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SRU Installation

17286-1000 Rev. B 03/14/01

SRU Installation Manual

1-1

SRU Antenna Alignment

1.1

Introduction

This chapter gives instructions for aligning the SRU antennas to the BRU for maximum

signal strength.

Before alignment of the antenna, perform the following steps:

Refer to “SAS Installation Manual” and perform the indicated procedures. Most of the

principles used to locate a site for the Base Radio Unit can be applied to SRU

placement.

Install the Base Station as explained in “BSIS Installation Manual.”

Install one or more Subscriber terminals as explained in “SAS Installation Manual.”

Install the Link Explorer PMP and configure the Base Station as explained in “BSIS

Installation Manual.”

The direction in which the SRU antenna points must be aligned to the location of the

associated BRU to ensure that maximum received signal strength is achieved at both ends of

the microwave link. Although the antenna radiation pattern is typically thought of as a

“beam,” the radiation pattern actually consists of “lobes,” as shown in Figure 1-1. How you

planned your network will help identify which specific antenna is used in this ST and the

BRU for the link.

Summary of content (8 pages)

PAGE 1
SRU Installation 1. SRU Antenna Alignment 1.1 Introduction This chapter gives instructions for aligning the SRU antennas to the BRU for maximum signal strength. Before alignment of the antenna, perform the following steps: 1. Refer to “SAS Installation Manual” and perform the indicated procedures. Most of the principles used to locate a site for the Base Radio Unit can be applied to SRU placement. 2. Install the Base Station as explained in “BSIS Installation Manual.” 3.
PAGE 2
SRU Installation Figure 1-1Antenna Pattern 1.2 SRU Alignment This chapter contains information about SRU alignment. 1.2.1 Preparation and Overview of Procedure It is recommended that a person be present at both the SRU and the associated BRU for this antenna alignment procedure. It is also advisable to have some form of communication between the two sites, such as cell phones, two-way radios or telephones.
PAGE 3
SRU Installation the SRU is drastically out of alignment. Re-align the SRU visually and wait for it to readmit. If the reading is between 0 Volts and 4 Volts, then the SAS has admitted. Tighten the lock nut/washers to eliminate most freeplay, but not so tight that you can’t move the SRU in both directions. During the rough alignment procedure (see below) the purpose is to align the SRU visually, both elevation and azimuth.
PAGE 4
SRU Installation Figure 1-3 Incorrect Antenna Alignment on a Sidelobe Typically, if your final receive signal level (RSL) is approximately 30 dB below the calculated value, the link is either aligned on a side lobe or the antenna polarizations are mismatched. 1.2.2 Alignment of SRU Before proceeding, verify that the antenna and mount have been properly assembled. Verify that both ends of the link are powered-up. 1.2.2.
PAGE 5
SRU Installation Azimuth Adjustment Lock Nut/Washer Elevation Adjustment Lock Nut/Washer x(2) NTR98-62 Figure 1-4 26 GHz and 39 GHz SRU Elevation and Azimuth Adjustments Azimuth Adjustment Lock Nut/Washer NTR98-1023 Figure 1-5 10 GHz SRU Azimuth Adjustment Lock Nut/Washer 17286-1000 Rev.
PAGE 6
SRU Installation Elevation Adjustment Lock Nut/Washer NTR98-1024 Figure 1-6 10 GHz SRU Elevation Adjustment Lock Nut/Washer 1.2.2.2 Elevation Procedure Make rough elevation adjustment using the same technique used for adjusting azimuth. Move the antenna up or down until it points directly at the BRU. Use a mirror or strobe light to make the opposite end more visible. Tighten the elevation adjustment nuts when complete. 1.2.
PAGE 7
SRU Installation 1.2.4 Final Alignment After completion of the initial alignment procedure, begin to further align the antenna. This alignment is accomplished by adjusting the elevation and azimuth while observing the Receive Signal Level (RSL). This adjustment procedure involves panning the antennas in order to zero-in on the maximum receive signal, as indicated on a voltmeter, thereby properly aligning the main lobe of the microwave radiation pattern.
PAGE 8
SRU Installation 1-8 SRU Installation Manual 17286-1000 Rev.