Honeywell International Inc. 9PGTPL-100A 사용자 설명서

Page 50

1 Mar 2006

TPL-100A Processor / Part No. 940-0530-001

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(2) TCAS Directional Antenna Description and Basic Functions

The directional antenna is a phased array and consists of four top-loaded monopole 
elements. The directional antenna is steered electronically.

Unlike mechanically steered antennas, the antenna pattern can be pointed in one of 
four directions without physically moving the antenna. This is achieved by 
independently varying the drive level and phase to each of the four antenna elements 
contained in the directional antenna.

The four beam-forming elements are located on the perimeter of the antenna. The 
whole assembly is in an aerodynamic fiberglass enclosure just over one inch in height. 
The top directional antenna should be mounted at or near the longitudinal centerline of 
the aircraft +5

°

 and as far forward as is practical. The bottom directional antenna or 

omni antenna (if used) should be collocated as near as possible to the vertical plane 
of the top directional antenna.

During TCAS transmission, the directional antenna (top or bottom) radiates 1030 MHz. 
The directional antenna main beam patterns and directional antenna omni beam 
patterns are under control of the four antenna element drive signals from the 
MILACAS-FR Processor (see beam patterns in Figure 6).