AS 680/682
Installation and Setup Description, Operation and Maintenance
ADS−B
3−10 Ed. 10.07
3.1.6.4 Installing the GPS Antenna
To mount the GPS antenna preferably use the associated mounting material if possible. To fulfill the
installation criteria consider the following recommendations and mounting aspects:
− Ensure obstacle free line of sight to the satellite.
− Avoid shadowing by shelter and/or buildings.
− The mounting tube shall have conductive connection to earth.
− The antenna cable connector (TNC type) is inside the antenna adapter (see Fig. 2−25).
− Check correct fitting of gasket between antenna and adapter.
− The antenna can be mounted to an optional mounting tube with thread, L=990 mm, 25 mm ∅.
To connect the GPS antenna perform following connections (refer to Fig. 3−9):
a) RF cable from building to GPS antenna; the RF cable characteristics shall be similar to Cellflex 1/4",
attenuation < 15 dB/100 m. The cable length can be up to 20 m.
b) Earth cable to building; the earth cable shall be a cable with more than 16 mm
2
∅. It shall be as
short as possible and be connected to the earth of the shelter or building.
The cable shall be fixed by mounting brackets or UV resistant cable ties. The cable shall have addi-
tional earthing/shielding to protect against lightning stroke. The GPS antenna is supplied with +5 V
DC via the RF cable. Therefore the antenna output may not have a quarter wave lightning protector
because of DC blockage.
3.1.6.5 Performing the Outdoor Cabling
The outdoor cabling includes all cables outside the shelter or building:
a) ADS−B antenna cable from "RFout" (AAU or antenna assembly):
the characteristics shall be similar to 1/2" cellflex (attenuation < 8db/100m),
the cable length shall not exceed 30 m
b) Site Monitor cable to the antenna monitor probe (or antenna assembly):
the characteristics shall be similar 1/4" cellflex (attenuation <15db/100m),
the cable length shall not exceed 30 m
c) GPS antenna cable:
all cables shall have N−type male connectors (except GPS antenna input: TNC)
All cables shall be protected against lightning strokes or surge (primary protection) preferably at the
shelter entry. No filters are allowed for cables to GPS and AAU because they individually provide sup-
ply voltage for GPS antenna and AAU. Also no quarter wave lightning protectors are allowed (block-
age of DC); only gas filled protectors may be used. All cables shall be as short as possible, avoid
loops. Fix the cables with mounting brackets or UV resistant cable ties. Proper earthing is required:
use earth clamps every 2 meters.
3.1.6.6 Installing the Indoor Equipment Ground Station AS 680, Site Monitor
See Figs. 3−9, 3−10, 3−15.
This section contains general procedures for installation of the equipment in the shelter or building.
Mount the Ground Station (GS A) in the provided rack:
a) Fix the Ground Station with the supplied mounting material (screws, nuts and washers).
b) Be sure that the air inlet at the front panel as well as the fan outlet at the right side of the Ground
Station is free (minimum distance to rack cover: 40 mm).
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