SatSig topic:

Carrier

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Aug 10^th, 2009 at 10:24am

Sir,
We have one ku –band transition here, the Eb/no received in DMD is very less and showing half of the value which we used to have before .That is before we used to have 8.0 db and now the eb no is 4.0 .
We have checked with Spectrum Analyzer and the wave shape it is showing is constant. ie that waveshape in spectrum analyzer is showing fine like we used to have before.

But the the Eb/no is showing very less that is half of the value which we used to have before.
Is there anyway to find that whether this is due to interference or carrier issue?

By viewing the picture shape in Spectrum Analyzer,,,, how do we analyze the signal which we receiving is getting
Interference or any other issues ?
.Can u tell me the examples of problems by seeing the picture shapes of Spectrum Analyzer

Thanks in advance

Aug 10^th, 2009 at 1:19pm

I would expect interference of sufficient amplitude to cut your signal in half would be displayed by the spectrum analyzer as well; a spike, a shadow, or - more typically - a distortion in the shape of your original carrier waveform.

As such - and I hope I'm not overstating the obvious here - but have you tried moving the reflector (dish) while observing the Eb/No?

//greg//

Aug 10^th, 2009 at 5:50pm

yes sir , we done that too but no improvement in signal shape .

Aug 10^th, 2009 at 8:24pm

did you check line of sight? maybe some trees growing in front of the dish?

Do you use LNB or LNA/LNC? What make and model? and what kind of spectrum do you use?

Aug 11^th, 2009 at 6:50pm

Thank you all , finally it was problem from trasnmitting side and it was fixed by the Sat Provider .