The RST  and  RSV System

Readability Strength (T)one / (V)ideo

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 AC or less, very rough and broad.

2- Very rough AC, very harsh and broad.

3- Rough AC tone, rectified but not filtered.

4- Rough note, some trace of filtering.

5- Filtered rectified AC 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.
Video
1- Unreadable.

2- Barely Viewable,  just distinguishable.

3- Viewable  with considerable difficulty.

4- Viewable  with practically no difficulty.

5- Perfectly Viewable  .
eg.,
for Voice mode  =  
RST 59 or 59 Plus ( incase the signal is stronger than 9 then put Plus "xx"dB
for Morse ( CW )  = 599  or 599X                                      or   599C    
                                                X = Rock steady signal !             C = Signal with Chirp
for SSTV   RSV = 595