Installing a motorised satellite dish system can be a tricky business to the uninitiated. If you have never installed even a simple satellite dish before, this is best left to an expert satellite TV installer. For those of you determined to have a go, here is a rough guide to what is involved. Motor mounts will usually come with comprehensive installation instructions and if you follow the manufacturer's instructions carefully you should have no problems.
DiSEqC and USALS
First of all, a little bit of theory. Eutelsat developed the original DiSEqC protocol to allow receivers to control a monoblock LNB, switching it between Eutelsat and Astra satellites. The DiSEqC protocol is basically a standardised set of control codes that are sent from a receiver up the LNB cable to some “intelligent” circuitry in the LNB to tell the LNB to do something.
It was quickly realised that the DiSEqC protocol could be used to control a motor mount on the satellite dish. Italian company Stab developed the DiSEqC 1.2 standard with Eutelsat and then went on to develop USALS. USALS is a program for calculating the positions of satellites in orbit and is capable of an accuracy of 0.1°. Both DiSEqC 1.2 and USALS are widely adopted by manufacturers for motorised satellite dish systems worldwide.
Practically speaking, DiSEqC 1.2 can be implemented in your receiver and does not require you to have any additional hardware. A receiver designed to control a motorised dish should have a more powerful LNB power supply. When installing the dish for the first time, it only needs to be aligned to 1 satellite as a reference point. The receiver can then take care of finding the rest. If your receiver also has the USALS software installed, finding satellites should be a no-brainer since all their positions are stored in the receiver.
Installing DiSEqC and USALS mounts (H-H mounts).
In the UK , the site of you dish needs to have a clear line of sight in all directions facing south. No obstacles like tall buildings or trees should be in the way of your dish's rotational field of view southwards. If you are going to use a motor mount, there would be little point in having a dish less than 80cm, since you will need a dish size that is capable of receiving signals from all the additional satellites you want to use. For, motorised pole mounted dishes, the most common type of dishes used are offset dishes which are designed to be mounted almost vertically.
The motor mount fits between the dish and the fixed pole, where a fixed dish is normally fitted to. Your pole should be installed as perfectly vertical as possible. The base unit side of your motor should be clamped securely to your pole. Your dish should then be clamped to the motorised pole on your motor.
The tricky part is getting your motor inclination and dish elevation settings correct. With a motorised dish, the dish does not rotate on a perfect horizontal axis. Rather, it rotates the dish on a slight arc (due to the curvature of the Earth). You will notice that the motorised pole is bent to achieve this arc rotational effect.
Before mounting your motor, make sure it is set a zero (0°) (south) to make for easier checking later. If it is not at zero, simply connect it to your receiver and move it to zero (0°). At the base of the motor where it is attached to the pole, there is an inclination mount where you can adjust the “motor inclination”. This inclination mount consists of a hinge bolt and another bolt to lock the inclination of the motor in place. The motor inclination needs to be adjusted according to your latitude. You motor will include instructions on the correct inclination; you just need to find the latitude of your location from an atlas.
The dish needs to be clamped after the bend on your motor pole. Once you have mounted your motor correctly to the pole, you will notice that after the bend of your motorised pole, it is almost vertical. Attach your dish to this section of the pole and clamp it securely. Normally the dish is secured to the motorised pole using U-bolts. The elevation of your dish needs to be adjusted according to the following formula:
Dish Elevation = motorised pole offset angle – column declination
The motorised pole offset angle is the angle of the motorised pole after the bend to the motor axis. This angle varies between motor models and is usually 30° or 45° to the motor axis.
The column declination is a slight adjustment required to account for the fact that a geostationary satellite is not exactly seen from an angle perpendicular to the polar axis but slightly lower. In the UK this varies between 7.3° at Land's end to 8° in Orkney. It shouldn't be to difficult to estimate the figure for where you are based, alternatively just use a figure of 7.5°.
Once you have correctly set your motor inclination and dish elevation and your motor is at zero (south) you should now have the correct elevation for the top of the satellite arc or arc apex.
Horizontal Alignment
The motor installation must be adjusted to point south. To find the correct horizontal alignment of the motor mount, position the motor to a known satellite and adjust the horizontal rotation of the motor installation accordingly. In the UK , probably the best satellite to use as a reference point is Hotbird.
This is much easier to do if you have USALS on your receiver. Using the USALS software on your receiver, enter your latitude and longitude. Then instruct the receiver to point your dish to Hotbird. This will position the motor to where Hotbird is expected to be found. Then using a meter, adjust you're the horizontal rotation of your motor installation until you get a strong signal. To ensure you have the correct satellite, tune your receiver into a known channel. A good channel to use is RAI News @ 11.804GHz/V 27500 2/3, it has a strong signal and is broadcast 24 hours a day. Check that you can receive this channel with a good strong signal on the receiver's signal indicator. Also, it would be useful confirmation to do a quick transponder scan.
If you do not have USALS installed but only have the DiSEqC system, you will have to position the motor to a known satellite manually. The correct position of a motor is calculated using the following formula:
Motor Position = Satellite Position – longitude
Note that Eastern longitudes are negative and Western Longitudes are positive. Let us take Swansea as an example. Swansea 's latitude is 4 ° west. Hence the motor position should be: - 13 – 4 = - 17, or 17° East. Set your motor position to 17° East, then rotate your motor installation until you get a string signal using a meter. Again, in the same way using USALS, conform that you have the correct satellite using a reference TV channel.
