There are two major causes of poor satellite reception. The first is view obstructions; your reception is going to be very poor if you don't have a clear view of the southern sky, if you can get a signal at all. The other is in the wiring between the dish and the receiver box inside your house. There are many environmental factors that can degrade the wiring run between your dish and your receiver.
Go to where your dish is located. If it's up high, use a ladder.
Look along the line of sight of your dish. This should be from the back of the dish to roughly the front of the Low Noise Block (LNB) converter. Check for obstructions, such as tree branches or other foliage.
Use branch cutters to remove branches that block the dish's view of the satellite. Make sure that you have permission if the branches are on another person's property.
Check the signal strength and repeat if necessary.
Check the entire run of cable. Start at the satellite dish and work your way back to the receiver.
Look for crimps, slices or gouges in the cabling.
Note the location of any damage that find.
Tighten any loose connections that you find.
If there is damage, proceed to the next section. Otherwise, check the signal strength.
Cut out the damaged section; remove between three to five inches of cable to either side of the damaged point.
Cut a piece of new cable that is long enough to cover the gap left by removing the damaged section. Add three inches to the overall length on either end.
Using the crimping tool, strip the coax about an inch back from the ends, both on the new cable and the original cable.
Install the coax connectors. The new cable should have a male connector on one end and a female connector on the other; the original cable should have a female connector on one side of the splice and male on the other.
Crimp down the connectors and screw the splice into place.
Check the signal strength at the receiver and repeat if necessary.
If the original cable is more than five years old or needs more than two or three splices, you should consider replacing the entire run. If your signal strength is still less than optimal, you may need to replace the LNB on the dish, the receiver or both. Check to make sure that your cabling is up to par. Many older houses use RG-59 cable, which is not sufficient for the long runs that satellite connections usually require.