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Field
Test by Gene Scullion
Tesoro Electronics has done it again!
Since their inception nearly 20 years ago, Tesoro has built
a reputation of quality machines at affordable prices with
topnotch workmanship and a lifetime guarantee. Their name
has been synonymous with tough, easy to use, quiet machines
that out perform competitor units costing twice as much. The
Tesoro name is also a very dominant player at competition
hunts, easily the preferred choice of the majority of
regular entrants at hunts held all around this great
country. That in itself is a huge indication of Tesoro’s
ability to make great machines. They also have a service
department that is second to none. I am here to introduce
the newest addition to the Tesoro family, the next
generation target ID machine, the Cortés.
I find it somewhat daunting to believe
some field test reports, especially if I know nothing of the
person performing the test. That said, allow me to list my
credentials. First of all I do not work for Tesoro or any
detecting magazine. This field report is a freelance effort.
I have been detecting since 1977, and I consider myself a
very avid detectorist. Some label my detecting desire as
"fanatic," but I prefer to call it "my passion." My
experience with Tesoro machines started back in 1984 and I
have owned and used many different models since then, as
well as a few "other" brands from time to time. I have been
a very active member of the Four Lakes Metal Detector Club
(Madison, WI), serving as Vice President and President
repeatedly since I first joined the club back in 1983. I
have been the editor of our club newsletter now for nearly
three years and have won our club’s "Treasure Hunter of the
Year" award 8 out of the last 9 years. I divide my detecting
time between water hunting and relic/ghost town hunting, and
I would be hard pressed to say which of those I like more.
My first Tesoro field test report was published last year in
the 17th Edition of the MDI magazine, on the
Tiger Shark, and now I find myself blessed yet again testing
the new Cortés.
Gene Scullion with the new Cortés
The anticipated introduction of the
Cortés held my keen interest because my primary land machine
for the past 7 years has been the Toltec II, Tesoro’s
previous production model target ID machine. I was ready for
a new target ID machine and I wanted it to be a Tesoro. The
Toltec II has now been out of production for nearly 2 ˝
years, and needless to say, dedicated Tesoro users (myself
included) have been anxiously awaiting its replacement. In
the following report, I will only make minor comparisons
between the Cortés and the Toltec II because they truly are
entirely different machines all together.
My first involvement with the Cortés
actually occurred way back in April of this year. Tesoro
sent me the very first prototype for three days, not to
actually write a report on, but to view, play with, try,
test, and otherwise offer some general feedback on. In the
limited time I had to play with it, I only made a few
recoveries but one was outstanding (more on that later).
FIRST IMPRESSION
My first impression as I opened the box
was that the control housing is obviously bigger than the
existing line of MicroMAX machines, but only slightly. I
then noticed that the battery compartment had been moved
externally to the upper end of the arm assembly just below
the arm bracket.
I had initially thought that the actual
display size seemed too small to be effective and that
surely the characters would be too small to seen
effectively, but I have since totally reversed my stance.
There is an amazing amount of information constantly within
easy view of the user. I also noticed that the lower pole
extension (the part of the pole assembly that attaches to
the coil) was entirely made from plastic. The previous
standard had been part plastic and part metal. I surmised
that the entire piece now needed to be plastic so as not to
interfere with the increased depth capability of the new
spoked coils.
The feel was great and it seemed very
well balanced. It is a pinch heavier than the MicroMAX
family machines (2.9 pounds vs. 2.2 pounds) but still
lighter than most competitors’ target ID machines. A glance
at the control panel did not create any immediate confusion
or questions in my mind. Having had previous experience with
Tesoro machines, I recognized all the intended uses of each
control. In fact, I was able to use the machine easily
without reading any operating instructions. It is that easy
to use. The display is straightforward and easy to
understand, and you have a lot of target information always
available to see, including target depth and battery power.
SPECIFICATIONS
The unit comes equipped with the standard
S-handle pole assembly (3-piece, interlocking), the new 9 x
8 concentric "spoked" coil, and a padded grip and arm
bracket. It has a built-in 2Ľ" speaker situated on the
backside of the unit with a louvered opening to prevent dirt
and debris from entering the housing, and it has a fixed
audio output volume. Also on the backside is a Ľ" stereo
headphone jack. Eight AA batteries are housed in two
different compartments, one on each side, below the armrest
bracket. Drop-in style holders are used, each holding 4
batteries apiece, making changing them a snap. Tesoro rates
the battery life at 10 to 20 hours, but that is if no
headphones are used and the display light is not used. Using
headphones should greatly improve on this rating. It
operates at 10kHz, has an optimum operating range of from 30
to 100 degrees F and from 0 to 75% relative humidity. It is
compatible with all 5-pin µMax and Series II coils (some
ground balance calibration may be required for optimum
performance) and carries Tesoro’s famous Lifetime Warranty.
