bids are invited for vayulink (composite position transmission and reception unit) - transceiver with internal software defined radio, at least 30 db power output, 4x sdr. independent operation of each sdr. temperature stablised crystal, modulation fsk, bpsk, psk. encryption key generator and receiver, linux based interface, 5-28 v dc operation, air cooled design, independent antenna for each sdr, usb connection, uart and wlan connection. frequency stability better than 25 khz. operation from 300 to 20000 ft, fanless cooling capable - convection cooled casing, programmable at user end. temperature stability -20 to +80°c, remote access platform, irnss, gps, glonass integrated unit., position display system with satcom gis ground stations installation of ground stations maintenance of ground sensors for 2 years display system with 32 inch screen. gis interface unit for converting satcom position data to map interface, data software to record, replay and distribute data. all cables, interface and connections. integrated ground stations with aircraft position receiver, radio relay station, weather monitoring station, weather camera system, data connectivity on dual band dual standby sets. power supply with dual standby sets solar and wind supply backup for 48 hrs. air band radio minimum 10 watts 118-136 mhz installation in forward location, with earth work and pole. maintenance of ground stations for two years, including all data connectivity, system repair at central location and battery changes total quantity : 1