CZ-21 Quick Silver – Premium Underwater Detector Whether it be Dry Land,
Saltwater or Fresh Water, the CZ-21 Delivers.
CZ-21 Quick Silver with search
coil 27cm.
/10.5”/
Saltwater or Fresh Water
Submersible up to 250 feet
Dual Frequency Fourier Domain Signal Analysis
Touch-Button., VCO no Motion, Precise Pinpointing
Easy Manual Ground Balance
High Performance in Mineralized Soil
All-Metal Auto-Tune Mode
Large Target Alert / Faint Target Audio Boost
3-Tone Audio Target ID
Removable Control Housing for Belt Mount
8” and 10” Coil Options - choose down
Operating Frequency: 5 and 15 kHz
Fisher Research Laboratorys Cz-21 Quicksilver Metal Detector
By Andy Sabisch
From page 24 of the June, 2009 issue of Lost Treasure
Copyright © 2009 Lost Treasure, Inc. all rights reserved
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Fisher Research Laboratory, the industrys oldest metal detector manufacturer,
has been building metal detectors since 1931 for commercial and recreational
users. Their engineers have developed many ground-breaking advances found on
virtually all other detectors today including silent-search searching,
slow-motion VLF-discrimination, the S-shape handle, and turn-on-and-go
operation. The CZ Quicksilver circuitry, first introduced more than a decade
ago, quickly gained the reputation of being able to handle even the most
challenging of ground conditions while providing above-average detection depth.
Expanding from the land-based models originally introduced, Fisher developed a
fully waterproof model called the CZ-20 which became a mainstay for water
hunters worldwide. Recently, the hobbys business landscape changed and, in 2006,
the original Fisher company was acquired by First Texas. Despite this
acquisition, First Texas has maintained the Fisher commitment to producing
first-rate equipment for the most demanding detectorists, and taking the company
into new directions using the latest technology available. The CZ-20 was one the
models that was revisited and had several changes made to address certain issues
that had been identified over the years. Since Ive been a Fisher CZ fan since
they first came out (and actually wrote a book on the entire line for Fisher in
the mid-90s), I was looking forward to giving the new CZ-21 a workout. Features:
The CZ-21 is a dual-frequency VLF detector designed to be equally at home on
land as it is 250 feet below the surface. Designing a detector to operate
reliably in the water is a challenge for any manufacturer due to the rigors
water-hunting places on the equipment. Any leakage can kill the detector in
short order and saltwater is even more damaging to the circuitry inside the
case. Over the last few decades, there have been water machines that faded from
the market due to leakage issues; however, since the introduction of the 1280-X
in 1985, and the CZ-20 several years later, Fisher has been recognized as having
a design that is virtually bullet-proof when it comes to remaining watertight
with minimal maintenance. A feature unique to the Fisher lines is the separate
battery compartment. The CZ-21s battery compartment is entirely separate from
the electronics, so in the event any water gets past the O-ring protecting the
batteries, the most you will need to do is replace the batteriesno water can
reach the electronics! The CZ-21 is a VLF-detector that shares its "Fourier
Domain Signal Analysis System" circuitry with other Quicksilvers - past and
present. This circuit transmits signals at two different frequencies
simultaneously (5kHz and 15kHz), resulting in a high level of performance that
provides accurate target identification and improved detection depth in even the
most highly mineralized or salt-laden ground. The mention of target ID
capabilities in a report on a waterproof detector may catch the attention of
many readers. The CZ-21 features the familiar 3-tone CZ audio target ID system
that allows the user to identify targets with a high degree of accuracy and
decide if they are worth recovering. Iron will produce a low tone, pull-tabs,
tin foil and most gold rings will produce a medium tone, and silver objects,
large gold jewelry and U.S. coins (including nickels) a high tone. The on-line
version of this report will cover techniques that can be used to increase the
number of gold rings and other pieces of jewelry you can find per hour in the
field though the use of the CZ-21s audio target ID system. Operation of the
CZ-21 couldnt be simpler. It is controlled through four knobs and a push-button
located on the face of the control housing. The VOLUME control also turns the
unit on and, if turned past 5, activates the Faint Target Audio Boost which
amplifies weaker signals from smaller or deeper targets while holding the
response to larger targets constant. Many beach hunters have found deep,
valuable targets using this feature. The DISC control has seven distinct
settings, which allow the user to select both the level of discrimination to be
used as well as the operating mode to search in. Selecting a setting of "0" thru
"6" activates the silent search motion discriminate mode with the amount of
discrimination determined by the value selected. Placing the knob in the
position labeled AUTOTUNE will activate a VLF motion all-metal mode. While this
mode does not provide any discrimination, it does give a wide-scan search field
with a slight increase in detection depth over the motion-discriminate mode. In
areas which do not contain a great deal of trash, this mode would be the
preferred search mode. The SENSITIVITY control also serves two functions.
