Its slope produces mixed polarization and an asymmetric pattern strongly influenced by mast, ground and feed line.
Antennas · F1SYH
Sloper antenna
A Sloper is a dipole or resonant wire installed at an angle between a high and low support.
HF
Incliné
Polarisation mixte
Operating principle
Main characteristics
Typical gain
Proche du dipôle
Impedance
Variable
Polarization
Mixte
Difficulty
Facile
Dimensions and design
A dipole Sloper remains close to normal dipole length. A half-Sloper often uses the mast as part of the RF system.
Construction and tuning
Step 1
Choose a strong high support.
Step 2
Keep the wire away from metal structures.
Step 3
Install a balun or choke.
Step 4
Keep the low end out of reach.
Step 5
Measure in the final configuration.
Advantages
- Simple installation from a tower.
- Mixed polarization.
- Few supports.
- Some pattern orientation is possible.
Limitations
- Pattern is difficult to predict.
- Interaction with the mast.
- High-voltage end near ground.
- Common-mode current may occur.
History and origin
Slopers have been used to obtain directional or compact wire antennas from existing supports.
Safety
The lower end must be strongly insulated and inaccessible.