Hewlett Packard Enterprise Company MST200DFS 用户手册
10
Aruba MST200 Wireless Mesh Router
| Installation Guide
RF Interference Sources
Other 802.11a/b/g/n or broadband access equipment operating nearby
Industrial RF welding equipment or other Industrial, Scientific and Medical (ISM) equipment that utilizes
RF to heat or alter the physical properties of materials
RF to heat or alter the physical properties of materials
Military, Commercial Aviation or Weather Radar Systems
Line of Sight (Radio Path Planning)
A wireless bridge or mesh link requires a “radio line of sight” between the two antennas for optimum
performance. The concept of radio line of sight involves the area along a link through which the bulk of the
radio signal power travels. This area is known as the first Fresnel Zone of the radio link. For a radio link, no
object (including the ground) must intrude within 60% of the first Fresnel Zone.
performance. The concept of radio line of sight involves the area along a link through which the bulk of the
radio signal power travels. This area is known as the first Fresnel Zone of the radio link. For a radio link, no
object (including the ground) must intrude within 60% of the first Fresnel Zone.
Figure 6
illustrates the concept of a good radio line of sight.
Figure 6 Line of Sight
If there are obstacles in the radio path, there may still be a radio link but the quality and strength of the
signal will be affected. Calculating the maximum clearance from objects on a path is important as it directly
affects the decision on antenna placement and height. It is especially critical for long-distance links, where
the radio signal could easily be lost.
signal will be affected. Calculating the maximum clearance from objects on a path is important as it directly
affects the decision on antenna placement and height. It is especially critical for long-distance links, where
the radio signal could easily be lost.
When planning the radio path for a wireless bridge or mesh link, consider these factors:
Avoid any partial line of sight between the antennas
Be cautious of trees or other foliage that may be near the path, or may grow and obstruct the path.
Be sure there is enough clearance from buildings and that no building construction may eventually block
the path.
the path.
For very long distance links, the curvature of the earth (20 cm per km) may need to be considered in the
calculation of relative heights.
calculation of relative heights.
Check the topology of the land between the antennas using topographical maps, aerial photos, or even
satellite image data (software packages are available that may include this information for your area)
satellite image data (software packages are available that may include this information for your area)
Avoid a path that may incur temporary blockage due to the movement of cars, trains, or aircraft.
!
Never construct a radio mast, pole, or tower near overhead power lines.
Local regulations may limit or prevent construction of a high radio mast or tower. If your wireless bridge or mesh link
requires a high radio mast or tower, consult a professional contractor for advice.