Continuous wave

Continuous Wave

A Bencher paddle used in Morse code transmission

Continuous wave (CW) is a type of radio wave transmission where a signal is transmitted at a constant amplitude and frequency. This form of transmission is primarily used in Morse code communication, where the signal is turned on and off to represent the dots and dashes of the code.

History

The concept of continuous wave transmission dates back to the early days of radio communication. It was first developed as a method to improve the efficiency and reliability of telegraphy over long distances. The use of continuous wave allowed for clearer and more consistent signals compared to earlier methods such as spark-gap transmitters.

Principles of Operation

In continuous wave transmission, a transmitter generates a radio frequency signal that is modulated by turning the signal on and off. This is typically done using a telegraph key or a paddle, such as the Bencher paddle shown in the image. The key or paddle controls the transmission of the signal, allowing the operator to send Morse code messages.

The receiver, tuned to the same frequency, detects the presence or absence of the signal and converts it back into audible tones, which can be interpreted as Morse code by the operator.

Advantages

Continuous wave transmission offers several advantages:

• Efficiency: CW signals are narrowband, meaning they occupy a small portion of the radio spectrum, allowing for more efficient use of available frequencies.
• Simplicity: The equipment required for CW transmission is relatively simple and inexpensive compared to other forms of modulation.
• Reliability: CW signals can be detected at lower signal-to-noise ratios than other types of modulation, making them ideal for long-distance communication.

Applications

While continuous wave transmission is not as widely used today as it once was, it remains popular among amateur radio operators and is still used in certain military and aviation applications. CW is valued for its simplicity and effectiveness in low-power and long-distance communication scenarios.

Related Pages

• Morse code
• Radio wave
• Telegraphy
• Amateur radio