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MediaPortal 1
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Television (MyTV frontend and TV-Server)
Lof1, LofSW, Lof2 in TVServer ?
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<blockquote data-quote="Frodo" data-source="post: 164881" data-attributes="member: 10277"><p>I will try:</p><p>A satellite consists of 1 or more transponders</p><p>Each transponder transmits 1 or more tv-channels / radio channels</p><p>A transponder is defined by:</p><p>- frequency</p><p>- fec</p><p>- modulation</p><p>- polarisation</p><p>- (and pilot/rolloff in case of DVB-S2)</p><p></p><p></p><p>The normal frequency range for satellites is 10.7GHz - 12.75 Ghz</p><p>These SAT frequencies are much too high to transport via a normal coax cable to your sat receiver. </p><p></p><p></p><p>This is where the LNB comes in.</p><p>The LNB converts the high SAT frequency to a much lower frequency</p><p>(950-2150 MHz) which can be transported via coax to your sat receiver.</p><p>To do this conversion, the LNB uses the LOF1,LOF2 and LNBSW frequencies</p><p></p><p>I'll take as an example the Astra 19.2 satellite here.</p><p>For Astra 19.2 the values are</p><p>LOF1: 9750</p><p>LOF2: 10600</p><p>LNBSW: 11700</p><p></p><p></p><p>Now suppose you want to watch a transponder at 10.7 GHz (lowest frequency)</p><p>The LNB has to down-convert this to 950 MHz. </p><p>Todo this it uses the LOF1 frequency.</p><p>the formula for this is : 10.7Ghz - LOF1(9750) = 950 Mhz</p><p></p><p>Now lets suppose you tune to the highest sat frequency (12.75 Ghz)</p><p>The LNB has to down-convert this to 2150 MHz. </p><p>Todo this it uses the LOF2 frequency.</p><p>the formula for this is : 12.75Ghz - LOF2(10600) = 2150 Mhz</p><p></p><p>Notice that now it uses LOF2. </p><p>How does it know when to use LOF1 / LOF 2?</p><p>This is mentioned by the LNBSW</p><p>for all frequencies < LNBSW the LNB will use LOF1</p><p>for all frequencyes > LNBSW the LNB will use LOF2</p><p></p><p></p><p>Now about other countries.</p><p>Not all countries use the full range of all satellite frequencies</p><p>There are several 'band' types defined. </p><p>The universal (Ku band) is the one i just described.</p><p>But besides the Ku band, we also have</p><p>- C-Band</p><p>- Circular</p><p>- North American DishPro Band Stacked Ku Hi</p><p>- North American DishPro Band Stacked Ku Lo</p><p>- North American Band Stacked Ku Hi</p><p>- North American Band Stacked Ku Lo</p><p>- North American Legacy</p><p></p><p>All those bands are slight variations on the Ku band we've described</p><p>-Some dont use the LOF2/LNBSW since the SAT frequency used is much smaller (e.g. only from 10.7GHz - 11.7GHz)</p><p>-Others use the polarisation (horizontal/vertical) to selected a frequency range</p><p>instead of the LNBSW etc.</p><p></p><p>etc</p><p></p><p>In TV3 we have pre-defined values for LOF1/LOF2/LNBSW for all these bandtypes.</p><p>However since i can only receive Ku-band satellites here i cannot verify if all other bandtypes are implemented correctly.</p><p>So any feedback on this would be nice.</p><p></p><p>For those tweakers wanting to control everything, </p><p>we added the option to tweak the LOF1/LOF2/LNBSW values</p><p></p><p></p><p></p><p></p><p></p><p></p><p></p><p>Frodo</p></blockquote><p></p>
[QUOTE="Frodo, post: 164881, member: 10277"] I will try: A satellite consists of 1 or more transponders Each transponder transmits 1 or more tv-channels / radio channels A transponder is defined by: - frequency - fec - modulation - polarisation - (and pilot/rolloff in case of DVB-S2) The normal frequency range for satellites is 10.7GHz - 12.75 Ghz These SAT frequencies are much too high to transport via a normal coax cable to your sat receiver. This is where the LNB comes in. The LNB converts the high SAT frequency to a much lower frequency (950-2150 MHz) which can be transported via coax to your sat receiver. To do this conversion, the LNB uses the LOF1,LOF2 and LNBSW frequencies I'll take as an example the Astra 19.2 satellite here. For Astra 19.2 the values are LOF1: 9750 LOF2: 10600 LNBSW: 11700 Now suppose you want to watch a transponder at 10.7 GHz (lowest frequency) The LNB has to down-convert this to 950 MHz. Todo this it uses the LOF1 frequency. the formula for this is : 10.7Ghz - LOF1(9750) = 950 Mhz Now lets suppose you tune to the highest sat frequency (12.75 Ghz) The LNB has to down-convert this to 2150 MHz. Todo this it uses the LOF2 frequency. the formula for this is : 12.75Ghz - LOF2(10600) = 2150 Mhz Notice that now it uses LOF2. How does it know when to use LOF1 / LOF 2? This is mentioned by the LNBSW for all frequencies < LNBSW the LNB will use LOF1 for all frequencyes > LNBSW the LNB will use LOF2 Now about other countries. Not all countries use the full range of all satellite frequencies There are several 'band' types defined. The universal (Ku band) is the one i just described. But besides the Ku band, we also have - C-Band - Circular - North American DishPro Band Stacked Ku Hi - North American DishPro Band Stacked Ku Lo - North American Band Stacked Ku Hi - North American Band Stacked Ku Lo - North American Legacy All those bands are slight variations on the Ku band we've described -Some dont use the LOF2/LNBSW since the SAT frequency used is much smaller (e.g. only from 10.7GHz - 11.7GHz) -Others use the polarisation (horizontal/vertical) to selected a frequency range instead of the LNBSW etc. etc In TV3 we have pre-defined values for LOF1/LOF2/LNBSW for all these bandtypes. However since i can only receive Ku-band satellites here i cannot verify if all other bandtypes are implemented correctly. So any feedback on this would be nice. For those tweakers wanting to control everything, we added the option to tweak the LOF1/LOF2/LNBSW values Frodo [/QUOTE]
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