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ABC guide to
Adding extra satellites and LNB switches Want more than one satellite? Prepare yourself to go beyond Sky and Freesat with our LNB-switching tutorial If you’ve browsed through Channel Check and want to watch TV from farther afield than Sky or Freesat, but also want to keep an eye on BBC One, Sky1, and the other UK channels, then you are going to need to pick up the signals from another satellite position. That can mean using a second dish – but it doesn’t have to. How to receive from two satellites
01 A satellite dish will collect the
signals transmitted from only the satellite position that it’s aligned on, into the LNB at the focal point. So to receive the signals from two different satellite positions (say, Sky and Freesat at 28.2°E and the European channels at 19.2°E) to increase your choice of channels you need a separate dish pointed at each satellite position, each with its own LNB and cable to feed the different signals to the receiver. How many dishes can I have? 02 In a normal house (less than 15m high) that is not a listed building or in a conservation area, an ‘area of outstanding natural beauty’, a National Park, or the Norfolk or Suffolk Broads you are allowed two dishes – one 60cm or less and one up to 1m diameter. That’s two dishes a building, so if you live in a flat and both you and a neighbour already have a single dish you will need to apply for planning permission for your second dish. Your council can give you full details of the regulations. Can I use a Sky/
03 Freesat minidish? Many other satellites are less powerful than those transmitting the Sky/ Freesat services at 28°E so their signal strength in the UK is lower and your second dish needs to be larger than the Zone 1 minidish. 2 What Satellite & Digital TV
Approximate dish sizes for popular satellites Satellites
Position
Southern dish size
Northern dish size
Astra 1E, 1G
23.5°E
60cm
60cm
Astra 1F, KR-M
19.2°E
60cm
60cm
Hot Bird 6-9
13°E
60cm
70cm
Eutelsat W3A
7°E
70cm
100cm
Eutelsat W1
10°E
90cm
80cm
Eutelsat W2
16.E
60cm
60cm
Thor 5
1°W
80cm
80cm
Intelsat 10-02
1°W
60cm
90cm
Atlantic Bird 3
5°W
50cm
70cm
Atlantic Bird 2
8°W
50cm
60cm
Telecom 2D
8°W
50cm
70cm
Atlantic Bird 1
12.5°W
80cm
100cm
Hispasat 1C, 1D
30°W
60cm
80cm
But you can use a Zone 2 minidish for several satellites in some parts of the UK. For reliable reception in southern England and the Midlands, and in the north of England and Scotland, these are the approximate dish sizes you need to get at least most of the channels on some of the more popular ‘alternative’ satellites (see above). (below) A typical two-way DiSEqC switch
How to use one dish for two
04 satellites
The simplest way to pick up two satellites is to use two dishes (or three dishes for three satellites and so on), but it can often be difficult to accommodate more than one dish on your home. Instead, you can cheat with one multi-feed dish. This relies on the fact that a dish aligned on one satellite, to focus the signal onto the LNB at the end of
the feedarm, will also focus the signals from other satellites adjacent to main focus, at points alongside to the LNB position – in a mirror image of their positions in orbit (East becomes West, and vice versa). So by placing a second LNB in the correct position next to the main LNB you can receive the signals from two satellites as though you had two dishes. You’ll need a larger dish than normal and it’s trickier to install (more on this next time) but it’s a nifty solution. How to connect one receiver to
05 two LNBs
You can use a separate receiver for each satellite position, but one receiver with access to both positions is a more economical and convenient solution and takes up less room under the TV. Although many receivers have two LNB inputs (such as Sky+), they’re not necessarily intended for use with two LNBs (on one or two dishes). Except for a few older receivers, two IF sockets are provided for two tuners – required for a PVR receiver to record one channel while you’re watching another.
abc guide to... LNB1
LNB2
How to use an LNB switch
06 The simplest switches are
0/12V switch 0/12V switching control
Two-way 12V switch: A receiver with a 0/12V switching output can be programmed to automatically select the LNB required for each channel LNB1
LNB2
Manual switch
LNB2
LNB3
manually operated, usually with just two inputs and operated by hand, so you have to get up from the armchair to switch over LNBs when you want to change channel. Often these switches are designed as aerial switches and are not really suitable for the higher frequencies from an LNB. With a Sky Digibox you have to use a manual switch as it cannot control one itself – however, a Sky Digibox is not ideal for ‘other’ satellites in other ways too. For the past 10 years, most receivers have been DiSEqC (Digital Satellite Equipment Control) compatible. A DiSEqC switch is powered by the receiver via the LNB cable and this carries digital commands to select the required LNB too, so they are very easy to install. What’s more, a DiSEqC switch can be positioned close to the dish(es), so just one long cable down to the receiver is required. Different DiSEqC switches
07 Originally, the DiSEqC switching
Two-way manual switch: A manual LNB switch is cheap and simple, but you have to select the LNB by hand when you change channel LNB1
You can still connect the two tuners of a PVR to LNBs receiving different satellites, but with some machines (Freesat+, for example) this can confuse the hell out them. For most setups you should use an LNB switch – a small device to select which of two (or more) LNBs is connected through to the receiver’s LNB input.
LNB4
system was intended for just two satellites but it was extended to encompass four possible satellite positions. This is level 1.0 DiSEqC and both compatible receivers and two-way or four-way switches are easily available. DiSEqC level 1.1 caters for up to 16 LNBs and an increasing number of LNB1
LNB2
LNB3
4-way DiSEqC 1.0 switch
LNB4
receivers support this standard; 16-way LNB switches are not normally used but instead a special ‘uncommitted’ four-way switch is connected to the receiver and further standard switches (up to four-way) connected to each of that switch’s inputs, to make a possible 16 inputs. There are also unofficial DiSEqC 1.1 switches, supported by few receivers, which provide an eight-way uncommitted selection that can be cascaded with eight standard four-way switches to provide automatic switching of up to 64 LNBs and satellite positions. Such an antenna setup would be the ultimate fixed-dish satellite system – even if it would be hard to see your home under all those dishes! n Geoff Bains
Glossary Committed DiSEqC switch
Two-way or four-way LNB switch that responds to commands from a DiSEqC 1.0 or 1.1-compatible receiver
Uncommitted DiSEqC switch Four-way LNB switch that responds to commands from receiver compatible with DiSEqC 1.1. Used in a cascaded system to select between Committed switches.
Zone 1, Zone 2 minidish
Zone 1 minidishes are about 55 x 40cm in size and intended for most of the UK. Zone 2 dishes are needed for the south-west of Wales, Cornwall, England north of Newcastle-Carlisle, and Scotland.
LNB5
LNB6
LNB7
4-way DiSEqC 1.0 switch
4-way DiSEqC 1.0 switch
4-way DiSEqC 1.0 switch
Four-way DiSEqC switch: DiSEqC switches are simple to install and automatic in operation. A level 1.0 switch will select between up to four satellite positions
Many-way DiSEqC 1.1 switch: If your receiver is DiSEqC 1.1-compatible then you can cascade an uncommitted switch with up to four, 4-way committed switches, to control up to 16 LNBs – you’ll probably need several dishes What Satellite & Digital TV 3