Uat Antennas - Garmin GDL 90 Installation Manual

should be considered when computing the cable loss. A typical loss of -0.2 dB can be used for each
connection. The typical cable loss for 20 feet of RG-400 coax with a connector one each end is 4 dB.
During the post-installation checkout, susceptibility to harmonics of VHF comm. transmitters will be
evaluated. If problems arise, then better isolation, or distance, may be required between the GPS and
comm antennas, or a 1575.42 MHz notch filter may be installed in series with the antenna coax of the
VHF comm transceiver to reduce or eliminate the harmonic interference. A notch filter (part #162-1059)
is available from Garmin AT.
If a VHF comm transmitter causes problems with the GPS on the selected frequencies as listed in the
post-installation checkout, the problem may be due to the ELT. This can be verified by disconnecting the
ELT antenna coax at the ELT unit. If the ELT is found to cause the problem, then contact the ELT
manufacturer or replace the ELT.
Cable
STEP 1
STEP 2
STEP 3
STEP 4
2.6.2 UAT A
NTENNAS
The UAT antenna is a standard 50Ω vertically polarized L-band antenna that operates at 978 MHz. Any
antenna meeting the requirements of TSO-C66, C74, C112 or C154 and presenting a VSWR of less than
1.7:1 at 978 Mhz is acceptable. Follow the antenna manufacturer's installation instructions for mounting
antennas.
GDL 90 Installation Manual
Shield 0.250
Solder Outer Shield
to Connector
Figure 2-7. Right Angle Coax Connector Assembly
560-1049-00 Rev B
1.000
0.125 -Slide shrink tube over cable.
-Strip cable as shown.
Insulation
Shrink
Tube
.125
-Flare Outer Shield as Shown
Cap
Matching Ring
-Place cable in connector as shown placing inner
shield inside connector.
Solder Center
-Flatten outer shield against connector.
Conductor
-Solder outer shield to connector.
-Solder center conductor
-Slide matching ring into connector and around
conductor.
-Attach cap.
Solder Cap
2 Places
-Solder cap into place, 2 Places.
-Shrink tube as shown.
Installation Procedures
2-9