If the motor mount has been installed correctly, you should be able to find all the other available satellites easily. You may need to make slight adjustments to the motor inclination, declination and azimuth for the dish to correctly track the satellite arc.
Once you have performed the final adjustments, you are ready for multi-satellite reception.
DiSEqC and USALS
First of all, a little bit of theory. Eutelsat developed the original DiSEqC protocol to allow receivers to control a monoblock LNB, switching it between Eutelsat and Astra satellites. The DiSEqC protocol is basically a standardised set of control codes that are sent from a receiver up the LNB cable to some “intelligent” circuitry in the LNB to tell the LNB to do something.
It was quickly realised that the DiSEqC protocol could be used to control a motor mount on the satellite dish. Italian company Stab developed the DiSEqC 1.2 standard with Eutelsat and then went on to develop USALS. USALS is a program for calculating the positions of satellites in orbit and is capable of an accuracy of 0.1°. Both DiSEqC 1.2 and USALS are widely adopted by manufacturers for motorised satellite dish systems worldwide.
Practically speaking, DiSEqC 1.2 can be implemented in your receiver and does not require you to have any additional hardware. A receiver designed to control a motorised dish should have a more powerful LNB power supply. When installing the dish for the first time, it only needs to be aligned to 1 satellite as a reference point. The receiver can then take care of finding the rest. If your receiver also has the USALS software installed, finding satellites should be a no-brainer since all their positions are stored in the receiver.
Installing DiSEqC and USALS mounts (H-H mounts).
In the UK , the site of you dish needs to have a clear line of sight in all directions facing south. No obstacles like tall buildings or trees should be in the way of your dish's rotational field of view southwards. If you are going to use a motor mount, there would be little point in having a dish less than 80cm, since you will need a dish size that is capable of receiving signals from all the additional satellites you want to use. For, motorised pole mounted dishes, the most common type of dishes used are offset dishes which are designed to be mounted almost vertically.
The motor mount fits between the dish and the fixed pole, where a fixed dish is normally fitted to. Your pole should be installed as perfectly vertical as possible. The base unit side of your motor should be clamped securely to your pole. Your dish should then be clamped to the motorised pole on your motor.
The tricky part is getting your motor inclination and dish elevation settings correct. With a motorised dish, the dish does not rotate on a perfect horizontal axis. Rather, it rotates the dish on a slight arc (due to the curvature of the Earth). You will notice that the motorised pole is bent to achieve this arc rotational effect.
Before mounting your motor, make sure it is set a zero (0°) (south) to make for easier checking later. If it is not at zero, simply connect it to your receiver and move it to zero (0°). At the base of the motor where it is attached to the pole, there is an inclination mount where you can adjust the “motor inclination”. This inclination mount consists of a hinge bolt and another bolt to lock the inclination of the motor in place. The motor inclination needs to be adjusted according to your latitude. You motor will include instructions on the correct inclination; you just need to find the latitude of your location from an atlas.
The dish needs to be clamped after the bend on your motor pole. Once you have mounted your motor correctly to the pole, you will notice that after the bend of your motorised pole, it is almost vertical. Attach your dish to this section of the pole and clamp it securely. Normally the dish is secured to the motorised pole using U-bolts. The elevation of your dish needs to be adjusted according to the following formula:
Dish Elevation = motorised pole offset angle – column declination
The motorised pole offset angle is the angle of the motorised pole after the bend to the motor axis. This angle varies between motor models and is usually 30° or 45° to the motor axis.
The column declination is a slight adjustment required to account for the fact that a geostationary satellite is not exactly seen from an angle perpendicular to the polar axis but slightly lower. In the UK this varies between 7.3° at Land's end to 8° in Orkney. It shouldn't be to difficult to estimate the figure for where you are based, alternatively just use a figure of 7.5°.
Once you have correctly set your motor inclination and dish elevation and your motor is at zero (south) you should now have the correct elevation for the top of the satellite arc or arc apex.
Horizontal Alignment
The motor installation must be adjusted to point south. To find the correct horizontal alignment of the motor mount, position the motor to a known satellite and adjust the horizontal rotation of the motor installation accordingly. In the UK , probably the best satellite to use as a reference point is Hotbird.
This is much easier to do if you have USALS on your receiver. Using the USALS software on your receiver, enter your latitude and longitude. Then instruct the receiver to point your dish to Hotbird. This will position the motor to where Hotbird is expected to be found. Then using a meter, adjust you're the horizontal rotation of your motor installation until you get a strong signal. To ensure you have the correct satellite, tune your receiver into a known channel. A good channel to use is RAI News @ 11.804GHz/V 27500 2/3, it has a strong signal and is broadcast 24 hours a day. Check that you can receive this channel with a good strong signal on the receiver's signal indicator. Also, it would be useful confirmation to do a quick transponder scan.
If you do not have USALS installed but only have the DiSEqC system, you will have to position the motor to a known satellite manually. The correct position of a motor is calculated using the following formula:
Motor Position = Satellite Position – longitude
Note that Eastern longitudes are negative and Western Longitudes are positive. Let us take Swansea as an example. Swansea 's latitude is 4 ° west. Hence the motor position should be: - 13 – 4 = - 17, or 17° East. Set your motor position to 17° East, then rotate your motor installation until you get a string signal using a meter. Again, in the same way using USALS, conform that you have the correct satellite using a reference TV channel.
If the motor mount has been installed correctly, you should be able to find all the other available satellites easily. You may need to make slight adjustments to the motor inclination, declination and azimuth for the dish to correctly track the satellite arc.
Once you have performed the final adjustments, you are ready for multi-satellite reception.
