Amateur Radio:

An amateur radio operator is an individual who typically uses equipment at an amateur radio station to engage in two-way personal communications with other similar individuals on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted anamateur radio license by a governmental regulatory authority. As a component of their license, amateur radio operators are assigned a call sign that they use to identify themselves during communication. There are about three million amateur radio operators worldwide.

Amateur radio operators are also known as radio amateurs or hams. The term «ham» as a nickname for amateur radio operators originated in a pejorative usage by operators in commercial and professional radio communities. The word was subsequently welcomed by amateur radio operators, and it stuck. An amateur radio operator who has died is referred to by other amateur radio operators as a silent key.

Gallery

<gallery> Image:Dj1yfk in sweden.jpg|An operator running High Speed TelegraphyImage:MM3OXB.jpg|An operator working HF </gallery>

PSK31 or «Phase Shift Keying, 31 Baud» is a digital radio modulation mode, used primarily in theamateur radio field to conduct real-time keyboard-to-keyboard informal text chat between amateur radio operators.

History

PSK31 was developed and named by English amateur radio operator Peter Martinez (G3PLX) and introduced to the wider amateur radio community in December 1998.

PSK31 was enthusiastically received, and its usage grew like wildfire worldwide lending a new popularity and tone to the on-air conduct of digital communications. Due to the efficiency of the mode, it became, and still remains, especially popular with operators whose circumstances do not permit the erection of large antenna systems and/or the use of high power.

Use and implementation

A PSK31 operator typically uses a single sideband transceiver connected to the sound card of the PC. When the operator enters a message for transmission, the software produces an audio tone which sounds, to the human ear, like a continuous whistle with a slight warble. This is then fed through either a microphone jack (using an intermediate resistor to reduce the sound card’s output power to microphone levels) or an auxiliary connection into the transceiver, where it is transmitted. (PSK31 Station Setup)

From the perspective of the transmitter, this amounts to little more than somebody whistling into the microphone. However, the software rapidly shifts the phase of the audio signal between two states (hence the name «phase-shift keying»), forming the character codes. These phase shifts serve the same function as the two tones used in traditional RTTY and similar systems.

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