Land-Based Antennas
Dartcom 1.2m land-based antenna
Dartcom radome-enclosed 1.5m land-based antenna
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 |
1.2m and radome-enclosed 1.5m antenna options are available for land-based ground stations. Both provide continuous tracking of satellites with no “cone of silence” (data loss at high elevations).
The Dartcom XPA dual-axis rotator controller with PID function and closed-loop feedback gives excellent pointing accuracy and smooth satellite tracking. A high-speed RS-232/RS-422 serial data link allows the ingest PC to control the rotator and provide status information and 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.
The 1.5m antenna allows future system upgrades to receive X-Band EOS data from Terra, Aqua, Suomi-NPP, JPSS and FY-3 satellites.
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 mounted on 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 which is mounted on the pedestal.
The whole dish and rotator assembly is mounted on a galvanised steel pedestal for fixing to a suitable concrete base or steel structure.
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.
The dish is mounted on 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 which is mounted on the pedestal.
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 an inspection hatch on the bottom or side. The radome can be fixed to a suitable concrete base or steel structure.
Land-based antenna specifications
| 1.2m antenna | 1.5m antenna | |
|---|---|---|
| Bit error rate | 1:106 from 3.5° elevation | 1:106 from 2° elevation |
| Azimuth range | 0° to 359.9° (minimum) | 0° to 359.9° (minimum) |
| Elevation range | 0° to 180° (minimum) | 0° to 180° (minimum) |
| Azimuth rate | 10°/second (±10%) | 48°/second (±10%) |
| Elevation rate | 10°/second (±10%) | 10°/second (±10%) |
| Mechanical tolerance | ±0.15° azimuth ±0.15° elevation |
±0.15° azimuth ±0.15° elevation |
| Tracking accuracy | ±0.1° | ±0.1° |
| Temperature | –20°C to +60°C operational | –20°C to +60°C operational (–40°C with optional heater) |
| Wind speeds | 85km/h (46kt) operational 145km/h (78kt) survival |
185km/h (100kt) operational 240km/h (130kt) survival |