Motorola RF Amplifier User Manual

STARLINE®

RF Amplifier
Quick Start Guide 498160-001

Motorola’s STARLINE RF amplifier series share many common features, functions and safety
precautions. This Quick Start Guide is intended to cover basic installation and operation
procedures common to all amplifiers. To obtain complete product documentation and compliance
information for your specific amplifier, go to http://www.motorola.com/broadband
HTML/Modem Version/Customer Support/Product Documentation/Manuals.

Before you begin to install your amplifier, verify the model number and confirm that it
accurately reflects the product configuration and options that you ordered.

CAUTION!

To avoid possible injury to personnel or damage to the equipment, remove 60/90 volt ac power from the system
before you install the amplifier.

and click

Document Conventions

Before you begin using the RF Amplifier Quick Start Guide, familiarize yourself with the
stylistic conventions used in this manual:

SMALL CAPS

* (asterisk)

(asterisk)

(asterisk)(asterisk)

Italic type

Denotes silk screening on the equipment, typically representing front- and rear-panel
controls and input/output (I/O) connections, and LEDs

Indicates that several versions of the same model number exist and the information applies
to all models; when the information applies to a specific model, the complete model number
is given

Denotes a displayed variable, or is used for emphasis

Installing the Housing

STARLINE amplifiers are mounted horizontally below the strand or on a pedestal. To reduce
the weight of the amplifier and prevent possible damage, it is recommended that you remove the
electronics chassis before you install the housing.

To install the amplifier on the strand, use the two strand clamp assemblies located on the long
side of the housing and torque to 10 to 12 ft-lbs.

To install the amplifier on a pedestal, use the bolts from the strand clamps and the two holes on
the bottom of the housing. Torque the bolts to 10 to 12 ft-lbs. The centerline distance between
the holes on the bottom of the housing is:

Amplifier Model Distance Between Hole Centers (inches)

BLE*/*

MB*/*, MBE*/*

BT*/*

4.0 vertical centerline

7.7 horizontal centerline

11.0 horizontal centerline

RF Amplifier Quick Start Guide

2 STARLINE

Installing the Coaxial Cables

Connections to the housing are made using standard KS-type housing port entry connectors.
Pin-type connectors with a nominal center conductor diameter of 0.067 inches are required. The
following table provides the center conductor pin length for the various amplifiers:

Amplifier models Pin length (inches)

BLE*/*, MB*/*,
BT*/*, MBE*/*

1.50 minimum to 1.65 maximum

Pin

length

Use a torque wrench or Phillips screwdriver to tighten the center conductor seizure screw to a
torque of 12 in-lbs.

Powering the Amplifier

For optimal operation, verify that the ac input from the feederline to the power supply is
between 38 and 90 Vac (rms) with a line frequency of 50 or 60 Hz. The waveshape of the input
voltage must be quasi-squarewave.

The power supply provides the additional feature of a two position (
the startup voltage of the power supply. The startup voltage is 38 Vac for the
55 Vac for the

HI position. All units are shipped with the selector set in the LO position. The LO

LO and HI) selector that sets

LO position and

position is used with 60 Vac systems where 38 Vac startup voltage is required. For systems
operating at 90 Vac, the selector can be in the

LO or HI position. Note that changing the selector

does not change the upper voltage limit but affects only the startup voltage. The voltage selector
should be switched only if the power supply approaches its maximum load rating.

There is no damage to the amplifier if the jumper is not changed. However, changing the jumper
ensures that the dc supply does not turn on until the proper input voltage level is reached —
either 38 Vac or 55 Vac. This prevents excessive loading of the system power supply during
turn-on after a system shutdown.

DANGER!

Voltages up to 90 Vac are accessible. To avoid a shock hazard, confirm that the STARLINE amplifier is not powered
before removing the cover or replacing the fuses.

To power the amplifier:

1 Set the power supply jumper for 90 Vac operation if required by your system.

2 Determine which fuses should be installed to route power to the appropriate ports.

3 Verify that the power supply output voltage is +24 Vdc.

RF Amplifier Quick Start Guide

STARLINE 3

Forward Path Alignment

The following subsections describe procedures required to obtain proper forward path
alignment.

Before You Begin

For proper forward path alignment obtain:

1 RF output levels and tilts of all amplifiers

2 RF input level for the amplifier being set up (from system design or as-built map)

3 A carrier at the system’s highest frequency. It can be modulated or continuous wave (CW)

and should be inserted in the headend at standard video levels. This carrier is used to
simplify field set up.

It is recommended that you:

1 Install the system design value SFE-*-* and a high value (20 dB or above) forward input pad

before you install or remove the electronics chassis or activate the system.

Leave the forward input pad location open if a high value pad is not available. A more
accurate forward input test point reading is achieved with a high value pad installed.

2 Do not use wire jumpers to bypass the SFE-*-* location.

3 Recognize that actual pad and SFE-*-* values may differ slightly from their design values.

This is caused by factors such as walkout errors, worst-case data utilization during design
and temperature variation from 70ºF.

4 Secure the electronics chassis in the housing and torque to 18 to 22 in-lbs to facilitate heat

transfer.

5 Perform a bench alignment. Pre-aligning the amplifier response on the bench for system

signature simplifies field alignment. (If the unit is bench aligned properly, only minor
adjustments may be necessary in the field.)

6 Field sweep the entire bandwidth of the amplifier in the field to correct frequency response

for passive signature and roll-off.

7 Close the housing in accordance with the instructions provided in the subsection Closing the

Housing at the end of this guide.

Manual Gain Control

To adjust manual gain control:

1 Verify that the electronics chassis is installed correctly.

2 Ensure that there is continuity in the forward path by installing the design value SFE-*-*

and design value input JXP-*B attenuator.

3 Ensure that the drive control select jumper is in the MAN position.

4 Use a signal-level meter to measure the high band-edge carrier-input-level at the input test

point: 750 MHz = channel 116, 870 MHz = channel 136. This carrier should be at standard
analog level, non-scrambled.

RF Amplifier Quick Start Guide