- User's Guide.

The Metaldetector GOLD FISH 2 PRO is the improved successor of the GOLD FISH 2. All search coils remain unchanged and can be used with both models. The same applies for the other accessories. The GOLD FISH 2 PRO has the following improvements:

Improved noise immunity
More detection depth
Increased dynamic range of the signal
Very stable tuning, no drifting
More accurate battery condition measurement
Less weight

Metaldetector GOLD FISH 2 PRO is a PULSE-INDUCTION (PI) system which incorporates a large search coil (one meter by one meter as standard equipment) for the main purpose of finding large objects at great depths. These detection depths can almost be compared with those of magnetometers, which can detect nothing but ferromagnetic objects. Another great advantage of using the metaldetector GOLD FISH 2 PRO together with the large search coil is being able to cover a large area in a short period of time. The actual search coil isencased in a square plastic frame (PVC tubing) and can be carried by one or two persons. Using the PI-principle offers some decisive advantages. First, the search coil is not part of a resonant circuit as it is the case with VLF detectors and can, therefore, be of almost any size and shape. This is absolutely necessary in order to increase the location depth considerably. In the second place there is a timely discoupling between the transmitting and the receiving phase which makes it possible to work with far greater transmission power. A further advantage is that small objects like bottle caps, pull tabs, pieces of aluminium foil, but also single coins are naturally rejected while using the large search coils.

But still the metaldetector GOLD FISH 2 PRO is an easy-to-operate metal detector: you only have to deal with three simple controls, of which you need just one while normal operation. Objects are simultaneously indicated by a meter and by an audio signal which increases in frequency while approaching the object. The audio response has a very wide frequency range in order to avoid signal saturation when the search coil approaches a very close object. This makes it easy to pinpoint the exact location.

The function of the metaldetector GOLD FISH 2 PRO is divided into two time intervals:

Transmission Phase

A strong duty current is flowing through the search coil about 600 times per second. The linearly increasing current builds up a primary magnetic field which radiates as shown in Fig. 2. The current is abruptly cut off after a certain time, so that the primary magnetic field collapses quickly causing so-called eddy currents in the metal object. Strength and duration of these eddy currents depend on the electrical conductivity, size and shape of the object. After a short time delay the search coil is connected to the receiver input.
 

Receiving phase

The decay of the eddy currents in the object produces a secondary magnetic field, which is radiated by the object . This secondary magnetic field has its effect also on the coil and here induces very low voltages, which are amplified and displayed by a meter and an audio signal. Obviously the detection range has physical limits, because these voltages are extremely weak and can be obscured by externalmagnetic fields.

In general, the possible detection range will increase quickly with increasing target size. This is especially true for the PI-principle. But the electrical conductivity and the shape of the object are also important factors. Related to this, ferromagnetic metals take a special position. If these metals are exposed to the magnetic fields of a PI-detector, they will be momentarily magnetized. Although the electrical conductivity of these metals is poor and, therefore, the decay of the eddy currents is very short, the strength and the slow decay of the magnetization causes a strong signal. This is why PI-detectors are very sensitive to even small ferrous objects. The GOLD FISH 2 PRO offers you the possibility of reducing the sensitivity to these objects (some smaller ferrous objects can even be completely rejected), while still being sensitive to most non-ferrous metals.
 

Brief summary of the advantages and capabilities of GOLD FISH 2 PRO metal detector:


Operation is very simple and the internal adjustments are performed automatically each time the GOLD FISH 2 PRO is turned on.
The PI-principle allows to enlarge the search coils and to use a high transmission power in order to achieve extraordinary detecting capabilities.
Using large search coils will allow the operator a fast search covering larger areas. Many different coils (various sizes and shapes) can be connected to the GOLD FISH 2 PRO (1m x 1m is standard equipment):
The 28cm (12 inches) search coil is very effective for exact location and can also be successfully used in overgrown and bushy areas.
The 2m x 2m (80 inches x 80 inches) search coil covers four times as much ground as the standard coil and achieves even 30 to 40 percent more depth on large objects. However, sensitivity to smaller objects will be reduced. All search coils are waterproof and can, therefore, be used in shallow water.
Integrated systems for auto ground tracking.
Integrated systems for noise suppression.
Integrated system for auto tuning.

Detection Depths

The conditions while testing and recording the below objects were as follows: The SIGNAL (SAMPLING DELAY) was in position for maximum performance and a one meter by one meter coil was used. A clear increase of the ticking-noise had to be noticed. The largest surface of each object was measured.
Object Detection Range in Inches (Air Tested)

Object Detection range
 

Detection Depths

The conditions while testing and recording the below objects were as follows: The SIGNAL (SAMPLING DELAY) was in position 1 and a one meter by one meter coil was used. A clear increase of the ticking-noise had to be noticed. The largest surface of each object was measured.

*Maximum detection range – 235" (650 cm)

These depths can be far exceeded when detecting larger objects. All mentioned detection depths may differ either positively or negatively when using reference objects of the same size, but possibly made of different alloys.

Technical Data

Power Source Built-in Lead/Acid Battery 12 volts, 2.3 amp hours

Power Consumption approx. 120mA (without audio signal)

Usage Time approx. 18 hours

Battery Charging Built-in quick-charging electronic, universal charging possibilities: AC adapter (120/230 volts), Car Cigarette Adapter

Recharge Time max. 5 hours on empty battery

Recommend Operating Temperature Range 0 ... +55° Celsius (32 ... 131° Fahrenheit)

Dimensions

Electronic Unit in Leather Case 165 x 70 x 190 mm (6.5" x 2.7" x 7.5")
One Meter Coil in Case approx. 1100 x 200 x 200 mm (41" x 8" x 8")

Weight of Equipment

Electronic Unit in Case approx. 1.6 kg (4 lbs.)
One Meter Coil approx. 1.8 kg (4 lbs.)