Senior Project Engineer & DFX Designer
White's Electronics, Inc
it is. The finest all-around metal detector. White's new DFX
is simply unsurpassed in its ability to find treasure older,
deeper and smaller items that other metal detectors pass over.
DFX brings together the ultimate combination of sophisticated
microprocessor technology, and "Turn-On-And-Go" simplicity.
You're out hunting right away, but there are dozens of adjustable
features available if you choose.
Pick your program and GO! Nine "Turn-On-And-Go" Programs including
our user designed EEPROM programs you can override with your
own custom programs. Listen for the distinctive sound of "treasure,"
then see what you've detected on the screen. Pull the trigger
and DFX shows you how deep to dig.
A revolutionary, new multifrequency method. Partnered with
the target I.D. you get only from White's metal detectors,
now DFX uses dual frequency detection to "see through"
minerals in the ground and detect coins, jewelry and relics
other metal detectors are missing. Hunt in 3 kHz, 15 kHz,
or use both together for unequalled hunting. This is concentrated
power from the two individually processed frequencies that
work best for finding treasure. Detecting together or singly,
choose Best Data and the DFX displays data from the most
reliable frequency. Choose Correlate and questionable targets,
including iron, are rejected. All happening automatically,
behind the scenes, while you hunt!
The DFX (Dual Frequency XLT®)
was conceived of as a detector which would maintain the most
popular attributes of the Spectrum XLT®, while adding the
benefits and capabilities provided by multiple frequencies.
Multiple frequency, for our purposes, refers to a method of
detection in which signals at two or more frequencies are transmitted,
received, and processed in a more or less simultaneous fashion.
We will refer to a detector in which these operating frequencies
do not run at the same time, but can be chosen between by the
operator, as selectable frequency operation.
The primary intent of adding multiple frequency operation is
to enhance performance particularly on the salt water beach.
Selectable frequency operation is provided primarily to allow
an operator to optimize the detector's performance according
to the types of targets he or she is most interested in finding.
I will explain these things in more detail shortly.
Keep in mind, although technically more advanced all the features
and benefits are available to the "Turn-On-And-Go" PRESET user
with nine Factory Set Up programs to chose from, as well as
those who like to tailor the features to their exact preferences.
The DFX is truly a leap above traditional single frequency
models not only in the technical internal circuitry, but in
the performance gains and end results, finding more desirable
items, in more difficult conditions, digging less trash, and
returning home with more prized finds.
Senior Project Engineer & DFX Designer
White's Electronics, Inc.
The choice of operating frequency in a
metal detector will have a significant effect on the detector's
ability to find certain types of objects. Just as important,
it will effect the detectors ability to distinguish between
certain desirable and undesirable metal alloys.
White's Goldmaster Series, running at 50,000 cycles per second
(50 kHz), is an excellent choice for finding tiny flakes of
gold. It would be a poor choice, however, for coin shooting
in an environment where aluminum trash rejection is important.
It would also be a poor choice for salt water hunting, because
the same principles that make it sensitive to small nuggets
make it sensitive to salt water. A detector running at 1.75
kHz (like the old Coinmaster V) would have good salt water rejection
and good sensitivity to targets like silver coins; but its sensitivity
to most gold jewelry, and its ability to distinguish nickels
from foil and pull tabs, would be poor.
White's has been very successful building general purpose detectors
which run at 6.6 kHz. This frequency was chosen years ago as
a standard because it provides both good sensitivity and good
discrimination for a wide variety of targets and environments.
Still, for jewelry hunters and prospectors it may be too low,
while for beachcombers and cache hunters it may be too high.
Clearly, providing the flexibility to match the operating frequency
with the application is a desirable thing.
