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 Field
Test Report
C-Scope
CS990-XD
by
Dave Stuckey
Those
of us who have been in the
hobby from the early days can
probably remember when the
range and diversity of metal detectors
that
were available on the market was
relatively small. In the 26 years that I’ve
been detecting, I have seen the market
expand enormously with the range of
detectors
now available reaching quite
staggering
proportions.
In the 1970s you had a simple
choice of one of the few Beat Frequency
Oscillation (B. F. O.) units or maybe an
Induction Balance (I. B.) unit. The early
B. F .O. units were hideous machines that
seemed  to
generate more noise than an
air raid siren. The I. B. units, on the other
hand, were definitely more user-friendly
with just a gentle threshold
tone.
If your detector had more than two
knobs on the control panel then it was
regarded as a top-of-the-range model,
as it probably had a discrimination
facility. If it had four knobs then you
were definitely a poser!
Quite naturally, along with those
“low-tech” machines you also had a
very limited choice of accessories to go
with them. In fact, generally the only
accessories you could get were the
headphones and, of course, something to
dig with. This is quite unlike today
where you can now select from an
arsenal of different search coils, coin
probes, detector harnesses - you name it!
Ergonomics didn’t play a part in
detector design either, as Repetitive
Strain Injury hadn’t been invented
then! Machines simply had a handle
jutting out of the control box or maybe
the giant “swan neck” handles, which
were the hallmark of the early range of
C-Scope detectors. In fact, when
somebody first told me that a machine
was “ergonomically” designed I
thought it was meant for someone
with a higher IQ!
Nowadays,
however, microprocessor
technology has changed almost
everything. We now see machines that
incorporate degrees of sophistication
and technology that were undreamt of
in the 1970s.
Hardly a month goes by where we
don’t see new innovations appearing on
the market that promise far greater performance
than the previous models.
Fortunately, most of them perform
exactly as their manufacturers claim
and we’re often left wondering what
kind of machines are “just around the
corner”?
It does surprise me, however, when
a leading manufacturer seems to take a
step backwards and produces a new
machine that is relatively “low-tech” in
comparison to the super machines it
already markets.
Of course, while we all look forward
to the day when a machine has the telepathic
capability to say to its operator
“Keep moving, it’s junk!” we tend to
forget that the market still has to cater
for the newcomers to the hobby.
Undeniably, numerous models currently
exist on the market, which are
already aimed at this sector with varying
degrees of simplicity to operate.
C-Scope,
however, have come up with a
new machine that is aimed specifically
at the newcomer, and which is neither
too basic nor too sophisticated. It
comes in the form of the C-Scope
CS990XD.
The CS990XD is designed to slot in
somewhere between C-Scope’s current
basic starter model, the CS660, and
their best-selling CS1220XDP. C-Scope
have also “stayed with the grain” by
maintaining the familiar, and highly
popular, design of many of their current
range of detectors. Like many C-Scope
models, the 990XD is powered by eight
AA type batteries of either the standard
alkaline type or rechargeable ni-cads.
If the latter are used then these can
be re-charged within the battery
compartment
by use of a charger unit,
available as an optional accessory.
On either side of the battery compartment
are two sockets: the larger
one is for the headphones while the
smaller is for the charger unit.
The CS990XD is a non-motion
detector and comes fitted with a standard
8in search coil, which is
non-interchangeable.
So, what has the 990XD got to
offer? Well, for a start, you’re getting
two detectors in one at a price you
would expect to pay for a much more
basic model. This machine has both an
“inland” detecting mode and a “beach”
mode. By using the switches on the
control panel the operator can combine
the signals of both modes in order to
combat the problems of ground effect
and heavy mineralisation.
The
Control Panel
The
CS990XD has five basic controls
on
its facia panel. These
are:
On/Off switch and Tune control;
Level
control and Battery check; the
Ground
Exclusion switch; a Disc mode
switch;
and a Retune push button.
Also on the control Panel is a signal
meter
- of the same type that is featured
on the CS1220XDP.
On/Off
& Tune Switch
This
rotary switch is situated on the
lower right of the control panel and,
after switching on, is then adjusted to
give the preferred level of audio, or
threshold, tone. It is important to try
and maintain this level of threshold
while detecting in order to achieve
maximum depth.
The meter will give a visual indication by reading mid-scale when tuned
to threshold. The Tune control is used
in conjunction with the Retune button,
which must be depressed while making
any adjustments to the Tune
control.
Retune
Push Button
Should
you experience any drift, or
change in audio tone, during detecting
then this button should be pressed in
order to reset the machine to its threshold
level. If any adjustments are made
to any of the machine’s controls then
the retune button must be pressed
while this is carried out.
Ground
Exclusion Switch & Disc
Mode
Switch
As
this is basically a machine for
beginners
it may be a good idea to try
and explain what ground effect actually
is and how to eliminate it by using
these controls. Some areas of land contain deposits
of iron or iron oxides, which can make
it very difficult to operate a metal
detector with any degree of success.
