Section 7
Operating practices and procedures
Codes and abbreviations
7E2 Recall the meaning of the RST code, the number of divisions of each of the three items, and their order of merit
In the amateur radio world the RST convention means Readability Strength Tone.
The readability section has 5 levels where 1 is unreadable, to 5 which is totally readable.
The Strength is referring to the Signal strength which had 9 levels level 1 meaning faint, barely perceptible, to level 9 meaning Very Strong.
The Tone is referring to CW tone and has 9 levels level 1 meaning Extremely rough note through to level 9 meaning a pure DC note.
Readability
- R1 Unreadable
- R2 Barely readable, occasional words distinguishable
- R3 Readable with considerable difficulty
- R4 Readable with practically no difficulty
- R5 Perfectly readable
Signal strength
- S1 Faint, signals barely perceptible
- S2 Very weak signals
- S3 Weak signals
- S4 Fair signals
- S5 Fairly good signals
- S6 Good signals
- S7 Moderately strong signals
- S8 Strong signals
- S9 Extremely strong signals
Tone (used only with CW signals)
- T1 Extremely rough hissing note
- T2 Very rough note, not musical at all
- T3 Rough, low-pitched note, slightly musical
- T4 Rather rough note, moderately musical
- T5 Musically modulated note
- T6 Modulated note, slight trace of whistle
- T7 A musical note with some ripple
- T8 A very good note with just a trace of ripple
- T9 A pure musical note