The two frequencies available in the DFX are 3 kHz (actually
2.98) and 15 kHz (14.91 kHz). The detector can be configured
as multifrequency in two different formats, Best Data, and Correlation,
or a conventional single frequency machine at either of those
two frequencies. 15 kHz will be a better choice for finding
small gold items, including most jewelry. It will provide better
sensitivity and more accurate discrimination for targets in
the foil through pull tab range. 3 kHz will be preferable for
finding copper and silver coins, and will provide better sensitivity
improved discrimination in the screw cap through silver dollar
range. It will also be less salt sensitive.
Preset Starting Programs
The selection of "turn-on-and-go" programs
has been greatly expanded. Preset Programs let the detector
do the work for you selecting the most desired options for the
application. The standard Preset Programs; COINS, COINS & JEWELRY,
JEWELRY & BEACH, RELIC, and PROSPECTING can be chosen. In addition
to that there are four EEPROM (Electronically, Erasable, Programmable,
Read, Only, Memory) Custom Programs that are set up at the factory
when the first five Preset Programs are installed. EEPROMs contain
more advanced settings that experienced hunters have found useful.
The four EEPROMs can be overwritten to hold one's own custom
programs. Or one of the standard Preset Programs can be modified
and saved in one of the EEPROM positions. In other words the
first five standard preset programs are permanent. You can modify
them for temporary use, and/or copy past those modifications
of that program to one of the EEPROM positions by SAVING and/or
NAMING it, for future use. However, the first five standard
Preset Programs will always revert to their original factory
settings upon battery changes and/or fresh start up procedures.
Once any modifications have been SAVED in an EEPROM position,
they will remain during battery changes and fresh start up procedures
until manually overwritten with a new program and that program
SAVED in that position.
You can SAVE and continue using that EEPROM position with the
same name, or select NAME and manually NAME & SAVE at the same
time allowing you to type in a descriptive name for your special
The DFX provides a wealth of information
on the LCD display.
VDI (Visual Discrimination Indication): provides a reference
number for all alloys and sizes from -95 to +95. Assigning a
VDI number for each target type allows the DFX to selectively
accept or reject like targets. The chart painted on top of the
control box references VDI numbers and common targets.
Target Icons: Along with the VDI number, a representation
of common targets within that range are displayed providing
a quick and easy on the eye reference.
SignaGraph: Along the bottom portion of the display the
SignaGraph provides a conductive/magnetic signature of that
alloys characteristics. Magnetic irons are easily identified
by their magnetic signature (to the left of center) where as
alloys of the non-ferrous precious class pattern to the right
of center and tend to provide narrower taller patterns.
Status Indicators: The battery check is automatic upon
turn on. If the battery gets low during searching LOW BAT appears
on the display. The Multi Frequency mode of operation is also
indicated in the center/bottom portion of the display. Best
Data (automatically chooses the best frequency for the target
range), Correlate (compares both frequencies), or individual
frequencies 15 kHz or 3 kHz.
Depth Reading: Once a good target has been located, squeezing
and holding the Trigger Switch on the handle changes the display
to indicate the depth of the coin sized target in inches and
provides a non-motion pinpoint mode for zeroing in on the exact
spot to dig. Once the Trigger is released the DFX returns to
the search mode.
What does the display tell me?
1. V.D.I. Visual Discrimination Indication
("target reference number") In the upper left hand-side
of the display there is a V.D.I. number that corresponds to
the V.D.I. SCALE painted on the top right-hand side of the control
box. It also corresponds to the Discriminate Edit feature allowing
you to reject or accept targets based on their V.D.I. reference
number. There are "+" numbers for nonferrous (not of iron) targets,
and "-" numbers for ferrous (iron) targets. Rejected V.D.I.
numbers may not appear if the VISUAL DISCRIMINATION feature
is ON. Reasonably consistent V.D.I. reference numbers (± five
digits), in a desirable area of the chart is a vote for digging
2. Possible Target Identities ("Probable or most likely target")
To the right of the V.D.I. number, possible target identities
will be represented graphically. These graphics are called ICONS.
A fairly consistent indication of a desirable target is another
vote to dig the target. One or two possible target icons may
appear. There is significance to which icon appears first. The
first target to appear is always the most likely, the second
is another possibility, slightly less likely than the first.
