Fisher Fx-3 Ferro Probe
By Greg Moscini
From Page 52
March, 1988 issue of Lost Treasure

When I first received the Fisher FX3 Ferro Probe I was taken back a bit. Being primarily a coinshooter at heart, I have never used a magnatometer before. Magnatometers are highly sensitive instruments designed mainly for the locating of any ferrous (iron containing) object that can generate a magnetic field.
I remember my first experience with the FX-3 from Fisher Research came at Sacramento's Holiday Inn during a demonstration at a Whites Electronics Seminar by Jimmy Sierra. Jimmy said that Fisher had brought a magnatometer to market at an affordable price compared to other brands costing several thousands of dollars. I remember him taking a small cow magnet, roughly the size of a C-cell battery and holding it out about 5 feet. He got an audio response from it which was heard throughout the presentation room and beyond the range of conventional metal detectors.
Non-ferrous items such as coins and gold rings will not cause the FX-3 to sound off. This can be an advantage for those of you looking for a ferrous container containing a cache of coins or other treasures. Remember, a standard metal detector in the all-metal mode will respond to both ferrous and non-ferrous metals.
The FX-3 is primarily designed to locate survey markers, pipes, valves, well casings, septic tanks and a variety of other ferromagnetic objects. It is also used by treasure hunters to search for relics and caches buried far beyond the reach of ordinary metal detectors.
Similar to other magnetic locators, the FX-3 has two sensors which respond only to the magnetic field off ferromagnetic objects, ignoring all other materials (aluminum, -copper, brass, etc.). Unlike its competitors costing hundreds of dollars more, the FX-3 differs in the, following ways:
1. The FX-3 responds to targets only when it or the target is in motion.
2. The FX-3 "nulls" (goes quiet) directly over the target. As a target is approached, the output tone increases in volume and pitch, then momentarily disappears (goes quiet) as it passes directly over the target. As the FX-3 leaves the target area, it will also respond.
3. The FX-3 has simple one-knob operation.
I decided to concentrate primarily on using the FX-3 on several local beaches. Upon turning it on, I noticed it had a constant soft tick...tick...tick... slightly faster than one every second. As the battery gets weaker, intervals between signals will slow down until it eventually disappears from an extremely weak or dead battery.
The manual recommends that the FX-3 is swung in a half moon. I chose to Swing it using a shallow figure-eight motion, much the way I hunt with a motion metal detector.
The sensitivity was set at mid-range (preset 5). Anything higher would cause the FX-3 to occasionally false., not on ground mineral but on the actual magnetic field on the earth. I found I could work maximum sensitivity but I would have to slow the sweep speed down considerably. I was using a medium handle sand scoop to dig with, and I had to hold it in back of me with my left hand. The FX-3 had a tendency to respond to the sand scoop at sensitivity settings higher than 5. My last time out I used a PVC Sand Scoop manufactured by Reilly's Treasured Gold (305/971 6102) and did not experience any falsing.
I found lots of interesting items missed by conventional detectors using discrimination or beyond the range of a conventional metal detector: bobby pins, pens, nails, bolts, cigarette lighters, etc. Some objects were too large and too deep. The hard-packed sand in some places was like cement due- to dry weather, and I couldn't get to some of the targets as I only had a sand scoop and needed a pick. One small object which appeared to be actually a piece of magnet was found at approximately 18 inches in depth.
The FX-3 pinpoints fairly easily. The pitch increases as the probe comes over the target. As the probe passes directly over the target there is a split-second nulling. I had little or no trouble locating any of the targets at the beach. Some targets that are lying horizontal will give a double null at each end and a high pitch response when the probe is directly over it.
I expected to dig lots of bottle caps, but I noticed that the FX-3 did not respond to them unless they were near the surface. This would have something to do with their inherent weak magnetic field. Of course, puff tabs and other aluminum junk were ignored, enabling more time to go after articles of value.
Remember to empty out your treasure pouch often as the FX-3 will respond to the targets you have collected and placed in your pouch. It's best to wear the pouch opposite whatever hand you use to handle your machine and more toward the back.
The FX-3 is lightweight and an incredible instrument. it will locate objects missed by most hunters using conventional metal detectors as: 1. It locates the objects via a different principle, responding to the magnetic field rather than the conductivity of the metal, and 2. It locates these objects as greater depths. Although the FX-3 will not respond to non-ferrous items, it will locate a ferromagnetic target like an iron pot containing valuables. This feature makes it ideal for the relic/cache hunter. Remember, conventional metal detectors respond to all metal including nonferrous aluminum which may take up more of the hunter's time needlessly investigating.
How many times have you gone back to your favorite hunting spots with a Merent make/model of detector to find treasures missed by your other detector? Try the FX-3 and see the complexion of your finds change. At $460, it is a bargain compared to competitor units.
In my front yard, I picked up several iron responses. Of course, it ignored my non-ferrous target plant. I experienced no radio frequency interference from 60-cycle which would plague relic hunters using conventional metal detectors.
I would like to see the design incorporated in more of an S-mount configuration along with an LED target light.
Otherwise, I have no complaints with the FX-3. It will definitely add a new dimension to your treasure hunting.
Editor's Note: Greg Moscini is a multi-line detector dealer in the San Francisco Bay area (Trans Bay Metal Detectors, 321 SeaHorse Ct., Foster City, CA 94404). Greg welcomes any questions or comments you have concerning this field test. Please provide him with a self-addressed, stamped envelope so that he may respond to your letters.

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