For those of you that would like a
nutshell listing of its features: The Cortés has four
operating modes: No Motion ALL METAL, Silent Search
DISCRIMINATION, SUM Discrimination, and NOTCH Discrimination
(narrow/wide). The All Metal Mode is a manually ground
balance mode with adjustable threshold level, and the
Discrimination Mode is factory preset ground balanced. The
two Notch Modes have factory preset widths. The Sum
Discrimination Mode allows improved target identification by
averaging signal information and utilizes a 9-tone audio ID.
It also has a backlit display (low/high) for hunting in
minimal lighting conditions. The digital display ID’s
targets 3 different ways simultaneously (alpha characters,
numerical, bar graph), shows probable target depth, and
battery condition constantly, and in all modes.
DISPLAY
The Cortés is a combination of
microprocessor technology and traditional Tesoro analog
technology. This combination makes for a powerful detector
that is very easy to adjust and operate. Tesoro decided long
ago to design this new machine without requiring any
complicated set-up routines or programming, and as a result
it is very easy to use and a joy to hunt with.
Faceplate
The heart and soul of the machine is the
2x16 character display, and it shows a lot of information in
a very easy to understand fashion. Nearly all of the
information displayed is target specific, that is it
pertains to whatever you just scanned and after 6 seconds,
this information will be erased from the screen. By clearing
the screen every 6 seconds, the user will be able to tell if
another discriminated target has been passed over. Seeing
this information allows the user to make better decisions on
when to dig and not dig. It also allows you to see how much
"trash" is in a given area without the constant beeping in
your ears (nice feature!). When no target information is
displayed, the Cortés displays alpha characters indicating
what mode you are presently in: ALL METAL, DISCRIMINATION,
DISCRIMINATION NN (for narrow notch mode), or DISCRIMINATION
WWW (for wide notch mode).
The top line of the display I will call
the "alpha character" display line. It will indicate
potential target information in abbreviated terms, such as:
"IRON OR FOIL," "NICKEL RING TAB," "ZN CENT SCREW CAP," or "SIL
COIN CU CENT." This line will also display a special message
if a target is overdriving the circuits, and it will tell
you to lift the coil for a more accurate reading. This
display works in all modes and regardless of the
discrimination settings. What that means is that you can
visually see what targets you have passed over, even when no
audio is present because of discrimination or notch
settings.
The bottom line of the display is the
meat and potatoes of the machine. On the left-hand side is a
two-digit probable depth indicator, calibrated in inches.
When a target is scanned, it will display its probable depth
to the nearest inch. On the right side is the battery power
indicator, which is a solid rectangular block when at full
power, and it gradually shortens in height as your battery
power decreases. This icon is always displayed so you have a
constant indication of your battery life. Also, on the right
side is a two-digit numerical display called ID NUM (ID
Number), which is a numerical representation of target
characteristics. In the center is a nine-segment bar graph
also representing target information. The last two areas
described (bar graph and ID NUM) display the most important
user information so I will spend some time explaining each.
The engineers at Tesoro applied a 0 to 95
numbering scheme to the standard range of targets. "Zero"
being the far left or bottom end of the scale (iron) and
"95" being the far right or top end of the scale (dollar).
Additionally, they decided to put the most resolution in the
middle of the scale, this being the area where nickels, pull
tabs, gold rings and virtually everything else lies. Because
of this approach, iron will always read "0" and silver
targets will always read "95". A benefit of this "expanded
recognition" is that pull tabs, for example, can vary
greatly in different areas around the country, making it
difficult for a machine to be calibrated and accurately
identify them equally. By widening the resolution in the
middle range of targets, each hunter can be assured of more
accurate readings once the pattern of targets (and their
associated ID NUMBERS) have been determined. For example,
round pop-tops in my area generally read between 36 and 40
on the ID NUMBER, but in another area of the country they
may read between 30-36. With repeated use, you will learn
the pattern of ID NUMBERS for the typical targets in your
area. The bottom line is that this gives you more
information on your targets, allowing you to make better
decisions on whether to dig a target or pass it by. This
feature gives the Cortés great versatility no mater where it
is used.
In the center of the bottom line is a
nine-segment bar graph display. Tesoro divided the full
meter spectrum of targets into nine segments, and each is
represented by a solid bar on the screen. From left to right
the nine segments represent: IRON (1), FOIL (2), NICKEL (3),
ROUND TAB (4), SQUARE TAB (5), ZINC PENNY (6), COPPER PENNY
AND DIME (7), QUARTER (8), HALF AND DOLLAR (9). I have added
the numbers in parenthesis only to aid in my descriptions
during this report. I may refer to the NICKEL segment, for
an example, as "graph segment 3." Additionally, signal
strength of a target will be displayed by varying the height
of the bar graph section. A strong signal will fully light a
graph segment (about 3/16" actual height), but a weak signal
may only display the block at half height, and a very weak
signal as only a solid line across the bottom of that
segment.
