I believe that most people in the sport of metal detecting would agree that detecting relies heavily on the sense of sound and its interpretation.
Without some sort of tone and/or visual identification, detectorists have but few clues as to what a buried, un-retrieved target might be. Several target identity clues can be obtained from the discrimination dropout point of a target and also from its 'tone' and volume.
Generally, once a target is heard on a non-I.D. metal detector, it's a good set of ears and experience alone that tells the operator whether to dig or not.
At best, to the inexperienced--and sometimes experiencedbetween the ears audio discrimination is a daunting task that often results in the retrieval of many trash targets, with an occasional keeper. Eventually, with countless hours of use and effort under one's belt, detecting with a non-I.D. metal detector becomes almost second nature and the trash-to-treasure ratio improves.
There are many metal detectors that do not incorporate or provide any type of audio tone identification. While they can be very effective to use for many detectorists, audio tone identification, in most detecting situations, provides a detecting edge to those who understand its use, language, limitations and benefits.
I have always felt that a metal detector that incorporates audio tone identification should have a minimum of three audio tones--one for iron, one for pull tabs and one for coins (copper cent and up). While a three-audio-tone system is informative and beneficial, more is always better--to a point--with four or five tones being about ideal for most detecting situations.
Several years ago (May 1999 issue of Lost Treasure magazine) I had an opportunity to evaluate and field test Fisher's then-new CZ-7a Pro QuickSilver Metal Detector. The CZ-7a Pro QuickSilver that I field tested had a 3-tone audio identification system which produced a low tone (200Hz) for iron targets, a mid-tone (450 Hz) for foil and pull tab-range targets, and a high-tone (1 kHz) for most coins including nickels.
Many detectorists like and have done quite well with the 3-tone audio I.D. of the CZ-7a Pro QuickSilver, but others were discovering that some old coins, like early Indian Head and Flying Eagle cents, and marginal signals from deep coins, coins on edge, coins located close to aluminum trash, and brass and lead relics were not always identifying as coins and producing the usual high-tone audio and corresponding meter indication.
Most metal detectors cannot accurately identify deeply buried, tilted or masked targets with a reasonable degree of accuracy--as there is just not enough signal strength, or there is additional metal being sampled and analyzed, which interferes with the desired target's true response and reading.
Realizing that detectorists could significantly benefit from the addition of a fourth (old coin/relic) audio identification tone and the additional visual target category provided by it. Fisher has recently introduced a new detector model, the CZ-70 Pro QuickSilver, which now incorporates a 4-tone audio identification system with corresponding meter indication.
The CZ-70 Pro is a dual VLF frequency (5kHz & 15 kHz) multi-notching metal detector with both tone and visual target identification capability. The new 4-tone audio I.D. system produces a low tone (200Hz) for iron targets, a mid tone (450 Hz) for foil and tab I.D., a mid/high tone (800Hz) for old coin/relic I.D. and a high tone (1 kHz) for coin I.D.
Seven easily programmable notches control the acceptance or rejection of any target providing a user with 256 possible combinations of target-notching discrimination.
The front panel of the CZ-70 Pro is well designed and labeled, easily accessed and quite logical. Even without reading the user's manual, most experienced operators can intuitively operate the CZ-70 Pro the first time they use it, another credit to Fisher engineering.
Ten slightly raised tactile touch-pads and a single rotary knob control its entire operation. For enhanced operation to meet any ground condition a ground balance control and circuit are provided. Ground balancing is fast and easy, using one of two methods outlined in the user's manual.
The CZ-70 Pro has the following controls and options available. Starting from left to right, top to bottom, the front-panel touch-pads are labeled as and control the following options: LIGHT - Turns the LCD soft-blue/green display back light on or off.
VOL - Adjusts the audio headphone and speaker volume level. Six levels are selectable. NORM/Salt - Adjusts the detector for operation for land or saltwater detecting. The selected mode is displayed on the LCD panel. AUTO/I.D. - Selects either the wide-scan all-metal auto tune mode or the VLF motion I.D. mode of operation. The selected operating mode is displayed on the LCD panel.
SENS - Adjusts the level of operating sensitivity. Six levels are selectable. PRESET - Sets the detector to factory presets-coins only, medium sensitivity and volume. NOTCH - Permits seven notch ranges to be accepted or rejected. Thus enabling 256 different combinations of detecting notch-discrimination programs.
LEFT-POINTING ARROW - Moves the display cursor to the left. RIGHT-POINTING ARROW - Moves the display cursor to the right. PINPOINT/SEARCH - Enables the VCO pinpoint and depth-reading mode (when pushed and held). Coin-depth readings are indicated on the LCD display and range from 0 to 10 inches. The VCO audio range is automatically varied from 500 Hz to 1 kHz, depending on target centering, size and conductivity. As mentioned before, a single rotary control knob sets the ground balance point and powers the detector on and off. When set to the red numeral "5", a preset, average, ground balance is achieved.
