Comtech EF Data CST-5000 - Manual (Page 21)

CST-5000 C-Band Satellite Terminal Introduction
Rev. 9 1–5
1.1.3 Low Noise Amplifier (LNA)
The feed assembly consists of an LNA and a wave guide transmit reject filter.
The transmit reject filter provides receive system protection from transmit energy fed
back through the antenna feed system.
The LNA standard noise temperature is 65
°K, with optional upgrades down to 33°K,
depending on gain over temperature (G/T) requirements.
1.1.4 Outdoor Enclosure
The RFT-500 assembly is a weatherproof enclosure housing the following:
• Solid State Power Amplifier (SSPA)
• Up and down converters
• M&C microprocessor
• Power supply and cables, which interface with an antenna subsystem
In the transmit (uplink) direction, the RFT-500 accepts a 70 MHz IF signal, and transmits
it in the 5.845 to 6.425 GHz frequency band.
In the receive (downlink) direction, the terminal accepts an RF signal in the 3.620 to
4.200 GHz band, and converts the signal to a 70 MHz IF output.
Power levels range from +8 dBm (for driving an external Traveling Wave Tube (TWT)
or amplifier) to 40W, depending on Equivalent Isotropically Radiated Power (EIRP)
requirements.
The up and down converters are dual conversion, with individual synthesizers for
independent transmit and receive transponder selection.
The microprocessor provides:
• On-line loop monitoring
• Dynamic control functions
• Configuration control
• Fault/status monitoring
• Serial computer/terminal interface