Ground station antennas
Our ground station has two Yagui model X-Quad from Wimo for both 2 m and 70 cm bands.
Antenna used in 2 m band is the following:
Antenna used in 70 cm band is the following:
This table shows their characteristics, note the geometry of the 2m antenna that allows double polarization.
| 2m X-Quad | 70cm X-Quad | ||
|---|---|---|---|
| Elements | 12 | 18 | |
| Gain | 10,5 | 12,8 | dBD |
| 3dB HPBW horizontal (E) | 47 | 36 | Deg |
| Vert. (H) | 46 | 36 | Deg |
| Front/Back ratio | 19 | 21 | dB |
| Max. power | 1500 | 1000 | Watt |
| Stacking distance | 2,8 | 1,1 | m |
| Length | 1460 | 1270 | mm |
| Width | 730 | 220 | mm |
| Height | 2,3 | 1,6 | Kg |
| Windload a 160km/h | 74 | 48 | N |
| Connector | 2x N jacks | ||
| Connector for circular polarisationNo. | 18047 | 18049 | |
See the instruction manual here and here (70cm).
We can work in both vertical and horizontal polarization; moreover, if we use an emphaser we would work in LHCP and RHCP polarization.
In a radio-link between the satellite and the ground station we need circular polarization because radio waves passing through the Earth™s ionosphere are likewise subject to Faraday effect. You can look up a better explanation in the book: Antenas, ediciones UPC, Cardama y otros. Tema 2: Propagación.
The following figure shows the radiation pattern of both antennas:
No, we show you some photos of our antennas:
