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Channel tuning data definition:
Receiver: With nowadays technology, the price of satellite receiver is down the earth price. Many makes of low-end receivers has surpassed the value you are paying. The digital receiver, in fact, is a specialized computer with built in
The high-end receiver called PVR, personal video recorder has built in hard drive can allow you record and playback later. Our experience found that different makes of receivers has different quality. Below are some tips to select your receiver.
The larger the dish, the stronger is the signal you could receive, that is, the less intermittent is the picture. However, the risk of wind disturbance, cost, and space is proportionally higher. There are two bands of microwave signal normally used for TV. C band is the older generation; it requires a huge dish. Ku band is the modern generation, requires a smaller dish. Many pay TV provide you strong signal by aiming at a smaller coverage area, such that a smaller fixed position dish is good enough. For FTA signal, because of broadcaster is aiming at larger coverage area, so you must use a bigger dish than those pay TV. You might found that not all stations on the same satellite are equal. Different transponder on same satellite can give different signal quality. It is very depending on how much power that transponder is transmitting and which coverage area it is pointing to. Satellite is using solar energy. Power is precious in space. Depending on how far you are away from the equator. We recommend 39” or 100cm dishes. This is the biggest dish size, which can be driven by a standard sized rotor. For northern or southern territory, you might need even bigger dish. The actual size of the dish is very often exaggerated. Many dishes are oval shaped. The dimension given is based on the longest measurement. A round dish with same size rating of oval shape dish has more area. Some manufacturers use the curvature as measurement. The size claim could be boasted by three inches. We found that every 3 inches increment gives significant improvement on performance. Same size dishes made by different manufacturer can give observable differences on reception because of the real size is different. Do not trust the dimension claimed by manufacturer. You must compare it with your own measurement. The atmosphere can attenuate
signal. The shortest route of air traveled is directly under the equator. When
you are away from the equator, the signal has to travel a thicker air. When the
satellite is located at the same longitude with you, it has the shortest air
path to your site. When you point your dish to another satellite, which is
further away from your longitude, your air path is longer. The signal
attenuation is proportional to the air path. Cloud, rain, and snow can weaken
your signal. Wind can cause temporary off alignment of dish. The dish is never
too big. You could receive the signal well on new installation. Your dish could
be off aligning after some severe weather. This is especially troublesome on
small dish because it is touchy on alignment. Our experience shows that weather
is not a major factor of poor reception. Dish size plays a more important role. Besides the dish, you need a good
rotor if you want to receive multiple satellites, unless you want to install
several dishes. Some rotor has a weak motor. You might have to push it to get
moving. USALS compliance is a good feature to select. Theoretically is supposed to use two motors to control the dish. One
motor rotate horizontally, and the other vertically. Since the vertical rotation
always follows a fixed geometrical pattern. By using a tilted shaft rotor, we
can eliminate the vertical motor. Survey: All geostationary satellites were installed at a high altitude of 35,800Km above the equator. On northern hemisphere, we must point the dish toward south ±70°. On southern hemisphere, it is just the opposite way. At equator, you have to point the dish upward. At northern or southern hemisphere, depending how far you are away from the equator, you have to point the dish at an elevation angle. Before installation, you have to find out the longitude and latitude of the installation site. Below website could help you to locate your co-ordinates. http://www.multimap.com/map/home.cgi?client=public&overviewmap=ap. You could also use a GPS. On the chart http://www.lyngsat.com,
find a satellite, which is closest to your longitude as reference to true south.
For example, if you are at 79.6 °W
longitude. The closest satellite is AMC-5 at 79°W.
From the calculator below http://www.ses-americom.com/tools/lookangle/index.html,
enter the data and calculate your azimuth and elevation. In this case, the
azimuth calculated is 179.1°W,
and elevation is 39.7°. If the
satellite has the same longitude of your site, then, your azimuth should be 180°W,
that is the true south. Select a rigid sport which has a clear vision to south ±70°, with the height as high as possible. No trees or objects in front.
Most rooftop is using very thin wood; your dish could off align or even blow
away if not properly reinforced. You can use concrete patio slab as support. Blowing wind on the dish can give extreme load on the rotor.
Occasionally the rotor can fail to rotate to the predetermined position. You can
switch to a near by satellite and then come back. It is wise to install your
dish on a wall facing south, because you can use the wall as shelter. In
Northern hemisphere, wind is often blowing from Northwest. Mounting on rooftop
and chimney has nuisance wind disturbance. Your dish should be mounted as high
as possible. Mounting on ground level is for sure has blockage to reach remote
satellite, because the elevation angle on such satellites could be as low as
near zero degree. Rigid dish support is important. Your dish has to be aligned within ±0.1°. Off alignment of ±0.5° can severely weaken the signal. Strong wind can cause intermittent signal. The pole has to be absolutely vertical. Non-vertical pole can make some satellite off align while the others are on target. The weight of the dish itself can also give tolerance. Electric drill concrete drill bits, spanner, and ladder. Level. Use this tool to align vertical pole. Compass. Compass can read roughly the azimuth. It can give you severe error on placing near a dish. It is not needed if you know the direction. The final fine adjustment is done on field strength meter. Rope. Use it to hoist up the dish.