A number of factors such as a target’s
metal composition or its orientation in the ground can cause
what is called "smearing," where signal information will be
displayed in multiple graph segments simultaneously. This is
where the ID NUMBER display can be very helpful. You may
encounter targets that smear multiple graph segments but
always ring up in a repeatable range of ID NUMBERS allowing
you to better identify them as a potentially good target.
Immediately below each segment of the
display (printed right on the face of the unit) is a label
identifier so that you don’t have to memorize what each
segment represents. In time you will not even refer to these
labels, but they are handy references when learning the
specifics of the display.
CONTROLS and OPERATION
The controls include MODE (All Metal,
Discriminate, and Sum), ON/OFF/SENSITIVITY, DISCRIMINATION,
GROUND BALANCE and THRESHOLD (for All Metal only), NOTCH
FILTER, and LIGHT.
The MODE control switch is a three-way
toggle. The right position is the ALL METAL Mode, the center
position is the DISC (Discrimination) Mode, and the left
position is the SUM Discrimination Mode.
The ALL METAL Mode has an adjustable
THRESHOLD level and will accept signals from the full range
of metal targets. Target depth and ID information is active
in this mode and continually displayed as targets are
encountered. The machine specification claims a "no motion"
all metal mode, and that is technically true, but because of
a fast auto-retune built into the Cortés, the machine will
quiet itself rather quickly when held motionless over a
target. A very slight movement is needed, which is actually
a great feature because you can pinpoint very easily using
only a small amount of coil movement.
When in the DISC Mode, the user is in a
motion-based mode, meaning the coil must be moving in order
to detect a target, and it is a Silent Search mode meaning
no threshold will be heard. In this mode, you may reject
various types of metals by varying the setting of the
DISCRIMINATION LEVEL control, and you can also enable preset
notch filters (see the NOTCH description below).
The SUM Mode is the left switch position
and you must press and hold the switch in that position to
engage it (it will spring back to the center position when
released). I should add here that it is very easily done
with your right-hand thumb while still sweeping the coil.
The SUM Mode is a totally new feature from Tesoro. It is
basically a "fine-tune" feature that improves on the normal
target identification capability of the Cortés. The SUM Mode
is an extension of the DISC Mode and works in conjunction
with the Notch feature and the Discrimination Level settings
and will not produce any audio on targets that have been
blanked out by either of those two settings.
The SUM Mode allows the machine to
analyze the target through a series of multiple passes and
then average that information and display it on the screen.
By averaging the coil passes over the target, the processor
can filter out most of the signal noise that makes accurate
target identification sometimes difficult. In addition, when
in the SUM Mode, the machine switches to a multi-tone audio
output. This audio ID has 9 different tones (matching the
nine different bar graph segments) and ranges from a low
tone at the "zero" end of the scale (iron) to a high tone at
the upper end of the scale (dollar).
The SUM Mode comes into play on targets
that are hard to pinpoint and/or identify because of
smearing (multiple graph segments and inconsistent ID
Numbers). When you wish to SUM the signals on a target, you
must push and hold the MODE toggle to the SUM position and
shorten your signal sweeps from 2 to 4 inches in length. By
repeating this short sweep pattern directly over the target
3 to 7 times, the Cortés will average the information
together, which usually allows for a more accurate reading.
During this sweep process you will hear the audio ID
progressively getting higher and when it plateaus, the
machine has reached its most accurate ID possible. You may
then decide if you wish to dig the target or pass. This
process does not always narrow the bar graph ID to one
segment. You may still get some smearing, but it does narrow
down the meter’s response. It is a very nice tool to
complement your "dig vs. don’t dig" decision-making process.
I found it sometimes helpful to vary my stance while
"summing", turning 45 degrees to one side or the other, in
an effort to find the optimum stance. Occasionally, I would
get a much better reading this way.
The SENSITIVITY control is also the
ON/OFF switch. It is adjustable from 1 through 10, which is
the normal range of adjustment. Turning the knob into the
orange area beyond 10 puts you into the MAXBoost range. You
should normally run the sensitivity as high as you can to
maintain maximum depth capability but having it set too high
may sometimes cause unwanted noises such as "pops" and
"ticks." This "interference" can be caused by any number of
external factors such as ground mineralization, RF
transmissions, proximity to high power lines, just to name a
few things. When this happens you should turn the
SENSITIVITY control down until the unit runs quietly.