Turning it fully counterclockwise, battery strength can be checked by listening
to the resulting audio signal. When searching with the CZ-21, the higher the
SENSITIVITY setting the more sensitive the detector becomes. Remember, however,
that if it starts to operate erratically, drop the control until the chatter is
eliminated. Additionally, when in the AUTOTUNE position, the SENSITIVITY control
also adjusts the audio threshold. The final knob labeled GROUND is used to
precisely compensate for the mineralization present in the search area in
conjunction with the PINPOINT pushbutton. Ground balancing, even in areas
containing black sand or salt water, is a quick and simple process even
underwater and is well explained in the manual. As with many of the Fisher
detectors, there are preset marks on all of the controls making it easy to start
hunting immediately after unpacking the detector. The CZ-21 has been designed as
an all-purpose detector for uses ranging from land hunting (especially in
adverse weather conditions) to beach and shallow water hunting to Scuba diving.
Unlike other detectors that require portions of the shaft to be added / removed,
depending on the type of hunting one plans to do, the CZ-21 can be easily
adjusted from 30 to 50 thru the use of the unique two-piece fiberglass shaft. It
can be purchased with your choice of either an 8 or 10 search coil. There are
advantages and disadvantages to each size; however, in general, the smaller the
coil the more sensitive it will be to small targets and the more effective it
will be in separating good targets from trash buried nearby. The larger coil is
more suited for wreck divers or hunters that desire a slight edge in detection
depth over their competition. Consideration should be given as to which coil
size is desired, as they are not interchangeable and the larger coil does
produce more drag when swinging it in shallow water. If weight is a concern (as
waterproof detectors tend to be heavier than land-only detectors), the control
housing slides easily off the shaft and can be hipmounted in a matter of seconds
with the belt clip that comes with the unit. When hipmounted, the handle and
search coil weighs around 2.5 pounds, which allows the CZ-21 to be used for
hours without fatigue. The CZ-21 is powered by four 9V batteries and a quality
set of alkalines can operate the detector for upwards of 50 hours. Rechargeable
batteries can be used; however, the battery life will be noticeably reduced.
Note : When re-installing the battery compartment cover, ensure the O-ring is
oriented correctly and that the seating surfaces are clean and undamaged to
prevent leakage. Field Test: As with any new detector, the first thing I did was
conduct some air testing to see where specific targets registered and the audio
response each produced. My results confirmed what was shown in the manual and
what my past experience with CZs had been. The next stop was the test garden.
Ive found that in most cases, the easiest way to ground balance a CZ is to raise
the coil off the ground, set the GROUND BALANCE control to 10, tap the PINPOINT
button and lower the coil to the ground. Slowly turn the GROUND BALANCE control
clockwise until you start to hear a slight tone. Simply back off until the tone
just disappears and the detector is perfectly balanced. All of the targets in my
test area produced clear, repeatable signals and were accurately identified via
the audio ID system. Unlike some detectors where optimal performance is closely
tied to sweep speed, even the deepest targets were detected at sweep speeds that
ranged from very slow to quite fast, making the CZ-21 well suited for
applications ranging from slowly scanning a sunken wreck to whipping the
detector across the beach in a seeded hunt. My family has come to realize that,
when it comes to metal detecting Im a bit fanatical so when I announced I was
going up in a steady rain to test the CZ-21, I got little more than a
questioning glance and the comment Dinner will be ready in a few hours. With a
steady rain for the past few days, I figured the conditions would be a good test
of how the detector performed at a land site. I had permission to hunt a wooded
area that had a few old foundations scattered about and that was where I headed.
Opting for the target-ID search mode, I set the DISCRIMINATE control to 0,
SENSITIVITY to 9 and quickly ground balanced the CZ-21. Signals were plentiful;
however, most were iron and were easily identifiable by their audio response. A
mid-tone signal surrounded by low-tone iron signals near a large tree sounded
promising. Clicking the DISCRIMINATE knob to 1, the iron signals were rejected
yet the mid-tone signal still came through. This was a good sign that, when
using iron-elimination, very few good signals would be missed due to masking.
