User's Manual

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User Manual

Page 1 of 8

1. GENERAL DESCRIPTION

1.1. INTRODUCTION

This manual contains installation and operating information for the Crescend High Power VHF

Power Amplifier. The manual is organized into three sections as follows:

Section 1. General Description

Section 2. Installation

Section 3. Operating Information

1.2. PRODUCT DESCRIPTION

The Crescend Technologies High Power VHF RF power amplifier is designed for paging and

other VHF applications that use a single carrier constant envelope waveform. The amplifier is

designed to be powered from a 48 VDC source, but optionally incorporates an internal AC power

supply. The amplifier covers a 150-174 MHz without retuning. Amplifier specifications are shown

in Table 1-1. There are four input ranges available as shown in Table 1-2. Closed loop power

control is used to maintain a constant output power under varying voltage, signal input level,

frequency and output load conditions. Several design features work to protect the amplifier under

adverse conditions.

The amplifier is designed to fit into 5.25 inches (3RU) of vertical 19 inch rack space. The front

panel includes LED indicators for monitoring status and alarm conditions. This information is also

accessible via a monitor connector on the rear of the amplifier. The fan assembly draws ambient

air in from the front and blows the air across the heat sink fins out the back of the amplifier.

• Notice: The manufacturer’s rated output power of this equipment (see Table 1-1) is specified

for single carrier operation using constant-envelope modulation. This equipment is NOT

designed for multiple-carrier operation, nor is it intended to be used with non-constant envelope

modulation types.

Table 1-1. Amplifier Specifications

Specification Value

Instantaneous Bandwidth 150-174MHz

Output Power 350W

Input Impedance

50Ω

Output Impedance

50Ω

Table 1-2. Amplifier Input Power Ranges

Input Power Designator Code Input Power Range

Nominal Gain (350W Output)

5 5-10 W

18.5dB

10 10-20 W

15.5dB

20 20-50 W

12.4dB

50 50-100 W

8.5dB

Summary of content (8 pages)

PAGE 1
User Manual 1. GENERAL DESCRIPTION 1.1. INTRODUCTION This manual contains installation and operating information for the Crescend High Power VHF Power Amplifier. The manual is organized into three sections as follows: Section 1. General Description Section 2. Installation Section 3. Operating Information 1.2. PRODUCT DESCRIPTION The Crescend Technologies High Power VHF RF power amplifier is designed for paging and other VHF applications that use a single carrier constant envelope waveform.
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User Manual 2. INSTALLATION 2.1 INSTALLATION INSTRUCTIONS The amplifier is designed for installation in a rack that permits access to the rear of the rack for connection of DC power, RF, and monitor/control cables. The amplifier must have a minimum of 3 inches of open space in front and to the rear of the chassis to allow adequate air flow and ventilation. To install the amplifier proceed as follows: 1. Mount the amplifier in equipment rack and secure in place. 2.
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User Manual 2. Apply 48 VDC from your power supply or AC mains power (depending on whether amplifier has optional power supply) to the amplifier with the supplied line cord. The fans will power on. Check that all four fans are running. 3. Visually check the indicators on the front of the amplifier and verify the following: a. The PWR ON indicator (green) is on. b. All other LED indicators (red and yellow) are off. 4.
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User Manual 3. OPERATING INFORMATION 3.1 INTRODUCTION This section contains general amplifier operating information 3.2 STATUS INDICATORS AND MONITOR CONNECTOR The amplifier status indicators and alarms are described in Tables 3-1 and 3-2. Table 3-1. High Power VHF Amplifier Status LED Indicators STATUS LED PWR ON FUNCTION Green LED. Illumination indicates unit is on EXCITER DRIVE Green LED. Illumination indicates RF input power has been applied HIGH TEMP Red LED.
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User Manual Table 3-2. Monitor Connector Description PIN NO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 NAME POWER CTL LOW PWR HI INPUT REV PWR GND FORM C (NC) FORM C (COM) FORM C (NO) RF DRIVE HI TEMP HI VSWR FWD PWR GND GND N.C.
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User Manual 3.3 RF ENERGY EXPOSURE AWARENESS, CONTROL INFORMATION, and OPERATIONAL INSTRUCTIONS for COMPLIANCE with FCC RF EXPOSURE LIMITS NOTICE: This power amplifier product is intended for use in environments in which personnel have full knowledge of their exposure and can exercise control over their exposure to meet FCC limits. This power amplifier is NOT authorized for use by the general population, consumer, or for use under conditions where unintended or accidental exposure may occur.
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User Manual 2) The licensee must undertake the responsibility to manage the site in accordance with the applicable regulatory requirements. This may include, but is not limited to, providing advisory notices to all personnel who may be exposed to RF energy in the vicinity of the antenna, restricting access to areas adjacent to the antenna, or ceasing use of the power amplifier when RF energy exposure safety cannot be guaranteed.
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User Manual 3) In instances where the effective antenna gain (antenna gain – feedline loss) differs from the example above, the MPE radius must be calculated by the licensee. The table below presents the results of calculations of the MPE radius for a 350 Watt VHF transmitter having various effective antenna gain values. Effective Antenna Gain (dBi) 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 • Minimum Safe Distance (meters) 5.27 5.92 6.64 7.45 8.35 9.37 10.52 11.80 Minimum Safe Distance (feet) 17.29 19.42 21.