Published: July 21, 2025 by: Rungruang Huanraluek
What is Satellite Television?
Satellite Television is a system for distributing television signals that sends video and audio signals from a ground station (Uplink) up to communication satellites in space. The purpose is to expand the coverage area widely. The satellite then sends signals back down to Earth (Downlink), allowing viewers to receive television signals by installing a satellite dish aimed at the target satellite. The dish connects to a Satellite Set-top Box Receiver to decode the signals into TV programs. This enables viewers to watch television anywhere within the satellites coverage area.
Satellite Signal Transmission and Reception (Uplink / Downlink)
1. TV Station sends television program signals to the Earth Station via fiber optic cables as IF (Intermediate Frequency) signals carrying video and audio modulated on IF.
2. At the Earth Station, the IF signal is converted by an Up-Converter to microwave frequencies for uplink transmission to the satellite. A High Power Amplifier (HPA) boosts the signal strength enough to travel through the atmosphere to the satellite.
3. Generally, satellite TV signals are transmitted at microwave frequencies in the C-band around 6 GHz and Ku-band around 14 GHz, using large satellite uplink dishes at the Earth Station.
4. The satellite receives the uplink signal via a Transponder (which receives, amplifies, and retransmits the signal) and sends it back to Earth (Downlink). The coverage area depends on the satellites frequency band and transmission power.
5. Viewer Reception: Viewers receive the TV programs within the satellites coverage by installing a Satellite Dish to capture the retransmitted signals. The dish connects to a Satellite Set-top Box Receiver that converts the signals for TV viewing.
6. Typically, satellite TV signals are transmitted at microwave frequencies in the C-band (3.74.2 GHz) and Ku-band (~14 GHz) via large uplink dishes at the Earth Station.
7. Downlink frequency bands for satellite TV reception are microwave frequencies in the C-Band or Ku-Band (10.712.75 GHz).
What is Intermediate Frequency (IF)?
IF (Intermediate Frequency) is the frequency band used before TV signals are converted into microwave signals for uplink transmission or converted back from microwave signals received by the satellite dish into TV programs. The video and audio signals are always converted into IF first because it has low loss, is suitable for processing, and can travel well through transmission lines (Uplink IF is typically 70 MHz or 140 MHz; Downlink IF is 9502150 MHz).
References and Image Sources
https://www.essearth.com/satellite-ground-stations/
https://en.wikipedia.org/wiki/Transponder_%28aeronautics%29
