QRP operation

AhomebrewQRP low-power transmitter and receiver that fits inside anAltoidstin.

Inamateur radio,QRP operationrefers to transmitting at reduced power while attempting to maximize one's effective range. QRP operation is a specialized pursuit within the hobby that was first popularized in the early 1920s. QRP operators limit their transmittedRFoutput power to 5 W or less regardless of mode (Some call 10 W on Phone QRP).^[1]

Reliable two-way communication at such low power levels can be challenging due to changingradio propagationand the difficulty of receiving the relatively weak transmitted signals. QRP enthusiasts may employ optimizedantennasystems, enhanced operating skills, and a variety of special modes, in order to maximize their ability to make and maintain radio contact. Since the late 1960s, commercialtransceiversspecially designed for QRP operation have evolved fromvacuum tubetosolid statetechnology.

A number of organizations dedicated to QRP operation exist, and aficionados participate in variouscontestsdesigned to test their skill in making long-distance contacts at low power levels.

Etymology

The term "QRP" derives from the standardQ codeused in radio communication, whereQRPis used to request "Reduce power"andQRP?is used to ask "Should I reduce power?".^[2]^[a]

Philosophy

Most amateur transceivers are capable of transmitting approximately 100 watts,^[3]but in some parts of the world, such as the U.S., amateurs can transmit up to 1,500 watts. QRP enthusiasts contend that this practice is rarely necessary, and doing so wastes power, increases the likelihood of causinginterferenceto nearbytelevisions,radios,andtelephonesand, forUnited States' amateurs, is contrary toFCCPart 97 rule, which states that one must use "the minimum power necessary to carry out the desired communications".^[4]QRP can also be used foremergency communicationsduringdisaster recovery,when frugal use of available battery power and generator fuel is crucial.^[5]^[6]^[7]

Practice

The practice of operating with low power was popularized as early as 1924, with a variety of reports, editorials and articles published in U.S. amateur radio magazines and journals that encouraged amateurs to lower power output, both for purposes of experimentation, and for improving operating conditions by reducing interference.^[8]

Although not universally agreed upon, the ARRL makes a recommendation for QRP power limits. Most amateur organizations agree that forCW,AM,FM,anddata modes,thetransmitter output powershould be 5watts(or less).^[9]The maximum output power forSSB(single sideband) is sometimes agreed to be no more than 10 Wattspeak envelope power(PEP), while some organisations opine that the power limit should be 5 Watts. QRPers are known to regularly use less than 5 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".^[4]^[5]^[6]^[10]

Communicating using QRP can be difficult since the QRPer must face the same challenges ofradio propagationfaced 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 efficientantennasystems and enhanced operating skills.^[10]^[7]

Weak signal modes

QRP enthusiasts may use special modes that employ technology and software designed to enhance reception of the relatively weak transmitted signals resulting from low power levels.^[11]

QRSS:Very slow speed Morse code

QRSS uses very slow speedCW(Morse code) to compensate for the decreasedsignal-to-noise ratioinvolved in QRP operation.^[11]^[b]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 analyzer.^[12]^[13]

Coherent CW:Critically-timed Morse code transmission

Coherent CW uses transmitters that clock-out signals calibrated to a precise rate, allowing receivers to employ extremely narrowband filtering to increase readability.^[11]

WSJT:Weak Signal – Joe Taylor

WSJT is a software system that utilizes several separate modes, each optimized for a different signal path; these includemeteor scatter,troposcatter,andEME communications.WSJT was named afterDr. J.H. Taylorto acknowledge his work in developing weak signal communication modes for radio.^[11]^[c]

WSPR:Weak Signal – Propagation Reporter

WSPR is a software suite and computer network used to monitor propagation paths for optimal communication conditions.^[11]

Equipment

Many of the larger, more powerful commercial transceivers permit the operator to lower their output level to QRP levels. Commercialtransceiversspecially designed to operate at or near QRP power levels have been commercially available since the late 1960s.

