Upskill / Avionics / Communications and datalink: VHF, CPDLC, SATCOM and link budgets
Communications and datalink: VHF, CPDLC, SATCOM and link budgets
How messages reach the flight deck and how engineers prove the links are good enough: VHF voice and 8.33 kHz channels, radio horizons, ACARS and VDL Mode 2, FANS 1/A and ATN B1, CPDLC and required performance, geostationary and low-earth-orbit SATCOM, link budgets, and a real integrated radio failure. Part 3 of the Avionics engineering series.
By Aerospace Garage Desk · In practice · 50 minutes · 24 narrated pages
What you will be able to do
✓ Describe the classes of aeronautical communication and the VHF, HF and satellite bearers that carry them, and build a route-by-route communications plan.
✓ Explain VHF voice operation, 8.33 kHz channel spacing and its European legal basis, and calculate radio-horizon coverage and gaps.
✓ Compare ACARS, VDL Mode 2, FANS 1/A and ATN B1, describe CPDLC and ADS-C, and check datalink performance against RCP 240 and RSP 180.
✓ Compare geostationary and low-earth-orbit SATCOM, and calculate satellite elevation and path delay for a given latitude.
✓ Build a simple link budget in decibels, from transmitter power to margin, and use it to choose an antenna and data rate.
✓ Analyse an official investigation of integrated radio and transponder failures and draw lessons for independence, testing and recovery.
Course content
Session 1 · The communications picture: voice, data and the three bearers
1.1
A message to a crew ten kilometres up · free preview
Who is talking to whom: classes of message
Three bearers: VHF, HF and satellite
Worked example: which link where? A communications plan for three routes
Session 2 · VHF voice: channels, spacing and line of sight
1.2
One frequency, many voices
From twenty-five to eight point three three kilohertz
Worked example: a month of datalink performance — finding the slow aircraft
Session 4 · SATCOM: geostationary and low-earth-orbit links
1.4
Where VHF ends: the aeronautical satellite service
Geostationary systems
Low-earth-orbit constellations
Worked example: can the aircraft see the satellite?
Session 5 · Link budgets in plain terms
1.5
Decibels: the language of the link
Noise: what the signal must beat
Margin, fades and the installation
Worked example: an L-band return-link budget — which antenna for which data rate?
Session 6 · When the link fails: an integrated radio failure, and the road to Part 4
1.6
When the radio goes quiet
One system, many functions: common-mode failure
Recovery: procedures, the emergency frequency and the fix
From the investigation file: three integrated radio failures over France, 2024 to 2025, and the road to Part 4
Who this course is for
Avionics and communications engineers at manufacturers, suppliers and design organisations who specify, install or certify VHF, HF, datalink and satellite communication systems
Airworthiness, continuing-airworthiness and avionics engineers at operators and MROs who manage datalink performance, SATCOM installations, radio defects and related airworthiness directives
Flight operations engineers, datalink and PBCS specialists, and safety managers who need to understand communication performance, coverage limits and loss-of-communication risks
You need: Basic familiarity with aircraft radio and flight-deck systems; Parts 1 and 2 of this series are useful but not required; comfort with square roots, logarithms and simple percentages.
Upskill courses are for professional development and are not approved by any aviation authority. Learner Terms