Code Practice Oscillator


1. Built-in key and external key jack.

2. Pleasant sine wave tone.

3. Built-in audio amp and speaker.

4. On board 9 volt battery holder.

5. One evening build time.

A code practice oscillator is a must for learning to send and receive Morse code. Our CPO includes a built-in key to get you started (you should start learning with a key until you can send and receive 8 to 10 words per minute).

This CPO uses a Twin-Tee oscillator which produces a pure sine wave audio tone. Many other designs use square wave oscillators which are not as comfortable to listen to.  A second key can be attached so you can practice with a frend or student (makes learning fun and faster)

NOW JUST $24.95


Build Instructions

This new version has a new larger base for more stability and accurate keying. The new brass key has a smooth feel and is easy to mount.  Plus, this version produces more volume when desired.


This CPO allows two people to use one CPO together if desired.  Two can learn together ... just plug in a key to the phone jack while the built-in key is also used.

Practice mock QSO's, drill letters, words or numbers with a study buddy.  Makes learning fun!