TQ Aviation
KTX2-F.0100
EASA.AP445
MAN
KTX2-F.A-MAN.0001.docx
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•
Double braid screens or a foil and braid screen.
Once the cable length from the transponder to the antenna is known, a cable type can be chosen which
has a loss per meter low enough to meet the above requirements (see table below).
Note:
Low loss cable typically uses foamed or cellular dielectrics and foil screens. These make such cables
especially prone to damage from too-tight bends or from momentary kinking during installation. Once
kinked, these cables do not return to full performance when straightened.
The following table is shows a list of some common cable types and the maximum usable lengths.
Cable Type
Max Length in
meters (feet)
Insertion Loss
dB/meter
(db/100ft)
1
Remarks
RG-400
M17/128-RG400
2.5 (8’ 2”)
0.6 (18.5)
RG-304
M17/112-RG304
4.2 (13’ 9”)
0.36 (11.1)
RG-393
M17/127-RG393
5 (16’ 5”)
0.3 (9.2)
Carlisle IT Type
3C142B
3.1 (10’ 2”)
0.48 (14.5)
Carlisle IT Type
311601
5.2 (17’ 1”)
0.29 (8.7)
Carlisle IT Type
311501
6.5 (21’ 4”)
0.23 (7.1)
Carlisle IT Type
311201
8.3 (27’ 4”)
0.18 (5.6)
Carlisle IT Type
310801
12.5 (41’)
0.12 (3.6)
Table 9: Common Antenna Cables
When routing the cable, ensure that you:
•
Keep the cable length as short as possible.
•
Avoid routing the cable round tight bends.
•
Avoid kinking the cable, even temporarily during installation.
•
Secure the cable so that it cannot interfere with other systems.
•
Route the cable away from any heat sources.
1
RG type coaxial cable insertion loss can vary significantly between manufacturers. The insertion loss for RG type
cables shown in this column is considered 'worst case'. Refer to the cable manufacturer's specification sheet for
actual attenuation (insertion loss) for the cable being used.