Use the dish support as hoist. The dish is bulky and heavy. Pre-assemble the
dish before installation. Do not attempt to carry it on a ladder; you could lose
your balance and fall. Portable TV or professional satellite finder. Amateur satellite finder cannot identify the satellite. It won’t help even you found one of them. Portable TV is the best and cheapest choice. Most receivers have built in satellite search feature and field strength meter. It can out perform professional satellite finder. Make measurement on highest side of wall. Make sure your disk would not
hit the trough. Dill holes to mount the wall mount. Use a small carbide drill
bit to make one hole first. Then enlarge the hole to the correct size. Mount the
bracket with one screw. Use a chisel to punch a small hole to guide the drill.
Drill the rest of the holes. The holes have to be precisely drilled. If you do
not follow this procedure, there is a chance of off alignment. You might have
damaged the wall. There are two adjustments on elevation angle. One variable adjustment is
on the dish. The other fixed setting is provided on the rotor. If you do not
intend to receive multiple satellites with motorized dish, you can simplify the
installation. Get the latitude of your site and set it on your rotor and fix it
permanently. Install your dish; with lose elevation and azimuth alignment
screws. Attach receiver and portable TV near the dish. Before doing alignment, set your receiver to installation mode. Entry data such as satellite’s name, longitude of satellite, transponder frequency, symbol rate, your own longitude, and latitude. Make sure the initial transponder frequency is valid. Otherwise, you can never detect the signal. On the control program, rotate your rotor to the azimuth of target satellite, in this example case, is 179.1°W. Point your dish approximately to that direction. Rotate your dish up and down by hand until you observed some signal. If you cannot find any, rotate the azimuth by half degree and repeat again and again until you find the satellite. Do a channel search to verify your Satellite. Select the weakest transponder on a remote satellite. Peak the signal. Tighten alignment screws. A strong signal would give more room for off alignment. Do not use a strong signal to peak. Some satellites are installed on a higher orbit by 1 Km. The USALS calculated azimuth could be off by a fraction of a degree. You can deviate the longitude setting to compensate the error. Adjust focus by pushing LNB in and out. Peak the signal again. Switch to another satellite and check for signal strength, and do channel search again. If your dish is properly aligned to true south or north, you can switch satellites and still under precise alignment. When microwave enter the
atmosphere, it has similar optical property to light passing through glass. The
signal trail could be deflected by a small angle. This tolerance is noticeable
on bad weather, and could vary day by day. As we have mentioned, the digital
receiver is in fact a computer. It inherits all the flaws of a computer. For
example, it could crash or hung as a computer does. It requires time to boot up
and tune into a station. If you are experiencing a freeze, just unplug and
reboot. Turning off and on won’t help, because this computer is not really
shutdown. Occasionally, you are unable to tune to a station, because of the
computer cannot process the signal correctly. You can tune to another station of
the same satellite and go back and forth to wake it. One advantage of digital TV
is it does not give snowy picture on weak signal as analogue TV does. You can
always get a clear picture even on low signal. But it gives jerk and squares. On
sudden lost of signal. The picture will remain there as a stable image. The
clarity of picture depends on the symbol rate of the station. In other words, it
is the bandwidth of the channel. To make it easier to understand, say, it is
equivalent for you to have a 56K dial up line or a high-speed internet line.
