Every VOR and NDB navaid in the world identifies itself in Morse code, on a continuous audio loop. As of 2026 this is still required pilot knowledge — student pilots learn it during instrument training, and every IFR chart shows the navaid's identifier in Morse next to its frequency.
Why Morse, not voice?
VOR and NDB transmitters are simple, unattended ground stations. They put out a tone modulated with the navaid's three- or four-letter ID in Morse, every few seconds. The advantages over a synthesized voice ID:
- Bandwidth-efficient — fits in a sub-carrier without disrupting the primary navigation signal.
- Unambiguous — Morse audio is recognizable under noise that would garble speech.
- Cheap to broadcast — VOR ID transmitters are simpler than voice synthesizers.
- International — pilots from any country can decode it without speaking the local language.
What pilots actually do
- Tune the VOR/NDB frequency on the radio.
- Listen to the audio — there's a continuous tone with periodic Morse ID.
- Compare the heard ID against the chart (printed or on the EFB).
- If they match, the navaid is identified and the indicator is trustworthy.
- If they don't match (or if the ID is missing or replaced by a "T-E-S-T" pattern), the navaid is out of service.
Examples
Common navaid identifiers you'd hear on a chart:
- JFK VOR — .--- ..-. -.- (JFK)
- SFO VOR — ... ..-. --- (SFO)
- LAX VOR — .-.. .- -..- (LAX)
- BOS VOR — -... --- ... (BOS)
You can try any of these in the translator to hear what they sound like.
What the patterns sound like in the cockpit
VOR IDs are sent at about 7 WPM — much slower than amateur radio CW. The slow speed is intentional: pilots in busy cockpits should be able to identify the navaid without dedicated focus. Many ID's are sent in a "1020 Hz" sub-carrier that pilots can selectively mute, leaving only the nav signal.
NDB (Non-Directional Beacon)
NDBs are older than VORs and now mostly retired in the US (their service was phased out through the 2010s and 2020s). In countries with sparse VOR coverage they're still active. NDB identifiers are usually only two letters and the broadcast is the navaid's only identifier — there's no separate digital data stream.
Charted vs heard
FAA Sectional and IFR charts always print the navaid ID with Morse dots and dashes underneath the three-letter abbreviation. Pilots cross-reference visually first, then audibly. EFB apps (ForeFlight, Garmin Pilot, etc.) do the same.
Will it stay?
Probably. Even as GPS-based navigation replaces VORs, the FAA maintains a Minimum Operational Network of VORs across the US specifically as a backup for GPS outages. Those VORs keep their Morse IDs. So learning Morse remains, in a small but real way, a piece of aviation safety.
To listen to an aircraft-style identifier yourself, type a 3-letter callsign like JFK into our translator and hit Play.