Info about Wireless Networks 3

3.0 Implementing a Wireless Link

3.1 Stages

Common stages for implementing a wireless network are:

Site survey
Link budget calculation/terrain modeling
Trial/implementation
Testing/commissioning

Some of the main issues to be considered are:

Data rate required
Link distances
Natural high points
Obstacles
Spectrum congestion
Cabling issues
Access

3.2 Radio Path Obstacles

Typically the biggest challenge in a radio link is achieving a good line of sight between the two antennas. Figure 7 shows the "no obstacle radius" for 2.4GHz and 5.8GHz at different distances.

Hills and vegetation are normally the biggest obstacles to achieving these sort of clearances. In practice, short 2.4GHz links will often work through small amounts of vegetation although packet loss frequently increases once the vegetation gets wet.

The best solutions for improving radio paths is normally to use higher towers or repeaters at midpoints.

pacsat image
Figure 7: No Obstacle Radius

3.3 Other Considerations

All masts, antennas and equipment must be solidly attached. Wind loading can create very high forces on exposed structures.

All RF joints need to be double taped with self-amalgamating tape and electrical tape.

Consider the need for lightning protection equipment/systems

Cables need to be taped/strapped to poles/towers

Ingress through roof structures walls must be waterproofed

Bed mast structures in silicone

Use outdoor rated cables

Set & test wireless gear in the office before deploying

Be methodical

Ask for advice if required

< return to 2.0 Choosing an Antenna
< return to 1.0 Introduction to Wireless Networks

top of page