jotron TR-2600, Operation And Installation Manual

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82695
_Op&Ins MAN_TR2600_K 4-4
4.2 Cabling
The cable should be kept as short as possible to minimize signal attenuation.
The table below gives recommendations on cables that can be used for the GPS antenna
connections:
Type Attenuation
@1.5 GHz
(dB/100m)
Remark
RG58 90 Default for use if length< 20 m and antenna = Procom GPS4
RG214 35 If combined GPS/VHF antenna from either Procom or Comrod is
used, this or better can be used
RG225 30 Cable with lower loss
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
RG214 Procom AIS2/GPS 28 10-30 meter
Comrod AC17-AIS 20 10-20 meter
RG225 Procom AIS2/GPS 28 10-40 meter
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.