The signal turned out to be a flat button from the early 1800s. The pinpoint
mode worked extremely well and the VCO audio allowed me to zero in on signals
with a high degree of precision. Two hours in the pouring rain produced several
keepers, including two more buttons, a copper disc which may have been a coin, a
few round balls and a silver plated spoon from depths up to 10 inches. The next
site I visited was actually a water sitean informal swimming area on a lake
about 35 miles away. Unlike many of these types of beaches, this one was not
littered with trash, which made hunting enjoyable rather than a chore. The sand
/ mud allowed targets to sink quickly, so I was hoping the CZ-21 could pull more
targets from areas my partner and I had already searched. Wanting maximum
detection depth, I opted to search in AutoTune. Setting the SENSITIVITY at 10
and ground balancing, I waded into the water. Based on the chatter, it was clear
that 10 was too high and dropping it to 8 produced stable operation. Signals
were fairly plentiful and coins that had clearly been there for years turned up
on a consistent basis. A useful trick when hunting in AutoTune is to click the
DISCRIMINATE knob into the 0 position when a target is detected to take
advantage of the audio target ID system. Many of the targets I recovered were in
the 8 to 10 range and produced solid, repeatable signals. The day before this
report was due I was able to return to the beach and strap on my Scuba gear to
see what was out past where the bottom dropped off. Collapsing the shaft made it
the ideal length for diving without the need to remove portions of the shaft, as
many other dive detectors require. Dropping to the bottom, I checked my depth
gauge and saw 25. Volume was more than adequate to be heard over the bubbles
from the regulator and I picked up a nice pile of targets during my dive,
including a 14KT gold mans ring with 13 diamonds (OK, real small diamonds). The
on-line version of this report contains additional field test data as well as
more technical information on the detector itself. Summary: Theres an old adage
that says If it aint broke, dont fix it and, in the case of the CZ-21, the
engineers at First Texas kept that in mind as they brought out this latest
addition to the Quicksilver line. The redesigned faceplate with the new pinpoint
button, a new gasket system, and improved circuit board protection are built on
a proven design that works better than its predecessor. To repeat what I said
about the CZ-20 in my original field test, the CZ-21 is truly a detector that
performs just as well submerged in saltwater as it will in a fresh water lake, a
schoolyard, park, battlefield or mineralized ghost town. If you are looking for
a single detector that will provide above-average performance in a wide variety
of applications regardless of the weather conditions, the Fisher CZ-21
definitely fits the bill. When the CZ-21 was first introduced, there was a
manufacturing glitch that resulted in a number of units being released that
would not ground balance properly and these units were recalled and repaired.
Thanks to the Internet, word quickly spread about the problem with the new CZ-21
and some would-be buyers shied away. In talking to First Texas, this issue was
corrected many months ago and all of the CZ-21s being shipped are functionally
tested and checked by a QC group before they leave the factory. The build
quality of my CZ-21 was first rate and, with a bit of care, will easily be in
use a decade from now. The CZ-21 metal detector comes with a limited 2-year
warranty, which is on par or better than other underwater detectors on the
market, showing that the factory is confident that it will hold up under
virtually any condition one might use it in. A padded, lockable hard-sided
carrying case is available as an option for added protection.
Be sure to mention you read about the CZ-21 in Lost Treasure Magazine.
Specifications
CZ-21 Specifications
- Length Extended: 50”
- Length Collapsed: 30”
- Control Housing Weight: 2.8 lbs
- Weight
- Complete (with headset):
8” Coil 5 lb 11 oz
10.5” Coil 6 lb 1 oz
5” Coil 5.4 lb
- Handle and Search Coil:
8” Coil 2 lb 6.9 oz
10.5” Coil 2 lb 12.9 oz
5” Coil 2.1 lb
- Frequency
1. Dual, VLF Search 5 KHz and 15 KHz
2. Audio Target Response
Iron I.D.: 200 Hz (Low tone)
Foil and Tab I.D.: 450 Hz (Mid tone)
Coin I.D.: 1 KHz (High tone)
- Autotune: 500 Hz - 1 KHz (VCO)
- Pinpoint: 500 Hz - 1 KHz (VCO)
- Operating Modes
1. Autotune - VLF-Motion, all-metal with threshold tone
2. Target I.D.: VLF-Slow Motion, Silent Search Discrimination
3. Pinpoint: VLF, All-Metal, No Motion
- Search Coil
Type: Concentric, Co-Planar
Diameter: 8”, 10.5” or 5”
Shielding: 100% ESI
Interchangeable: No
- Headset: Waterproof, Piezo Electric
Interchangeable: No
- Ground Balance: Touch Pad, Manual or “Preset” Control
Markings
- Hipmountable Control Housing: Yes
- Salt Water/Fresh Water Operation: Yes
- Land Operation: Yes
- Submersible: to 250 feet
Recommended for:
Beach Hunting
Shallow Water, Lake /Surf, Diving
