Elliptical dish rotation

N1501

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My Satellite Setup
Fracarro Penta 85 Brick Red Aluminium Dish,
Inverto Black Ultra 0.2 dB Single Output LNB,
TM-2600 Super H-H Motor,
Vu+ Duo DVB-S2 receiver,
Stock Vu+ image V7,
Labgear PF100 cable,
Atlanta ASF304+ Sat-Finder,
4:2:2 VLC / Ubuntu,
53E to 45W
My Location
51.8ºN, 0.0ºW East Hertfordshire
The majority of domestic fixed elliptical dishes ( 28E ) that I see on people's houses always look horizontal with the LNB rotated. It is my understanding that elliptical or diamond shaped dishes have better side-lobe discrimination along their widest axis and that if the axis is orientated along the orbit, interference from the adjacent satellites will be minimised. Wouldn't this give a better BER ? With that in mind, why is the lnb not put in the 6 O'clock position and then
the whole dish rotated for the desired skew angle ? I know that some Sky dishes have an elliptical feed-horn lnb but I still don't understand why the dish isn't rotated like a motorised one would be.
 

PaulR

Dazed and Confused Admin
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Wirral, NW UK and Vaucluse, France.
Technically you're right, the dish should be rotated slightly, but in practice it's close enough!

And, besides, it's easier to position the dish on a wall using vertical and horizontal rather than a few degrees off kilter.
 

rolfw

Believe it when I see it Admin.
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Technomate 5402 HD M2 Ci, DM7000s, Transparent 80cm Dish, Moteck SG2100 DiseqC motor, lots of legacy gear. Meters: Satlook Digital NIT, Promax HD Ranger+ spectrum analyser.
My Location
Berkshire
You can improve the MER and BER by rotating a Sky minidish dish, but as it is normally pretty acceptable without, most people don't bother.
 
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