Garmin International Inc 01443 Manual De Usuario
Page 2-4
GTX 3000 Installation Manual
Revision A
190-00926-01
2.4 Cabling and Wiring
Refer to the interconnect examples in Appendix C for wire gauge guidance.
In some cases, a larger gauge wire such as AWG #18 may be needed for power connections. If using #18
barrel contacts, ensure that no two contacts are mounted directly adjacent to each other. This minimizes
the risk of contacts touching and shorting to adjacent pins or to ground.
barrel contacts, ensure that no two contacts are mounted directly adjacent to each other. This minimizes
the risk of contacts touching and shorting to adjacent pins or to ground.
Ensure that routing of the wiring does not come in contact with sources of heat, RF or EMI interference.
Check that there is ample space for the cabling and mating connectors. Avoid sharp bends in cabling and
routing near aircraft control cables. It is also good practice to avoid routing cables near sharp edges
because aircraft vibration might wear away the insulation on the wires, which will leave them exposed to
moisture and potentially create arcing or intermittent short circuits.
Check that there is ample space for the cabling and mating connectors. Avoid sharp bends in cabling and
routing near aircraft control cables. It is also good practice to avoid routing cables near sharp edges
because aircraft vibration might wear away the insulation on the wires, which will leave them exposed to
moisture and potentially create arcing or intermittent short circuits.
The maximum attenuation at 1090 MHz between the unit and the antenna must not exceed 3.0 dB. This
loss specification includes connector loss; for example, through a bulkhead connector (0.2 dB is typical
loss for each bulkhead connector). The GTX 3000 back-plate assembly utilizes a BNC-type (bayonet
connection) coaxial connector.
loss specification includes connector loss; for example, through a bulkhead connector (0.2 dB is typical
loss for each bulkhead connector). The GTX 3000 back-plate assembly utilizes a BNC-type (bayonet
connection) coaxial connector.
Table 2-5 lists examples of recommended antenna cable. Use the table to determine the length of cable
needed to connect the transponder to the antenna, and to look up a recommended cable manufacturer and
part number that will meet the 3.0 dB loss spec. The table assumes a loss figure of 0.2 dB per connector.
Note that any 50 Ω, double shielded coaxial cable assembly that meets airworthiness requirements and the
3.0 dB maximum loss figure (including connectors) may be used.
needed to connect the transponder to the antenna, and to look up a recommended cable manufacturer and
part number that will meet the 3.0 dB loss spec. The table assumes a loss figure of 0.2 dB per connector.
Note that any 50 Ω, double shielded coaxial cable assembly that meets airworthiness requirements and the
3.0 dB maximum loss figure (including connectors) may be used.
Differential cable loss: If the cable loss difference between top and bottom channels is less than 1 dB, the
unit’s default cable loss values are applicable, and the unit does not require cable loss configuration. If that
cable loss difference is more than 1 dB different between antennas, then cable loss configuration is
required..
unit’s default cable loss values are applicable, and the unit does not require cable loss configuration. If that
cable loss difference is more than 1 dB different between antennas, then cable loss configuration is
required..
Table 2-5 Cable Specifications
Max. Length
(feet – [m])
Insertion loss
(dB/100ft)
ECS Type
MIL-C-17 Type
RG Type
17' 5.2" [4.40m]
18.0
M17/128-RG400
RG-400
17' 11.7" [5.48m]
14.45
3C142B
21' 7.8" [6.60m]
12.00
M17/112-RG304
RG-304
29' 6.7" [9.01m]
8.80
311601
M17/127-RG393
RG-393
36' 6.2" [11.13m]
7.12
311501
47' 4.9" [14.25m]
5.56
311201
71' 7.4" [21.83m]
3.63
310801
Supplier
Information
Vendor: Electronic
Cable Specialists
5300 W. Franklin Drive
Franklin, WI 53132
Tel: 800-327-9473
414-421-5300
Fax: 414-421-5301
See current issue of
Qualified Products
List QPL-17.
RG types are
obsolete and are
shown for
reference only;
replaced by M17
type numbers.
DRAFT