The signal from the detector will often
fluctuate if the search coil isn’t kept at
a constant height from the ground
when in use. This is termed as “ground
effect”.
This problem can be reduced, or
eliminated, by using the Ground Exclusion
Switch, which is situated on the
top left of the control panel.
The switch, which is used in conjunction
with the Disc mode switch,
has two settings: Inland and Beach.
When set to the Inland setting the
machine will give a positive response to
every type of metal. This is also known
as the “all metal mode”. Like mineralised soil, metals and
wet sand also have their own characteristic
exclude point. When used in the
Beach mode, at the correct exclusion
point, ferrous targets (usually iron) will
give a negative signal while non-ferrous
targets will continue to give a positive
response. When used at a higher exclusion
setting small pieces of aluminium
foil (which are often found in abundance
on beaches or recreation areas)
will
also give a negative signal.
Level
Control
The
CS990XD’s discrimination
level is centred at about that of wet salt
sand but can be varied from iron reject
through to aluminium reject by adjusting
the Level control, which is situated
on the lower left of the control panel.
This control also adjusts the “exclude”
point of Meter Disc, and Meter & Audio
Disc.
Inland
& Disc Mode Switch
If
used in the Inland mode the
CS990XD operates at a fixed level of
ground exclusion that is factory set. All
metal targets will produce an increase
in audio volume regardless of the Level
control setting. The Beach/Disc facility
will continue to operate and, if
required, can be selected to drive the
meter or control the audio pitch by
selecting the appropriate setting on the
Disc Mode Switch. The level of discrimination
in
the Beach/Disc mode
can be adjusted by operating the level
control.
If the 990XD is used in the Inland
mode on any mineralised inland site it can be used in conjunction with
any of
the Disc modes described below.
In the Meter Disc setting any nonferrous
targets will cause the meter
needle to move to the right (green sector).
Ferrous targets will cause it to
swing to the left (red sector).
In the Meter and Audio Disc setting
the meter needle reacts as in the previous
setting but also the audio tone
increases with non-ferrous targets but
decreases for ferrous objects.
In the “None” setting the meter
needle swings to the right for all targets
and the audio pitch remains constant.
Beach
& Disc Mode Switch & Level
Control
The
CS990XD is equipped with an
adjustable level of ground exclude in
Beach mode in order to cope with varying
types of beach or soil conditions.
This is the mode that is best suited for
operating on beach sites where fine
adjustments of level control are needed
to cope with wet salt sand.
When used in the Meter Disc mode
the needle swings to the right for nonferrous
targets and to the left for
rejected targets.
In the Meter & Audio Disc mode the
needle reacts as in the previous mode
and the signal increases for non-ferrous
targets. Ferrous or reject targets are
ignored.
If operating in the “None” Disc
mode the needle swings to the right for
non-ferrous targets and to the left for
reject targets.
The Level control acts primarily as a
ground exclude control in Beach mode
and also varies the discrimination point
when operating in the Meter Disc or
Meter
& Audio Disc mode
Battery
Check
The
CS990XD is fitted with a battery
check indicator. To operate this
turn on the Power On/Off Tune Control,
and then turn the Level control
switch fully anti-clockwise to the battery
check position. If the batteries are
good the needle will indicate this by
moving to the green area of the meter.
Remember to switch out of Battery
Check when the procedure is complete.
(Note: Rechargeable batteries will
not read as high as alkaline batteries
even when fully charged).
Field
Appraisal
The
timing of this particular field
test
certainly gave me a bit of a problem.
The weather of late December/
early January wasn’t exactly kind to any
detectorist, as you all probably remember.
If it wasn’t persistent rain then we
had the freezing temperatures to contend
with. I had quite a few problems
finding any slots in between in order to
take the machine out and put it
through its paces.
At the first opportunity, I took the
CS990XD to a site beside a busy main
road on the outskirts of a village. The
roadside edge of this field was once
occupied by a row of cottages, until
sometime in the early 20th century.
Although the site has been restored to
arable land traces of building material
still litter the site. It also offers a profusion
of metal finds, which mainly
consist of house and furniture fittings.
This seemed an ideal site on which to
test the discrimination capabilities of
the detector.
For those who have never handled
any of the C-Scope range of detectors,
the first thing that impresses you is
their lightness and superb balance.
 They
are extremely comfortable
machines to use. As a current C-Scope
user I am already well adapted to them.
Ground effect wasn’t a particular
problem on this site although there
were large amounts of iron objects
from the earlier buildings. I tried first
in the Inland mode and set the Disc
switch to Meter Disc.
Most of the targets I first encountered
were of a ferrous nature, which
was indicated when the meter needle
swung to the left (red) sector. All of
these signals I ignored. My first positive
signal wasn’t very loud but after
digging out a few inches of soil and
then sweeping the search coil over the
hole it certainly got louder. The target
was only about 5in down and turned
out to be a George III cartwheel penny.
