Installing a UK Sky satellite dish
Created | Updated Sep 29, 2003
Installing a UK Sky satellite dish
Installing a dish for satellite TV couldn't be easier - or could it? What most people can't get their heads around is that the satellite which interests them is sitting some TWENTY THREE THOUSAND MILES AWAY in space. It's about the size of a Renault Clio but it's a LONG WAY AWAY (yes, even further away than London is to a northerner) and it's broadcasting with no more than the power of an average light bulb.
So there you have your Renault Clio far out in space (maybe the best place for a French automobile? <grin>) glowing like an invisible 60 watt light bulb, and you are hoping to get enough signal from it to give a nice picture on your TV screen.
Firstly, just appreciate the fact that you couldn't see this satellite with that telescope you got from Aunty Mary for your tenth birthday. It's a long way away. You certainly won't see it with your naked eye, even at night time.
Size Matters
So the first thing you need is a "dish" which will act as a reflector to collect as much signal as possible and focus it onto an LNB (Low Noise Block-downconverter). The dish needs to be big enough to collect enough signal for the LNB to process. If it's too small, there won't be enough signal.
The job of the LNB is to convert the microwave frequency signal into a band of lower frequencies that can go through a cable to your satellite receiver and also amplify the very weak signal so it doesn't evaporate before it reaches the other end of the cable.
Height Doesn't Matter
Since the satellite is 23,000 miles away, it doesn't matter if your dish is sitting on the ground or on the roof of your house. Thirty feet just isn't going to make any difference. However, the satellite may be only perhaps twenty degrees above the horizon so your dish needs to be high enough to see over any obstructions.
Alignment Does Matter
Although the satellite isn't quite at the edge of the universe, it's a heck of a long way away, so the alignment of the dish is absolutely critical. You won't get a signal simply by waving the dish around like a TV aerial. It has to be bolted to something really solid (such as your house) and then finely adjusted so that it can "see" the satellite. Just to complicate matters further, there are dozens of broadcast satellites out there so not only must you align the dish to get a signal - you must align it to get the RIGHT signal!
How to Align the dish
Assuming that you want to watch the English programmes provided by SKY you'll need to align your dish on the bunch of satellites called "Astra 2" and located above the equator at 28.2 degrees East of true South. Decide where your dish is going to go and lie a stick on the ground below that position. Take a compass and find 28.2 degrees East of magnetic South. Look up the "magnetic variation" on this year's Ordinance Survey map of your district. For the sake of this description, assume that the magnetic variation is 5.2 degrees. Subtract this from 28.2 and position your stick so that it's pointing at 23 degrees East of where the compass thinks South is.
If you are in Leeds (for example) the satellite position is roughly 22 degrees above the horizon. Steal a protractor from your child's pencil case and sellotape a cotton thread to its zero point. Hang a small weight on the cotton thread (another "use for a dead cat"?) With the cotton hanging at the 22 degree mark, sight up the flat edge of the protractor while looking in the direction in which the stick is pointing. That's the position of the satellite. If it's obstructed by a tree, building, fence or your washing, move somewhere else or find a ladder.
Fixing the dish
Make a paper template of the dish wall-mount bracket and use it to mark out the fixing holes on the bricks (not in the mortar). Use proper dish-fixing bolts (not wood screws!) You'll need a 10mm masonry drill bit, a hammer drill, 13mm spanner and goggles.
When the dish is in place and roughly aligned, use a satfinder meter to finalise the alignment. A low cost meter such as the H28-8235 will do just fine. People have managed to align their dish by trial and error "in under three days without a meter". That's probably something to be proud of but a satmeter will let you do it in minutes!
And, no, a multimeter won't do. One man spent several frustrating days up a ladder with a multimeter. He didn't realise that an LNB needs a power supply in order to amplify the satellite signal. Proper satmeters either have internal battery cells or else let the power from the receiver go through to the LNB.
The coaxial cable has to be the proper double-shielded stuff. Ordinary TV cable won't do. It needs to have a threaded "F" connector fitted to each end. There's a useful web page that gives a pictorial explanation here: http://www.satcure.co.uk/tech/fconn.htm
When the dish is aligned, connect the cable to the LNB. Waterproof the connection with "self-amalgamating tape" (other tapes simply won't do) and hold the cable to the dish arm with PVC tape or cable ties, leaving a "drip loop" beneath the LNB. Hold the cable to the wall with appropriate cable clips and drill a 10mm hole through the wall where the cable must enter. Make another drip loop below the entry hole and seal the hole to prevent water ingress. Connect the cable directly to the satellite receiver after cutting off any excess and fitting an "F" connector.
The LNB "skew" is now set by rotating the LNB slightly in its clamp to get the best "signal quality" reading from the satellite receiver (read the manual).
Finally, the dish can be painted to protect and disguise it and so can the cable.
