- 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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