The antenna is capable of receiving replies from all directions simulta-
neously with bearing information using amplitude-ratio monopulse
techniques. Insertion loss differences in
coaxial cable lengths from
the antenna to the TCAS computer need only be matched to within 0.5 dB
which corresponds to a 5 to 10 foot difference
in length depending on
the specific cable type.
Losses between the antenna and the computer
unit must be 2.5 t 0.5 dB, including line connections.
All antenna lobes work across the face of the antenna. J1 is located at
the rear of the antenna and produces the forward looking lobe. In
addition the antenna ports are both color-coded and electrically coded
with a resistance to ground that is checked by the TCAS computer and can
be checked by the technician.
J1
J2
J3
J4
O degree port.
Color
coded yellow. Located on the rear of the
antenna and installed to the rear of the aircraft.
Resistance to
ground is
1000 ohms.
270
degree port. Color black. Installs toward right wing.
Resistance to ground is 8000 ohms.
180 degree port. Color blue.
Installs toward front of aircraft.
Resistance to ground is 4000 ohms.
90 degree port. Color red. Installs toward left wing. Resistance
to ground is 2000 ohms.
22-14-00
Page 198.190
Apr 15/93
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