2-1
May 2000
Part No. 001-2008-204
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% relative humidity at 50
°
C.
Air Quality.
For equipment operating in a controlled environ-
ment with the Repeaters rack mounted, the airborne
particles must not exceed 30
µ
g/m
3
.
For equipment operating in an uncontrolled envi-
ronment with the Repeaters rack mounted, the air-
borne particles must not exceed 100
µ
g/m
3
.
NOTE: If the Repeater is installed in an area that ex-
ceeds these environmental conditions, the site should
be equipped with air filters to remove dust and dirt that
could cause the equipment to overheat. The cabinets
and filters should be placed on a maintainence sched-
ule.
When the repeaters are installed in an environ-
ment that contains small airborn 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 low power
repeater (85W) requires >1200 BTU/hr dissipation to
maintain exterior cabinet temperature. Each high
power (160W or 175W) requires >2100 BTU/hr dissi-
pation to maintaim 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.
•
Cabinet enclosures must provide air vents for ade-
quate air circulation.
•
Temperature and humidity must be considered
when several Repeaters are installed at a site. This
might require air conditioning the site.
