Introduction

The concept of a global telecommunications system using satellites
was put forward first in an article for the British Magazine "Wireless
World" in May 1945 by the science fiction author, Arthur C. Clarke.
A brief extract from this article addressing the issue of orbital
location for geostationary communications satellites is quoted below.
"All these problems can be solved by the use of a chain of
space-stations with an orbital period of 24 hours, which would
require them to be at a distance of 42,000 Km from the center of the
Earth. There are a number of possible arrangements for such a
chain but that shown (Figure 1.1) is the simplest. The stations would
lie in the Earth’s equatorial plane and would thus always remain
fixed in the same spots in the sky, from the point of view of terrestrial
observers. Unlike all other heavenly bodies they would never rise
nor set. This would greatly simplify the use of directive receivers
installed on the Earth."

"The following longitudes are provisionally suggested for the stations
to provide the best service to the inhabited portions of the globe,
though all parts of the planet will be covered.


30° E - Africa and Europe
150° E - China and Oceania
90° W - The Americas



Each station would broadcast programs over about a third of the
planet. Assuming the use of a frequency of 3,000 megacycles, a
reflector only a few feet across would give a beam so directive that
almost all the power would be concentrated on the Earth. Arrays a
meter or so in diameter could be used to illuminate single countries if
a more restricted service was required."

Vsat Basics

We will start Vsat basics on daily basis to help us be on our way to understanding vsat solution and solve vsat problems. The tutorial will start on monday.

Link Budget Calculation

To do link budget you need to know certain parameters about
1. Tx station: HPA size(db)+ TX Antenna gain(dbi)- Free space loss(200db) + Transponder TX EIRP

2. Rx station: Transponder RX EIRP + LNA gain + Rx Antenna gain

Then you have to specify the bandwidth and send the details to your satellite provider of your choice.

You can also check www.intelsat.com for LST5 link budget calculator

link budget

how can i do a link budget for a 4.5m antenna

Troubleshooting vsat links.

When you have trouble with your vsat links, I can give you a help on how to find a solution to your problem.

Vsat has several points of failure which I can help you locate when you post in your questions.