John KD4IDY, wrote:

A suitable analogy for the Grab feature might be an optical filter that happens to have the same response curve as the incandescent light source being shone through it. The more such filters one stacks in front of the light (that is, the greater Grab depth), the narrower the range of wavelengths which will be visible to the eye. Ultimately, the light would

appear nearly monochromatic, just as the decoder would clearly begin to output one character more often than all others; but it would never truly become--pardon the expression--coherent.

... the human ear/brain combination seems to have a similar stack of
filters built-in. The effect is known to all of us LF operators: when you
have listened to weak CW signals for a couple of hours, you still hear
signals even if you disconnect the antenna and listen to the white noise of
your receiver.

... and sometimes this continues even when you switch off your gear and go
to bed    ;)

Vy 73

Geri, DK8KW (W1KW)