L-TAC™ from Inmarsat Government

L-Band TACSAT Capability to Complement Existing UHF channels

U.S. government users rely on UHF TACSAT radios to provide all-informed communications for command, control and coordination of widely dispersed forces in austere environments without the delay of deploying terrestrial infrastructures or the operational burden of protecting and sustaining them. TACSAT is in very high demand by government users as it easily and reliably extends tactical Push-to-Talk radio networks to wide area Beyond Line of Sight (BLOS) communications where existing networks are over utilized. However, UHF TACSAT channels are in short supply and relatively expensive.

Designed with U.S. military users in mind, Inmarsat’s global L-TAC service complements the scarce UHF satellite capacity with a single-hop, low-latency voice and data service, providing additional reliable capacity when UHF channels are inaccessible. Available on a global, seamless basis, L-TAC enables existing in-service tactical radios to access BLOS without the need to modify the radio hardware or the cryptos.

The L-TAC service utilizes the ability of Inmarsat-4 satellite fleet to connect L-band transponders on the satellite to provide a single-hop relay in space through existing UHF tactical radios. This is accomplished using a small external frequency adaptor on the existing UHF radio, which converts between the UHF and L-band, and connects to one of a range of directional or omni-directional L-band antennas substituted for the existing UHF antenna.  This approach enables L-band to augment UHF capacity resources, offering service throughout the global footprint of the Inmarsat-4 constellation. Inmarsat has partnered with Spectra to provide the hardware package that will include the L to UHF frequency convertor, an integrated power supply and omni-directional antenna which will support both fixed and on-the move applications.

Inmarsat’s L-TAC service is fully flexible and designed to meet the U.S. government’s security and reliability requirements cost-effectively. It is quick to set up, providing a fully-configured solution which needs minimal user intervention before deployment. Once deployed, remote management and support is provided through a 24/7 network operation center.

Inmarsat’s L-TAC communication-on-the-move service is available for vehicles and dismounted warfighters, providing a combination of reliable voice and data connectivity that is available globally, independent of local infrastructure. The L-TAC service is easy to acquire, available via flexible bandwidth leasing options for coverage and duration.


  • BLOS communications using existing UHF radios
  • Reliable global coverage, independent of local infrastructure
  • Dedicated bandwidth for netted voice and data
  • Communications on the move, on the pause, or at the halt
  • Flexible bandwidth lease options

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