Installation guide

Determining Range and Clearance Tsunami MP.11 Antenna Installation Guide

Calculations

Availability of the microwave path is a prediction of the percent of time that the link operates. In the absence of direct

interference, availability is affected by the following:

• Path length

• Fade margin

• Frequency

• Terrain (smooth, average, mountainous)

• Climate (dry, temperate, humid)

Depending upon the type of information carried over the link and the overall network design redundancy, you may want to

design for a specific availability rate. For example, if the data or voice traffic carried by the radio is critical, the link can be

designed for a very high availability rate (for example, 99.999% or 5.3 minutes of predicted outage per year).

Availability can be improved by increasing the fade margin either by making the path shorter or by using the higher gain

antennas in conjunction with lower loss antenna cable (using a higher quality antenna cable, shortening the length, or

both).

Calculating Link Budget

Use the calculator provided on the Proxim Wireless Web site to calculate link budget. Use the following formula to

estimate the received signal level (RSL):

RSL (dBm) = P

out

- L

+ G

- L

where:

• P

out

is the transmitter output power (in dBm)

• L

is the total loss of all transmission elements between the antenna and the RF Unit on one side of the link (in dB)

• G

is the gain of the antenna on one side of the link (in dB)

• G

is the gain of the antenna on the opposite side of the link (in dB)

• L

is the total loss of all transmission elements between the antenna and the RF Unit on the opposite side of the link

(in dB)

• L

is the Path loss, defined by: Lp (dB) = 96.6 + 20 log

F + 20 log

where:

– F is the Frequency of the radio system in GHz (3.5 GHz)

– D is the Distance of the path in miles

NOTE: This formula is available on a calculation sheet provided by Proxim to generate an estimate of link distance and

reliability.

See the following figure for a visual representation of the elements of this equation.