| READABILITY |
| 1 |
Unreadable |
| 2 |
Barely readable; only occasional words distinguishable |
| 3 |
Readable but with considerable difficulty |
| 4 |
Readable with practically no difficulty |
| 5 |
Perfectly readable |
| SIGNAL STRENGTH |
| 1 |
Very faint signals |
| 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 |
A sixty-cycle hum is present on the signal. Very rough and raw to listen to |
| 2 |
Very rough, harsh and broad a.c. hum is present on the signal. |
| 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 note, no trace of ripple or modulation of any kind. |