4RF Aprisa XE User Manual page 26

24 | Preparation
Yagi Antennas
It is possible to increase the gain of a Yagi antenna installation by placing two or more of them in a stack.
The relative position of the antennas is critical.
Factor
Frequency
Gain
Stackable gain increase
Wind loading
Tower aperture required
Size
Front to back ratio
Cost
Example of stacked antennas
Aprisa XE User Manual
Explanation
Often used in 330-960 MHz bands
Varies with size (typically 11 dBi to 16
dBi)
2 Yagi antennas (+ 2.8 dB)
4 Yagi antennas (+ 5.6 dB)
Less than a parabolic grid antenna
Unstacked: Less than a parabolic grid
antenna
Stacked: about the same as a
parabolic grid antenna
Range from 0.6 m to 3 m in length
Low
Low