3. SignaGraph® The SignaGraph® at the bottom
of the display provides a final vote as to whether or not the
target should be dug.
A. Sweep the loop over the target several times and look
at the SignaGraph®. The SignaGraph® automatically clears
itself (FADE RATE) so that it doesn't fill the screen with information
from past loop sweeps. An operator has limited time to look
at the SignaGraph®. If you want to look at the information
again, sweep the loop over the target several more times. The
fading of the SignaGraph® information can be slowed or speeded
(FADE RATE) to operator preference. This is completed in the
PRO OPTIONS under DISPLAY. Automatic AVERAGING and/or ACCUMULATING
of SignaGraph® information is also available (See PRO OPTIONS).
B. Valuable targets will show up on the positive side
of the graph. The positive area of the chart is the section
located to the right of the zero.
C. Look for consistency. In ideal conditions, coins and
jewelry produce one or two bars to the right of zero. Trash
produces several bars, sometimes on both sides of zero.
D. In less than ideal conditions, coins may produce a
wider pattern of bars. Most trash targets produce a recognizably
different pattern than valuable targets.
E. One of the most visual benefits of the SignaGraph®
is the ability to show a smear pattern on iron targets that
often fool the other methods of identification. An iron target
will likely show definite bars on both the negative and positive
sides of the SignaGraph®, often smearing all the way across
the entire chart. Valuable targets should not produce such obviously
wide patterns. In very bad ground conditions, a good target
may have a few small bar segments in the negative area due to
mineralization. However, the pattern will show mostly positive
bars, in a fairly narrow tall group.
Within the DFX circuitry, the identification
and discrimination of targets are performed by the same proven
basic techniques used in the XLT®. Bandpass filters are
used to remove most of the slowly changing ground signal, while
allowing most of the more rapidly changing target signal to
pass through. In the XLT®, this filtering is done entirely
with analog hardware. Each signal channel passes through two
stages of hardware filtering. In the DFX , the second stage
is accomplished by a digital filter, which is entirely under
software control. This allows for a greater degree of user adjustment,
including a less aggressive filtering mode (two filter/three
filter) similar to that found in many popular lower-end machines.
We have upped the microprocessor clock
frequency from 6.75 MHz (XLT®) to 14.32 MHz (DFX ).
You will immediately notice a result of this in the form of
"snappier" display response.
All the MENU items are tied together so that the ARROW up and
down controls scroll through every adjustment screen. If you
continue to press the ARROW down you can go beyond the last
BASIC ADJUSTMENT (View Angle) and into the PRO OPTIONS. If the
ARROW up control is pressed after VOLUME, you will be scrolling
backwards through the options starting with the end of the Preset
Programs, then the MAIN MENU, then the end of the PRO OPTIONS.
An important feature of the ARROW controls; If a BASIC ADJUSTMENT
has been made (for example Volume) and the trigger has been
squeezed and released to return to a search mode, you can return
to the volume adjustment simply by pressing either of the ARROW
controls. This shortcut returns to the last adjustment that
was made thereby allowing an operator to switch directly from
a search mode to the adjustment currently being fine tuned.
This feature is desirable as you start using BASIC ADJUSTMENTS
or PRO OPTIONS that are located further down the menu listings,
or any adjustment that may require some trial and error to find
the appropriate setting.
If care is taken to use a desired adjustment screen last (just
prior to squeezing and releasing the TRIGGER for a search mode),
Custom Programs can use this ARROW RETURN feature to allow quick
easy access to the most used feature. Use that feature (adjustment
screen) last, just prior to squeezing and releasing the TRIGGER
for searching. Then during searching, press either ARROW to
return directly to that adjustment screen.
"HOT KEYS" will save time as they allow easy access, from the
search mode, to the most needed adjustments. They are painted
on the bottom of the control box for field reference.
