Crossed loops generate phase-shifted fields that produce circular polarization with relatively broad coverage.
Antennas · F1SYH
Eggbeater antenna
The Eggbeater uses two perpendicular vertical loops fed in quadrature for satellite reception and transmission.
VHF
UHF
Satellites
Operating principle
Main characteristics
Typical gain
Faible à modéré
Impedance
Réseau d’adaptation nécessaire
Polarization
Circulaire ou elliptique
Difficulty
Avancée
Dimensions and design
Loop perimeter and phasing network geometry must be calculated for the centre frequency.
Construction and tuning
Step 1
Form two identical loops.
Step 2
Mount them at right angles.
Step 3
Build the phasing network.
Step 4
Maintain symmetric geometry.
Step 5
Install 50 Ω matching.
Step 6
Measure across the complete band.
Advantages
- Coverage without mechanical tracking.
- Circular polarization.
- Compact structure.
- Suitable for VHF or UHF.
Limitations
- Less gain than a tracked directional antenna.
- Delicate phasing.
- Pattern depends on geometry.
- Fairly complex construction.
History and origin
The Eggbeater became popular among radio amateurs as a fixed antenna for low-Earth-orbit satellites.
Safety
Loops must be firmly secured against wind deformation.