Proxim CPN 65756B manual Clearance Factor, Fresnel Zone

Tsunami MP.11a Antenna Installation Guide

Note: The allowed antenna cables depend upon local radio regulations, the frequency, and the antenna gain used as listed in Table 5 on page 24 “Minimum Antenna Cable Loss in 5 GHz Bands.”

Clearance Factor

For optimal performance of your outdoor wireless link, the signal path between the Base Station Unit and Subscriber Unit must provide sufficient clearance.

Note: A outdoor wireless link that lacks sufficient clearance will suffer from poor performance, which is typically perceived as slow network response times. Although your Tsunami MP.11a equipment automatically retransmits every lost 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.

In “Chapter 1. Preparing for Installation” on page 8, we described the shape of the antenna beam as being “bulged” in the middle.

Figure 5. Fresnel Zone

If any significant part of this bulged zone 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.

Chapter 2. Determining Range and Clearance	18
CPN 65756B	Issue Date: August 2003