NOTICE: "HOT KEY" shortcuts will not function from a cold start
(batteries just installed). To function from a cold start the
DFX must be turned on and air/ground balanced in any mode,
then turned off. "HOT KEY" shortcuts will then function.
DFX New Features
Motion discrimination is based on the fact
that the signal received from the ground tends to remain the
same, or change very slowly, while the signal received from
a metal object buried in the ground tends to change much more
rapidly as the loop is swept over it at a reasonable speed.
We are thus interested in the rate-of-change of the signal more
than we are in the magnitude of the signal itself.
An electronic device which is sensitive to the rate-of-change
of a signal is known as a differentiator, or, alternately, as
a "high-pass filter". A single high-pass filter is often used
in the all-metal channel to provide what we call S.A.T., or
"Autotune". For discrimination purposes, one high-pass filter
is not usually good enough. We need at least two Ń which is
the origin of the term "two-filter detector". A potential point
of confusion here is that discriminating detectors need at least
two signals, or channels, commonly called X and Y (or X and
R). White's high-end detectors use three channels. But in any
event, each channel needs at least two high-pass filters which
is the origin of the term "four-filter detector".
Detectors in the 6000 - Eagle - XLT® line have three high-pass
filters per channel. In addition, a "feedback" technique is
used to increase the gain for fast changing target signals,
which in some sense is like adding yet another, forth high-pass
stage "four-filter machine". Our experience has been that this
additional filtering provides superior depth and discrimination
in ferrous mineralized ground, however, with it some compromise
responding quickly to targets near to each other.
In the DFX, the first two high-pass filters are implemented
in hardware. The third high-pass, and the feedback element,
are implemented in software with what is known as a digital
filter. The digital filter is easily adjustable, requiring only
the change of a few numeric constants in the microprocessor.
Here is a summary of Ground Filter settings:
2- digital filters disabled - hardware filters only (quick "two-filter"
3- third high pass enabled; no "feedback"
4- feedback enabled (XLT®-like response)
5- additional feedback (more filtering than XLT®)
6- maximum feedback (maximum ground filtering)
Use a lower setting for faster recovery between targets, and
for greater freedom to sweep fast or slow without losing depth.
Use a higher setting for better ground rejection.
The digital filter can be tuned so that
it is more sensitive to a faster sweep, or more sensitive to
a slower sweep. When Ground Filtering is set to 2, the digital
filter is disabled and so the Sweep Speed adjustment has no
effect. Use higher settings of Sweep Speed to quickly move through
an area with few targets, and lower settings to move more slowly
through areas in which you need to get in between the trash.
This feature has changed compared to the
XLT®. It has been pointed out for some time that setting
this control up beyond 4 or so wasn't very practical in the
field. A lot of people wished they could turn it down below
1. So, the range has been shifted. A setting near mid-scale
should give you fairly good and familiar results. Turning it
down will provide a little more depth on coins at the expense
of poorer iron rejection. Turning it up should provide some
useful reduction in the iron trash you dig.
The range of this control has been shifted by a considerable
amount. While there is not a direct conversion factor to equate
XLT® settings with DFX settings, our intent was to
make a setting of 10-12 (in the DFX) about equal to a setting
of 2-4 in the XLT®. Since most of the Preset Programs have
BOTTLECAP REJECT set to 4, we are actually running at reduced
levels in DFX, when compared with XLT®. While the effect
is most pronounced on bottlecaps and similar iron targets, this
control will have some impact on all aspects of the discrimination
Hot Rock Rejection
Setting or clearing +95 in the DISC Editor
(on the XLT®) can have a pretty dramatic effect. So, we
have provided an adjustment to allow for more "shades of gray"
between the extremes of simply accepting or rejecting this number
with the DFX.
A setting of 20 with the DFX does the same thing as selecting
+95 to reject regarding XLT® models. Turning it all the
way down to 0 makes it a "hot rock accept" control Ń like making
+95 an accepted target did previously with the XLT®. A setting
of 10 means that the detector will neither accept nor reject
the target; it does nothing. Other settings give greater or
lesser degrees of acceptance/rejection.
