Koch Lesson 7: Add the Letter T
Last verified: August 2026 · Unique to this step — not a duplicate of the hub.
Why this step
T is one dah — the second most common English letter. Koch delayed it so you would not treat every dah as T. After M (two dahs) is solid, a single dah becomes a new length, not a guess.
What to hear
T is short. M is twice as long. If you name T whenever you hear “a dash,” you will steal copies from M. Measure length against the character speed you already use.
Drill
Active set: K, M, R, S, U, A, P, T. Isolated T vs M is the exam. The shareable URL keeps lesson=7 so a friend does not inherit a later unlock from their own browser storage.
Letter groups you can type in the translator once the ear is warm: AT, ST, RT, TM
Pitfall
Dropping character speed “just for T.” That reintroduces counting. Use Farnsworth if you need thinking time.
Practice text
TM MT TMT MMM TTT. Single dah T versus double dah M — measure against the same WPM you used in lesson 1.
Common mistakes
- Labeling every dash as T.
- Slowing character speed only for T — use Farnsworth gaps instead.
Session notes
T versus M is duration discrimination at the same pitch. Use a metronome app only to check that your practice sessions start on time, not to count inside letters. Copy MTMT and TMTM until boring — boredom is a signal the ear is automatizing. If you plan to take amateur radio exams where Morse is optional, this drill still helps recognize report elements and abbreviations sent quickly. Keep lesson 7 share links handy for elmer sessions so mentors hear the same material you practiced.
Practice schedule
Days 1–2: T against M so one dash is not two. Days 3–4: T inside short English words. Days 5–6: the full set at the same speed. Day 7: stop while accuracy is still high. Count dashes only after the character ends. One dash is T and two dashes with a one-unit gap are M. If they still blur, widen the Farnsworth gap and leave the character speed alone. A longer dash is not a new letter. It is the same T held too long.
Contest and ragchew CW still use T constantly; duration discrimination is essential.