← Frequency Reference
The Toolbox — Frequencies
Aviation
VHF airband, VOR/ILS navigation, DME, transponder, radar altimeter, and HF aviation frequencies.
VHF Airband (118–137 MHz)
| Frequency | Use |
|---|---|
| 118.000 – 136.975 MHz | VHF voice communications — worldwide allocation |
| 121.500 MHz | Emergency / Guard frequency — monitored continuously by ATC |
| 121.600 MHz | Ground control (common at larger airports) |
| 122.800 MHz | UNICOM — uncontrolled airports |
| 122.900 MHz | MULTICOM — no tower, no UNICOM |
| 123.000 MHz | UNICOM / heliports |
| 123.450 MHz | Air-to-air communications |
| 123.500 MHz | UNICOM / parachute operations |
| 128.825 MHz | ARINC datalink (ACARS) |
| 136.900 MHz | ACARS datalink (North America) |
VOR / ILS Navigation
| Frequency | Use |
|---|---|
| 108.000 – 117.950 MHz | VOR navigation — all VOR stations |
| 108.100 – 111.950 MHz | ILS localizer — odd tenths only (108.1, 108.3, etc.) |
| 112.000 – 117.950 MHz | VOR only — above 112 MHz |
| 329.150 – 335.000 MHz | ILS glideslope — paired with localizer frequency |
| 75 MHz | ILS marker beacons — all three markers (outer/middle/inner) |
DME, Transponder & Other
| Frequency | Use |
|---|---|
| 960 – 1215 MHz | DME and TACAN — distance measuring equipment |
| 1030 MHz | ATC SSR transponder interrogation (Mode A/C/S) |
| 1090 MHz | Transponder reply / ADS-B Out transmissions |
| 1176.450 MHz | GPS L5 — used in newer aviation receivers |
| 1227.600 MHz | GPS L2 — dual-frequency receivers |
| 1575.420 MHz | GPS L1 — primary civilian aviation GPS |
| 4200 – 4400 MHz | Radio altimeter — actual terrain clearance |
| 9000 – 9500 MHz | Airborne weather radar (X-band) |
| 5400 – 5900 MHz | Airborne weather radar (C-band) |
HF Aviation Voice (ICAO)
| Frequency | Use |
|---|---|
| 2.850 MHz | ICAO Region 1 HF voice (North Atlantic) |
| 3.016 MHz | North Atlantic Track System |
| 5.550 MHz | ICAO worldwide HF voice |
| 8.825 MHz | North Atlantic, Pacific — common SELCAL frequency |
| 11.330 MHz | ICAO HF voice — Pacific |
| 13.300 MHz | ICAO HF voice — international |
| 17.900 MHz | ICAO HF voice — international |
| 21.955 MHz | ICAO HF voice — international |