RST

R-S-T	Readability R	Strength S	Tone T (cw only)
1	Unreadable	Faint signals, barely perceptible	Sixty cycle a.c or less, very rough and broad
2	Barely readable, occasional words distinguishable	Very weak signals	Very rough a.c., very harsh and broad
3	Readable with considerable difficulty	Weak signals	Rough a.c. tone, rectified but not filtered
4	Readable with practically no difficulty	Fair signals	Rough note, some trace of filtering
5	Perfectly readable	Fairly good signals	Filtered rectified a.c. but strongly ripple-modulated
6	N/A	Good signals	Filtered tone, definite trace of ripple modulation
7	N/A	Moderately strong signals	Near pure tone, trace of ripple modulation
8	N/A	Strong signals	Near perfect tone, slight trace of modulation
9	N/A	Extremely strong signals	Perfect tone, no trace of ripple or modulation of any kind

Reporting RST for Phone (AM, FM, SSB)

Select the signal's most prominent characteristic from each of the R and S columns in the chart (the T column is not used for phone). Select the number from the R-S Numeral (left) column which corresponds to each characteristic chosen. This R-S sequence of numbers becomes the RS signal report.

For example, a signal of "5 9" means that the phone signal is Readability 5, and Strength 9; a perfectly readable and extremely strong signal. The term "S-9" is also used to report a Strength 9 for an extremely strong signal. If an S-Meter is being used as a basis of the signal report, an S-9 is the numeric level of 9 (S-Units) on the meter. This reporting system may also be used for phone operation by leaving out the Tone (T) portion of the report.

Reporting RST for CW

Select the signal's most prominent characteristic from each of the R, S, and T columns in the chart. Select the number from the R-S-T Numeral (left) column which corresponds to each characteristic chosen. This R-S-T sequence of numbers becomes the RST signal report.

"RST is 599" - means that the morse code cw signal being assessed is Readability 5 (perfectly readable), Strength 9 (extremely strong signal), Tone 9 (perfect tone). This is the ultimate cw signal.

If the signal has the characteristic stability of crystal control, the letter X may be added to the end of the RST report. Use the the letter C to indicate a chirp on the signal and the letter K for key clicks.