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218 & 218.1 Ground Plane (Monopole) Antennas 225-400MHz
For Air-Band Communications

Rev : 02 | Rev date : 26 Apr 2022

These omnidirectional antennas have constant patterns and impedance over a greater bandwidth than a conventional ground plane or coaxial dipole antennas. This superiority makes them eminently suitable for use at base stations for mobile systems and particularly for ground to air communication services.
They are of rugged construction. Standard models are manufactured from aluminium. 


  • Broad elevation radiation pattern provides superior coverage for ground to air links
  • Designed to withstand the most severe weather conditions
  • Robust design and construction
  • Heavy-duty welded on radials
  • Painted finish for additional weather protection
  • Can be mounted to a horizontal surface (model 218) or to a mounting pole (model 218.1)

Model 218.1 shown

Technical features

Electrical Specifications

Operating Frequency Range MHz225-400
Gain dBi2.0 (+0 / -1)
Azimuth Radiation PatternOmni Directional ± 0.25dB
Half Power Beamwidth Elevation degrees95
Maximum Power Rating kW0.3 average. Higher power ratings available upon request
Input ConnectorN-type receptacle
Impedance (unbalanced), ohmsΩ50

Mechanical Specifications

DimensionsRefer to diagram

218 Model:  Designed for horizontal mounting. Refer diagrams.

218.1 Model:  Permits mounting onto vertical surfaces.
U-bolts supplied for use on poles with OD of up to 50mm

Wind Survival Rating (No ice) km/h (mph)220 (136.7) to AS1170.2
Weight kg (lb)Model 218: 2.3 (5.1)
Model 218.1 : 3.1 (6.8)
Effective Projected Area sq m (sq ft)0.96 (10.3)

Temperature Specifications

Operating Temperature Range °C (°F)-40 to 80 (-40 to 176)


ColourGrey or Olive Drab
FinishExternal metal surfaces are painted

External Document Links