Sensitivity can be used to optimize
another form of searching and that is when you might be
looking for a target directly on the surface. If someone
asks you to search for a freshly lost article of jewelry,
for example, you would then know that it must be right on or
very near the surface. In this case, you are not concerned
with any deep targets, so you could turn your sensitivity
down until you are only registering surface targets (by
watching your depth meter). Many hunters fail to recognize
and utilize this ability of metal detectors when searching
for surface or very shallow objects.
The DISCRIMINATION LEVEL control has
"named" settings as opposed to numerical levels, which I
think makes it easier for beginners and occasional users to
relate to and remember. Instead of 1 through 10 reading left
to right, it reads MIN, followed by IRON, then FOIL, 5˘,
TAB, 1˘/ZN, ending with MAX. You will effectively
discriminate out the item you have the adjustment set on and
everything below it (to the left), meaning if you set it to
TAB, everything below that (IRON, FOIL, and 5˘) will be
discriminated out and create no audible indication. The
display will visually register any of those targets, but you
will hear no "beep."
GROUND BALANCE and THRESHOLD are two
controls used to manually ground balance the Cortés. The
GROUND BALANCE control is a 3 3/4-turn pot allowing users
ample adjustment range and is simply labeled with a "–"
on the left-hand side and a "+" on the
right. The THRESHOLD knob acts like a volume control (low to
left, higher to the right). Ground balancing is a
simple but very important task that you must perform in
order to operate the machine at its peak performance. Tuning
your machine to the exact ground matrix that you are hunting
in will give you the best possible depth and performance. I
will only summarize the procedure here because it is well
explained in the operator manual. You must first find an
area free of any metal targets, set the MODE to ALL METAL,
and raise the coil straight up from the ground (but always
keep it level). You then adjust the THRESHOLD until you hear
a very slight "hum." Next, lower the coil straight down to
the ground stopping just above it. If the machine goes
quiet, you must adjust the GROUND BALANCE up (positive) by
turning the GB knob clockwise. If it gets louder, you must
adjust it down (negative) by turning the GB knob
counterclockwise. You make these adjustments in small
increments and repeat the process until you hear no change
in the threshold volume as you lower the coil to the ground.
At this point you have balanced the ground level of the
machine with the actual ground level of your search area.
Keep in mind, this ground balance is active only in the ALL
METAL Mode (the DISC Mode has a factory preset ground
balance level).
The NOTCH FILTER control is a three-way
toggle switch. In the normal center position, the notch
feature is OFF. Switched to the left, it is in the narrow
position (NAR.) and to the right in the wide position
(WIDE). Notch is a term for effectively blanking out certain
targets from registering a response from your metal
detector. The two notch positions on the Cortés are factory
preset. The narrow notch effectively blocks round and square
pull tabs (graph segments 4 and 5), and the wide setting
additionally blocks zinc pennies (graph segment 6) or any
other targets falling within those ID ranges. The Cortés
display will still register bar segments as you pass over
these types of targets, but you will not hear any audio
indication.
The last control on the front panel is
the LIGHT control. This is also a three-way switch with the
center position being the normally "off" position. The left
switch position produces a small amount of backlight (marked
LOW), and the right switch position creates a brighter
amount of backlight to the display (marked HIGH). This
feature comes in handy in when hunting at dusk or dawn or
inside shelters such as barns, caves, or root cellars.
Now that I have explained the controls,
let me explain the operation. Turn the machine on, set the
SENSITIVITY on 10 (for additional sensitivity, turn it the
entire way clockwise past "10" into the MAXBoost range), set
the DISCRIMINATION LEVEL just below nickels, and go! That’s
it! That is all you have to do to begin finding coins right
away.
TRASH vs. GOOD
Tesoro machines have a history of being
rather good at eliminating iron, and the Cortés is no
exception.
Another long running theme with Tesoro
machines is that you should dig any target that has a
strong, REPEATABLE signal. This holds true with the Cortés
as well. When I encountered targets that defied a repeatable
pattern, either in the ID NUMBER or on the bar graph, it was
always trash. This is true in the All Metal Mode as well
when the variable audio tones would also jump all over the
scale. These types of targets also defied repeatability in
the SUM Mode. In my experience these always turned out to be
iron or some type of twisted and/or torn pieces.
In contrast, you may get some targets
that may not lock on to a specific single graph segment or
ID Number but may bounce between a specific range of ID
numbers and smear two or three graph segments in varying
degrees of signal strength. I don’t mean the kind of signal
that jumps all around the meter but one that consistently
stays localized between a couple of graph segment positions
and a small range of ID Numbers. You should treat these as
questionable but repeatable (to a certain degree) and dig
them just to be sure of what they are. Trash items near good
targets can mask and alter what the processor sees as well
as two dissimilar items like a copper cent next to a nickel.