Martin Pickering B. Eng.
Technical Author
Installing a dish for satellite TV couldn't be easier - or could it? What most people can't get their heads around is that the satellite which interests them is sitting some TWENTY THREE THOUSAND MILES AWAY in space. It's about the size of a Renault Clio but it's a LONG WAY AWAY (yes, even further away than London is to a northerner) and it's broadcasting with no more than the power of an average light bulb.
So there you have your Renault Clio far out in space (maybe the best place for a French automobile? <grin>) glowing like an invisible 60 watt light bulb, and you are hoping to get enough signal from it to give a nice picture on your TV screen.
Firstly, just appreciate the fact that you couldn't see this satellite with that telescope you got from Aunty Mary for your tenth birthday. It's a long way away. You certainly won't see it with your naked eye, even at night time.
Size Matters
So the first thing you need is a "dish" which will act as a reflector to collect as much signal as possible and focus it onto an LNB (Low Noise Block-downconverter). The dish needs to be big enough to collect enough signal for the LNB to process. If it's too small, there won't be enough signal.
The job of the LNB is to convert the microwave frequency signal into a band of lower frequencies that can go through a cable to your satellite receiver and also amplify the very weak signal so it doesn't evaporate before it reaches the other end of the cable.
Height Doesn't Matter
Since the satellite is 23,000 miles away, it doesn't matter if your dish is sitting on the ground or on the roof of your house. Thirty feet just isn't going to make any difference. However, the satellite may be only perhaps twenty degrees above the horizon so your dish needs to be high enough to see over any obstructions.
Alignment Does Matter
Although the satellite isn't quite at the edge of the universe, it's a heck of a long way away, so the alignment of the dish is absolutely critical. You won't get a signal simply by waving the dish around like a TV aerial. It has to be bolted to something really solid (such as your house) and then finely adjusted so that it can "see" the satellite. Just to complicate matters further, there are dozens of broadcast satellites out there so not only must you align the dish to get a signal - you must align it to get the RIGHT signal!
How to Align the dish
Assuming that you want to watch the English programmes provided by SKY you'll need to align your dish on the bunch of satellites called "Astra 2" and located above the equator at 28.2 degrees East of true South. Decide where your dish is going to go and lie a stick on the ground below that position. Take a compass and find 28.2 degrees East of magnetic South. Look up the "magnetic variation" on this year's Ordinance Survey map of your district. For the sake of this description, assume that the magnetic variation is 5.2 degrees. Subtract this from 28.2 and position your stick so that it's pointing at 23 degrees East of where the compass thinks South is.
If you are in Leeds (for example) the satellite position is roughly 22 degrees above the horizon. Steal a protractor from your child's pencil case and sellotape a cotton thread to its zero point. Hang a small weight on the cotton thread (another "use for a dead cat"?) With the cotton hanging at the 22 degree mark, sight up the flat edge of the protractor while looking in the direction in which the stick is pointing. That's the position of the satellite. If it's obstructed by a tree, building, fence or your washing, move somewhere else or find a ladder.
Fixing the dish
Make a paper template of the dish wall-mount bracket and use it to mark out the fixing holes on the bricks (not in the mortar). Use proper dish-fixing bolts (not wood screws!) You'll need a 10mm masonry drill bit, a hammer drill, 13mm spanner and goggles.
When the dish is in place and roughly aligned, use a satfinder meter to finalise the alignment. A low cost meter such as the H28-8235 will do just fine. People have managed to align their dish by trial and error "in under three days without a meter". That's probably something to be proud of but a satmeter will let you do it in minutes!
And, no, a multimeter won't do. One man spent several frustrating days up a ladder with a multimeter. He didn't realise that an LNB needs a power supply in order to amplify the satellite signal. Proper satmeters either have internal battery cells or else let the power from the receiver go through to the LNB.
The coaxial cable has to be the proper double-shielded stuff. Ordinary TV cable won't do. It needs to have a threaded "F" connector fitted to each end. There's a useful web page that gives a pictorial explanation here: http://www.satcure.co.uk/tech/fconn.htm
When the dish is aligned, connect the cable to the LNB. Waterproof the connection with "self-amalgamating tape" (other tapes simply won't do) and hold the cable to the dish arm with PVC tape or cable ties, leaving a "drip loop" beneath the LNB. Hold the cable to the wall with appropriate cable clips and drill a 10mm hole through the wall where the cable must enter. Make another drip loop below the entry hole and seal the hole to prevent water ingress. Connect the cable directly to the satellite receiver after cutting off any excess and fitting an "F" connector.
The LNB "skew" is now set by rotating the LNB slightly in its clamp to get the best "signal quality" reading from the satellite receiver (read the manual).
Finally, the dish can be painted to protect and disguise it and so can the cable.
Martin Pickering B. Eng.
Technical Author