Some station pay higher price to least a wider bandwidth channel. It also
assigns more data bits on parity check for errors, so the quality of picture
will be good. Some station will cut cost by leasing a narrow bandwidth channel,
so the picture is blurry. Digital TV is very different from analogue TV you get used too. You can hear or see some noise on weak analogue signal. But on digital signal, you would get nothing on very weak signal. On barely decodable signal level, you would get square on you pictures, and intermittent sound. You cannot use the picture to do alignment as in analogue TV, because the picture will have delay time to show up, which; by that time you might have missed that alignment position. Because of the dish needs precision alignment before you can receive something. After installation is complete, you still have to calibrate the dish and entry channel data. For beginners, it could take you several weeks of work. It might not worth to do it by yourself. That could be the reason FTA TV is not as popular as pay TV. However, the FTA is in fact more interesting if you are not an aggression movie bug. To simplified the installation instruction. Zero the rotor to center position. Point the dish to true south. Select a weak signal. Peak the signal strength on adjusting elevation angle and focus. Free to air TV programs are very interesting to watch, because you can see different cultures. You used to have to travel to that country to watch their TV programs. With nowadays technology, the whole world is within your reach. There are many cultural, educational, health, news, sport, family, and religion channels. It has very few violence programs. It is suitable for all ages. One major feature with FTA is religion programs. All religions are teaching people towards good. However, not many of them could tell you the real truth. What is the world’s future looks like? Is there Hell? What would people be after death? Amount all the religion channels I watched, 3abn on satellites AMC-4, PAS-9, Hot bird, Thaicom-3, and Optus-B3 gave me the best answer. Michael Tung 董邦富 Mr. Michael Tung 羅緝熙 Dr. C. H. Laws
接收器： 現今的科技，使人造衛星接收器的價格大跌．很多低檔的接收器，其實用價值遠超越你所付的代價． 數碼接收器其實是一部特製的電腦包含內置的
高檔的接收器叫做PVR個人錄像機，它有內置的硬磁盤機，可讓你記錄及重播．我們的經驗告訴我們不同牌子的接收器有不同的品質．很多低價或沒有品牌的接收器受到廠家的抵制．你可能買到一份名牌盒子和包裝，內裡卻是不同牌子的產品或次貨．下面就是一些選擇接收器的貼士：