In the last example (a copper cent next to a nickel), you
will not see the NICKEL segment and the COPPER CENT segment
fully lighting on the bar graph, but rather some varying
segments between those two positions. Or the display may
favor one or the other occasionally as you vary your sweep
or your scanning stance but still favor graph segments
somewhere in between. The ID Number will also be an odd
number not normally representing either one of those two
items. The user needs to be aware that conditions like this
can occur, as my air testing points out (see below).
On the other hand, under ideal conditions
with clean targets (not masked by trash or other targets),
the Cortés is brilliant in target identification. Under
these conditions, the ID numbers are stable (or stabilize
very quickly in the SUM Mode) and the bar graph is solidly
lit in one segment. Occasional targets will have
conductivity that may fall directly on the line between two
bar graph segments. When this happens, you may get varying
degrees of signal strength in the adjoining graph segments
(or it may jump from one to the other), but it will be
consistent in that it only lights those two segments and
doesn’t bounce around to adjoining segments. On targets like
this, the ID NUMBER usually remains very stable, even though
the graph segments may not, which is a good indication that
the target has a fixed form and conductivity, and you should
probably dig it.
AIR TESTING
One of the first things I do with any new
machine is perform an air test using a standard set of
items. I record this information and keep it for future
comparisons. I don’t place a lot of emphasis on air test
depths because actual in-ground results can be totally
different, but it is a nice indicator when used for
comparison purposes.
All of the air testing I do is done with
the exact same targets. I carefully maintain a group of
items so that my statistics always have a common basis. This
kit includes one of each silver coin type, clad coins,
copper zinc and large cents, pop-tops and tabs, a gold ring,
a .55 cal musketball, an eagle button, and various sizes of
rusty iron nails.
The Cortés air tested slightly better
(deeper) than the Toltec II, which was a good indication to
me but not too surprising since my Toltec II is 7 years old.
I made my comparisons using the 9x8 and 12x10 spoked coils
on both machines.
Another air test I performed was to see
how target masking would affect the graphic display. I used
a silver Mercury dime and a pop-top taped one inch apart on
a wooden ruler. Individually, the dime would read "95" and
light graph segment 7 (Dime) and the pop top would read
about "37" and light graph segment 4 (RND Tab). I ran this
set of targets under the coil center, first centering the
coil directly over their center, then centering the coil
over the dime, then centering the coil over the pop-top. In
each case the target ID numbers showed slight differences
but grouped very close (between 46 and 60) and the bar graph
segment was always segment 5 (SQ Tab). But when I switched
to the SUM Mode in the above three examples, there were
notable differences. When centered between the targets, the
SUM settled on "50" and segment 5. When centered over the
dime, it settled on "60" and segment 5. But when I centered
on the pop-top, it settled on "44", and the bar graph
segment dropped to position 4 (RND Tab). I did not expect
the bar graph to change all that much and indeed it did not,
but the target ID NUMBER showed significant differences
between the three cases when the SUM Mode was used.
I next tried the same sequence of tests
using a smaller 7" concentric coil. I assumed the numbers
would be better and more stable due to the better
pinpointing ability of smaller coils, and I was correct. The
numbers showed slight improvement. But even when centering
over the dime, I did not get a clear indication that this
target could be a silver dime.
I tried similar tests using a rusty iron
nail and a silver dime, but because of Tesoro’s great
ability to mask iron, the results were much better. When
centering on the silver dime, it was somewhat erratic but
stable enough to always read "95" and segment 7 (Dime), and
SUMMING locked strongly on "Dime".
I also experimented with a copper cent
and a nickel, one on top of the other, first with the cent
closer to the coil, then the nickel. As expected, the
machine did not match the individual characteristics of
either, even when SUMMING. The numbers and graph segments
were always somewhere in-between the two expected. Even when
the nickel was on top of the cent, the machine saw both
coins in the same fashion and responded accordingly. I could
throw more numbers at you here, but I don’t think that’s as
important as recognizing what is happening and using it to
your advantage.
What does all this mean? It tells me that
masking can have significant effects on what your display
tells you. That’s not a bad thing, but it means you need to
be aware that it can happen.
It also means that a target masked by a
lower value target (good or bad) will always read lower on
the ID and graph scales than expected. As seen above, a
silver dime masked by a pop-top SUMMED at "60" instead of
the normal "95". The same would hold true in an opposite
case if a nickel was masked by a screw cap (which is higher
up the scale). The resulting ID and graph indication would
read somewhere between the two. The target would read higher
than a normal nickel would read. This is important
information to know if you hunt areas that have a lot of one
particular kind of trash. You should do some testing on your
own to see how it affects the meter values of the "better"
targets you hope to find, thereby arming yourself to
recognize potentially good targets that don’t read as "good"
targets. Instead of passing on a poor reading, you may
recognize the ID pattern as being that of a masked target,
and then dig this particular target. Even if it turns out to
be a good target only half of the time, you have still
recovered a keeper that you would have otherwise missed.
