Aviation Antennas Glideslope and ILS

ILS Glide Slope Antenna ILS-420 Certified 328-336 MHz

Frequency Range: 328-336 MHz
Gain: 10 dBi +
VSWR: 1.2:1 max
Polarization: Horizontal

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SKU: GS-420 Category:

Additional Product Info

The GS-420 glide slope antenna was designed, tested and certified as part of the new generation and more stable ILS-420 system. The GS-420 antenna contains numerous improvements over existing glide slope antennas. Improvements Include: • Extremely stable monitor coupling and phase operation over the environment service conditions, as well as during dipole heater operation. • Improved sealing of the antenna. • Improved vibration tolerance, in both transportation and installed conditions. • Improved dipole design. • Improved solderability. • More precise tuning and phase matching of cables.

Spec Sheet


Frequency Range 328-336 MHz
Impedence 50 Ohms
RF Power 50 Watts CW
Monitor Coupling -6 to -10 db over 328-336 MHz
Polarization Hoizontal
Cross Polarization

At least -25 dB as measured in front of the antenna and within +/- 25 degrees in azimuth of a vertical plane perpendicular to the reflector and passing through the center of the antenna array

Front-To-Back Ration More than 16 db
VSWR 1.2:1 Max over 328-336 MHz
Gain More than 10 dBi
Horizontal Radiation Pattern Between the upper and lower limit lines as shown in following table
Vertical Radiation Pattern

Symmetrical around 0 degrees elevation and decreasing smoothly in amplitude in either direction from 0 degrees elevation.

Dipole Phase Left and right dipoles with 20-30 degrees phase of center dipole
Monitor Stability Signal Level Constant within +/- 0.2 dB over the service condition range; track other antennas within 0.15 dB.
Monitor Amplitude Stability Test Max change from baseline is +/- 0.075 dB when heaters are energized.
Phase Stability Test Max change from baseline is +1.1 degrees, -0.4 degrees when heaters are energized.
Dipole Heaters Yes