Confused

Discussion in 'Free To Air (FTA) Discussion' started by Alexander Olar, Jun 29, 2018.

  1. Alexander Olar

    Alexander Olar Topic Starter SatelliteGuys Pro

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    I had my DMS DSS922 Circular LNB hooked up today and I was surprised it was picking up linear TP’s as well as circular TP’s. It was picking up all the DVB-S feeds on 103w (NHK, RT, CGTN) and LPB on 87w when it is a circular LNB. Why is it picking up all these Linear Channels when it’s only a Circular LNB? It never did this before.
     
  2. Alexander Olar

    Alexander Olar Topic Starter SatelliteGuys Pro

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  3. Martyn

    Martyn SatelliteGuys Pro

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    If you use an LNB with the wrong polarization, there's an approximate 3dB drop (50%) in signal received but it still receives something. If the signals are strong enough and if there is nothing on the opposite polarity to interfere with them, it's still possible to pick up a usable signal as you have discovered.
     
  4. KE4EST

    KE4EST SatelliteGuys Is My Second Home
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    What he said. :)
     
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  5. Alexander Olar

    Alexander Olar Topic Starter SatelliteGuys Pro

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    I’ll keep my circular and linear separated . I was getting 32%Q on NHK and 26%Q on LPB with the DSS LNB. Today was a sunny day so that’s why I’m guessing I was able to pick up anything with the DSS LNB.
     
  6. spongella

    spongella SatelliteGuys Pro
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    Here's my take, a few years back I connected my STB to the circular output of an Invacomm QPH-031, did some scans on different Ku sats (using Ku dish and H-H motor) and came up with only one ITC station, was some kind of lottery or on-line game/gambling promo, no audio. When I switched back to linear, that promo did not appear. I figured it was circular polarization. Not sure if others have tried this or not.

    Good post, great comments.
     
  7. Magic Static

    Magic Static FTA Geek
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    While this occurrence is interesting, we have not talked any specifics. Such as transponder frequencies and L.O. frequency. One might think you could use any DSS LNBF and obtain similar results but that DMS DSS922 is a unique design specifically for ANIK F3. It has a FSS L.O. of 10750 and DSS circular polarity. So this is strictly a phenom of polarization and not frequency. And is characteristic of that special LNBF.
     
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