SKY899
Installation Manual
Page 2-18 - Installation
009-11900-001
July 18, 2013
Revision F
2.6.1
Antenna Cables
NOTES
1.
If you fabricate your own cables, you must verify that the attenuation
and VSWR does not exceed the specified values.
2.
To add strain relief and alleviate stress caused by aircraft vibration,
place 4-6 inches (10.2 to 15.2 cm) of heat shrink tubing over each
antenna connector and cable.
The directional antenna requires three cable assemblies; sum (Sigma Port), bit probe (Probe Port) and
difference (Delta Port). Cable attenuation for the sum and difference ports must not exceed 2.5 dB.
Attenuation for the bit probe cable must not exceed 6 dB. VSWR, on cables attached to the sum, bit
probe, and difference ports, must not exceed 1.5:1. (See paragraph 1.7 for antenna cable vendors and
specifications.)
At the antenna, each connector has an identifying color band. To ensure the cables are connected to the
correct port, affix the following marking at the termination points of each cable:
Sum (Sigma) Port
The Sum (Sigma) port is the forward antenna connector. It is marked with a
blue band. Fabricate the sum antenna cable with a TNC connector at each
end. Affix a blue marking band on each connector. At the TRC, the sum port
(J9) is identified with blue marking.
Bit Probe Port
The Bit Probe port is the center antenna connector. Fabricate the probe cable
with a BNC connector at each end.
Difference (Delta) Port
The Difference (Delta) port is the rear antenna connector. It is marked with a
red band. Fabricate the difference antenna cable with a TNC connector at
each end. Affix red marking band on each connector. At the TRC, the
difference port (J11) is identified with red marking.
When routing antenna cables, observe the following precautions:
• All cable routing should be kept as short (do not exceed maximum cable length detailed in table 1-9)
and direct as possible.
• Avoid sharp bends (do not exceed maximum bend radius detailed in table 1-9).
• Avoid routing cable near power sources (e.g., 400 Hz generators, trim motors, etc.) and near power
for fluorescent lighting.
• Avoid routing cable near ADF antenna cable (allow at least a 12-inch (30.5) separation).
2.6.2
Audio Output Cable
For audio output cable use #22 AWG (minimum) twisted shielded pairs with the shield grounded at both
ends. Cable runs can be up to 30 ft., but should be as short as practicable.
The document reference is online, please check the correspondence between the online documentation and the printed version.