UBS Axcera 420A Low Power Television User Manual

UBS-Axcera Low Power Television Table of contents

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Chapter 3

100 Watt High Band VHF Transmitter            Chapter 3, Installation and Setup Procedures420A, Rev. 0 3-1Chapter 3Installation and Setup ProceduresThere are special considerations thatneed to be taken into account before the420A transmitter can be installed. Forexample, if the installation is completedduring cool weather, a heat-relatedproblem may not surface for manymonths, suddenly appearing during theheat of summer. This section providesinformation that will assist in planning forthe installation and set up of thetransmitter.3.1 Site ConsiderationsThe transmitter requires an AC input lineof 115 or 230 VAC with a rating of 10amps. Make sure that the proposed sitefor the transmitter has the voltagerequirements that are needed.The 420A is designed and built to providelong life with a minimum of maintenance.The environment in which it is placed isimportant and certain precautions mustbe taken. The three greatest dangers tothe transmitter are heat, dirt, andmoisture. Heat is usually the greatestproblem, followed by dirt, and thenmoisture. Overtemperature can causeheat-related problems such as thermalrunaway and component failure. Eachamplifier tray in the transmitter containsa thermal interlock protection circuit thatwill shut down that tray until thetemperature drops to an acceptable level.A suitable environment for thetransmitter can enhance its overallperformance and reliability and maximizerevenues by minimizing down time. Aproperly designed facility will have anadequate supply of cool, clean air, free ofairborne particulates of any kind, andwithout excessive humidity. An idealenvironment requires temperatures inthe range of 40° F to 70° F  throughoutthe year, reasonably low humidity, and adust-free room. It should be noted thatthis is rarely if ever attainable in the realworld. However, the closer yourenvironment is to this design, the greaterthe operating capacity of the transmitter.Although the fans and blowers designedand built into the transmitter will removethe heat from within the cabinet,additional means are required forremoving heat from the building. Toachieve this, a few considerations shouldbe taken into account. The first step is todetermine the amount of heat to beremoved. There are generally threesources of heat that must be considered.The first and most obvious is the heatfrom the 100-watt transmitter itself. Thiscan be determined by subtracting theaverage power to the antenna (69.5watts) from the input power (750 watts).This number in watts (680.5) is thenmultiplied by 3.41, which gives 2320, theBTUs to be removed every hour.The second source of heat is otherequipment in the same room. Thisnumber is calculated in the same way asthe equation for BTUs. The third sourceof heat is equally obvious but not assimple to calculate. This is the heatcoming through the walls, roof, andwindows on a hot summer day. Unlessthe underside is exposed, the floor isusually not a problem. Determining thisnumber is usually best left up to aqualified HVAC technician. There are fartoo many variables to even estimate thisnumber without detailed drawings of thesite showing all construction details. Thesum of these three sources is the totalamount of heat that must be removed.There may be other sources of heat, suchas personnel, and all should be taken intoaccount.Now that the amount of heat that mustbe removed is known, the next step is todetermine how to accomplish this. The
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Document ID80250
Application ID4c+HKm7jMl4rg9yoqQg3Tw==
Document DescriptionChapter 3
Short Term ConfidentialNo
Permanent ConfidentialNo
SupercedeNo
Document TypeUser Manual
Display FormatMicrosoft Word - pdf
Filesize20.68kB (258561 bits)
Date Submitted2000-01-10 00:00:00
Date Available2000-04-03 00:00:00
Creation Date2001-05-03 07:55:08
Producing SoftwareAcrobat Distiller 4.0 for Windows
Document Lastmod2001-05-03 07:55:09
Document TitleChapter 3
FCC ID Filing: OUS420A

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