E.F. Johnson Company 242-20X1-213 Manual Download Page 25

Page: 25 / 198

2-1

August 2000

Part No. 001-2001-200

INSTALLATION

SECTION 2 INSTALLATION

2.1 INTRODUCTION

Information in this section tells how to set up the

repeater for operation in an LTR system. It is assumed
that the repeater has been previously aligned at the
factory or as described in the alignment procedure in
Section 7.

Even though each repeater is thoroughly aligned

and tested at the factory, it is good practice to check
performance before it is placed in service. This
ensures that no damage occurred during shipment and
that the repeater is otherwise operating properly. Per-
formance testing is described in Sections 7.1, 7.2, 7.3
and 7.4.

2.1.1 SITE PREPARATION AND ANTENNA IN-

STALLATION

Site preparation and antenna installation are not

within the scope of this manual. Basic installation
requirements are discussed in the "Dealer Guide To
Site Preparation", Part No. 004-8000-100. Factory
installation is also available. Contact your Johnson
representative for more information.

2.2 ENVIRONMENT

The following conditions should be considered

when selecting a site for the Repeater.

Operating Temperature.

-30

C to +60

C (-22

F to +140

F).

Humidity.

Less than 95% non-condensing relative humidity

at 50

Air Quality.

For equipment operating in a controlled environ-

ment with the Repeaters rack mounted, the airborne
particles must not exceed 30

g/m

For equipment operating in an uncontrolled envi-

ronment with the Repeaters rack mounted, the air-
borne particles must not exceed 100

g/m

NOTE: If the Repeater is installed in an area that
exceeds these environmental conditions, the site
should be equipped with air filters to remove dust and
dirt that could cause the equipment to overheat.

When the repeaters are installed in an environ-

ment that contains small airborne particles, e.g. grain
dust or salt fog, the repeater cabinets need to be
sealed. A heat exchanger, i.e. air conditioner, is then
required to cool the cabinets. The air conditioners
must be suited for the environment. Each repeater
(110W) requires >2400 BTU/hr dissipation to main-
tain exterior cabinet temperature.

2.3 VENTILATION

The RF modules and the power supply are

equipped with fans, controlled by thermostats, that
force air through the equipment for cooling. The air
flow is from the front to the back of the equipment.
This permits the Repeaters to be stacked or rack
mounted (see Figure 2-4). There are a few consider-
ations when installing Repeaters to provide adequate
air circulation.

1. The Repeaters should be mounted with a minimum

of 6 inches clearance between the front or back of
the cabinet for air flow. The power supply requires
a minimum of 18 inches at the back of the Repeater
for removal.

NOTE: Repeaters should not touch. Leave a mini-
mum of one empty screw hole (approximately 1/2")
between repeaters vertically especially for bottom
ventilation slots in high power repeaters.

2. Cabinet enclosures must provide air vents for ade-

quate air circulation.

3. Temperature and humidity must be considered

when several Repeaters are installed at a site. This
might require air conditioning the site.