SYSTEM INSTALLATION MANUAL
89000016
• A characteristic impedance of 50 ohms
• Double braid screens or has a foil and braid screen.
(5)
Once the cable run length is determined, a cable type with the correct attenuation (loss) for
each foot that meets the above requirements can be chosen. Longer runs require lower loss
cable. Consider moving the KGX closer to the antenna to minimize the losses in the antenna
cable subject to the limits identified above.
(6)
Table 1025 is a guide to the minimum and maximum usable lengths of some common cable
types. Actual cable loss varies between manufacturers and Table 1025 is based on typical data.
(7)
Use Table 1025 as a guide only and refer to the manufacturer’s data sheet for the specific
cable chosen to calculate the minimum and maximum lengths.
Table 1025. Common Cable Types
Cable
Attenuation
(dB/100 feet (30.5 m) at 1 GHz)
MIN Length
feet (m)
MAX Length
feet (m)
RG-142
12.8
11.7 (3.56)
39.1 (11.92)
RG-174
27.1
5.5 (1.67)
18.5 (5.64)
RG-316
25.8
5.8 (1.76)
19.4 (5.91)
RG-393
7.5
20 (6.09)
66.7 (20.33)
RG-400
14.5
10.3 (1.34)
34.5 (10.52)
(8)
When routing the cable, make sure of the following:
• Route the cable away from heat sources.
• Route the cable away from away from potential interference sources such as ignition wiring,
400-Hz generators, fluorescent lighting, and electric motors
• Allow a minimum separation of 12 inches (300 mm) from an ADF antenna cable
• Keep the cable run as short as possible
• Avoid routing the cable around tight bends
• Avoid kinking the cable even temporarily during installation
• Secure the cable so that it cannot interfere with other systems.
15. GPS Antenna Installation (KGX 150 Series Only)
A.
General
(1)
The antenna must be installed according to the manufacturer’s instructions. Selecting
appropriate GPS antenna locations is critical to the correct performance of the KGX 150 series.
The following considerations must be taken into account when selecting the antenna location.
(a)
Typically, a GNSS antenna is located forward or aft of the wings on top of the fuselage.
(b)
GNSS antennas must be installed to give the widest, unobstructed view of GNSS
satellites.
NOTE:
Shadowing by aircraft structure (and in some cases by rotorcraft blades) can
adversely affect operation of the GNSS equipment.
(c)
Antenna placement on the airframe must be optimized to make sure that the sensor can
take full advantage of a 5 degree mask angle. This includes consideration of antenna
EFFECTIVITY
ALL
Page 1023
22 Dec 2016
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