+95 in the disc editor controls whether the number is displayed,
but has no effect on the audio response.
Remember that +95 in the DISC editor now only controls the Visual
Discrimination of those readings. Audio Discrimination response
to +95 readings is controlled by HOT ROCK REJ. A setting of
20 is the same as setting +95 to reject in an XLT. Setting to
0 is the same as clearing +95 to accept. A HOT ROCK REJ. setting
of 10 means that the reading will have no effect on the audio
Ń it will neither accept nor reject the target. Other settings
give various degrees of acceptance or rejection.
When a target is analyzed and a VDI number
computed based on signals acquired at 3 kHz, the results will
not be the same as the familiar numbers we see in a 6.6 kHz
machine. The microprocessor, though, can easily compute what
the result would be at 6.6 kHz when given 3 kHz data. We call
this process "Normalization". Similarly, the 15 kHz VDI results
can be normalized to 6.6 kHz units.
There are several reasons for performing normalization. First
is the fact that many people have already committed the 6.6
kHz VDI scale to memory. Second is the fact that it would be
extremely annoying to have to edit your discriminator every
time you changed frequencies. Finally, normalization makes it
possible to do the dual-frequency discrimination techniques
Here is a chart showing the non-normalized, and normalized,
data for some familiar targets:
3 kHz VDI #
6.6 kHz VDI #
15 kHz VDI #
So, why would you want to turn normalization off? Notice that
you get much more "spread" between foil and pulltabs at 15 kHz;
this means better VDI resolution, which might make it easier
to identify rings. The same applies to the spread between Zn
pennies and dollars at 3 kHz. Normalization is forced ON when
either "Best Data" or "Correlate" are selected. Only in the
single frequency 3 kHz or 15 kHz modes can normalization off
The DFX transmits, receives, and processes
data continuously at both frequencies. When you pass over a
target, the processor looks at the magnitude and phase of both
signals, and decides which one is more likely to give an accurate
VDI result. It then computes the VDI at that frequency, normalizes,
and reports the result to the LCD as well as using it to perform
audio discrimination. Thus you should get good results on nickels
and rings (where 15 kHz is the frequency of choice) as well
as on deep silver coins (where 3 kHz is likely to be selected
by the processor).
When Best Data is selected, the all-metal signal (both for pinpointing
and searching with the discriminator off) will also be derived
using both frequencies. The 3 kHz signal will be factory balanced
to reject salt; same with the 15 kHz signal. The resulting salt-balanced
signals will be highly sensitive to ferrous ground, as well
as to most metal. We combine these two signals in the correct
proportions in order to achieve ferrous ground balance. We now
have an all-metal signal which is balanced to salt, balanced
to ferrous minerals, and still sensitive to metal objects.
When the normalized VDI results from each
of the two frequencies do not agree, we can be pretty certain
that the target response at one or both of these frequencies
is too weak to be useful, or that one or both signals have been
corrupted in some way - by interference or ground noise. If
the agreement is excellent, we can feel pretty confident in
reporting the result to the operator, both visually and audibly.
This is what Correlation does; when the two results are the
same or nearly the same, the target is treated as valid; when
they don't agree, the results are ignored. Early indications
are that iron targets do not correlate well, and thus some improvement
in iron trash rejection may be had by selecting "Correlate".
Single Frequency Modes; 3 kHz, 15 kHz
These two modes should be fairly self-explanatory.
Both disc. and all-metal data comes from the frequency you select.
Use 15 kHz for small gold, nickels, jewelry etc. Use 3 kHz for
copper and silver coins, larger objects, etc.
