Technically, QRP is the universally accepted "Q" signal meaning "Decrease Power." QRP has become generally accepted to represent amateur radio operations at low power: output power of 5W or less on CW and 10W input/5W output (assuming PA efficiency of 50%) on SSB.
OK, so what's the big deal about QRP? Well, in the true nature of amateur radio, QRP'ers are always trying to "push the limit." Whereas for many the thrill is to log as many countries as possible (and many QRPers share that thrill), "pushing the limit" in QRP means, "doing more with less." The challenge is to improve your operating skills and technical capabilities to go "further with fewer."
Assume two amateur radio stations have identical antennas and identical transmitting and
receiving equipment. One of the stations transmits a 1000-watt CW signal and that signal is
measured at "10 dB over S9" on a receiving station. If the CW transmitter output is reduced to
5 watts, it will be measured at the receiving station as a little under S7!
|Power Output||Signal Strength Received|
|1000 watts||S9 + 10 dB|
One of the earliest references to "miles per watt" was in 1923, when Robert Kruse, 1XAM, noted in QST "…doesn't more credit belong to the man who hauls signals fifty miles per watt than to the one who has to use greater power to haul them only 25 miles per watt?" (quoted by Richard Arlan, K7YHA, in the September 1995 QST, page 66).
QRPp is QRP operating at power levels less than one watt (milliwatts or microwatts). For example, on December 26, 1994, Fran Slavinski, KA3WTF, copied Paul Stroud, AA4XX's, 221 microwatt (211 millionths of a watt) signal on 7050KHz at a pre-arranged time. He immediately sent back a 229-signal report to complete a 2xQRP QSO, establishing a new 40-meter world record of over 1,900,000 miles per watt! They were using standard QRP equipment (an Oak Hills Research "Classic" QRP 40/20-meter transceiver at AA4XX and a Ten-Tec Argonaut II at KA3WTF).
Another advantage of QRP is that by running less power out, less power supply is needed, allowing for more easily transportable gear. Many QRP enthusiasts are also backpacking, hiking and camping enthusiasts and many QRP contests involve field operations.
Finally, many QRP operators enjoy designing and building their own equipment. Building your own gear is not a requirement of QRP operations, but can be a whole lot of fun-especially the first time you realize that Ohm's Law really does work! Not only does home-brew improve the state-of-the-art, but it also improves the individual's technical skill. Truth is, though, that very few home-brew rigs are ever "finished," as there is always "one more mod" to do!
Copyright ©, 1999, Mike Boatright, KO4WX (Copies may be freely made with attribution)