  This paper is concerned with modelling and simulation of VSAT (very small
aperture terminal) data messaging network operating in India at Karnataka with
extended C-band. VSATs in Karnataka of KPTCL use VSATS 6.875-6.9465G Hz uplinks
and 4.650- 4.7215 GHz downlinks. These frequencies are dedicated to fixed
services. The Satellite is Intelsat -3A, the hub has a 7.2 m diameter antenna
and uses 350W or 600W TWTA (Travelling wave Tube Amplifier). The VSAT's are 1.2
m with RF power of 1W or 2W depending on their position in the uplink beam with
data rate of 64 or 128 K bit/s. The performance of the system is analysed by
the error probability called BER (Bit Error Rate) and results are derived from
Earth station to hub and hub to Earth station using satellite Transponder as
the media of communication channel. The Link budgets are developed for a single
one-way satellite link.