Know your machine, it will put more goodies in your pouch!
Granted, this is only an air test and
actual field results might be totally different (given the
same circumstances) because of soil and "halo" conditions.
But nonetheless, it does indicate that masking can affect
meter readings in significant ways. Further proof that if
you’re in doubt about the identity of a target, the only
sure way to know is to dig it, and all the more reason to
dig any target that is stable and repeatable.
FIELD TEST
Due to circumstances beyond my control, I
only had a three-week time frame in which to test the Cortés.
This three-week time frame happened to coincide with a
rather dry spell here in Wisconsin, so I knew the depth
capability of the machine would suffer. Additionally, I
should tell you that the soil here in Wisconsin is highly
mineralized and pulling a coin at 10 inches, even under the
best circumstances is almost unheard of. A coin found in the
6 to 9 inch depth range is considered a deep target (and
coins found at 9 inches are rare). I was also unable to test
it at my favorite ghost town and stage stop sites because
most of these areas were planted with soybeans and
impossible to hunt at this time of year. I did all my
testing with the standard 9x8 coil, unless otherwise noted.
5.68 pounds of "float copper."
As I mentioned earlier, my very first
experience with the Cortés was way back in April of this
year, when I had a weekend to try the very first working
prototype. At a favorite ghost town site, I detected a very
strong, repeatable single reading at the extreme high end of
the scale (dollar). Even though I had to cut through an inch
of frost, I was bound and determined to recover this target.
At 6 inches no target and still a strong reading. At 10
inches, no target but still a strong reading. I nearly gave
up. At 14 inches I finally hit a target but from what I
could initially see, I knew it was not a coin. At the bottom
of this 14-inch deep hole, I could clearly see the deep
green patina of a large piece of copper. Initially, I
thought it to be a large sleigh bell or a small piece of
sheet copper, but I soon realized it was neither. I
carefully widened the base of the hole where this piece
rested and somehow I was able to do this without nicking the
target (which is amazing considering I did not even know
what I had at the time). Twenty minutes later I finally
pulled it from the ground and was shocked by its weight.
When I finally pulled it from the hole, I immediately knew I
had recovered a large chunk of natural copper ore! I quickly
ran the piece back to my truck where I rinsed the mud and
dirt from its surface, then stood in awe looking at this
gorgeous piece of copper! I have since had several experts
tell me it is known as "float copper." Float copper is
copper that is torn from host rocks and moved by glaciers,
hence the term "float copper." This specimen weighed in at
5.68 pounds and is rounded and worn smooth from long-term
glacial action.
My first test with the present machine
was during a workday lunchtime, only hours after receiving
the machine from the UPS driver. At the time the manual had
not yet been completed so James included a one-sheet set of
brief explanations and instructions. The instructions were
so straightforward that I could comprehend everything
without even looking at the faceplate of unit. I want to
stress here that this machine is very easy to use and even
easier to use if you have had previous "Tesoro" experience
(because you will recognize nearly all the controls). In a
flash I was half a block away at the site of a local
farmers’ market. There is a large open-air tent covering an
area maybe 30 feet by 60 feet, where once a week for 3
hours, the local growers sell their goods to the public. I
had cleaned this area out early this spring finding close to
$10 in change and a few kids’ rings. I did not expect to
find much but it was close and I would be sheltered from the
hot noonday sun, and it would be easy to recover targets
from the wood-chip "floor." I was amazed to pull 73 coins
(nearly $9 in change) in only 45 minutes! Some of the coins
were dark and deep in the wood chips indicating I had
previously missed them. The display readings were right on
the money each and every time, clearly identifying each coin
type and several square tabs as well. I tested the
effectiveness of the notch each time the meter indicated a
target in that range, and in every instance the notch would
blank out the pop-tops and tabs. My first outing was a
success. The machine was accurate and very easy to use, and
I found a lot of coins. After one outing I was already
"hooked" on this machine!
Treasure finds with the Cortés
I made several other outings purposely to
trashy areas because I wanted to test its abilities to work
well in junk. I must say it was admirable. Given the air
testing results I did after this search, I probably missed
some good targets that were masked by trash. Nonetheless I
managed to pull a man’s silver ring in an area loaded with
pop-tops and bottle caps, along with several wheaties in the
4 to 5 inch range and a silver earring.
I then lined up several private yards to
hunt—one home built in 1858, the other built in 1900. Both
had historical significance in the Madison area and I
thought the great finds I would surely make would make for
great writing and pictures in this report. I was disgusted
to discover both had been previously hunted. Nonetheless, I
pulled three wheaties at six inches and managed a silver
Roosevelt dime and an interesting cuff link. I also dug some
deep chunks of lead, all in the 5-6 inch depth range. The
signals were strong and repeatable, even in the dry soil
conditions.
