Sun Ray Dti Ii
By Joe Patrick
From Page 16
January, 1997 issue of Lost Treasure
Several years ago, a revolutionary new type of metal detector was introduced on the U.S. market. Up to that point, metal detectors operated on a single operating frequency, which was usually in the VLF (very low frequency) portion of the electromagnetic spectrum.
In the late 1980s, Minelab Electronics Limited Pty. of Australia invented a new type of metal detector that operated with multiple transmit frequencies 17 to be exact.
This multi-frequency metal detector, named the Sovereign, was, and still is, the only detector incorporating Broad Band Spectrum (BBS) multi-frequency technology.
Within a short while, other detector companies were offering multi- or dual-frequency detectors of their own design. Detector users often debate the pros and cons of multi-frequency operation, but three attributes seem to be common to all multi-frequency detectors:
They seem to provide above average depth;
They seem to work well in mineralized ground, and
Their ID capability is above average.
No matter how good a product is, there always seems to be room for improvement or innovation. Sun Ray Detector Electronics of Hazelton, Iowa, is one of those innovators and strived to produce an accessory target-identification meter that would maximize the Sovereigns already excellent performance. This product has now arrived in the form of the Sun Ray DTI II target-ID classification meter.
Before I begin to explain the features and merits of Sun Rays DTI II ID meter, I want to say that I am impressed by Sun Rays attention to detail. The DTI II meter mounted to the Minelab pole assembly meter-mount bracket with a precise and positive click. Commercial-grade quality and first-rate construction heavy-duty cable, high-quality connectors and flexible strain reliefs all contribute to an excellent product. It is readily apparent that Sun Ray puts a lot of thought and attention to detail into its product design, development and manufacturing.
The DTI II meter is for exclusive use with Minelab Electronics Sovereign or Sovereign XS. It is a redesign of the previous DTI meter, which required its own battery for operation. The new DTI II meter obtains all necessary operating voltage from the Sovereign itself. This alone is a significant improvement. Unlike Minelabs target ID meter, which offers 17 ID segments and must be manually switched between operating modes, Sun Rays display features large easy-to-read half-inch high digital numbers and requires no range or mode switching. Some 29-plus target classification ranges are available with iron (ferrous) targets being identified with negative numbers. For easy viewing, the meter is tilted to an optimal viewing angle.
An external, user-adjustable meter-calibration control permits easy, fast and accurate calibration to match any Sovereign coil used Coin Search, Sea Search or Sun Rays S-5 Intruder or S-12 Ultra Depth coils. The DTI II meter calibration adjustment is very easy to make. The screwdriver-slotted user-adjusting shaft is firm, with very little rotational or lateral play which facilitates smooth, accurate meter calibration.
Passing a quarter across the searchcoil while adjusting the calibration control for a consistent and steady numeric reading of 180 is all that is required for accurate calibration of the DTI II meter to any coil used.
An easy-to-read DTI reference chart is attached to the meter face. The yellow and black colors used on the ID reference label contribute to easy readability and look attractive. Its probably no accident that this color scheme was selected as advertising studies have found that a yellow background color with black text provides optimal contrast, visibility and readability. The use of a plain, bold, sans-serif font in the label also contributes to easy reference number readability.
A 50-inch connecting cable is supplied to facilitate either pole or hip mounting configurations. The suggested retail price of the DTI II ID meter is $179.99, and it is covered by a 12-month warranty.
Two sites were selected for my field test of the DTI II meter. One has been heavily detected by a small group of detector users for almost four years now. Many thousands of items have been recovered here, but for about the last year, targets have noticeably become scarcer, especially coins, which were never found in great abundance even when we first discovered and began detecting the site four years ago. In approximately five hours of detecting, I recovered 40 desirable items, including a 1946 dime, two old religious medals, a numbered lead freight-seal and 20 old coat and cuff-size military-type buttons many dating to the turn of the century.
I observed the DTI II meter to be very accurate and consistent in its ID readings. I was able to consistently identify most buttons before recovery and the silver dime gave a reading of 178. The large LCD numeric display is very easy to see.
As with most ID-capable metal detectors, for accurate ID readings targets must be swept precisely under the coils center and at the correct sweep speed. Once the target is scanned and a lock-on ID reading is obtained, it is very important not to move the coil or the ID meter may reset to another reading, which will cause you to have to rescan the target again.
For the next location, I chose an old county fairgrounds. Because it has an abundance of high-trash sites, it seemed to be the ideal spot to test the DTI II meter in combination with Sun Rays new S-5 Intruder searchcoil. This particular location has been in continuous use since the late 1920s and has plenty of coins left, but due to the heavy concentration of intermixed trash, they are difficult to isolate and find, especially with standard-size or large searchcoils.
Most targets identified accurately and at a couple of locations I operated at the Sovereigns preset discrimination level and used the meter to ID all targets. This worked fairly well except when too many targets were under or near the coil, at which point ID become impossible this is a typical problem with all ID units.
In about six hours of detecting, I recovered four worthwhile items a 1944 Mercury dime, a 1918-S Mercury dime, a 1954 Roosevelt dime and a 1943 Washington quarter. Very little trash was recovered due to the accuracy of the meter iron, pull-tabs and screw caps were identified with deadly accuracy and simply avoided. All four coins were found in very high-trash, difficult-to-detect areas where I observed a lot of small trash visibly lying on the grounds surface.
Although Sun Ray states that the DTI II meter can also be used to somewhat estimate depth and as a visual pinpointing aid (these techniques are explained in detail in their operating literature), I found it to be much more useful for what it is precisely designed and engineered to do: identify targets. I still prefer the audio method of pinpointing targets and estimating depth based on the all-metal modulated audio signal strength of the Sovereigns audio output signal to the headphones.
Sun Rays DTI II target ID meter performed very well for me. With its additional numeric classification ranges, accuracy and ability to readily identify iron targets, it made my Sovereign even more versatile and accurate in its already excellent ID capability.
For referral to a dealer in your area or for additional information about Sun Ray searchcoils or other Sun Ray products, see the ad in the Christmas Gift Guide section in this issue or contact Sun Ray Detector Electronics, 106 North Main, Hazelton, Iowa 50641, phone (319) 636-2244.