HRPT/AHRPT System > Land-Based Antennas

Dartcom 1.2m parabolic dish and rotator
Dartcom 1.2m parabolic dish and rotator

Dartcom 1.8m parabolic dish and rotator
Dartcom 1.8m parabolic dish and rotator

Dartcom radome-enclosed 1.5m parabolic dish and rotator
Dartcom radome-enclosed 1.5m parabolic dish and rotator

All antenna options provide continuous tracking of satellites with no “cone of silence” (data loss at high elevations). A state-of-the-art dual-axis rotator controller with closed-loop feedback gives excellent pointing accuracy and smooth tracking. An RS-232–RS-422 link allows the ingest PC to control the rotator and provide diagnostics.

The reflector is a prime focus aluminium parabolic dish finished in matt white paint (RAL 9010). An integrated feed/downconverter (IFD) is mounted at the focal point in a hermetically sealed unit.

1.2m parabolic dish and rotator

The 1.2m antenna has a 0.38 F/D ratio and 24.4dBi gain to achieve a system G/T of better than 2.6dBK at 1.7GHz and 5° elevation, and a bit error rate of better than 1:106 from 3.5° elevation.

The dish is fixed to the rotator using a counter-weighted aluminium frame assembly. The rotator is a compact unit with a separate housing for the power supply and controller. The dish and rotator assembly is mounted on a galvanised steel pedestal.

1.8m parabolic dish and rotator

The 1.8m antenna has a 0.42 F/D ratio and 27.5dBi gain to achieve a G/T of better than 6.0dBK at 5° elevation, and a bit error rate of better than 1:106 from 1° elevation.

The dish is fixed to the rotator using interface steelwork galvanised to BS729. The rotator is precision engineered using aluminium castings and machined steel for strength. The controller is mounted inside the rotator with a seperate remote housing for the power supply. The dish and rotator assembly is mounted on a durable galvanised steel pedestal.

1.5m radome-enclosed parabolic dish and rotator

The 1.5m antenna has a 0.36 F/D ratio and 26.0dBi gain to achieve a system G/T of better than 4.3dBK at 1.7GHz and 5° elevation, and a bit error rate of better than 1:106 from 2° elevation. This antenna allows future upgrade to receive X-Band data from Terra, Aqua, Suomi-NPP and FengYun-3.

The dish is fixed to the rotator using a counter-weighted aluminium frame assembly. The rotator is a compact unit with a separate housing for the power supply and controller. The dish and rotator assembly is mounted on a zinc plated, powder coated steel pedestal and enclosed in a two-part (plus base) composite radome with inspection hatch on the bottom or side.

Land-based antenna specifications

 1.8m antenna1.2m antenna1.5m antenna and radome
Bit error rate 1:106 from 1° elevation 1:106 from 3.5° elevation 1:106 from 2° elevation
Azimuth range 0° to 359.9° (minimum) 0° to 359.9° (minimum) 0° to 359.9° (minimum)
Elevation range 0° to 180.0°(minimum) 0° to 180.0°(minimum) 0° to 180.0°(minimum)
Azimuth rate 12.0°/second (±10%) 10.0°/second (±10%) 48.0°/second (±10%)
Elevation rate 1.0°/second (±10%) 10.0°/second (±10%) 10.0°/second (±10%)
Mechanical tolerance ±0.1° azimuth and elevation ±0.15° azimuth and elevation ±0.15° azimuth and elevation
Tracking accuracy ±0.1° ±0.1° ±0.1°
Survival temperature –35°C to +63°C –20°C to +60°C –20°C to +60°C
Wind speeds 100km/h operational
210km/h survival
85km/h operational
145km/h survival
185km/h operational
185km/h survival

Integrated feed/downconverter specifications

Feed:  
    Beamwidth 3dB at 80°, 10dB at 150°
    Gain +4.5dBi
    Polarisation Right-hand circular
Input filter:  
    Insertion loss 0.3dB maximum
    Bandwidth 120MHz maximum
Overall:  
    Noise figure 1.2dB typical
    Gain 60dB minimum
    Converted bandwidth 50MHz typical
    Input range 1682–1710MHz
    IF output 117–145MHz


Marine Antenna

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