Sections are separated or connected by phasing devices that maintain the required current phase.
Antennas · F1SYH
Collinear antenna
A collinear stacks several vertical radiating sections fed in phase to concentrate energy toward the horizon.
VHF
UHF
Gain vertical
Operating principle
Main characteristics
Typical gain
Variable selon nombre de sections
Impedance
Adaptation nécessaire
Polarization
Verticale
Difficulty
Avancée
Dimensions and design
Lengths and phasing must be designed together. More sections increase gain but narrow the vertical beam.
Construction and tuning
Step 1
Define the number of sections.
Step 2
Calculate phasing lines.
Step 3
Maintain vertical alignment.
Step 4
Build base matching.
Step 5
Check pattern and SWR.
Advantages
- Omnidirectional gain.
- Low radiation angle.
- Suitable for repeaters.
- Narrow physical width.
Limitations
- Large overall height.
- Critical phasing.
- Very narrow vertical beam.
- Demanding mechanical construction.
History and origin
Collinear arrays have long been used for broadcasting, repeaters and base stations.
Safety
A tall collinear requires protection from wind, lightning and mechanical stress.