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How to Hook Sounder to Morse Code Keys

Imagine an amateur radio operator hunched over a telegraph key late at night while the warm glow of vacuum tubes provide a dim light in the room. Morse code (or CW) was once a requirement in the amateur radio service, but it was dropped years ago. Some operators still use it, and once a year, the Amateur Radio Relay League has Straight Key Night to celebrate the earliest form of radio communication. Use of a hand key and a sounder or code-practice oscillator develops proficiency.

Things You'll Need

Telegraph key
Code-practice oscillator

Instructions

- 1
  Attach the telegraph key to the code-practice oscillator. Two binding terminals are on the key, and the oscillator leads connect to both without regard to polarity. Modern solid-state oscillators operate at low voltages that pose no risk to the operator. If you find an old tube-type practice oscillator at a hamfest or garage sale, check the leads for high voltage with a multimeter before using it.
- 2
  Adjust the contacts on a standard telegraph key for a gap of no more than 1/16th of an inch. Set the spring tension to a comfortable level. As your speed increases with practice, decrease the gap and reduce the spring tension. Placing two fingers on the knob helps to minimize fatigue.
- 3
  Connect a code-practice oscillator to the terminals on a semi-automatic key -- or "bug" -- in the same manner as the straight key. These keys are more complicated mechanical devices than the straight key. Dashes are timed by the operator according to how long the key is held to the left. Dots are formed when the paddle is held to the right, their timing determined by an adjustable spring and pendulum.

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