jotron TR-2600, Operation And Installation Manual

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82695
_Op&Ins MAN_TR2600_K 4-1
4 INSTALLATION
Important notice
In a Base Station environment, depending of frequency and antenna separation, it may be
necessary to use cavity filters to avoid transmitter noise and receiver blocking problems.
4.1 Antenna Unit
4.1.1 GPS antenna location
Install the GPS antenna unit referring to the drawing Figure 4.1.1. When selecting a mounting
location for the antenna, keep in mind the following points.
1.There should be no interfering object within the line-of-sight to the satellites. Objects within line-
of-sight to a satellite, for example a mast, may block reception or prolong acquisition time.
2. Mount the antenna unit as high as possible to keep it free of interfering objects and water spray,
which can interrupt reception of GPS satellite signal if the water freezes.
4.1.2 VHF antenna location
Location of the mandatory AIS VHF-antenna should be carefully considered. Digital
communication is more sensitive than analogue/voice communication to interference created by
reflections in obstructions like masts and booms. It may be necessary to relocate the VHF
radiotelephone antenna to minimize interference effects.
Install the VHF whip antenna referring to drawing Figure 4.1.2. Separate this antenna from other
VHF radiotelephone antennas to prevent interference to the TR-2600.
To minimise interference effects, the following guidelines apply:
1.The AIS VHF antenna should be placed in an elevated position that is as free as possible with a
minimum of 0.5 meters in the horizontal direction from constructions made of conductive
materials. The antenna should not be installed close to any large vertical obstruction. The
objective for the AIS VHF antenna is to see the horizon freely through 360 degrees.
2.The AIS VHF antenna should be installed safely away from interfering high-power energy
sources like radar and other transmitting radio antennas, away from and out of the transmitting
beam.
3. Regarding distance to another VHF antenna for a Base station, is dependent of power and which
channels the Base station uses.
Example: The AIS uses channels 87-88 as transmit/receive channels and the VHF Base station
uses channel 81. The frequency spacing between them is 300 kHz or 0.3 MHz. Measurement done
on the TR-2600 transponder shows that blocking will occur if the signal from channel 81 on the
location of the AIS antenna is more than –11 dBm, if the wanted signal of the AIS is at a level of
–101 dBm.
The free space loss between the antennas must be at least the difference between VHF Base