User's Manual

D044-13432 Rev A 1
Chapter 1
Theory of Operation
1 Introduction
This manual contains information and procedures for installation, operation, maintenance, and
troubleshooting of the LNKF100 Modules. The manual is organized into the following chapters:
Chapter 1 Theory of Operation Chapter 3 Antenna Installation
Chapter 2 Operation Chapter 4 Return for Service
1.1 Overview
A LinkNet FM Module is a radio repeater that simultaneously receives and transmits a single narrow
band radio channel. The normal application of a LinkNet FM Module is as an on-frequency repeater
where the input and output are on exactly the same frequency. It can also be used as a frequency
translating repeater where the input and output can be set to any frequency in the specified band (see
Table 1 for details).
The LinkNet FM Module accomplishes its repeater function without store and forward circuitry, or
expensive conventional simulcasting techniques. The fact that the same frequency can be
retransmitted by a LinkNet FM Module means that additional frequency allocations are not required in
situations where an existing radio coverage pattern needs to be extended. The most common LinkNet
FM Module applications are the extension of above ground signals into buildings, tunnels, vehicles or
the extension of radio coverage patterns into outdoor shaded areas such as deep valleys.
From an applications standpoint, a LinkNet FM Module is very similar to a regular two-way radio
repeater. LinkNet FM Modules can be combined using regular two-way radio multicoupling or
duplexing equipment and have input and output signal characteristics to those of regular transmitters
and receivers. The one special consideration in LinkNet FM Module systems is that of input to output
antenna isolation. This must be carefully engineered for each installation.
LinkNet FM Modules are designed for indoor use only and are intended for mounting in a standard EIA
19 inch rack. The Modular design of LinkNet FM Module circuitry allows for easy servicing, stocking of
spares, adaptability and upgrade ability.
1.2 Models
Table 1 LNKF100 Module Family
LNKF100 MODULE FAMILY
MODEL TYPE FREQUENCY
LNKF100-A1 25 KHz FM Channels 136-157 MHz (FM)
LNKF100-A2 12.5 KHz FM Channels 136-157 MHz (FM)
LNKF100-B1 25 KHz FM Channels 155-174 MHz (FM)
LNKF100-B2 12.5 KHz FM Channels 155-174 MHz (FM)