Very Small Aperture Terminal - VSAT Installation Tutorials

VSAT Installation Tutorial:

When chosing a site for a VSAT installation, the antenna needs to be located with a clear view to the satellite. Access to the antenna should be restricted to prevent any damage or harm from occurring to either the antenna or people. Ideally, the antenna should be sheltered from wind.

The outdoor unit (ODU) is mounted on the feed arm in front of the antenna and houses the Radio Frequency (RF) equipment required to transmit (TX) and receive (RX) from the antenna.

The outdoor unit (ODU) mainly consists of these devices:

• Low Noise Block (LNB) which is a down converter and receiver
• Block Up Converter (BUC) this is the up converter and transmitter
• Ortho-Mode Transducer (OMT) the Tx and Rx waveguide joint.
• Microwave filters which protect the LNB from the Tx signals.

Safety Is Important:

Installing a VSAT can be very dangerous especially on a roof. Follow the instructions carefully to ensure that the antenna is correctly assembled.

Care must be taken when working near the edge of roof tops such that you do not fall off or drop anything on people who may be below.

Never work alone and always look out for each other.

Static - Permanent Mounting:

This type of installation is usually a pole mount which is bolted securely to the ground. The pole can be concreted into a hole but in both cases must be completely vertical.

Temporary Mount (Non-Penetrating):

This is a quickly deployed mount which consists of a frame constructed to hold the pole vertically and securely whilst providing a large base for the addition of ballast. Ballast (heavy bricks or concrete) weigh down the mount preventing the wind from overturning the antenna assembly. In extreme conditions even a permanent mount can sustain damage and so a sheltered location and saftey lines attaching the mount to the building should be considered. The antenna could otherwise be blown of the roof of a building. A structural survey is required before any such mounts are installed on a roof to ensure the weight is not a risk to the building.

Tx & Rx Coax Cables:

Usually two coax cables carry the signals between the IDU and the ODU. Power for the LNB and BUC as well as control signals are carried along these coaxes.

Ensure that the ends of the coax cables are properly terminated in F type connectors.

There should be 2mm of copper coax centre conductor protuding from the connector in order to ensure a good connection is made.

The braided screen of the coax cable must not touch the inner copper conductor. This will cause a short and damage the equipment.

Connect the coaxes to the ODU noting which are Tx and Rx then run them to the IDU.

The connectors at the ODU should be sealed against the weather with the cables dropping down from the connectors before being taped up to the feed arm. This allows water to harmlessly drip from the cable rather than run into the connector, in other words the connectors should be higher than the cables.

The indoor unit (IDU):

The indoor unit (IDU) usually consists of a single box which should be located in a dry, cool and clean place. An office environment is ideal.

The coax cables run from the antenna ODU to the IDU and should not cause a hazard to anyone along the way.

Use cable ties to clip them safely to pipes, fencing or similar in order to make the installation neat, tidy and safe.

Cables that can blow around in the wind will fail long before cables that are securely tied down.

The IDU requires a stable mains supply and connection to the end user equipment. This could be further units for telephone exchanges or networks for internet or intranet connections.

Pointing and Polarisation:

Pointing the antenna is not easy but can be acheived with a compass and the required angles. (Azimuth and Elevation)

Azimuth is the angle bearing from True North. (North = 0 degrees)

Elevation is the angle up from the horizon. (Horizontal = 0 degrees)

The final step is done whilst communicating with the VSAT network 'HUB' staff and they will ask to adjust the polarisation by rotating the feed.

Whilst doing this do not stand in front of the antenna, it is transmitting RF radiation for one thing and your body will block the signal to the satellite for another. Stand to one side and adjust feed in one degree steps until the HUB or NOC is happy.

That's about it.

Check out Satellite Signals for details of how to point your antenna and a variety of online calculators to work it all out for you.

More Information and Tutorials:

We recommend looking at this training video from Ground Control to better understand the tutorials.

Click Here for the Ground Control VSAT Online Training Course and Training Video.

Here is an illustrated journal of an installation in Iraq showing all the stages of installation in detail.

Here is how PACTEC (Partners in Technology International) use VSAT technology to help is disaster relief efforts around the world.

More Information: