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iDirect Signal Problem

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Posts: 13
Apr 5th, 2009 at 7:57pm  
Dera All,

Kindly i need your urgent help,

We are facing a very strange problem in Iraq Baghdad , we had all things settled correctly and the signal strength is acceptable measured by a spectrum analyzer , also we have a TV channel using TV and Reciever on Intelsat 1002 ,however each time we connect by the  i-site through the i-direct modem , there is no signal at all , we changed amost every thing , Cables connectors Modem , BUC , LNB and option file.

Please advice were is the problem.

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Eric Johnston
Senior Member

Posts: 2109
Reply #1 - Apr 5th, 2009 at 8:28pm  
I presume that the reception of an identified TV program verifies that you are on the correct satellite.  What name polarisation is the TV carrier ?

Regarding the spectrum analyser display, does it show the wanted iDirect carrier at the rx frequency shown in the options file and does the width of the carrier match the symbol rate in the options file (versions 8.2.2 and higher).  If lower than 8.2.2 what is your bit rate, modulation type code and fec type code?.  Does the spectrum show a clean noise floor and deep notches between the carriers suggesting good polarisation adjustment for the TV carrier polarisation?

If the spectrum analyser display is correct, concentrate on the options file e.g wrong rx freq, rx bit rate, rx fec, rx mode type..

If the spectrum is wrong, consider the following:

Wrong type LNB.  Ku band LNBs come with various local oscillator down-converter frequencies.  9.6, 10.0, 10.6. 10.75, 11.3 GHz.  The one you need makes this calculation correct:   Satellite freq - LNB LO freq = Modem rx frequency.   What are these three frequencies supposed to be ?  Ask your service provider. if you have the wrong LNB LO freq the entire L band cable spectrum will be shifted sideways by several 100 MHz.

Wrong polarisation.  What name polarisation have you been told to receive for the iDirect carrier?. Step 1: You need to set the nominal polarisation (Horizontal means put the LNB arm at the top or bottom.  Vertical means put the LNB arm to either side.)  Step 2: apply the polarisation adjustment (e.g  +47 deg clockwise amount while facing towards the satellite)
Best regards, Eric
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