Is my demodulator Inmarsat or Spotbeam?

This depends on which antenna you have connected to your demodulator. If you don't know, you should follow the cable to the antenna and identify its type.

Spotbeam:

  • Spotbeam antennas are omnidirectional which means there is no need to alter the antenna's orientation when selecting a different satellite beam on the demodulator
  • In the demodulator the antenna power must be switched ON to be able to receive the spotbeam antenna signal
  • You may then select from all of the beams listed below

Inmarsat:

  • This gyro stabilised antenna will change direction depending on which satellite it is tracking. This means that when you change the satellite beam on the demodulator, care must be taken to ensure that the antenna also is changed to track the same satellite.
  • In the demodulator the antenna power must be switched OFF to be able to receive the signal from the Inmarsat antenna.
  • If you are using an Inmarsat antenna you will have access to the ARSAT, EASAT, ERSAT, IRSAT and OCSAT (not SASAT). Frequencies and symbol rates in the link shown below.

Note: Using Fleet Broadband to receive corrections is not recommended as Fugro transmits corrections on more L-band satellites than are used by Fleet Broadband. Using Fleet Broadband will thus limit the service offering, that again can in some set-ups, affect redundancy. Fugro instead recommends installing a second spot antenna for receiving the corrections.

You should also remember that the Fleet broadband terminal uses an internal GPS to determine which satellite it should use depending on your area, and change between the satellites automatically. The demodulator does NOT change satellites automatically, so you must manually go into the demodulator to change the satellite when entering an area covered by another satellite.

Fugro transmits the correction signals over the satellite beams shown in the table at fsp.support/beams.

Last reviewed: 16th May 2025