Enterasys Networks Outdoor Antenna - Manual (Page 15)

1-3
Determining the Antenna Locations
Typically, the RoamAbout directional and omni-directional antennas are installed on
rooftops. The directional antenna can also be installed to the side of a building. The
vehicle-mount antenna is mounted to a vehicle and connected to the client with a 2.5 meter
(8 foot) cable. The following sections describe the factors that affect the range of the
antennas.
Maximum Distances Between Antennas
The following tables list the maximum distance between antennas at a given data rate. The
distance in tables are based on the following:
•
15 meter (50 foot) low-loss antenna cable from the antenna to the AP.
•
Type of PC Card (standard or Hi-Gain matched). See the “RoamAbout PC Card
Variations” section on page 1-4 .
•
No obstructions in the line of sight. See Table 1-1 and Table 1-2 . The Line of Sight
Clearance column indicates the radius of the radio beam. Obstructions in the line of
sight reduces the total distance, as described in the
“Line of Sight” section on page
1-5 .
Table 1-1: Distances and Line of Sight Clearance (FCC)
Data
Rate
Mbit/s 14 dBi Yagi to 14 dBi Yagi 14 dBi Yagi to 7 dBi Omni 7 dBi Omni to
Vehicle-Mount
Distance Line of
Sight
Clearance Distance Line of
Sight
Clearance Distance Line of
Sight
Clearance
11 5.6 km
(3.5 mi)
9.8 m
(33 ft) 2.5 km
(1.5 mi) 6.3 m
(21 ft) 0.8 km
(0.5 mi) 3.4 m
(11.2 ft)
5.5 7.9 km
(4.9 mi)
12.1 m
(40 ft) 3.5 km
(2.1 mi) 7.5 m
(25 ft) 1.1 km
(0.7 mi) 4.1 m
(13.5 ft)
2 11.2 km
(6.9 mi)
15.4 m
(51 ft) 5 km
(3.1 mi) 9.1 m
(30 ft) 2 km
(1.2 mi) 5.6 m
(18.4 ft)
1 15.8 km
(9.8 mi)
20.3 m
(67 ft) 7.1 km
(4.4 mi) 11.3 m
(37 ft) 2.5 km
(1.5 mi) 6.3 m
(21 ft)