數碼電視與模擬式電視不同．數碼電視的畫像時常都很清晰．訊號很弱之時，你只見到小方塊和聽見古怪聲音．碟形天線越大，所收訊號越強．影像的間歇期越短．可是風的干擾，價錢，佔的空間也按比例增加．通常有兩個微波訊號波段供電視使用．C波段是舊一代的需要巨大的碟形天線．Ku波段是新一代的需較細小的碟形天線．很多收費電視提供強力的訊號對準較細的覆蓋區域，因此細小而位置固定的碟形天線就很足夠．免費沒有密碼的訊號因覆蓋區域大，所以需要較大的碟形天線．很多供應商庫存的小碟形天線是不足夠的．看你離赤道有多遠．我們建議你用36吋或90 – 95公分的碟．這是標準旋轉器所能帶動的最大碟子了．在很南或很北的地域，你可能需要更大的碟． 大氣會令訊號衰減．空氣中之行程最短是赤道底下．當你遠離赤道，訊號就需旅經較厚之空氣層．當衛星和你處於同一經度，所經路徑最短．當你的碟形天線指向另一衛星，那衛星較遠離你的經度，所經空氣路徑會較長．訊號衰減按與空氣路徑之長短成正比例．雲，雨，雪強減弱你的訊號強度．風可以造成碟形天線暫時性的偏歪．碟形天線永遠不會太大．新安裝的天線一般效果較好．經過惡劣天氣之後，可能造成偏歪，尤其是細小之天線． 如果你要接收多個衛星的訊號，除了碟形天線之外，你還需要一個好的旋轉器，除非你安裝多個碟形天線．有些旋轉器的馬達太弱．你必須用手推動來幫助它．購買這樣的旋轉器簡直是浪費金錢，除非你每次改變衛星都用手來推動它．用USALS全球人造衛星自動定位系統當然是好選擇．理論上是應該使用兩個馬達來控制的．一個水平，另一垂直．由於垂直旋轉常跟固定的幾何圖案旋轉．要作一傾斜之旋轉，我們可以省略垂直的馬達． 測量： 所有同步人造衛星都是放置在赤道上空35,800公里處．在北半球，我們必須將碟形天線面向南±70°．在南半球則剛好相反．在赤道上，你就要把碟形天線向上．在北半球或南半球，要視乎你離赤道有多遠，你必須調校一個適當的仰角． 在你安裝之前，你必須先找出安裝地點的經緯度．下列網站可以幫助你：http://www.multimap.com/map/home.cgi?client=public&overviewmap=ap.你亦可以用GPS全球定位系統來查出． 從這網站 http://www.lyngsat.com 的表中，找出一顆人造衛星最接近你的經度作為真南極之參考．例如你位於西經79.6°．最接近的衛星是AMC-5在西經79°．從 http://www.ses-americom.com/tools/lookangle/index.html 的計算機，輸入數據，計算你的方位角和仰角．在剛才所舉的例子中，計出的方位角是179.1°西，仰角是39.7°．如果該人造衛星與你的經度相同，那麼你的方位角將會是 180°，那就是真南極． 選擇一堅硬點，向南 ±70° 視野清晰，仰角低於你所計算的10 度．沒有樹或其他物體在前面．多數的屋頂所用的木板都太薄弱．如果沒有加固，風一吹你的碟形天線就可能偏歪甚而吹走．可用水泥板堅固． 堅固的支架十分重要．你的碟形天線對位偏差不能超過 ±0.1°．偏歪 ±0.5° 就足以令訊號嚴重減弱．強風可能造成訊號斷斷續續的現象． 支柱必須絕對垂直．不垂直的支柱令有些衛星對不準有些對得準．碟本身的重量一般不會超出容忍範圍． 電鑽，水泥鑽嘴，板手，梯． 水平尺：用此工具來樹立垂直支柱． 指南針：只能粗略地量度方位角．放置太近圓碟會出現嚴重的錯失．如果你知道方向可以不必要它．最後可用磁場強度計來作微調． 繩索：用以吊起圓碟．利用碟的支架來吊起它．圓碟又重又大．安裝之前預先裝配好．千萬不要試圖攜帶圓碟爬上梯以免失去重心跌下來． 手提電視機或專業人造衛星尋找儀．業餘人造衛星尋找儀不能識別衛星的名稱．即使你找到一個但幫助不大．手提電視機是最好和最廉價的選擇．多數的接收器都有衛星搜尋功能和訊號場強度錶．它比專業性衛星尋找儀做得更好． 在牆的最高那邊作量度．確保圓碟不碰到水槽．在牆壁鑽孔以安裝承托．先用一小硬鑽嘴鑽一小孔，然後改用更大而合適的鑽嘴．用一螺絲釘安裝承托．可用鑿先打一小洞來引導鑽嘴．鑽其餘的洞．洞要鑽得很準確．如果你不跟此指示去做，可能就對不準位置．你還可能破壞牆壁． 有兩處地方可以調整仰角．其一可變調節器在碟上．另一固定度數調節器在旋轉器上．如果你不打算用機動碟來接收多個衛星的訊號，你就可以簡化安裝程序．取得你位置的緯度，在旋轉器上校準你位置的緯度，然後作永久性的固定．安裝你的碟子，轉鬆調校方位角和仰角的螺絲．連接接收器和手提電視機．放近天線． 調校之前，將你的接收器設置在安裝模式．輸入數據例如衛星名稱，衛星的經度，轉發器（或稱應答器）的頻率，符號率，你自己的經度和緯度．確保轉發器的起始頻率是正確的．否則你永遠不能探測到訊號．在控制程序，旋轉至目標衛星的方位角，在所舉的例子中，是179.1°西．將你的碟形天線指向差不多的方向．用手向上，下方向旋轉直至你察覺收到一點訊號．如果不能收到任何訊號，旋轉方位角半度再試，直至找到該衛星為止．做頻道查驗以識別你找到的衛星．調校至訊號的峰值．最後旋緊螺絲．強的訊號雖然對得不太準仍可以接收得到．不要用強的訊號來取其峰值．有些衛星安放於更為高出一公里之處．USALS全球人造衛星自動定位系統計算出之方位角可能偏離一度之幾分一，你可以略為修改經度來作代償以糾正之． 將LNB拉出推入來調整焦點．再調校訊號至峰值．轉換至另一衛星，檢查其訊號強度，再作頻道搜尋．如果你的碟形天線洽當地對準真南極或北極，你可以轉換衛星而保持對位的準確性． 當微波進入大氣層，它會有些像光線進入玻璃的性質．訊號傳播的軌跡有可能有小角度的偏移．壞天氣特別容易察覺這現象，而且每日都不相同． 數碼電視與以前所用之模擬式電視大不相同．後者你會聽見或看到由於微弱訊號做成的雜音和雜影．但前者即數碼電視當訊號微弱之時，你將看不到甚麼．達到剛可解碼的水平，你將會看到小方格和聽到斷斷續續的聲音．你不能好像模擬式電視用這些圖像來做對位，因為圖像，出現有時間延誤的現象，你就可能因此失去機會捉住正確合適的位置． 因為碟形天線需要非常準確地對準衛星才能接收訊號．你想收看到一點東西之前就必須先對準衛星．安裝完成之後，你仍須校準碟子和輸入頻道數據．對於新手可能要花上幾個星期的工夫，未必值得你親手去做．或者就是為何免費電視沒有付費電視那麼流行的原因．但無論如何，FTA免費電影事實上更為有趣如果你不是電影蟲的話． 簡化安裝指示，首先將旋轉器的零度置於中央位置．圓碟指向真正南極．選一弱訊號．調整仰角及焦點使訊號增強至峰值． 觀賞免費衛星電視節目是非常有趣的，因為你可以看到不同的文化．本來你要旅遊到那些國家才能觀賞到他們的電視節目，但藉著今日的科技，你可以接觸到全世界．有很多文化，教育，健康，新聞，體育，家庭和宗教的頻道，適合各種年齡的人觀賞． FTA 免費衛星電視之主要特色之一就是宗教節目．所有宗教都是教人向善．但這些節目中卻很少告訴你真正的真理．例如世界將變成甚麼樣子？有沒有地獄？人死後怎樣？我看過的那麼多宗教頻道，用AMC – 4, PAS – 9 , Hot bird, Thaicom – 3和Optus –B3等人造衛星轉播的3abn最能給我滿意的答案．
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