For enthusiasts wanting to view channels from more than one satellite, there are two main options
- A motorized dish
- A fixed position dish with multiple LNBs
Which is best? Assuming your needs are all European and don’t include really difficult weak signals, like Nilesat, then you could use either one.
Here is a breakdown of the advantages and disadvantages of each type
Motorised Dishes
In a high wind location, it can be difficult to maintain alignment with a motor – so the fixed dish would be better.
The motor can take 30 seconds to move end to end, so quick channel hopping isn’t practical. The multi lnb fixed dish has instant switching between satellites.
If your main channels need a decoder, some official receivers like Sky, do not have motor controllers, but you can use a standard satellite receiver to control the motor, and use the decoder in tandem. More details on the Motor page
Fixed Multisat Dish
Instant switching between satellites
For multi-room installation, where channels from different satellites are needed in each room, only the fixed dish solution will work ( a motor cannot be in two positions at once )
The distribution of multi-room signals becomes more difficult depending on the number of rooms. But multi-switch boxes exist for up to 4 satellites and any number of outlets ( blocks of flats for example )
Signal Strength
As the Motorised dish points directly at ONE satellite, the whole dish surface collects signal from that satellite. A multi-dish is always a compromise, the lnbs nearer the centre have the most signal, those at the edges have less. So the dish size has to bear these restrictions in mind, it is generally bigger than a motor dish.
Note: In the example shown below, the green lnbs have a 40mm head, all the others are standard 60mm heads. The smaller head allows them to be positioned closer together
40mm – closest satellites 4 degrees
60mm – closest satellites 6 degrees
So lnbs 3&4 could be used for Eutelsat 9a and Hotbird ( 13 ) which are 4 degrees apart
Reception from a standard dish will allow strong satellites, up to 20 degrees apart to be seen. To overcome the bias towards the centre of a standard dish ( a parabolic dish) the Toroidal dish was invented. The specific shape of the two reflectors is calculated to give roughly the same signal from a wide angle, up to 40 degrees.
Toroidal Dishes
These dishes are slightly larger than their stated ‘reference’ size. The T55 Force dish measures about 65cm but it performs ( within its 40degree limits ) as a 55cm. The T90 version measures 112cm. But the signal level is very even across the 40 degree angle of acceptance.
This is sometimes preferable to using a parabolic dish where the end lnbs (1&5 in Triax dish pictured above ) get probably only 75% of the signal of the middle lnbs (2&3). One common use is for French from Eutelsat 5w and UK from Astra 2 ( 28.2 east ) a total of 33 degrees, which is beyond the capabilities of a parabolic dish. This is typically 20 degrees, for an 80cm dish.