Assembly Instructions Chapter 3

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3-kW UHF Transmitter Chapter 3, Installation and Setup Procedures

835-3, Rev. 0 3-1

Chapter 3

Installation and Setup Procedures

There are special considerations that need to be taken into account before the 835-3

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 835-3 transmitter requires two main AC input lines, a 3-phase 208/240 VAC, 60 Hz

input of at least 100 amp rating that connects to the amplifier cabinet assembly and a

single-phase 208/240 VAC, 60 Hz input of at least 40 amp rating that connects to the

exciter/driver assembly. Make sure that the proposed site has the necessary voltage

requirements.

The 835-3 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 and blowers 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. To achieve this, a few considerations should be taken into account. The first

step is to determine the amount of heat to be removed. There are generally three

sources of heat that must be considered. The first and most obvious is the heat from the

transmitter itself. This can be determined by subtracting the average power to the

antenna (2100 watts) from the AC input power (10,000 watts). This number in watts

(15,900) is then multiplied by 3.41, which gives 54,200, the BTUs to be removed every

hour. 12,000 BTUs per hour equals one ton, so a 5-ton air conditioner will cool a 3-kW

transmitter that is vented into the room. If the air exhaust will be vented externally, a

1-ton air conditioner will be needed to properly cool the 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

detailed drawings of the site showing all construction details. The sum of these three

Summary of content (7 pages)

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3-kW UHF Transmitter 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 835-3 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.
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3-kW UHF Transmitter Chapter 3, Installation and Setup Procedures sources is the total amount of heat that must be removed. There may be other sources of heat, such as personnel, and all should be taken into account. Now that the amount of heat that must be removed is known, the next step is to determine how to accomplish this. The options are air conditioning, ventilation, or a combination of the two.
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-kW UHF Transmitter Chapter 3, Installation and Setup Procedures 3. The inlet and outlet vents should be screened with 1/8" hardware cloth (preferred) or galvanized hardware cloth (acceptable). 4. 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. 5. The exhaust should be located as high as possible.
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3-kW UHF Transmitter Chapter 3, Installation and Setup Procedures and may need to be modified for unusually severe conditions. A combination of air conditioning and ventilation should not be difficult to design. System interlocking and thermostat settings should be reviewed with ADC. As with any equipment installation, it is always good practice to consult the manufacturer when questions arise. ADC can be contacted at (724) 941-1500. 3.
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3-kW UHF Transmitter Chapter 3, Installation and Setup Procedures coaxial cables with BNC connectors on both ends. Connect these cables from the (A9A1) splitter to RF input jack J1 on each 600-watt amplifier tray. Also in the installation material, should be six equal lengths of ½-inch superflex cable with N connectors on each end. Connect the cables from the output of each amplifier tray at J2 to the 6-way combiner. Connect the D connector jacks to J3 and J4 on the rear of each 600-watt amplifier tray.
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3-kW UHF Transmitter Chapter 3, Installation and Setup Procedures 3.5 Operation and Setup Procedures Initially, the transmitter should be turned on with the RF output at J2 of (A11) the output coupler assembly terminated into a dummy load of at least 3000 watts. If a load is not available, check that the output of the coupler assembly is connected to the antenna.
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3-kW UHF Transmitter Chapter 3, Installation and Setup Procedures This completes the transmitter setup and operation procedure for the 835-3 3-kW UHF transmitter. The transmitter can now be operated normally. 835-3, Rev.