Experienced White's users are familiar
with the types and the severity of interference which impact
the performance of those products operating at 6592.5 Hz. Since
the DFX operates at two less familiar frequencies, new interference
issues are sure to arise. One such circumstance which we are
aware of has to do with interference from power lines. In general,
power line interference is stronger at lower frequencies Ń thus
we expect to see more significant power line related interference
at 3 kHz than we do at 6.6 kHz or 15 kHz. To operate nearer
to power lines the single 15 kHz frequency is suggested.
General looks have not changed from the
earlier XLT® to the DFX . It has the same S-handle
framework and lightweight yet rugged design for long hours in
the field, without fatigue. You will also notice that, although
the size of the coil is the same 950, it is now the Wide Band
Multiple Harmonic coil and not interchangeable with the XLT®.
The display or meter is mounted at the top of a comfortably
padded handle, with the trigger switch near the index finger
for quick and easy pinpointing and non-motion, all-metal detection.
The armrest sits at elbow position over a control housing that
is noticeably smaller than White's boxes of just a few years
ago and therefore much lighter. The sides of the box read, "White's
DFX Spectrum E-Series," with start-up procedures and a
VDI (target ID) scale painted on top of the box, and the "Hot
Key" control shortcuts on the bottom. At the back of the box
is a hinged door to remove the battery pack, and a 1/4 stereo
headphone jack. The internal speaker is on the top. White's
has continued with this well thought-out design.
If you are a beginner, don't get "tech
freaked" when you read the following list of features. Remember
that the machine can automatically set everything, unless you
want to set a few or as many as you want yourself. White's has
the features divided into sections. First on the visual display
screen is the Main Menu with the prompt pointing to enter the
Preset Programs, ARROW down to the Basic Adjustments, or the
Pro Options, and continue ARROW down to find the Custom EEPROM
Programs. A Preset Program should be selected as a base or starting
point. If not, the DFX uses the standard COIN settings.
The starting point for selecting a base
program most likely needed for the days hunt. Nine programs
are available to choose from. The four EEPROMs can be used or
replaced by storing your own programs for future use. Let the
detector do the work for you and SAVE preferred settings.
These are the typical features and controls
found on high end models.
1. TARGET VOLUME - How loud a target beeps when detected.
2. AUDIO THRESHOLD - The slight hum or background sound
heard continuously during searching.
3. TONE (AUDIO FREQUENCY) - Selects the frequency or
pitch of sound the detector produces.
4. AUDIO DISCRIMINATION - The ability to reject trash,
different sounds for different types of targets.
5. SILENT SEARCH - The ability to operate without the
threshold or background hum.
6. MIXED-MODE - DC All-Metal non-discriminate mode, working
simultaneously with AC discrimination mode.
7. A.C. SENSITIVITY - Degree instrument is responsive
to signals in the discriminate (motion) modes.
8. D.C. SENSITIVITY - Degree instrument is responsive
to signals in All-Metal non-discriminate (non-motion) modes.
9. BACKLIGHT - Used in dark conditions to light the display
10. VIEWING ANGLE - Adjusts the display for low or high
These are the more detailed options one
should study in the manual prior to experimentation.
1. RATCHET PINPOINTING - Pinpoint feature, automatically
de-tunes for center of target location.
14. BLOCK EDIT - Speeds EDIT by dragging ACCEPT or REJECT
with ARROW controls.
15. LEARN ACCEPT - Target samples can be used to show
or teach ACCEPT discrimination.
16. LEARN REJECT - Target samples can be used to show
or teach REJECT discrimination.
17. RECOVERY SPEED - Speeds target responses, so close
together targets each respond.
18. BOTTLECAP REJECT - How strongly the instrument rejects
or breaks up on iron.
19. HOT ROCK REJECT - Degree the instrument is responsive
to signals in the +95 (hot rock) category.
20. SWEEP SPEED - Adjust signal sampling width thus the
ideal loop/search coil sweep speed.
21. GROUND FILTERING - How much circuitry (high-pass
filtering) used to separate ground/trash signals and targets.
22. VISUAL DISC. - Rejected V.D.I. numbers and ICONS do
not appear on display.
