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3.6.3
Outside Air Temperature (OAT) Probe Installation
Avoid mounting the OAT probe in or near prop airstream, engine or heater exhaust, transmitting
antennas or on dark painted surface. Failure to do so will result in improper OAT readings. The
OAT probe requires a 7/16” hole be drilled in the skin of the aircraft. The installer should consider
fabricating an appropriate doubler plate in accordance with accepted installation practices as outlined
in AC 43.13-1B. Skin thickness including doubler should be a minimum of 0.050” and a maximum
of 0.188”. See figure 3-47for mounting details. The OAT probe comes with a three wire pigtail
approximately 23 inches in length. The installer can cut this cable to length or extend it by adding
additional wire. Make sure that any connections are away from areas that can accumulate water or
chemicals.
10 - Nut
20 - Shoulder Washer
30 - Insulating Washer
40 - Lock Washer
Figure 3-7
STP 78 OAT Probe Dimensions
Figure 3-8
STP 78 OAT Probe Mounting
3.6.4
Antenna Connector
The transponder antenna (installer supplied) should be mounted vertically on the bottom of the air-
craft. The antenna requires the use of a ground plane that should have a radius of approximately 4”.
The STX 165 uses a SMA connector (supplied). Instruction for assembling the SMA connector are
shown in Figure 3-9. A BNC to SMA adapter can also be use without any measurable degradation of
transponder performance. This adapter can be obtained from your avionics parts supplier.
Summary of Contents for STX 165
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