Garmin MX20 Installation Manual - 3.3  Antenna Requirements

Specifications 

52 

MX20 Installation Manual 

Table 3-5 - MX20 I/O Connector Pin Out (J2) (Cont’d) 

Some features listed are not supported at this time

Pin 

Name 

I/O 

Description 

50 DISCRETE_IN_1 

I 

51 +28V 

I 

52 

429_OUT_1A 

O 

ARINC 429 Output port 1A 

53 

429_OUT_1B 

O 

ARINC 429 Output port 1B 

54 561_CLK_IN_B 

I 

55 561_CLK_IN_A 

I 

56 561_SYNC_IN_B 

I 

57 561_SYNC_IN_A 

I 

Reserved 

58 

429_IN_0B 

I 

ARINC 429 Input port 0B 

59 

429_IN_0A 

I 

ARINC 429 Input port 0A 

60 429_IN_3B 

I Reserved 

61 

429_IN_1A 

I 

ARINC 429 Input port 1A 

62 

429_IN_1B 

I 

ARINC 429 Input port 1B 

View from rear of unit 

3.3  Antenna Requirements 

3.3.1  A-33 Antenna 

Early production runs of PN 590-1104 were marked with TSO-C129a. This antenna was re-qualified to TSO-

C144 with no changes to the antenna. P/N 590-1104 antennas marked with TSO-C129a identification are 

identical to those marked with TSO-C144.  

Frequency: ......................................................1575 MHz 

Polarization:....................................................Right Hand Circular 

Axial Ratio:.....................................................3 dB Max at bore site 

Radiation Coverage: .......................................Elevation Angle 

Minimum Gain 

>15º -2.0 

dBic 

 10º 

-3.0 

dBic 

 5º 

-4.5 

dBic 

 0º 

-7.5 

dBic 

Finish: .............................................................Polyurethane Enamel 

Weight: ...........................................................3.9 oz.  (0.11 kg) 

Height: ...........................................................0.61 inches (1.55 cm) 

Operating Temperature: .................................-55°C to +85°C 

Operating Altitude:  ........................................55,000 feet (16,764m) max.