Datawell 45100, Руководство пользователя

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9
3 Installation
This chapter describes how to install the RX-D2. To function correctly, an RX-D2 needs at least
the following:

Power supply.

Receiving antenna.

Connection to a PC using the serial port.
The following paragraphs will discuss these connections as well as grounding and lightning
protection considerations.
3.1 Power supply
The RX-D2 is fed from an AC power source with a voltage between 100 and 240 V. Please
refer to
paragraph 6 for the exact voltage and power requirements.
The customer should provide for a cord set terminated with connector type C13 according to
IEC 60320-1 and a mains plug in accordance with national standards. The RX-C is a class I
appliance and requires an earthed socket for connection to protective-earth.
3.2 Receiving antenna
General HF link considerations
Directional Waverider buoys use a low power HF transmitter. The transmitting antenna is a
vertically polarized quarter wavelength whip. The receiving end of the link should receive as
much signal from the buoy transmitter and as little noise and interference as possible. To
achieve this the receiving antenna and -station should preferably be located at or near the coast,
see
Appendix A and Appendix E for more information.
Receiving antenna location and height
The transmitter antenna is vertically polarised, therefore the receiving antenna must also be
mounted vertically. For the assembly of the antenna and adjustment of its length to the transmit
frequency see
Appendix E .
Over sea the fieldstrength does not vary significantly with the height of the receiving antenna up
to 100 m. If the receiving antenna can be located within a few tens of meters of the sea, its
height is not important.
Over land the fieldstrength is attenuated by RF losses in the ground. For this reason it is
recommended that the antenna should be placed within a few tens of meters of the sea if
possible. If the distance from the sea is greater, the ground losses can (partially) be compensated
for by mounting the antenna at an height up to 20-30 meters. Generally, more than 20 -30m
above sea level will not improve the reception quality.
If possible mount the antenna in such a way that it has a free “sight” in the direction of the buoy.
Large structures such as embankments, ships and buildings in the direct optical path to the buoy
will attenuate the received signal.
For interference free reception it is advisable to install the Receiving antenna as far as possible
from local interference sources such as combustion engines, electric motors and fluorescent
lamps. In general a transmitting distance of 50 Km (30 n.m.) over sea water can be attained
when the receiving antenna is located at least 100 m from interference sources mentioned. If