Elliptical dish rotation

N1501

Member
Joined
Feb 21, 2012
Messages
49
Reaction score
5
Points
8
Age
65
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
Staff member
Joined
Jun 28, 2003
Messages
18,023
Reaction score
4,046
Points
113
My Satellite Setup
-----------See sig-----------
My Location
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.
Staff member
Joined
May 1, 1999
Messages
38,292
Reaction score
1,615
Points
113
My Satellite Setup
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.
 
Top