QRP operation
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In amateur radio, QRP operation means transmitting at reduced power levels. The term QRP derives from the Q code where "QRP?" was used to mean, "Should I reduce Power?".
There is not complete agreement on what constitutes QRP power. While most agree that for CW; AM; FM; and data modes, the transmitter output power should be 5 watts (or less), the maximum output power for SSB (single sideband) is not always agreed upon. Some believe that the power should be no more than 10 watts peak envelope power (PEP), while others strongly hold that the power limit should be 5 watts. QRPers are known to use even less than five watts, sometimes operating with as little as 100 milliwatts or even less. Extremely low power -- 1 watt and below -- is often referred to by hobbyists as QRPp. Commercial transceivers designed to operate at or near QRP power levels have been available for many years, but some QRPers prefer to design and build their own equipment, either from kits or from scratch. On the other hand, many of the larger, more powerful commercial transceivers permit the operator to lower their output level to QRP levels.
Most amateur radio operators use between 50 and 120 watts of power. However this isn't always necessary. When it's not, doing so wastes power, increases the likelihood of causing interference to nearby televisions, radios, and telephones and, for United States' amateurs, violates an FCC Part 97 rule which states that one must use, "the minimum power necessary to carry out the desired communications."
Communicating using QRP can be difficult since the QRPer must face the same challenges of radio propagation faced by amateurs using higher power levels, but with the inherent disadvantages associated with having a weaker signal on the receiving end, all other things being equal. QRP aficionados try to make up for this through more efficient antenna systems and enhanced operating skills.
QRP is especially popular with CW operators and those using the newer digital modes. PSK31 is a highly efficient, narrow-band mode that is very suitable to QRP operation. QRPers have their own awards, contests, clubs, and conventions.
Equipment for QRP use has been commercially available since the late 1960s. In 1969, American manufacturer, Ten-Tec, produced the Powermite-1 (PM-1). This radio was one of Ten-Tec's first assembled transceivers. (The MR-1 was available, and it was essentially the SAME radio, albeit in kit form.) This radio featured modular construction (all stages of the transceiver were on individual circuit boards): the transmitter was capable of about one or two watts of RF, and the receiver was a direct-conversion unit, similar to that found in the Heathkit HW-7 and HW-8 lines. Many amateurs became quite adept at QRP'ing through their use of these early, trend-setting radios.
As QRP has become more popular in recent years, radio manufacturers have introduced radios specifically intended for the QRP enthusiast. Popular models include Elecraft K2, the Yaesu FT-817, the Icom IC-703, and the Argonaut V from TenTec.
HFPack enthusiasts operate QRP radios on the HF bands in portable modes, usually carrying the radios in backpacks, with whip antennas.
The opposite of QRP is QRO--high-power operation.
