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Adam_UK
27th January, 2012, 11:22 AM
There are some channels on 0.8W that I can't get with my 1.1m dish. I noticed these channels don't have H or V polarity like Reuters World News Service (http://about.reuters.com/media/tvvideo/feeds/newsfeeds.htm) and have R or L values which I don't what these are and also strange symbol rate value like 4000. I noticed there are similar channels on 10E. Anyone know why we can't get these channels?

Manic01
27th January, 2012, 11:58 AM
For a more efficient utilization of the frequency bandwidth used in satellite transmitted signals, a spatial polarization is used; this enables transmitting two different streams at the same frequency with different polarization and hence duble the transponders for a given bandwidth.

There are two polarization methods Circular and Linear. We therefore need circular or linear LNBs depending on what channels we want to get. There are also combined LNBs circular and linear together in one housing, mostly used with motor dishes.
Circulars are mostly in use in North America and Linears in Europe.

The circular method has Left and Right polarization with wave propagation like rotating a screw right hand or left hand.

The linear method has Horizontal and Vertical polarization with wave propagation like a back and forth movement left-right or up-down.

The LNB polarization settings are controlled by the receivers by the voltage applied to the LNB (not applicable for dp or dpplus LNBs):

11.5 to 14 volt - for Right hand Circular or Vertical polarization
15.5 to 19 volt - for Left hand Circular or Horizontal polarization

As the same control voltages command the polarization switching for either circular or linear LNBs, some use the terminology:
Right = Vertical and Left = Horizontal

Adam_UK
27th January, 2012, 03:31 PM
Thanks Manic for this sceintific reply :)
Does this mean these channels are for broadcast in the US and we can't get them here in europe?

lincsat
27th January, 2012, 03:45 PM
There are some channels on 0.8W that I can't get with my 1.1m dish. I noticed these channels don't have H or V polarity like Reuters World News Service (http://about.reuters.com/media/tvvideo/feeds/newsfeeds.htm) and have R or L values which I don't what these are and also strange symbol rate value like 4000. I noticed there are similar channels on 10E. Anyone know why we can't get these channels?

The Reuters link isn't working but I guess they use C Band (Around 4 Ghz), you will not get this with a standard LNB as it's well outside the frequency range. Also C Band signals are much weaker, I would think you would need a dish of over 2m.

Adam_UK
27th January, 2012, 03:50 PM
I was trying to understand the different between the channels we get on all sats like 13e, 28e ..etc and those channels which have L or R values. There are many channels on 10e which have these values L or R, was not looking to get the Reuter channel specfically but to know if we can get these channels or not.
The link is here

Intelsat 10-02 / Thor 5 / Thor 6 (0.8W) - All transmissions - frequencies - KingOfSat (http://en.kingofsat.net/pos-0.8W.php)

Thanks

Manic01
27th January, 2012, 04:08 PM
What is the difference between a Linear and Circular LNB?

This has to do with the way the signal is transmitted from the satellite in the sky. There are two different ways that a satellite can broadcast its signal. If linear, it broadcasts Horizontal and Vertical. If circular, it broadcasts Right Circular and Left Circular. To understand this better, imagine the signal coming in like a screw that's turning left or right.

http://www.galaxy-marketing.com/ku_ban3.gifhttp://www.galaxy-marketing.com/ku_ban2.gifhttp://www.galaxy-marketing.com/ku_ban4.gifhttp://www.galaxy-marketing.com/ku_ban5.gif

Go to lyngsat.com and choose the satellite you are trying to pick up. Under the transponder frequency column (Freq. Tp) you will see a letter next to the frequency. If the letters used are R or L (Right or Left), then it's a circular broadcasting transponder. If you see the letters H or V (Horizontal or Vertical), then it's a linear broadcasting transponder.

lincsat
27th January, 2012, 04:21 PM
Typically L & R Circular polarised are C Band and the H & V are in the common Ku band. You can get a circular polarised signal on a standard LNB with a signal loss of around 3dB - so long as the signal is the correct frequency for the LNB.

Adam_UK
27th January, 2012, 04:43 PM
Thanks
I added the transponders to the sat. on my receiver and did a scan but none of the channels were picked up. It could be the frequency of the lnb. or weak signal of C type broadcast as you stated above.