40.5 W on a Linear LNB?

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Lone Gunman

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Mar 19, 2010
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OK I'm confused again. I'm on 40.5W, which is suppose to be a circular sat and I just got done scanning that thing with my 10ft Winegard with Corotor II and Norsat LNB using my Pansat 3500 and I've gotten about 15 Tps to show up with about 35 channels available, all with a linear setup? Those feeds look as good as the stuff I was getting on G3?


So is this “normal”?
 

pendragon

SatelliteGuys Pro
Oct 13, 2008
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Yes a linear feed will pick up one component of a circularly polarized signal, but because it does not pick up the other, you will lose 3 dB of CNR out of the starting gate. However a linear feed cannot discriminate between left and right circular polarization. If there are overlapping transponders of opposite polarities, you will probably get nothing from a linear feed.

One can draw somewhat of an analogy by considering what reception one would get by intentionally (mis)-skewing a linear feed by 45 degrees. The horizontal probe would pick up both vertical and horizontal polarizations, but you will lose 3 dB of CNR. If there are overlapping transponders of opposite polarities, you will probably get nothing.
 

carlospr43

SatelliteGuys Pro
Mar 20, 2010
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US
I'm using a 6' footer with a single output BSC421 with the Dielectric Plate (getting only the Horizontal (Right)polarities ) because I'm using a 4X4 swith to feed 4 boxes. You should enter most of the TPs manually since usually the blindscanning will not download all of them. Between SD and HD I'm getting approx 120+ channels
 

Lone Gunman

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Mar 19, 2010
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Mind you this was all "accidental" as I had no idea that the linear Corotor II on Cband would pick up any of it and it be viewable? I did notice that Q was down almost half of what I normally see but hey, there was a bunch of stuff there that was viewable, in Spanish!

40.5W only lists TPs in the C number range with the lowest one I picked up down at like 3630 if memory serves. I haven't gotten to that sat with my SAMI and LNBF yet and that one does have the the dielectric plate with it for circular. Will probably get around to that one within the next week or so.

Don't you just love this technology stuff!!;)
 

derint

SatelliteGuys Family
Jan 30, 2008
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Yeah you can get some circular with linear lnb but just a few depending on the skew of your LNB
 

johnnynobody

Star Trek fan
Aug 2, 2009
6,764
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OK I'm confused again. I'm on 40.5W, which is suppose to be a circular sat and I just got done scanning that thing with my 10ft Winegard with Corotor II and Norsat LNB using my Pansat 3500 and I've gotten about 15 Tps to show up with about 35 channels available, all with a linear setup? Those feeds look as good as the stuff I was getting on G3?


So is this “normal”?

I scanned in TP's with a linear LNBF also so I guess it's normal.
 

Mr Tony

SatelliteGuys Pro
Supporting Founder
Nov 17, 2003
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48
Mankato, MN
yeah I did that too...was looking for 45W and ended up finding 40W ;)
used a Geosat C2 LNB.....huh now that the leaves are off the trees I can aim through them and get 45W again ;)
 

nycrich

SatelliteGuys Pro
Jun 25, 2006
271
9
West Palm Beach, FL
You loose signal with the linear, however you will notice that most of the transponders that you received was the really high signal ones but at reduced level. The same applies using a circular to receive linear. You will get the stronger linear transponders. As mentioned above depending on the skew of the dish that is seeing the sat it will also help
 
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