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Why QRP?

QRP

A DEFINITION OF QRP#

QRP operation is the practice of transmitting at a lower power level while trying to achieve the maximum possible range. This type of radio operation began in the early 1920s. QRP operators limit their transmitted RF output power to 5 W or less, regardless of the mode they use. The term “QRP” originates from the standard Q Code used in radio communication, where QRP is used to request “Reduce power” and QRP? is used to ask “Should I reduce power?”

GOING FURTHER#

The above definition is helpful, but it does not provide a complete picture. Those of us who have passed the HAM radio exam know that we are supposed to use the minimum power needed to communicate. Therefore, we should always use QRP, or reduced power, to ensure efficient and responsible use of the radio spectrum.

WEAK SIGNAL MODES#

QRP enthusiasts often use special modes that employ technology and software designed to improve the reception of weak transmitted signals resulting from low-power levels. It is crucial to note that some of these modes allow communication over vast distances with only milliwatts of power. Here are some of the modes that apply to QRP:

  • QRSS — Very Slow Speed Morse Code: QRSS uses very slow speed CW (Morse code) to compensate for the decreased signal-to-noise ratio involved in QRP operation. QRSS enthusiasts may record a transmission for later analysis, sometimes decoding “by ear” while playing it back at much faster speeds, or decoding “by eye” on the waterfall display of a spectrum analyser.

  • Coherent CW — Critically Timed Morse Code Transmission: Coherent CW uses transmitters that clock-out Morse code signals calibrated to a precise rate, allowing receivers to employ extremely narrowband filtering to increase readability. This mode should be both machine and human-readable, although human readability depends on factors such as the rate of CW words per minute.

  • WSJT — Weak Signal by Joe Taylor: WSJT is a software system that uses several modes, each optimised for different signal paths, including meteor scatter, troposcatter, and EME communications. WSJT was named after Dr. J.H. Taylor in recognition of his work in developing weak signal communication modes for radio.

  • WSPR — Weak Signal Propagation Reporter: WSPR is a software suite and computer network used to monitor propagation paths for optimal communication conditions. This system allows operators to observe how signals propagate over various distances and times.

HOMEBREW AND KITS#

QRP embraces the DIY ethos, encouraging operators to build their own equipment. This practice is not just a nostalgic throwback; it is a return to the very fundamentals of radio communication. Radio communication was pioneered by non-professionals and professionals alike who engaged in experimentation. Homebrew refers to Amateur Radio equipment made at home. This equipment may come from a kit, be built from a schematic, or even be designed from scratch by the operator.

SUMMARY#

QRP operation is a fascinating aspect of amateur radio that challenges operators to achieve maximum range with minimal power. By using weak signal modes and embracing the DIY spirit of homebrewing, QRP enthusiasts push the boundaries of radio communication. Whether for the thrill of making long-distance contacts or the satisfaction of building their own equipment, QRP offers a unique and rewarding experience for radio amateurs.