I then tried the detector in the
Meter & Audio Disc mode and soon
found that it was much better. The
machine’s response to ferrous targets
was to give a lower pitched tone and it
wasn’t long before I became so accustomed
to this that I found myself
paying more attention to the sounds
rather
than the meter.
The sound pitch of the Audio Disc
signal varied according to what type of
object, or material, was being detected.
Bronze, or copper alloy, targets gave a
very high-pitched signal while lead targets
gave a slightly lower one.
Recognising iron from these very low-pitched
signals certainly makes for easy
detecting.
After about an hour’s detecting the
final tally left me with a pocketful of
brass fittings from the cottages
and a couple of musket balls.
As the CS990XD is mainly aimed at
newcomers to detecting I gave my
friend Tony an opportunity to try it out.
We took the machine to a Roman site,
which we had already been detecting
on for a couple of weeks. Tony, who
started detecting last year with a top-of-
the-range detector, took the machine
and started off in the Inland mode.
Iron wasn’t a major problem on this
site, other than the odd horseshoe, so
most of the signals he received were
positive. Being close to the hedge
though meant that many of these were
shotgun caps. I told Tony to switch
from Meter Disc and try the Meter &
Audio mode. Tony was already used to
this mode from his current machine
and found searching much easier. The
fact that the CS990XD is a non-motion
detector also made a difference, as the
machine could be held still over the target
until the signal became strongest.
This helped with pinpointing, although
Tony found it difficult to break the
habit of swinging the search coil as he
was already accustomed to using a
motion type detector!
Out in the middle of the field, Tony
was stopped in his tracks by a very loud
signal. Digging out a few inches of soil,
we soon found what I thought at first
to be a Roman lead plumb bob.
After closer inspection it turned out to
be a lead drawer handle.
Continuing across the field, despite
the impending rain shower, Tony had
another loud signal. This target turned
out to be a Roman silver denarius of one
of the Faustinas. Despite
the coin being very worn, the finding of
it certainly pleased Tony.
With all the Christmas festivities to
contend with, it was a couple of weeks
before I could take the CS990XD out
again. I wanted to try it out on a site
near where I live that has a notorious
mineralisation problem. The soil consists
of a very sandy loam, which often
gives plenty of false signals, making it
necessary to reduce sensitivity or
increase discrimination levels.
With the temperature hovering just
below freezing I ventured out onto the
“crunchy” soil. I only intended to use
the machine in Beach mode for this
exercise to see how it coped with the
mineralisation.
As this was predominately a
medieval site, which also had a coaching
road passing through it, I have
found many silver hammered coins
here in the past as well as an abundance
of horseshoes and nails.
Using Beach mode with Meter &
Audio Disc I set the level until iron targets
were completely rejected. The
CS990XD coped brilliantly with the
soil conditions, which were frozen
down to two or three inches. My first
decent signal turned out to be a large
lead spindle whorl, or loom weight
I persevered, despite the freezing
temperatures, and soon had my only
other target: a lead cloth seal.
After that my fingers were too numb to
continue so it was back to the car.
Conclusion
I
think that, for a beginner’s detector,
the CS990XD could be slightly
confusing to operate if the user has had
little or no previous experience with a
detector. With more experience using
this machine, however,
I doubt if most
users would find it too difficult to operate.
As for the CS990XD itself though,
I don’t think anyone could grumble
about the price tag for a machine that
gives you what you’d normally expect
to pay a great deal more for! This
machine is certainly value for money.
The feature I liked best about the
CS990XD was the Audio Disc. I could
certainly do with this particular mode
on my own detector! As for depth-seeking
capabilities, I found the 990XD to
be about average. If I were starting out
in the hobby with this machine, I think
that I would regard it as a superb stepping-
stone before upgrading to a more
expensive model.
Tony’s
comments
“Although I’ve only recently taken
up detecting, I started off with an
expensive top grade machine. This put
me in a situation where I was already
pretty familiar with many aspects of
detecting technology and so the operation
of the 990XD wasn’t too difficult
to grasp as most of this machine’s features
are incorporated in my own
machine.”
Specification
-
VLF
Non-Motion circuitry
-
Signal
strength/battery condition meter
-
Meter
discrimination
-
Infinitely
variable audio discrimination
-
Beach
mode
-
8
in Concentric Search head
-
Operating
frequency 17kHz approx.
-
8
x AA battery pack
-
Battery
Charger Socket
-
Headphone
Socket
-
Arm-saver
stem assembly
-
Light-weight,
1.6kg
-
5
Year parts warranty
-
Manufactured
by C-Scope International Ltd
-
List
Price (UK) £199.90 inclusive
©
Reproduced here (with text amendments) by kind permission of
‘Treasure Hunting’ magazine
click
here to
go to the C Scope CS990XD Metal Detector
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