User's Manual

3300-Watt VHF Low Band Transmitter Chapter 3, Installation and Setup Procedures
335B, Rev. 0 3-1
Chapter 3
Installation and Setup Procedures
There are special considerations that
need to be taken into account before the
335B 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 transmitter.
3.1 Site Considerations
The transmitter requires an AC input line
of 220 VAC with a rating of 50 amps that
connects to the transmitter cabinet.
Make sure that the proposed site for the
transmitter has the necessary voltage
requirements.
The 335B is designed and built to provide
long life with a minimum of maintenance.
The environment in which it is placed is
important and certain precautions must
be taken. The three greatest dangers to
the transmitter 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 tray in the transmitter contains
a thermal interlock protection circuit that
will shut down that tray until the
temperature drops to an acceptable level.
A suitable environment for the
transmitter can enhance the overall
performance and reliability of the
transmitter and maximize revenues by
minimizing down time. 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 transmitter.
The fans, designed and built into the
transmitter, will remove the heat from
within the trays, but additional means
are required for removing this heat from
the building.
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.