HRPT/AHRPT System > Marine Antenna

Dartcom 1.3m active-stabilised marine antenna installed on the NERC research vessel RRS Discovery

Dartcom 1.3m active-stabilised marine antenna installed on the NERC research vessel RRS Discovery
Dartcom 1.3m active-stabilised marine antenna installed on the NERC research vessel RRS Discovery

Equipment rack for marine antenna
Equipment rack for marine antenna

Active-stabilised pedestal
Active-stabilised pedestal

This antenna is designed to track polar-orbiting satellites on moving vessels using a state-of-the-art active-stabilised X-Y pedestal to compensate for pitch, roll and yaw. It has continuous axis movement to eliminate cable wrap problems without slip-rings or rotary joints. Together with the pedestal’s high speed and accuracy this ensures no “cone of silence” (data loss at high elevations).

The antenna has a 0.35 F/D ratio and 24.7dBi gain (S-band 27dBiC) to achieve a system G/T of better than 3.4dBK at 1.7GHz and 4.7dB/K at 2.252GHz, both at 5° elevation, and a bit error rate of better than 1:106 from 3.5° elevation.

The reflector is a 1.3m diameter prime focus aluminium parabolic dish finished in light grey paint (RAL 7044). An integrated feed/downconverter (IFD) is mounted at the focal point in a hermetically sealed unit – see Land-Based Antennas for specifications.

The dish and pedestal assembly is mounted inside a weather-tight glass fibre radome and base with access hatch.

The antenna control unit (ACU) is located below decks in a 19” equipment rack with the receiver rack, ingest PC, UPS and network switch. The ACU provides fully automatic control of the pedestal using an advanced stabilisation algorithm. Full diagnostics and maintenance facilities are available on a colour TFT screen.

This antenna is ISO9001/CE certified and has been designed to meet or exceed military standard (MIL-STD) specifications.

Marine antenna specifications

Pedestal:  
    Stabilisation Active, with gyro sensors for pitch, roll and yaw rates
    Azimuth range No limit (continuous)
    Elevation range –10° to 190°
    Pitch rate ±15° in 6 seconds
    Roll rate ±30° in 8 seconds
    Yaw rate ±80° in 50 seconds
    Turn rate 10°/second
    Total weight 150kg approx
Radome:  
    Height 1.68m approx
    Diameter 1.52m approx
Environment:  
    Operational wind speed 185km/h (100 knots)
    Survival wind speed 240km/h (130 knots)
    Operating temperature –30°C to +70°C
    Design specifications:  
    EMI/RFI MIL-STD-461
    Vibration MIL-STD-167-1
    Shock MIL-STD-901
Power requirements:  
    Voltage 115/230V AC @ 50/60Hz
    Power consumption 1000VA typical


Receiver Rack

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