Assembly Instructions Chapter 3

LX Series Power Amplifier Assembly Chapter 3, Site Considerations,
Installation and Setup Procedures
LX Series, Rev. 0 3-1
Chapter 3
Site Considerations, Installation and Setup Procedures
There are special considerations that
need to be taken into account before the
LX Series Power Amplifier Assembly and
exciter/driver assembly can be installed.
For example, if the installation is
completed during cool weather, a heat-
related problem may not surface for
many months, suddenly appearing during
the heat of summer. This section
provides planning information for the
installation and set up of the translator.
3.1 Site Considerations
The translator requires an AC input line
of 220 VAC @ 5 amps for the Driver
Assembly and an AC line for each 500
Watt Amplifier Assembly of 220 VAC @
17 amps maximum.
The LX Series Translators are designed
and built to provide long life with a
minimum of maintenance. The
environment in which they are placed is
important and certain precautions must
be taken. The three greatest dangers to
the translator are heat, dirt, and
moisture. Heat is usually the greatest
problem, followed by dirt, and then
moisture. Over-temperature can cause
heat-related problems such as thermal
runaway and component failure. Each
amplifier module in the translator
contains a thermal interlock protection
circuit that will shut down that module
until the temperature drops to an
acceptable level.
A suitable environment for the translator
can enhance the overall performance and
reliability of the translator and maximize
revenues by minimizing downtime. A
properly designed facility will have an
adequate supply of cool, clean air, free of
airborne particulates of any kind, and no
excessive humidity. An ideal environment
will require temperature in the range of
40° F to 70° F throughout the year,
reasonably low humidity, and a dust-free
room. It should be noted that this is
rarely if ever attainable in the real world.
However, the closer the environment is
to this design, the greater the operating
capacity of the translator.
The fans are designed and built into the
translator will remove the heat from
within the modules, but additional means
are required for removing this heat from
the building. To achieve this, a few issues
need to be resolved. The first step is to
determine the amount of heat to be
removed from the translator room. There
are generally three sources of heat that
must be considered. The first and most
obvious is the heat from the translator
itself. This amount can be determined for
a 100W translator by subtracting the
average power to the antenna (69.5
watts) from the AC input power (675
watts) and taking this number in watts
(605.5) and then multiplying it by 3.41.
This gives a result of 2,065, the BTUs to
be removed every hour. 12,000 BTUs per
hour equals one ton. Therefore, a 1/4-
ton air conditioner will cool a 100W
translator.
The second source of heat is other
equipment in the same room. This
number is calculated in the same way as
the equation for BTUs. The third source
of heat is equally obvious but not as
simple to calculate. This is the heat
coming through the walls, roof, and
windows on a hot summer day. Unless
the underside is exposed, the floor is
usually not a problem. Determining this
number is usually best left up to a
qualified HVAC technician. There are far
too many variables to even estimate this
number without reviewing the detailed
drawings of the site that show all of the
construction details. The sum of these
three sources is the bulk of the heat that
must be removed. There may be other
sources of heat, such as personnel, and
all should be taken into account.