A.1 Introduction

An essential part of the planning of a satellite system is the link-budget calculation. In Chapter 11 we presented the equations to be used in this exercise, but anyone entering the satellite communications field will need familiarity with the use of these equations. In this Appendix we have collected together some examples of link budgets and their use in planning satellite systems. It is recommended that the reader work through these in detail and by so doing master the art of satellite design. The detailed methodology and terminology, and the degree of accuracy employed, vary according to the application and requirement. It should be stressed that there is no one correct way to present a link budget.

The examples have been chosen to illustrate currently operating systems with a range of network scenarios, modulation and multiple-access techniques. They are as follows:

1. A simplified link budget for a TVRO from the EUTELSAT satellite.

2. An FDMA system design, typical of that used in the INTELSAT system, together with an earth-station G/T calculation.

3. A high-data rate TDMA design, again typical of the rates used in the INTELSAT system. Also illustrated is the calculation of frame efficiency.

4. An SCPC design example typical of that on domestic systems using leased transponders from INTELSAT. Also illustrated here is the use of companded FM.

5. A mobile satellite system example based upon the INMARSAT standard A ships earth terminal to and from a coastal earth station.

6. A military systems...