What Is L-Band?
L-Band is an alternative satellite frequency providing extremely reliable communications across the world. It has been used for the Global Maritime Distress and Safety System (GMDSS) for many years. It provides voice with data services that are much slower than VSAT and the new LEO super broadband and are generally only used for email, browsing and small downloads.
Iridium L Band services are truly global, whereas Inmarsat services reach to about 76⁰ N and S.Both use their own satellite constellations so there are no gaps, and no beam switching is required. The L-band frequency penetrates cloud and stormy weather, so all these features make this very reliable which is why L band systems are chosen as the certified safety systems for GMDSS compliance. They work well with VSAT as a companions when off-the-beaten-track to provide connectivity outside the VSAT coverage and with LEO super broadband systems to comply with GMDSS carriage requirement.
For explorer yachts, we recommend a VSAT service with an L-Band service failover. This Is built Into the Inmarsat Fleet Xpress (FX) as standard. It uses Ka band VSAT and when out of range of VSAT it seamlessly switches to the L-band Fleet Broadband service to increase the range of the FX service to 76⁰ N and S.
We also configure an alternative e3 HYBRID design using 4&5G, Ku band VSAT and L-band Iridium Certus to provide a truly global service with no limitations with seamless handover from 4&5G to VSAT to L-band and back.
The L-band Iridium or Inmarsat system can also be used with the new LEO super broadband services to fulfil the GMDSS carriage requirement and as a backup or companion.
For all the above configurations we always recommend a rugged L-band handheld or two for the grab bag.
The International Maritime Organisation (IMO) defined the rules of GMDSS in 1999 and the approved equipment that conforms to the SOLAS International standards such that “any emergency at sea will result in a distress call and the response to that call will be immediate and effective.”
Inmarsat has been IMO approved since 1999, whereas Iridium was approved in December 2020. As per the increased coverage provided by Iridium, their LT-3100S SOLAS GMDSS terminal provides Sea Area 4 GMDSS compliance, whereas the Inmarsat Sat-C GMDSS terminal provides Sea Area 3 GMDSS compliance. The Iridium terminal also provides a voice channel.
There are many evolving developments in L-Band. Inmarsat have on their roadmap new satellites to be launched in 2023 that will extend their L-band and Ka band across the Arctic to the north pole. Both Inmarsat and Iridium will be Increasing the bandwidth offered, but not up to broadband levels.
We are an Inmarsat Tier 1 distributor so can offer flexible services at very good prices with direct support for any changes. We are also an Iridium Reseller with the similar services. In addition, we are an Inmarsat Value Added Reseller (VAR) for the Inmarsat Fleet Xpress system for yachting.