Avionics Bending: VHF/HF COM Radio Integration with X-Plane (Part 6)

The Gables G6984 multi function radio head transmits 3 different ARINC 429 label. The labels are:

• Label 030 - VHF Frequency
• Label 205 - HF Frequency
• Label 207 - Additional Software information

For the flight simulator integration, only Label 030 and 205 are of interest to me right now. There are three (3) VHF frequencies and two (2) HF frequencies on the radio. Here are the details on the labels:

Label 205 - HF Word - From ARINC 429 Specification

Label 030 - VHF Word - From ARINC 429 Specification

All three VHF and both HF frequencies that can be set on the radio head are transmitted on the ARINC 429 bus with the same label. Each radio is identified with a unique SDI in the ARINC 429 word. The SDI is a 2 bit field.

VHF SDIs

01 -- VHF Radio 1
10 -- VHF Radio 2
11 -- VHF Radio 3

HF SDIs

01 -- HF Radio 1
10 -- HF Radio 2

Below is a short video that shows the radio head transmitting ARINC 429 data to a test program. Currently the ARINC data is read by a debug code and output to the screen. Over the next two days I will connect the Radio head data to the x-plane flight simulator.