Tesoro Cortes Metal Detector Field Test Report 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.
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 ½ 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 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.
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 2¼" 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 ¼" 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.
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.
Gene Scullion with the new Cortés
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.
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.
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.
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!