• Question: What kind of transmitter do ground stations use to transmit to satellites?

    Asked by Amrit S. to Naziyah on 8 Mar 2021.
    • Photo: Naziyah Mahmood

      Naziyah Mahmood answered on 8 Mar 2021:

      Hi Amrit! Ground stations often need to use systems that can transmit signals in a very high frequency band. Ground stations also receive these radio waves from the satellites, which carry information such as (examples) the health of the satellite, it’s location in orbit, science data such as space weather data etc
      It depends on how we use the ‘payloads’, meaning the main instruments onboard 🙂
      Here’s a little snippet on it from the NASA website!

      https://spaceplace.nasa.gov/x-ponder/en/

Comments

  • Photo: Ed

    Ed commented on :

    Ground stations, in the simplest case, are just radios. The dishes (sometimes large, like those we use at Goonhilly), are used to direct all the radio energy into a specific direction. This helps the radio signal travel a long way into space to reach spacecraft. Between the radio and the dish we add additional amplifiers to make the signal as strong as it needs to be for any mission. The signal strength needed for a low-earth orbit satellite is much lower than that needed to reach Mars or beyond. There are several types of amplifiers depending whether the ground station is small or large – with power output as low as 50W or as high as 20kW.
    The other key aspect is the frequency bands being used. There are specific frequencies which are allowed for use for space communications – these are labelled (for historical reasons) with letters: VHF, UHF, L, C, S, X, K, W and others. In our ground stations we use S and X for transmission. This means we have whole chains of equipment which run in S band, and whole chains that run in X band. These ultimately all connect together just behind the dish. Let me know if you want to know more about this.