This is stuff I use a lot and/or can never quite remember without help.
| R | S | T |
| 5 – perfectly readable | 9 – vy strong | 9 – pure dc |
| 4 – with little difficulty | 8 – strong | 8 – tr of ripple |
| 3 – with difficulty | 7 – moderate | 7 – smooth ripple |
| 2 – barely readable | 6 – good | 6 – modulated |
| 1 – unreadable | 5 – fairly good | 5 – strong ripple |
| 4 – fair | 4 – fairly rough | |
| 3 – weak | 3 – rough | |
| 2 – vy weak | 2 – vy rough | |
| 1 – barely detectable | 1 – extremely rough |