Assembly Instructions Chapter 3

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4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures

837B, Rev. 0 3-1

Chapter 3

Installation and Setup Procedures

There are special considerations that

need to be taken into account before the

837B 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 consists of three cabinet

assemblies, the Exciter Cabinet Assembly

and two Amplifier Array Assemblies. The

Exciter Cabinet Assembly requires an AC

Input of 208/240 VAC, Single Phase with

a rating of 20 Amps. Each of the

Amplifier Array Assemblies requires an

AC Input of 208/240 VAC, three Phase

with a rating of 55 Amps or Single Phase

with a rating of 100 Amps. Check that

the site has the voltage requirement

needed.

The 837B 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 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 tray in the translator 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 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 and blowers designed and built

into the translator will remove the heat

from within the trays, 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. The following example is

for a 5000 Watt Transmitter. The heat

can be determined by subtracting the

average power to the antenna (3225

watts) from the AC input power (20,000

watts). This number in watts (16,775) is

then multiplied by 3.41, which gives

57,202.75, the BTUs to be removed

every hour. 12,000 BTUs per hour equals

one ton; as a result, a 5-ton air

conditioner will cool a 5-kW transmitter.

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

Summary of content (10 pages)

PAGE 1
4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures Chapter 3 Installation and Setup Procedures There are special considerations that need to be taken into account before the 837B 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. excessive humidity.
PAGE 2
4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures 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. conditioned room temperature under 80° F, the unit must be derated, possibly by a substantial amount. Now that the amount of heat that must be removed is known, the next step is to determine how to accomplish this.
PAGE 3
4-6 kW UHF Translator galvanized (acceptable). 4. 5. hardware Chapter 3, Installation and Setup Procedures cloth Cooling air should enter the room as low as practical but in no case higher than four feet above the floor. The inlet must be located where dirt, leaves, snow, etc., will not be carried in with the cooling air. The exhaust should be located as high as possible. Some ducting is usually required to insure the complete flushing of heated air with no stagnant areas. 6.
PAGE 4
-6 kW UHF Translator Chapter 3, Installation and Setup Procedures A 1 kW typical layout for a combination of air conditioning and ventilation is shown in Figure 3-1. As with any equipment installation, it is always good practice to consult the manufacturer when questions arise. Axcera can be contacted at (724) 8738100 System interlocking and thermostat settings should be reviewed with Axcera. Figure 3-1. 1 kW Minimum Ventilation Configuration 3.
PAGE 5
4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures Cabinet and the A3 Side B Amplifier Cabinet. The Amplifier Arrays may have an (Optional) External Exhaust Kit for connection to duct work and the outside of the building. The UHF Amplifier Trays are labeled to indicate where they are positioned in the Side A or the Side B Amplifier Cabinets. They are mounted in each Cabinet from bottom left to top right, with A1 the bottom left Tray and A6 the top right Tray.
PAGE 6
4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures Figure 3-2. Chassis Trak Cabinet Slides 3.3 Installing the Cabinets and Trays There are three AC Input circuits to the Translator, one 208/240 VAC single phase 20 Amp for the Exciter Cabinet and two 208/240 VAC 55 Amp three phase or 100 Amp single phase for each of the Amplifier Array Cabinets. Caution: Each UHF amplifier tray has a hardline coaxial cable connected to the rear panel.
PAGE 7
4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures Assembly (1278-1100), located near the center right hand side, rear portion of Cabinet #2. Connect Line 1 to TB1-1A, Line 2 to TB1-2A, Line 3 to TB1-3A and Safety Ground to TB1-4A. Line 2 to TB1-3A and Safety Ground to TB1-4A.
PAGE 8
4-6 kW UHF Translator Chapter 3, Installation and Setup Procedures Figure 3-3 Typical Rigid Coax Reconnection Drawing 3.4 Setup and Operation Initially, the translator should be turned on with the RF output at J2 of (A11) the coupler assembly terminated into a dummy load of 4 to 6 kW, depending on output power of your system. If a load is not available, check that the output of the coupler assembly is connected to the antenna.
PAGE 9
4-6 kW UHF Translator Automatic. Automatic operation of the Exciter uses the Video Input to the Exciter as an Operate/Standby Switch. In Auto, if the Input Video is lost, the Exciter automatically reverts the Translator to Standby and when the Video Signal is restored, the Exciter will automatically return the Translator to Operate. Move the Operate/Standby switch on the UHF exciter tray to Operate. Observe the power supply reading, >+30 VDC(+32 VDC), on the front panel of the UHF amplifier trays.
PAGE 10
4-6 kW UHF Translator If the Translator is already connected to the Antenna, check that the Combined Output is 100%. If needed, adjust the Power Adjust Pot located on the UHF Exciter for 100% in the Combined Output position. This completes the translator setup and operation procedures for the 837B UHF 837B, Rev. 0 Chapter 3, Installation and Setup Procedures solid state translator. The translator can now be operated normally.