jotron RA-2500, Руководство оператора и инструкция по установке

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Op&Ins MAN_RA2500_D 4-4
For optimum performance of the transponder approxi10dB gain should be available
when the cable attenuation has been subtracted from the GPS antenna preamplifier gain. Note
that Procom AIS2/GPS and Comrod AC17-AIS are combined VHF/GPS antennas and additional
attenuation from connectors/ diplexer must be taken in consideration. Some examples below:
Cable Type Antenna Preamplifier Gain
(dB/100m) Recommended cable
length (m)
RG58 Procom GPS4 30 <20 meter
Procom AIS2/GPS 28 10-30 meter RG214
Comrod AC17-AIS 20 10-20 meter
Procom AIS2/GPS 28 10-40 meter RG225
Comrod AC17-AIS 20 10-30 meter
The table below is gives you the attenuation on the VHF frequencies with different cable types:
Cable Type Attenuation
@150 MHz
(dB/100m)
Diameter (mm) Weight (kg/100m)
RG214 7 10,8 18,5
RG225 8 10,9 23,3
Example : A RG 214 cable with length of 40 meters will have an attenuation of 2,8 dB.
Please keep the cables as short as possible, and be aware that 3 dB loss means only half the output
power. If you have a transmitter delivering 12,5 W, and you have 3 dB loss in the cable, only 6,25
Watts will be at the antenna.
4.2.1 Cable installation
All outdoor installed connectors on coaxial cables should be fitted with preventive isolation such as
vulcanizing tape to protect against water penetration into the antenna cable.
Coaxial cables should be installed in separate signal cable channels/tubes and at least 10 cm away
from power supply cables. Crossing of cables should be done at right angles (90°). The minimum
bend radius of the coaxial cable should be 5 times the cable's outer diameter.