Since all satellites for DTH (Direct To Home) TV are in geosationary orbit, they are positioned on an imaginary arc (now called the Clarke Belt in honour of Arthur C. Clarke) about 22,500 miles above the equator. This means a satellite dish always points upwards and in the direction of the equator i.e. generally southwards.
Terminology : Elevation and Azimuth
The up and down angle is called 'Elevation'.
The east and west rotation angle is called 'Azimuth'.
Offset Dishes : A Word of Warning
An offset dish may appear to point downwards!
Offset dishes may appear to be pointed low towards the horizon, when in fact they are aiming at a much high elevation as shown in the above diagram.
If you've never aligned a dish before, it can be very frustrating, especially if you don't have a signal meter of some sort. You may well end up thinking the receiver is faulty. Digital channels are either 'on' or 'off' and do not fade in or out gradually like analogue signals, further adding to the difficulty. Waving a dish about in the deluded hope that you will somehow find the correct location without either setting the elevation angle or knowing the azimuth angle is a complete and utter waste of time. However, if you follow the steps outlined below you will succeed ... eventually!
1. Attach the F-connectors - Make sure that the cable and F-connectors are properly fitted. The inner core of the coax cable and the outer braid must never come in contact with each other.
2. Set the elevation angle - For the majority of novice satellite users, the satellite they wish to align to is the Astra2/Eurobird cluster at 28 degrees east. This is where Sky, BBC, ITV and C4 are transmitted from. For Ireland, the dish elevation for Astra2 is approximately 22 degrees.
Most offset dishes have an elevation scale on the mounting bracket which allows you to adjust the dish to the correct elevation.
Set this to 22 degrees and then tighten the nut.
For satellites other than Astra2, a list of approximate elevation angles is provided.
3. Tune your receiver - If you don't have a signal meter, you will have to use your receiver's on-screen meter. Firstly, make sure you are tuned to an active channel or transponder and that all the parameters are correct - Frequency 10.774GHz, Symbol Rate 22000, Polarisation Horizontal, (FEC Auto or 5/6) is suitable for the BBC channels on Astra2.
You may have to enter the Setup/Installation menu in order to have a constant display of the meter.
4. Aim the dish - A compass can be used to get a rough idea of where to aim the dish but remember to keep the compass away from the metal dish. The Dishpointer tool below is especially helpful.
Alternatively you can use a calculated sunpass time for the satellite i.e. the time at which the sun's azimuth is the same as the satellite. A detailed explanation on how to locate a satellite using the position of the sun is provided.
5. Rotate the dish - Slowly move the dish east or west incrementally until you observe some activity on the receiver meter settings. If you rotate the dish too quickly, you will run past the satellite as there is a usually a small lag before the receiver quality meter reacts. When you do see activity on the meter, rotate the dish about that point until the level is at a maximum. Lock the dish into place.
6. Optimise the elevation - With the dish pointing in the right direction, readjust the elevation as per 2 until the quality is at a maximum
7. Set the skew angle - As you face the dish, rotate or twist the LNB clockwise for an easterly satellite or anticlockwise for a westerly satellite until the quality is again maximised. This can make a very significant improvement to the signal quality and should not be overlooked!
8. QED - Finished! If some channels are missing, then do a channel search to update the receiver's database.
1. When I perform a channel scan, I can only find German/Italian/foreign channels - if you find that mostly German or Italian channels are returned when you do a scan, then you are probably aligned to the wrong satellite. This will most likely be Astra 1 at 19 degrees east (or occasionally Hotbird at 13 degrees east). Therefore, the dish is aligned to a satellite which is both west of, and higher than, your target satellite at 28 degrees east. Note the current position of the dish using a marker or tipex, lower the dish by about 3 degrees and move it slowly east until you see activity again on the meter.
2. The signal meter is registering 80%, but all of the preprogrammed channels are still blank - again you are most likely aligned to the wrong satellite. The same frequencies are reused on different satellites across the arc e.g. on Astra 2D 28E, BBC One is transmitted on 10.818, V, 22000. But on Astra 1KR 19E, TVVI is also transmitted on 10.818, V, 22000. So if your receiver is tuned to BBC One, but your dish is aligned to Astra 1KR 19E, the signal level and quality meters will show readings of 80%, but the screen will remain blank. The solution is to align the dish to the correct satellite as per 1.