Nexus 21 NX2000 Manuel D’Utilisation

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VHF NX2000 
 
 
40 
 
                                                               Fig D 
The NX2000 requires a 12v DC supply to operate. This lead should be connected to the 
vessel’s power supply (the red wire is positive, black is negative), and the cable kept as 
short as possible. Although the Radio draws very little current when receiving, a heavier 
current is drawn when transmitting which may result in a voltage drop if very long cables 
are used of inadequate core diameter. If the supplied power lead is not long enough, an 
extension of up to 3m(10 ft) can be made using at least 2.5mm (13AWG) wire. 
 
The chassis of the NX2000 is not connected to either supply rail. This allows a direct 
connection to the ship’s earth connection for voltage and RF interface protection. The 
red wire is positive and black is negative. If polarity is accidentally reversed, the set will 
not operate. 
 
The antenna is connected to the NX2000 using a standard PL259 type connector as 
fitted to most marine antenna. If fitted to an existing antenna, check that the contacts 
are not corroded before connecting, as this will affect the quality of the signal, Ensure 
that the retaining collar of the antenna plug is securely tightened to prevent accidental 
disconnection. 
 
15.2 
Antenna Installation Recommendations 
 
The most important factor in the performance of the NX2000 will be the quality and 
positioning of the antenna. Most recorded problems with VHF Radios are related to 
poor antenna sighting, faulty cabling, poor quality cable joints and low voltage supply. 
Even the best performing Radio cannot compensate for these factors. If replacing an 
existing installation using the same antenna, it is important that these factors are 
checked when installing the Radio. 
As the range of VHF signals are governed by line of sight, the antenna should be 
placed as high as possible, while remaining clear of any metallic objects that could 
influence the resonance of the antenna.