Despite the fact that two-box detectors have been in use for over 60 years, they are probably the least understood and under utilized pieces of equipment available to treasure hunters. Primarily used by construction companies and utilities to locate buried pipes and cables before excavating, they are capable of finding deeply buried objects while ignoring smaller targets which often frustrate the serious treasure hunter.
While Discovery Electronics' name is still relatively new to the general treasure hunting public, they have been producing high-quality commercial metal detectors as well as equipment sold by other well known metal detector manufacturers under their own names since 1982. Discovery Electronics secured the engineering talents of George Payne who has personally been instrumental in developing many of the advances in metal detection circuitry over the last 25 years including ground balance, target identification, and depth reading.
Discovery Electronics goal is to be a company continually developing equipment at the cutting edge of current technology and offer it to treasure hunters at a cost everyone can afford. With this philosophy already demonstrated in the innovative Treasure Baron detector with its modular upgrade capabilities the Treasure Finder 900 was designed to provide the general treasure hunting community with a reasonably priced, high quality two-box detector.
Unlike a conventional metal detector, the TF-900 consists of a control housing and two separate coils with the front coil being the receive coil and the rear coil the transmit coil. Another unique design feature is, the TF-900 incorporates both a true VLF-ground canceling search mode for general applications and a separate frequency TR search mode for specialized applications, such as locating hidden mine-shafts, caves, or wells and tracing pipes and cables with the optional trace attachment.
The TF-900 is controlled with four knobs and a toggle switch on the housing and a push button located on the handle. The MODE knob serves multiple functions it turns the unit on/off; checks battery strength; and allows the user to select either the VLF or TR search modes.
The TONE knob is used to adjust the audio threshold heard through either the built-in speaker or headphones to a comfortable level. The SENSITIVITY control controls power output from the detector and is useful when trying to eliminate any interference caused by high-voltage electrical sources near the search area. The GROUND REJECT control allows the user to compensate for adverse affects of ground mineralization thereby achieving maximum detection depth under all conditions.
A feature of the TF-900 that sets it apart from other two-box detectors currently on the market is the AUTOTUNE toggle switch. With both a fast and slow setting, the AUTOTUNE circuitry will keep the audio threshold at a constant level even with slight changes in ground mineralization enabling users to detect targets at the edge of the TF-900's detection depth that others may have missed. The push button on the handle is used during initial tuning of the TF-900 as well as re-tuning if the AUTOTUNE feature is turned off. There is also a meter located on the top of the control housing which provides either an indication of signal strength or battery condition depending on the position of the MODE knob.
All controls have markings on them which allow even inexperienced hunters to set them and start hunting immediately after unpacking the detector.
As mentioned above, the TF-900 will not only detect deeply buried metal objects, but hidden mine-shafts, wells, and old foundations. By activating the TR mode, the TF-900 will be affected by changes in ground mineralization. Since voids such as caves, mines or wells and filled-in areas such as foundations will contain less mineralization than the surrounding ground, an increased audio signal will be generated when the TF-900 passes over one of these locations. Since this may be the only way an abandoned mine or covered-up well can be found (if there is no metal for a conventional detector to sense), the TF-900 is ideally suited for prospectors, ghost-towners, and bottle hunters.
The TF-900 is powered by six AA batteries designed to provide approximately 20 hours use when alkaline cells are used. Headphones, which plug directly into the control housing beneath the battery door, will improve battery life. Rechargeable nicads, while not currently offered as an option from the factory, can be used with no adverse effect on the unit's performance.
Before venturing into the field with the TF-900, I tried it out in my test garden to see what type of response it would give on various targets. An artillery shell at 2.5 feet was detected even with the coils 1-2 feet above ground. Surprisingly, a replica Civil War belt buckle at 10 inches also produced a signal. So while small targets will be ignored, even targets the size of a buckle can be detected at depths equal to that of a conventional detector.
My hunting partner, Denny, and I tested a heavily hunted Civil War battle site consisting of several deep ravines in which Confederate troops had been pinned down by U. S. artillery fire in the summer of 1864. Other relic hunters had reported finding some artillery shells in the area; however, they had all been deeply buried, some as deep as 3 feet. Considering the soil was fairly sandy and some of the area was wet much of the year, we were certain additional shells were just waiting to be found at even greater depths.
Arriving at the site, I quickly ground balanced the TF-900 and, opting for the slow re-tune mode, began searching. Denny proceeded to hunt as well using his conventional detector; however, since much of the area was overgrown or contained piles of old tree limbs, his search area was somewhat limited. It quickly became apparent that the TF-900 was well suited for searching under these conditions by passing the detector over brush piles I could tell if there were any targets hidden beneath them without having to spend time moving branches as I normally did when hunting with a conventional metal detector.
Receiving a clear signal from the second brush pile checked with the TF-900, I called Denny over to see what type of signal he could get with his detector. He got no any signal until we moved the branches then he got only a faint response.
At a depth of almost 2 feet, we recovered what was left of a Civil War-period shovel. Pinpointing was quite easy the loudest audio signal was produced when the front coil was over the target. By approaching the target from two different directions, it could be pinpointed with considerable accuracy. Continued hunting at this site produced several targets spanning the last 130 years, including a large artillery shell fragment.
My next search area was an abandoned home-site that dated back to the late 1800s. I had attempted to hunt this site previously; however, the combination of knee-high grass and high concentration of small trash such as pieces of the original tin roof, nails, and barbed wire had caused me to give up in frustration. Starting near the back porch, I quickly balanced the TF-900 and then decreased the SENSITIVITY control to just below the NORMAL range. This setting provided me with ample detection depth while ensuring I would not be bothered by any smaller trash targets throughout the search area.
Mentally laying out a grid search pattern using various landmarks on the property, I began walking back-and-forth across the yard. I found the TF-900 was not bothered at all by the tall grass which made searching virtually effortless. Moving over approximately 3-to-4 feet with each pass, I was able to cover the entire backyard and both side yards in less than an hour.
Despite being littered with small trash, the TF-900 had only responded to 7 targets which included three horseshoes, an ax-head dating back to the 19th century, a large wrench, a quart mason jar (half filled with some unknown food rather than $20 gold pieces), and the lid to an old toolbox. All targets had been at least 10 inches deep, with the toolbox lid being almost 2-1/2 feet down. Considering they all came from an area with knee-high grass, it was doubtful a conventional detector would have been able to detect all the targets the TF-900 had, especially in the same period of time.
While two-box detectors are not for everyone, individuals searching for relics, caches, or bottle dumps will find the quantity of their finds will increase significantly with the addition of the TF-900 to their equipment arsenal. Being able to quickly search an area and detect deeply buried objects while ignoring smaller targets will result in more finds for a given amount of time spent out in the field. With the addition of the reasonably priced TR-trace attachment, one could even start a part-time business locating buried pipes and cables for contractors or homeowners!
The Treasure Finder 900 sells for $689 and comes with a one-year warranty. The optional trace attachment sells for $199. For more information on the entire line of innovative treasure-hunting related products produced by Discovery Electronics or the name of your nearest dealer, contact the factory at (503) 367-2585 or write them at 1115 Long Street, Sweet Home, OR 97386. Be sure to mention you read about the versatile and simple-to-operate Treasure Finder 900 in Lost Treasure!