery life, increase privacy, and
increase your ability to hear signals clearly against
background noise. They are of benefit to those even with good
hearing. Crisp sound is typically more important than wide
frequency specifications. In most cases, higher impedance
headphones (100 ohms) offer crisper sounds.
What about rechargeable batteries? [Top
of page]
Rechargeable batteries will save you money if you use your
metal detector often, at least once or twice a week. If you
use your metal detector once a month, rechargeable batteries
will not likely save you money. Rechargeable batteries do
offer the same metal detection performance- most models use a
voltage-regulated system.
Where can I use a metal detector? [Top
of page]
You must have permission to search both private and public
property from the owner or person in charge of managing the
property. In most cases you can locate the owner, or available
permit system, through City Hall or the county seat.
If the area is city owned contact the Parks and Recreation
Department. If it is a State or Federal Park contact the
superintendent or grounds keeper. Known and marked historical
sites, historical parks, and historical monuments are
typically off limits to all metal detecting.
Start with your own yard. Valuables can be found anywhere
people have congregated, gathered, lived, sat, walked, played,
camped, picnicked, traveled, or fought. Any place inhabited
before 1965, is likely to have the older styles of collectable
coins.
How do I recover the target once I decide to dig it up? [Top
of page]
Care must be taken to use the appropriate digging tool for the
terrain, and not to leave unsightly excavations or holes.
There are hundreds of digging tools designed to minimize the
impact on grass and vegetation, and avoiding damaging the
items found. Sand scoops are all that is needed in some areas.
In others, a hand gardening trowel or spade. Challenging
ground conditions may require more sophisticated tools.
Some areas may have rules on the type and size of digging
tools allowed. Make yourself aware of these rules; respect the
laws and restrictions in your area. Unsightly holes left
unfilled are dangerous to people and livestock, and are
detrimental to the continued use of detectors.
What kind of Warranty comes with White's detectors? [Top
of page]
White's warranties standard models from all defects in
materials and workmanship for two years transferable parts and
labor. White's two year parts and labor warranty often offers
more warranty coverage than "limited lifetime" or
extended years of coverage. One must read the fine print
carefully when comparing warranties. Labor and high wear parts
are the most likely areas of cost in repair service.
What is sweep speed? [Top of
page]
All modern detectors require some movement (sweep) of the loop
in order to respond to metals. If the loop is swept too
slowly, metals do not respond, or do not respond at as great
of depths. Every model has an ideal loop sweep speed, usually
between two and four seconds per pass. Experimenting to find
the ideal loop sweep speed allows optimum detector
performance. A first time user typically has to practice to
find their comfortable loop sweep technique. Seeing others
with good loop sweep habits is a big aid in learning. Practice
makes perfect. The desire is to sweep the loop evenly with the
ground in smooth even swings. Overlap each pass by at least
50%, always keeping the loop in motion. Recognizing where the
beep is on each pass and shortening the passes to zero in on
the location (pinpoint) takes some practice as well.
What about the after market devices that are said to add
depth to my detector, do they work? [Top
of page]
A well-designed metal detector has all the usable detection
depth (gain) built into standard features. The only way to
significantly increase depth is to maximize the standard
features or use a larger loop. There are many after market
devices that can make it easier to hear the metal detector,
giving the impression of greater depth. Their degree of
success depends on the individuals hearing abilities.
I want to go nugget shooting once a year, beach combing
once a year, and the rest of the time I want to coin and
relic hunt. What model of instrument should I be looking at? [Top
of page]
A general purpose would give you the best all around
performance. Only when beach or prospecting consumes the
majority of your search time would it be wise to look at a
model specifically for that purpose. Although prospecting or
beach models offer increased performance for their purpose,
they are not as effective as a general purpose models for coin
and relic hunting.
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