HF Dipole Centre Fed Delta
Astel are specialist manufacturers of a wide range of HF communications antennas. Our world wide experience of antenna requirements enables us to offer the most suitable antenna for customer installation together with a prompt delivery service. All our antennas are made from high quality purpose designed components suitable for the most extreme environments. These antennas can be supplied ready made for specific frequencies or cut over length and supplied with line taps and frequency charts for simple on site adjustment.
These antennas are most suited for short to medium range working. When suspended about a quarter wave above ground level radiation is predominantly upwards, giving some omni directional coverage using skywaves. As the height above ground level is increased to a half wave, the radiation pattern tends to a figure of eight
Mechanical Specification
| Antenna Elements | 7/0.44" (7/1.118rnm) or 7/0.36" (7/0.914mm) hard drawn copper magnesium strand. |
| Insulators | Carbon loaded polypropylene. |
| Spreaders | Antenna spreaders used on FDA/1 are fibreglass. Feed Iine spreaders are porcelain or fibreglass as appropriate. |
| Baluns | SMC can supply a wide range of matching balun transformers for all combinations of input impedances and powers. |
General Specification
| Bandwidth: | +/- 2% of centre frequency |
| VSWR | Better than 1.5 : 1 |
| Power: | Up to 2kW |
| Impedance: | 50 ohms |
| Polarisation: | Horizontal |