My backup plan, if these two yards
failed, was yet another historical landmark in the area, a
mansion built in 1888 situated on the lake with a great view
of downtown Madison. I had previously hunted this site many
years ago, and even then I was not the first to swing a
machine there. But the grounds are large and spacious, and I
surmised that I could not have possibly cleaned it out on my
earlier trips.
Targets were few and far between and I
dug quite a bit of trash items. In many cases I knew these
targets would be trash by the way the meter jumped around,
but I dug them to prove the readings. I also dug some lead
chunks at 5 to 6 inches deep and those were all strong
repeatable signals. I found several newer coins at shallow
depths, one wheatie at about 6 inches, and two silver dimes.
Closeup view of the finds including the silver dimes
The silver dimes were both found in the
area right behind the house overlooking the lake. This is
where I had found the largest concentration of coins on
earlier hunts, and where I thought I would find nothing
because I had previously hunted this area using a bigger
coil (10.5 inch). Nonetheless, at three inches I dug a
silver dime that registered loud and clear. Not expecting
anything very old I wiped the dirt from the face of the coin
and was pleased to see a Mercury dime. A glance at the date
stunned me: 1916! My heart started racing immediately, and I
paused briefly before turning the coin over to look for the
mintmark, knowing full well the next few seconds might be a
glorious explosion of delight, or deep disappointment. After
turning the coin over I could see a mintmark at the bass of
the coin, but I could tell what it was without my glasses!
Dang! It was then that I remembered I had a magnifier in my
pocket, AND that I was very close to making a "scene" in
plain view of the occupants of the house. I slowly stood and
moved down toward the lake, below a terrace and out of sight
of the house. It only took seconds to find my magnifier (but
it seemed like hours), and I was quickly viewing a mintmark
of the letter "S". All of my excitement came to a screeching
halt. I was hoping for the elusive 1916 "D", the most rare
of all Mercury dimes and one in the condition of this coin
would have been worth about $2,400.00! As it stands, with
the "S" mintmark, it is worth about $15.00. I soon realized
that I had no reason to be disappointed. I had made a great
find, experienced the thrill and excitement that so attracts
me to this great hobby, and now I had another interesting
story to tell around the campfire, reliving the excitement
every time the story gets told.
The other silver dime was also a Mercury,
1942. This coin was over 6" deep but gave a strong and
accurate signal. I was impressed with machine’s ability,
especially in the dry soil conditions.
I also took the Cortés to one of my
favorite spots, a ghost town I have been hunting since I got
my first Tesoro detector (the Silver Sabre) back in the mid
80’s. Having worked this site for so many years, I decided
to put the 12x10 coil on the Cortés and give it a try. The
areas where I have found the most coins were all covered in
soybeans so I could only hunt a fringe area that is now a
pasture. I have never pulled much from this area, but it was
the only area where I could swing a coil. Normally cattle
are at one end near a very old stone barn, but today they
were up in the corner where I had wanted to hunt. It turned
out to be lucky for me because I ended up making a nice find
down by the old barn. After two hours of fruitless
searching, I finally got a good signal. In the hard packed
soil, down about 4 inches, I pulled a very nice 1854 large
cent! The signal was unquestionably strong and unwavering. I
have almost come to expect large cents from this site
(although not many lately). Over the years I have probably
pulled a couple dozen from this ghost town and many other
coin types as well (bust dimes and half dimes, seated dimes
and quarters, Indians, and even an 1806 half cent!) But as
you might guess, the finds are now few and far between,
especially since the land owner uses no-till planting (the
fields never get plowed anymore) which means fresh "stuff"
doesn’t keep getting turned up every year. At this site I
hunted with the SENSITIVITY at the maximum and I was getting
a lot of noise ("pops" and "ticks"), and I was a little
concerned. I was way out in the country, away from power
lines, houses, everything! Unless the noise is unrelenting,
I will always hunt with the highest sensitivity, especially
when hunting for relics.
On the way home I drove by another
favorite spot, an even smaller ghost town site. This one was
pretty much just a crossroads community, but again I have
pulled some nice coins here in the past. I discovered that
one small field had not been planted with crops at all, and
that the nearby owners had created a makeshift ATV figure-8
track on it instead, and they had it mowed! I could not let
this opportunity go to waste so I pulled into the driveway
to get permission (the last time I had hunted this field it
had been standing corn, several years ago). Permission was
granted and I spent the next 2 hours working this small
field. Here too I had the SENSITIVITY all the way up and at
this site the machine quieted down. I reasoned the soil
conditions at the last spot must have been really bad (I
found it interesting to finally learn that after so long, is
this machine that sensitive?) At this site, I became
convinced of the depth capability of the Cortés. I began
digging some very deep targets here. Nothing of any major
importance, but copper and brass items, pieces of old oil
lanterns, an old copper coat hook, a big heavy brass washer
(the size and thickness of a silver dollar), part of a brass
lock, things like that. I did not dig any coins, but the
items I was getting were locking on to one graph segment and
were very stable and repeatable. Some of these items were
between 8 and 10 inches deep, and I was delighted to be
digging targets at that depth.
