Installation guide

Determining Range and Clearance Tsunami MP.11 Antenna Installation Guide

Determining the Outdoor Range

data frame due to an out-of-range situation or frame collision, the larger the number of retransmissions, the lower

the throughput efficiency of your wireless link.

This section explains how to determine the clearance that applies in your environment and (if applicable) the effect of

insufficient clearance on the range of your outdoor wireless link.

If any significant part of the antenna beam is obstructed, a portion of the radio energy is lost, which can affect the

performance of your wireless link in terms of maximum range and transmit rate.

In the figure above, you see two variables that determine the shape of the antenna beam, also referred to as Fresnel

Zone:

• The distance between the antennas (a)

• The clearance required for optimal performance (b), where clearance should be interpreted as:

– Vertical clearance above the ground and the highest buildings or objects in the signal path

– Horizontal clearance from neighboring buildings and objects in the signal path

For optimal range and throughput performance, you must ensure that your antenna installation provides maximum

clearance in both horizontal and vertical direction.

Clearance should be interpreted as follows:

• In open areas without obstacles in the signal path, clearance is measured as height above the surface of the earth.

For example, if the antenna is mounted on the roof, this height includes the height of the building plus the height of the

mast above the rooftop.

• In areas with obstacles in the signal path between the two antennas, clearance should be measured as height above

the highest obstacle in the signal path.

• In dense urban areas, the clearance should be measured as height above the highest rooftop or any other obstacles

in the signal path between the two antennas.

For situations in which local authorities, the proprietor of the premises, or other factors do not let you set up an antenna

mast that lets you meet the listed clearance requirements, you may be unable to achieve a full line-of-sight clearance. At

the same time, however, when the distance that your wireless outdoor installation must cover is less than the listed

maximum range, you may not need full clearance.

To determine the effect of insufficient signal path clearance, you must determine the Clearance Factor as described

below, and calculate its effect on the range for your antenna installation using the formula described in Determining the

Outdoor Range.

• If the clearance for your antenna installation is equal to or better than the minimum clearance requirement, the

Clearance Factor for your installation is 100%.

BSU