The Toolbox — Charts
Communication Codes
ICAO/NATO phonetic alphabet, Q codes for amateur radio and aviation, RST signal reports, and transponder squawk codes.
ICAO / NATO Phonetic Alphabet
The ICAO and NATO phonetic alphabets are identical. Used in aviation, marine, military, and amateur radio communications worldwide.
| Letter | Word | Pronunciation |
|---|---|---|
| A | Alfa | AL-FAH |
| B | Bravo | BRAH-VOH |
| C | Charlie | CHAR-LEE |
| D | Delta | DELL-TAH |
| E | Echo | ECK-OH |
| F | Foxtrot | FOKS-TROT |
| G | Golf | GOLF |
| H | Hotel | HOH-TEL |
| I | India | IN-DEE-AH |
| J | Juliett | JEW-LEE-ETT |
| K | Kilo | KEY-LOH |
| L | Lima | LEE-MAH |
| M | Mike | MIKE |
| N | November | NO-VEM-BER |
| O | Oscar | OSS-CAH |
| P | Papa | PAH-PAH |
| Q | Quebec | KEH-BECK |
| R | Romeo | ROW-ME-OH |
| S | Sierra | SEE-AIR-RAH |
| T | Tango | TANG-GO |
| U | Uniform | YOU-NEE-FORM |
| V | Victor | VIK-TAH |
| W | Whiskey | WISS-KEY |
| X | X-ray | ECKS-RAY |
| Y | Yankee | YANG-KEY |
| Z | Zulu | ZOO-LOO |
ICAO Phonetic Numbers
Numbers are pronounced differently in ICAO standard to avoid confusion over radio — particularly 9 (niner) and 5 (fife).
| Number | ICAO Pronunciation |
|---|---|
| 0 | ZE-RO |
| 1 | WUN |
| 2 | TOO |
| 3 | TREE |
| 4 | FOW-ER |
| 5 | FIFE |
| 6 | SIX |
| 7 | SEV-EN |
| 8 | AIT |
| 9 | NIN-ER |
Q Codes
Originally developed for CW (Morse code) telegraphy. Still widely used in amateur radio and aviation communications.
| Code | Meaning | Context |
|---|---|---|
| QNH | Altimeter setting (sea level pressure) | Aviation |
| QFE | Altimeter setting (field elevation pressure) | Aviation |
| QNE | Standard altimeter setting (29.92 inHg / 1013.25 hPa) | Aviation |
| QSY | Change to another frequency | Both |
| QRG | Your exact frequency is... | Both |
| QRM | Interference from other stations | Both |
| QRN | Interference from static/noise | Both |
| QRO | Increase transmitter power | Both |
| QRP | Decrease transmitter power / low power operation | Amateur |
| QRQ | Send faster | Amateur |
| QRS | Send more slowly | Amateur |
| QRT | Stop transmitting / closing station | Both |
| QRZ | Who is calling me? | Both |
| QSB | Signal fading | Both |
| QSL | Acknowledgement / confirmation received | Both |
| QSO | Communication with another station | Amateur |
| QST | General call to all stations | Amateur |
| QTH | Location / my location is... | Both |
| QTC | I have messages to send | Both |
| QRX | Stand by / I will call you again | Both |
| QAM | Weather report for aircraft | Aviation |
| QDM | Magnetic course to steer (no wind) to reach station | Aviation |
| QTE | True bearing from station | Aviation |
| QUJ | True track to reach station | Aviation |
RST Signal Report Codes
Used in amateur radio to report signal quality. Voice contacts use RS (two digits). CW contacts use RST (three digits). Example: "Your signal is 59" = perfectly readable, extremely strong.
Readability (R)
| Code | Meaning |
|---|---|
| R1 | Unreadable |
| R2 | Barely readable — occasional words distinguishable |
| R3 | Readable with considerable difficulty |
| R4 | Readable with practically no difficulty |
| R5 | Perfectly readable |
Signal Strength (S)
| Code | Meaning |
|---|---|
| S1 | Faint — barely perceptible |
| S2 | Very weak |
| S3 | Weak |
| S4 | Fair |
| S5 | Fairly good |
| S6 | Good |
| S7 | Moderately strong |
| S8 | Strong |
| S9 | Extremely strong |
Tone (T) — CW Only
| Code | Meaning |
|---|---|
| T1 | Extremely rough — 60 Hz hum |
| T3 | Rough — ripple on note |
| T5 | Musically modulated |
| T7 | Near pure tone — slight trace of ripple |
| T9 | Perfect tone — no trace of ripple or modulation |
Aviation Transponder Squawk Codes
Reserved squawk codes with specific meanings. ATC assigns individual codes for IFR flights — these are the universal reserved codes.
| Code | Meaning |
|---|---|
| 1200 | VFR flight — general squawk for uncontrolled VFR in US airspace |
| 7500 | Hijacking in progress — do not use accidentally |
| 7600 | Lost communications (NORDO) |
| 7700 | General emergency |
| 0000 | Military — do not use in civil aviation |
| 7777 | Military interceptor operations — do not use in civil aviation |
| 1000 | ADS-B equipped aircraft operating in Class A airspace |
| 2000 | Entering controlled airspace from uncontrolled airspace without ATC contact |