All three vertical sections radiate in phase and create a low-angle bidirectional pattern.
Antennas · F1SYH
Bobtail Curtain
The Bobtail Curtain uses three quarter-wave vertical elements joined by two half-wave horizontal sections.
HF
DX
Réseau vertical
Operating principle
Main characteristics
Typical gain
Environ 5 à 6 dBi selon installation
Impedance
Élevée ou variable
Polarization
Verticale
Difficulty
Avancée
Dimensions and design
Vertical sections are near ¼ wavelength and horizontal sections near ½ wavelength.
Construction and tuning
Step 1
Install three vertical supports.
Step 2
Cut three quarter-wave sections.
Step 3
Join their tops with two half-wave wires.
Step 4
Choose the feed point according to the design.
Step 5
Maintain straight geometry.
Step 6
Measure impedance and pattern.
Advantages
- More gain than a Half-Square.
- Low take-off angle.
- No massive radial field.
- All-wire construction.
Limitations
- Very wide structure.
- Three supports.
- Bidirectional pattern.
- Complex feeding and tuning.
History and origin
The Bobtail Curtain evolved as a gain wire vertical array based on curtain-array principles.
Safety
All three low ends must be insulated, visible and inaccessible.