The RST system is a way of reporting on the quality of a received signal by using a three digit number. The first digit indicates " Readability" ( R ), the second digit indicates received "Signal Strength"(S) and the third digit indicates "Tone" (T). A fourth character is used on rare occasions to indicate the presence of a defectively keyed CW signal.
For example, a signal report of 589 indicates a completely understood strong CW signal with an excellent note. On the other hand, an RST of 387C would be a dificult-to-copy, chirpy transmission. Most signal reports have an "R" of 4 or 5 and "S" and "T" of 7 to 8.
READABILITY (R) Voice and CW
1 - Unreadable
2 - Barely readable, occasional words distinguishable
3 - Readable with considerable difficulty
4 - Readable with practically no difficulty
5 - Perfectly readable
SIGNAL STRENGH ( S) Voice and CW
1 - Faint signals, barely perceptible
2 - Very weak signals
3 - Weak signals
4 - Fair signals
5 - Fairly good signals
6 - good signals
7 - Moderately strong signals
8 - Strong signals
9 - Extremely strong signals
TONE (T) Use on CW contacts only
1 - Extremely rough ac tone and very broad
2 - Very rough ac tone, very harsh and broad
3 - Rough ac tone, rectified but not filtered
4 - Rough note with some trace of filtering
5 - Filtered rectified ac but strong ripple modulation
6 - Filtered tone with definite trace of ripple modulation
7 - Near pure tone, trace of ripple modulation
8 - Near perfect tone, slight trace of modulation
9 - Pure DC note with no trace of ripple or modulation of any kind
CHARACTERISTIC ( Optional, CW only)
X - Very stable signal, the quality of crystal control ( usually understood and hardly ever used )
C - Chirpy keyed signal or frequency variation defect
K - Key click or noticeable make/break keying flaw
RST 559 CW QSOs
CW QSO with Anton from Birmingham, England - 10901.9 km dari Kulaijaya, Johor.
