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| VHF NX2000 | ||
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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.
15.2Antenna 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.
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