READABILITY, signal strength tone 1

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

Infrequently used is the addition of a letter to the end of the 3 numbers.

These are: X = the signal is rock steady like a crystal controlled signal;

C = the signal is chirpy as the frequency varies slightly with keying;

and K = the signal has key clicks.

X is from the early days of radio when such steady signals were rare.

Today most all signals could be given an X but it is hardly ever used. It is helpful to report a chirpy or clicky signal by using the C or K, e.g. 579C or 579K.