[Hallicrafters] CW History

[Walt Cates]

To All,

The 5 letter group was chosen because of the character recognition properties of our brains. It was found that 5 letter groups could be instantly recognized and retained long enough to send the entire group. With experience these groups were sent as "words" rather than letters. The percentage of operators that could maintain 98% accuracy dropped of considerably when groups were increased to 6 letters. The 5 letter group turned out to be the optimum group size.  At least that is what they told us in the Navy code school back in 1961.

Walt, WD0GOF