Glenayre Tsunami series, Installation And Maintenance Manual

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I N S T A L L A T I O N A N D M A I N T E N A N C E M A N U A L
T s u n a m i F A M I L Y
F A S T E T H E R N E T W I R E L E S S B R I D G E S
J U N E 1 9 9 9
SECTION 3: INSTALLATION & ADJUSTMENTS PAGE 3-7
3.3.5 Availability Calculation
Availability of the microwave path is a measure of the percent of the time that the link will operate
without producing an excessive BER due to multipath fading. In the absence of direct interference,
availability is affected by the following:
- Path length
- Fade margin
- Frequency (5.3 or 5.8 GHz in the case of these Tsunami radios)
- Terrain (smooth, average, mountainous)
- Climate (dry, temperate, hot/humid)
Depending on the type of traffic carried over the link, the system designer may wish to design for
a specific availability. For example, if the data or voice traffic that is carried by the radio is critical
then it may be designed for a very high availability (e.g. 99.999% or 5.3 minutes of outage per
year). To improve availability, for example, the fade margin can be increased by making the path
shorter, or by using higher gain antennas in conjunction with lower loss feeders (by using high
quality transmission line or shortening feed length).