The 21-40-205 is a ‘high gain’ L-band satellite communications antenna designed for use with the Thuraya and Inmarsat satellite system. Electrical design comprises two quadrifilar helix elements, elevated above the mounting base to provide down to horizon coverage over the frequency range 1525 to 1661 MHz. The antenna element is encased in a radome, intimately bonded to an aluminum baseplate having two TNC female coaxial connectors. The complete assembly is foam-filled for reliability in Worldwide conditions of service on helicopters, low speed fixed wing aircraft and UAV’s.