Koch Lesson 4: Add the Letter U

Why this step

U is two dits plus a dah. It collides with S (three dits) if you only hear “a bunch of short tones.” Lesson 4 exists to force that distinction at speed.

What to hear

Wait for the last element. If the group ends on a dah, it is U. If it stays all dits, it is S. R (.-.) has a dah in the middle, not at the end.

Drill

Active set: K, M, R, S, U. Bias extra listens toward S vs U until the last-element test is automatic. The practice link sets lesson=4 so the trainer does not jump ahead.

Letter groups you can type in the translator once the ear is warm: US, RU, MU, SU

Pitfall

Writing “dot dot dash” on paper while listening. Put the pen down; name the letter out loud or click the button.