Satellite Technologies

A satellite is a telecommunications device in orbit around the Earth. Satellite communications utilizes radio freqencies as the communications meduim and uses satellites to receive, amplify and retransmit an earth-based station's uplink signal back down to a receiving earth station.

It is important to remember that all satellite communication is simplex--that is, the uplink and downlink are separated. All satellite connections are handled separately and frequently sold and purchased as separate services.

BASICS

• Satellite Orbits
• Satellite Tracking
• Satellite Subsystems
• Frequency Bands
• Polarity

THE RF CIRCUIT

• Uplink / Downlink Chains
• Power
  • Radiated
  • Reflected
  • Effective
• Interference
  • Noise
    • Carrier to Noise Ratio
    • Signal To Noise Ratio
    • Noise Floor
    • Noise temperature
  • Spectrum Interferance
    • Saturation
    • Solar/Sun Outage
  • Intermodulation
  • Harmonic Distortion
• Attenuation
  • Rain Fade
  • Atmospheric Absorbption
  • Impedance
• Gain
  • Antenna Gain
  • Amplifier Gain
    • Gain over Temperature (G/T)
    • Effective Output Power
• Voltage Standing Wave Ratio (VSWR)
• Free space loss
• Backoff

MODULATION

• PSK - Phase Shift Keying
  • BPSK
  • QPSK
  • nPSK
  • Concentric PSK
• QAM - Quadrature Amplitude Modulation

Multiplexing

• OFDM - Orthogonal Frequency Division Multiplexing

ERROR CORRECTION

• Forward Error Correction

Convolutional CODING (Line Coding Technologies)

• Viterbi
• Reed Solomon

DIGITAL SERVICES

• Single Channel Per Carrier (SCPC)
• Multiple Channels Per Carrier (MCPC)
• Digital Video Broadcast (DVB)

EARTH STATION EQUIPMENT

UPLINK CHAIN

• Data Source (Router)
• Modulator
• Up-Converter
• Amplifiers
• Wave Guide
  • Baseball Switch
• Dish
  • Antenna
  • Feed Horn
  • Mesh vs. Solid

DOWNLINK CHAIN

• Antenna (Dish)
• Low Noise Amplifier (LNA)
• Low Noise Block Downconverter (LNB)
• Down-Converter
• Demodulator
• Data Destination

 

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