System Description

System Description and Installation Manual for MXS ICD10004-01

antenna connects to the left connector and the bottom antenna connects to the right connector. Whenever power is

supplied to the MXS, a 50-ohm load should be provided to both SMA connections. Ensure that the antenna(s) selected

provide a 50-ohm termination for the MXS. If only one antenna is used, replace the top antenna with a 50-ohm

termination rated for 5W minimum.

The antennas used by MXS should be mounted on the outside of the aircraft according to the manufacturer’s installation

instructions, with additional guidance provided below and in Table 0-4Table 3-4:

 The MXS should have its own antennas. An exception to this rule is use of a high-quality diplexer that enables

antenna sharing between a MXS and certain ADS-B equipment. Further guidance on diplexer use can be found

in RTCA documents DO-282B and DO-260B, the minimum operational performance standards for UAT and

1090 MHz ADS-B, respectively.

 Minimize the distance between the MXS and its antennas. The antenna cable must have no more than 2dB of

signal loss from the MXS to the antenna.

 Take care to locate the antennas away from any objects that may disrupt the ground plane for the antennas, such

as doors and landing gear.

 Do not place the antennas close to engine exhaust.

 Try to keep the antennas located at least 36” away from other antennas on the aircraft. The antennas should be

located as close to the centerline of the fuselage as space allows, while trying to keep the antennas on a flat

surface.

 A ground plane is required for most antennas appropriate for MXS. Failure to provide a good ground plane can

result in degradation of antenna performance.

 Use antennas designed to be used with aviation transponders, with the characteristics documented in Table

0-4Table 3-4.

 Torque mating SMA connectors to: 7-10 lb · in [80-110 N · cm]. Take care not to over-torque the antennas in an

attempt to reduce a gap between the antenna and the mounting surface; torque the antenna to the manufacturer’s

instructions.

Note: If your installation does not meet all of the above requirements, MXS performance (range) may be hindered, and

damage to the MXS could result.

Table 0-4 MXS Antenna Requirements

AntennaRequirements

Frequency 1030to1090MHz

Polarization Vertical

NominalImpedance 50Ω

VSWR <1.5:1between1030to1090MHz

RFPower 500WPeak

RadiationPattern Thegainmustnotbelessthanthegainofamatchedquarter‐wavestubminus3dB

over90percentofacoveragevolumefrom0to360degreesinazimuthandfrom5to

30degreesabovethegroundplanewheninstalledatthecenterof1.2

m(4foot)

diameter(orlarger)flatcirculargroundplane.

MountingLocation

 Oneortwoantennasmaybeused.