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 tosmall pieces of
gold.
General Purpose models are typically not designed
to detect metals as small as a grain of rice,
however,
offer far superior trashmetal 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.
2. 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
search coils,
and/or to give up attempts to eliminate
trash metals.The
15" search coil 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
search coils.
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 search coil. Search coils
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 search coil producing
different shape
search patterns. The larger the search coil,
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 search coils
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 forexperience. 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.
3.
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.
4.
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.
5. 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 downtightly enough to
dig only one type
of metal. For example, a large
piece ofgold 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 agood
discriminator
increases the odds in your favor.
6. 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.
7. 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.
8.
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 todeal 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.
9. 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.
10. 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
Classic®
III, IDX Pro®, XLT®, QXT Pro™,
and
DFX® all have this feature.
11. What about all these different
sized search coils?
Do I need accessory search coils? [Top of page]
The standard equipment search coil is
ideal for
all-around searching. A person may want to use
a
smaller search coil for extreme trash (lots of
close-together targets). A person may want to use
a larger
size for increased depth. Larger search coils
15", are
recommended for larger targets (jars of
coins) at
extreme depths. Remember, with a 15"
search coil, sensitivity to
coin sized
targets decreases.
12. What about a carrying case for my
metal
detector? [Top of page]
For everyday use, the gun style detector bags are
recommended. The detecto rand accessories can be
installed
and removed easily, without taking
the detector apart.
Shock-proof cases are intended
for more serious storage
and travel.
13. 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.
14. What about rechargeable
batteries? [Top of page]
Rechargeable batteries will save you money if you
use
your metal detectoroften, 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.
15. 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.
16. 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.
17. 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
yearparts 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.
18. What is sweep speed? [Top
of
page]
All modern detectors require some
movement
(sweep) of the search coil in order to respond to
metals.
If the search coil is swept too slowly, metals do not
respond, or do not respond at as great of depths.
Every
model has an ideal search coil sweep speed, usually
between two
and four seconds per pass.
Experimenting to find the ideal
search coil sweep speed
allows optimum detector performance. A
first
time user typically has to practice to find their
comfortable search coil sweep technique. Seeing others
with good
search coil sweep habits is a big aid
in learning. Practice makes
perfect. The desire is
to sweep the search coil evenly with the
ground in smooth
even swings. Overlap each pass by at
least 50%,
always keeping the search coil 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.
19. 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
isto maximize the standard features or use
a larger search coil.
There are many aftermarket 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.
20. I want to go nugget shooting
once a year,
beach combing once a year, andthe 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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