Das Installation Considerations; Antenna Requirements; Isolation; Isolation Measurement Techniques - ZinWave UNITIVITY 5000 User Manual

In-building wireless solution

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UNItivity 5000

DAS Installation Considerations

User Manual

7 DAS Installation Considerations

This chapter describes requirements and considerations to get the best performance from your DAS.

This section describes antennas that can be connected to Remote Units. For physical connection of

"Connecting Antennas to Remote

Units".

the antenna to the Remote Units see

The minimum isolation between Tx and Rx required for correct operation of UNItivity 5000 in both the

uplink and downlink service bands is usually 40dB (this requirement should be confirmed for any given

installation within the Zinwave Coverage Tool). However, performance (uplink noise and downlink inter-

mode interference) of the system can be improved if greater isolation is achieved. Isolation between

the antennas is achieved by separating them at a sufficient distance to achieve at least 40dB over the

antenna passband or the entire UNItivity 5000 passband, whichever is narrower.

It has been found empirically that omni-directional antennas supporting the Cellular bands from

700MHz and above require a horizontal separation distance of approximately 20 ft (6m).

Although this distance provides a rule of thumb for initial planning, the particular antennas in use and

the environment in which they are installed will affect the isolation. It is recommended to check and

measure the isolation of each antenna pair (see isolation measurement section below) prior to enabling

service operation.

With directional antennas care should also be taken to ensure the high-gain propagation direction is

oriented towards the coverage area and the low-gain ("null") propagation direction is oriented towards

the second antenna. The effect of this null will be to reduce the distance between the antennas required

to achieve the 40dB isolation.

The most accurate way of measuring the antenna isolation, is to disconnect the cables at the Remote

Unit antenna ports and connect these directly to either a network analyzer or a spectrum analyzer with

a tracking generator. Every antenna in the installation should meet the requirements of the Tx-Rx

Isolation section above. The Hub Software also includes an antenna isolation check feature (System

Maintenance > System Check), which should be used for quick isolation checks where problems are

suspected or may arise.

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