23. ICONS - Graphic display representation of metal targets,
24. V.D.I. SENSITIVITY - Response intensity to produce
a display indication & 3rd V.D.I. digit@ 86 and higher.
25. D.C. PHASE - Measurement of ground, or metal target,
26. GRAPH AVERAGING - SignaGraph® information collects
over multiple loop passes.
27. GRAPH ACCUMULATING - Emphasizes common or predominate
28. FADE RATE - Clears or fades noncurrent SignaGraph®
29. PREAMP GAIN - Selects the intensity of the signal
received from the loop.
MULTI FREQUENCY METHOD
30. 2 FREQUENCY (BEST DATA) - Transmits and processes at
both 3 kHz and 15 kHz frequencies (salt eliminated). Automatically
chooses data from the most reliable frequency (based on both
magnitude and phase) for each specific target.
31. 2 FREQUENCY (CORRELATE) - Transmits and processes
at both 3 kHz and 15 kHz frequencies (salt eliminated). Compares
data at 3 kHz and 15 kHz. Target signals that do not provide
reasonably predictable information at both are automatically
rejected. Iron typically doesn't compare predictably between
frequencies, improved iron rejection can be expected.
32. V.D.I. (NORMALIZED) - 2 Frequency modes (Best Data
and Correlate) automatically have V.D.I Normalized ON as it
is required for these modes to operate predictably. Differences
at 3 kHz and 15 kHz skew the well known traditional (6.59 kHz)
V.D.I. chart/numbers painted on the top of the DFX control box.
Normalization recalculates signals for this traditional V.D.I.
number chart. OFF expands/compresses portions of this V.D.I.
scale (depending on the 1 frequency used).
33. 1 FREQUENCY (3 kHz) - Operates at 3 kHz providing
for superior high iron mineral use (no salt present) particularly
for high conducting silver/copper alloys. Normalized ON maintains
traditional (6.59 kHz V.D.I. chart/numbers. Normalized OFF significantly
expands higher end of V.D.I. chart/numbers compressing lower
end of the scale.
34. 1 FREQUENCY (15 kHz) - Operates at 15 kHz providing
in lower mineralized areas (no salt present) particularly for
lower conducting gold/nickel alloys. Normalize OFF significantly
expands lower end of V.D.I. chart/numbers compressing higher
end of the scale.
Only one of the four available multifrequency methods, BEST
DATA, CORRELATE, 3 kHz, and 15 kHz, can be "ON" at any one given
time. For example if BEST DATA is "ON", the remaining three
multifrequency options are automatically "OFF". To turn BEST
DATA "OFF", requires the selection of one of the three remaining
methods. In other words, an operator never turns "OFF" a multifrequency
method, they simply select the desired method and turn it "ON",
all other methods are automatically turned "OFF."
The MULTIFREQUENCY selection in use appears continuously on
the bottom of the LCD display during searching. The ideal multifrequency
or single frequency setting will depend on many different factors
such as the amount, degree, and type, of ground mineralization,
the types of metal alloys most desired, as well as personal
preferences. No one setting will be ideal for all situations.
A user should first trust the factory preset settings for the
general types of searching and then experiment to find the most
ideal settings for that particular area and type of search.
Generally multifrequency settings are better suited to areas
that have both magnetic (iron) and conductive (salt) components.
Inland areas may vary in this regard with the soils moisture
content. For example dry soil may present mostly iron type characteristics
possibly making one of the single frequency modes a better choice.
The same area when the soil is wet may exhibit conditions similar
to a combination of both iron and salt due to nonferrous metallic
type mineralizationŐs greater electrical activity when wet.
For example soils containing silver, copper, or nickel oxides/nitrates
react differently in conditions from wet to dry. These soil
traits can occur naturally and are typical of areas with mineral
springs or volcanic origins. However, be particularly aware
of this wet/dry phenomena in farming areas where the soil mineralization
is likely altered for agricultural purposes.