XPost: rec.video.satellite.tvro, rec.answers 
 From: drlev@hotmail.com 
  
 Archive-name: Satellite-TV/TVRO/part2 
 Posting-Frequency: 15 Days 
 Disclaimer: Approval for *.answers is based on form, not content. 
  
 PART TWO - How do I get started assembling a home TVRO satellite 
 system? 
  
 * About how much might it cost to put a system together? 
  
 A home TVRO system once cost as much as $100,000 in 1980! Prices 
 have dropped substantially since then, of course; a "typical" 
 retail price home system (dish included) with professional 
 installation could cost from $1500-$2500 depending on the setup. 
 The good approach these days is to find a decent used system, as 
 many of these are around; many people will actually thank you for 
 "ridding them" of their "antiquated" TVRO system! TVRO systems 
 are NOT antiquated, of course. Reasonably priced used systems can 
 range from free to $250-$300 or so. 
  
 * Exactly what equipment do I need? 
  
 There are six basic components to a big dish system: the 
 satellite dish, the feed assembly, the low-noise block 
 downconverter (LNB), the positioner/controller, the cable, and 
 the receiver or IRD.  The first component is the satellite dish. 
 The satellite dish is unquestionably the most visible component 
 of a home satellite system, and can range from five feet upwards 
 to twelve feet or larger. The "average" size for a TVRO satellite 
 dish is ten feet, but can be smaller in stronger signal areas. 
 Most IRDs have a built in controller for moving the dish. Some 
 receivers require an separate controller, sometimes called a dish 
 mover, to control the position. 
  
 Satellite dishes are also made of a variety of materials. 
 Aluminum mesh dishes are the most common type, but solid aluminum 
 and fiberglass dishes are not unusual. Each type has its 
 advantages and disadvantages. Mesh dishes are usually less 
 expensive than solid dishes, and easier to transport from the 
 manufacturer and vendor to the installation site. Solid aluminum 
 and fiberglass dishes generally have one primary advantage over 
 mesh dishes. Although usually more expensive, solid dishes are 
 usually better for overall reception quality, particularly with 
 Ku-Band signals. Whatever type of satellite dish, a properly 
 peaked antenna with a dish of the appropriate size should have no 
 problem receiving both C-Band and Ku-Band signals. For locations 
 subject to extreme weather, such as hurricane-force winds, 
 extreme heat, or extremely heavy winter snow, Paraclipse made 
 specially designed satellite dishes (the Classic series) ranging 
 from 12 to 16 feet; these are quite pricey if you can find one, 
 however, ranging from around $1000 to a whopping $7000 for the 
 16-footer! 
  
 In terms of size, bigger is usually better for a TVRO system. 
 Satellite signal strengths are almost always stronger in the 
 center of the signal footprint, where an eight foot dish should 
 have no problem receiving both C-Band and Ku-Band signals. The 
 farther from the center of the footprint, the larger the size of 
 the dish needs to be for quality C-Band reception. A twelve foot 
 or larger dish may be needed in fringe areas such as Alaska, 
 Maine, south Florida, Hawaii, and remote areas in Canada. For 
 Ku-Band, size is much less critical and for Ku- Band only 
 systems, a dish as small as 30 *inches* may work. However, it is 
 usually not advantageous to have a Ku-Band only TVRO setup unless 
 it is a fixed installation for reception of a specialty 
 satellite, such as one with a large amount of international 
 programming, for example. 
  
 The second component is the feed assembly, which is where the 
 real antenna is located. The feed assembly is used to "funnel" 
 the satellite signal from the parabolic dish reflector to the 
 antenna probe, which relays the signal to the LNB antenna for 
 subsequent frequency conversion and amplification. 
  
 The term feedhorn is often used interchangeably with feed 
 assembly; this is not entirely accurate, as the feedhorn itself 
 is just part of the overall feed assembly. The scalar ring is 
 used for precision in focal point adjustment in conjunction with 
 the dish reflector. 
  
 Some feed assemblies are designed to mount two or more LNBs. Such 
 feeds come in two basic types, those that mount one LNB each for 
 each band, C and Ku, and those that mount one LNB for each 
 polarity, vertical and horizontal for most satellites aimed at 
 North America, or right hand and left hand circular for most of 
 those aimed elsewhere. Hybrid types provide some combination of 
 dual polarity and dual band. 
  
 Multi LNB feeds usually have a separate antenna probe for each 
 LNB. For dual band, polarity is controlled in the same manner as 
 done for a standard single LNB feed, usually with a servo motor 
 to mechanically move the antenna probe to match the desired 
 polarity. Dual polarity feeds (orthomode) have no moving parts, 
 and are used primarily in multi receiver installations to provide 
 all receivers simultaneous access to channels on both polarities, 
 something impossible with a servo actuated antenna probe. A 
 disadvantage to using an orthomode feed is that, without the fine 
 control of the servo motor, signals that deviate from true 
 horizontal or vertical polarity cannot be optimally received 
 unless the dish is fixed upon one satellite, and the feed 
 assembly adjusted accordingly. 
  
 Another type of feed, called an LNBF, is similar to that used on 
 the little DBS dishes. An LNBF integrates feed, antenna, and LNB 
 into a single electronically controlled unit. 
  
 The third component is the low-noise block downconverter, or LNB. 
 The LNB is the component that amplifies the very weak signal 
 reaching the antenna from the satellite 22,247 miles above the 
 equator, and converts the downlink frequencies to a lower block 
 of frequencies more suitable for transmission through the cable 
 to the receiver. The standard block of frequencies is 950-1450 
 MHz. Some early block downconversion systems used a 900-1400 or 
 lower block of frequencies, and receivers designed specially for 
 those frequencies. 
  
 Older systems used separate components for signal amplification 
 (low-noise amplifier, or LNA) and downconversion (block 
 downconverter). Really old systems didn't downconvert a frequency 
 block for transmission to the receiver, instead sending in only 
 one specific frequency requested by the receiver. 
  
 C-Band LNBs are rated in degrees Kelvin; Ku-Band LNBs are 
 measured in decibels (dB) instead of degrees Kelvin. For C-Band 
 LNBs, up to 30 degrees K is usually suggested, but this is simply 
 to maximize picture quality. For C-band and a large dish 
 reflector, anything up to 100 degrees is adequate for 99% of the 
 video signals out there, and should give equal or better results 
 to a sub 30 degree LNB on a smaller dish. Only for very weak 
  
 [continued in next message] 
  
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