THE R-S-T SYSTEM

The RST System is a standard system used for reporting (R)eadability, (S)ignal Strength and

(T)one of received signals.

READABILITY

1. Unreadable.
2. Barely readable, occasional words distinguishable.
3. Readable with considerable difficulty.
4. Readable with practically no difficulty.
5. Perfectly readable.

SIGNAL STRENGTH

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

1. Sixty cycle a.c. or less, very rough and broad.
2. Very rough a.c., very harsh and broad.
3. Rough a.c. tone, rectified but not filtered.
4. Rough note, some trace of filtering.
5. Filtered rectified a.c. but strongly ripple-modulated.
6. Filtered tone, definite trace of ripple modulation.
7. Near pure tone, trace of ripple modulation.
8. Near perfect tone, slight trace of modulation.
9. Perfect tone, no trace of ripple or modulation of any kind.

If the signal has the characteristic steadiness of crystal control, add the letter X to the RST report.  If there is a chirp, the letter C may be added to so indicate.  Similarly for a click, add K.  The above reporting system is used on both CW and Voice, leaving out the tone report on voice.

For voice contacts only the "R" and "S" are used.  The "S" is the strength as judged by ear and generally is not the same as your S-Meter reading.  The RST System was developed in 1934, well before most radios had S-Meters, so few if any S-Meters produce readings that match the RST System.

Report signal quality honestly.  If you report a station as 59 when he's actually 33, he's likely to reply with a lengthy monologue about his station, weather, and hobbies and you will miss most of it.  If you report an accurate 33 the wise person will limit return comments to name, location and a minimum of details.  Accurate signal reports facilitate communication.