In addition to the above features, the CZ-70 Pro also includes: Microprocessor control; Surface Mount Electronics; Turn-On-and-Go Operation; Three-piece Breakdown; Big-Target Bell Tone; Faint-Target Audio Boost; Constant LCD Display Battery Monitor; Last Settings Memory. In addition, the CZ-70 Pro is rain proof and splash proof, features a double-locking pole stem and requires only two 9-volt batteries to operate. Battery life is approximately 15-20 hours with Alkaline and decreases to 7-10 hours if the display back light is used continuously. Battery installation and replacement is simple and easy. Two removable bottom-side covers open to expose a drop-in battery compartment. There are no wires or connectors to attach--or break! The CZ-70 Pro features a very unique slide-on/slide-off detector control housing mounting system.
A user can quickly switch from pole to chest or belt (hip) mounting as desired and required with a minimum of time and effort. The CZ's control housing mounting system is 'slick' and is one of the best I have ever used!
The CZ-70 Pro is supplied with an 8-inch submersible concentric Co-Planar Spider search coil. Optional 5- and 10-inch coils are available. Total detector pole-mounted weight is only 3.8 pounds.
All Fisher detectors are extremely well done. Their design, packaging and overall engineering is solid. Every aspect of their packaging is well thought-out and their detectors have a well built, polished quality look and feel to them.
One of the sites visited for this field test was an old home site that had two stone-lined cellar holes. These were located not far from my home and my detecting friend Scott had discovered them during one of his nature walks. Although no coins were found at this location, a number of relics were unearthed, including some old harness buckles, a mining tag and an old small-caliber round ball.
The CZ-70 Pro worked well at this site and I was amazed at how well it let me cherry pick through the trash to recover good items. The audio and visual identification of the CZ-70 Pro worked extremely well at classifying targets and the detector operated smoothly. I did discover though that the ground balance setting is crucial to a smooth-operating CZ. Make certain that you correctly ground balance the detector and check it once in a while to maintain smooth operation and peak performance. About the only thing I had wished for was a non-VCO pinpoint mode. I realize that this is a personal preference and opinion, but I just do not care for VCO pinpointing. Many detectorists love it, but I do not!
Other than that, I have to admit that the CZ-70 Pro was an awesome performer in the field! At another site, a 1920s-era park, I had two goals in mind; to see how well the CZ-70 Pro performs in heavy trash and check out its depth-potential in the soft, topsoil fields where I knew there should still be some very deep coins. Again, as at the cellar hole site, I found the CZ-70 Pro to work well in the trash. The CZ-70 Pro easily enabled me to cherry pick a number of old Wheat cents from between layers of accumulated trash.
Two silver coins were found while picking the trash--a 1941 Washington quarter and a 1942-P War Nickel. Neither coin was deep, but both were surrounded by abundant trash. On a personal note, I think the CZ-70 Pro would be a killer in the trash, using the optional 5" search coil!
I found that with many of the un-retrieved coins, I would get a solid hit in the discrimination mode and then when pinpointing in the VCO mode, the target would scream at me.
These screamer targets turned out to be a trash item near the good item. I would pinpoint and retrieve the screamer trash target and then go back over the same area to find the good item. Time after time, the CZ-70 Pro told the truth and I would in fact find a good item next to a trash item. I was impressed. Very impressed! Moving over to the adjacent soft-soil field area, I re-ground balanced and set my sensitivity to maximum. At this max setting, I was impressed with just how smoothly the CZ-70 Pro operated! The ground mineralization was not severe - as it balanced-out at about 3.5, but nonetheless, the CZ-70 Pro is a very powerful detector and for it to operate that smoothly at maximum sensitivity was notable.
It didn't take long to hear the 'sweet' sound of a deep coin, which produced a high audio tone and indicated coin on the meter. Sure enough at about nine inches depth, I recovered a 1943 Mercury dime.
While just an average find, it clearly proved to me that the CZ-70 Pro has the power to nail the deep coins. About ten minutes later, I again heard that same sweet coin-sound and just like before, at a depth of about 8-9 inches, I retrieved a 1926 Mercury dime.
This scenario was to be repeated on numerous Wheat cent recoveries from the same area and all of them were located deep!
With a retail price of $995.00, the new Fisher CZ-70 Pro QuickSilver may at first seem expensive. However, if you view its purchase as an investment, you soon realize just what a powerful, effective tool it is. What other hobby can actually pay for it and reward its participant with so much adventure, excitement, exercise, joy and monetary returns?
The Fisher CZ-70 Pro QuickSilver is truly a world-class metal detector. It is without doubt, one of the best metal detectors currently available and well deserving of the designation top end! I can easily recommend Fisher's CZ-70 Pro QuickSilver metal detector to anyone seeking quality, versatility, performance and results! The CZ-70 Pro is covered by Fisher's limited lifetime warranty.
For additional information, contact: Fisher Research Laboratory, 200 W. Willmott Rd., Los Banos, CA 93635. Phone (209) 826-3292, FAX (209) 826-0416, website: www.fisherlab.com, email: infofisherlab [dot] com.