One last site I stopped at was an old
tavern site. This field was standing corn but I decided to
brave it out. I only spent about two hours here because the
mosquitoes were lifting me off the ground. Here too, the
machine was quiet even with SENSITIVITY at max. I dug a few
more junk targets, but again they were deep. As before, a
few defied repeatability and they were always big pieces of
iron. I also dug two shot shell casings between 6 and 8
inches deep, and I got a one-piece flat button at about 6
inches. I also eyeballed a white porcelain button. More
proof of the depth capability of the Cortés. All of these
relic fields were very dry and pulling deep targets from
them was a pleasant surprise for me.
SUMMARY
The single biggest impression I have of
the Cortés is of how easy it was to learn and use (the word
"JOY" keeps springing to mind). There are no menus to scroll
through and no need to learn programming skills just to
change your settings. Every adjustment is achieved manually
with controls right on the faceplate. You turn it on, set
your discrimination level, and go. If you have previous
experience with any metal detector (not just Tesoro’s), you
should have no problem at all operating this machine right
out of the box. Really!
The display information was well thought
out and it is easy to view and comprehend. I found the
target identification and depth readings to be very
accurate. Even though the conditions here were very dry, I
was able to pull a good number of coins in the 6-inch depth
range. This impressed me. Using my older machine with a
bigger coil, I would have had difficulty reading a wheatie
at 6 inches in this dry, heavily mineralized soil. I am sure
I will be even more delighted when I am able to hunt under
better (wetter) soil conditions, as well as trying it with
the 12x10 coil. By the way, changing to a larger or smaller
coil on the Cortés will not affect the Target ID accuracy,
but your depth readings will be slightly off. In the All
Metal Mode, ground balancing will account for any impedance
difference, but if you plan on hunting in the DISC Mode, you
should have your coil and machine balanced at the factory.
This is a simple procedure that is performed at not cost,
and it will ensure that you are getting the optimum depth
capability from your equipment.
With most new machines of this caliber,
there is usually a significant period of time when you are
just not sure if you’re adjusting everything correctly and
you’re just not sure what your machine is really telling
you. It usually takes awhile to build that confidence level
and to learn and differentiate between all the different
sounds. I did not experience that with the Cortés. There was
no period of time when I was not sure that I was operating
it correctly because it very easy to use. And within a very
short period of time, I felt comfortable with the Target ID
information because each time I dug a target, it confirmed
and validated what the meter had indicated, both in depth
and target type. In time I am sure I will begin to notice
slight variations in the audio, which will only add to my
skill level with this machine.
There is also a lot more target
information available, allowing me to make better decisions
on whether to dig or not dig a target. Even though masking
can skew the Target ID information, it appears to do it in a
consistent fashion, which means in time I will better
recognize these patterns and be able to make even better
decisions.
In writing this summary, I found it
difficult to identify any negative features of this machine,
and I don’t want to minimize the terrific job that Tesoro
has done because I really like this machine. So let me say
that I would have been even more delighted if Tesoro had
found a way to make the control housing hip or chest
mountable. I realize that this would be a difficult task
with the battery pack being mounted separate from the
control housing, but arm fatigue is a concern of mine
because I typically hunt long hours. The unit is very
lightweight and acceptable as it stands, but changing to the
bigger 12x10 coil pushes the total weight to over 3.6
pounds, and that will certainly cause my arm some stress
after 6 or 7 hours of detecting.
Another thing that would have really
delighted me was if there were some target separation
between a copper cent and a silver dime. Copper cents and
dimes register on the same graph section of the display and
both will read "95" on the ID NUMBER, so you cannot tell the
difference between them. I would have liked it better if
Tesoro had been able to open up the resolution at bit, right
in that area, only because I would much rather dig a silver
dime than a copper penny. When I asked James Gifford about
this, he assured me that doing so would have taken away from
other areas of target ID, sort of like robbing Peter to pay
Paul, so they opted to group those two together. I was glad
I asked.
That said I still have to give the new
Cortés "two thumbs up"! Tesoro did a great job of making a
powerful, lightweight, easy to use machine that has great
depth and accuracy yet is very "display-friendly." Oh yes,
and it is actually fun to use.
Thank you, Tesoro, for affording me yet
another wonderful opportunity to test one of your great
products! |