In 1969 the American manufacturer Ten-Tec produced the Powermite-1, one of Ten-Tec's first assembled transceivers, and featured modular construction. All stages of the transceiver were on individualcircuit boards:the transmitter was capable of about one or two watts of RF, and the receiver was adirect-conversionunit, similar to that found in theHeathkitHW-7 and HW-8 lines, which introduced many amateurs to QRP'ing and led to the popularity of the mode.^[14]

Enthusiasts operate QRP radios on theHF bandsinportable modes,usually carrying the radios inbackpacks,withwhip antennas.Some QRPers prefer to construct their equipment from kits, published plans,^[15]orhomebrewit from scratch. Many popular designs are based on theNE612mixer IC, i.e. the K1, K2, ATS series and the Softrock SDR.^[16]

Organizations

Amateur radio organizations dedicated to QRP include QRP Amateur Radio Club International (QRPARCI), American QRP Club, G-QRP Club based in theUnited Kingdom,and The Adventure Radio Society emphasizing portable QRP operation. Major QRP gatherings are held yearly athamfestssuch asDayton Hamvention,Pacificon, andFriedrichshafen.^[7]

Contests and awards

There are specific operatingawards,contests,clubs,andconventionsdevoted to QRP enthusiasts. In the United States, the November Sweepstakes, June and September VHF QSO Parties, January VHF Sweepstakes, and theARRLInternational DX Contest, as well as many major international contests have designated special QRP categories. For example, during the annual ARRL'sField Dayevent, making a QSO (ham-to-ham contact) using "QRP battery power" is worth five times as many points as a contact made by conventional means. The QRP ARCI club sponsors 12 contests during the year specifically for QRP operators.^[4]^[7]

Typical awards include the QRP ARCI club's "thousand-miles-per-watt" award, available to anyone presenting evidence of a qualifying contact. QRP ARCI also offers special awards for achieving the ARRL'sWorked All States,Worked All Continents,andDX Century Clubawards under QRP conditions. Other QRP clubs also offer similar versions of these awards, as well as general QRP operating achievement awards.^[17]

Notes

^The opposite ofQRPisQRO,or increased power operation.^[2]
^QRSSis an exaggerated version ofQRS,the standardQ codeused in radio communications. "QRS?"asks"Shall I send more slowly?".^[2]
^Dr.Joseph Hooton Taylor Jr.is an astrophysicist who won theNobel Prize in Physicsin 1993 for discovery of a new type ofpulsarwhich is useful for the study ofGeneral Relativitybyradio astronomy.He is anamateur radiooperator (currently K1JT), and has generously contributed his technical expertise to the development of successful transmission of weak signals over otherwise rarely usable propagation paths.

References

^ "Why QRP?".arrl.org.American Radio Relay League.Retrieved10 December2019.
^^a ^b ^c Marchant, William Henry (1914).Wireless Telegraphy: A handbook for the use of operators and students.Whittaker. p.220– via Archive.org.
^ The ARRL General Class License Manual.American Radio Relay League.1998. pp.3.ISBN 978-0-87259-676-4– via Archive.org.The maximum power output from most amateur transceivers is about 100 W.
^^a ^b ^c Wells, Bradley (April 1984)."QRP: More than a state of mind".QST Magazine.Newington, CT:American Radio Relay League.p. 52.Retrieved24 November2019.
^^a ^b Arland, Richard H. (2007).ARRL's Low Power Communication: The art and science of QRP.American Radio Relay League.ISBN 978-0-87259-104-2– via Google Books.
^^a ^b Dobbs, George (1 September 2012).QRP Basics.Radio Society of Great Britain(RSGB).ISBN 978-1-905086-84-9– via Google Books.
^^a ^b ^c ^d H. Ward Silver (25 February 2011).Ham Radio For Dummies.John Wiley & Sons. p. 218.ISBN 978-1-118-05419-2– via Google Books.
^ Weiss, Adrian (1987).History of QRP in the U.S., 1924-1960.Vermillion, SD: Milliwatt Books.ISBN 978-0-9614139-1-0.OL 2411449M.
^ Rutledge, David(1999).The Electronics of Radio.Cambridge University Press. p. 312.ISBN 978-1-107-39366-0– via Google Books.
^^a ^b DeMaw, Doug (1991).W1FB's QRP Notebook.American Radio Relay League.ISBN 978-0-87259-365-7– via Google Books.
^^a ^b ^c ^d ^e "Weak signal modes".ARRL.org.American Radio Relay League.Retrieved24 November2019.
^ Dennison, Mike; Fielding, John (2007).Radio Communication Handbook.Radio Society of Great Britain(RSGB).ISBN 978-1-905086-33-7– via Google Books.
^ "Grabber compendium".QRSS Knights.digilander.libero.it.Bergamo, IT: I2NDT.
^ Chaffin, Kenny A. (February 1990)."Why QRP?".QST magazine.Newington, CT:ARRL.p. 43.Retrieved24 November2019.
^ Brown, George (2001)."CW QRP transmitter for 80 meters".Radio and Electronics Cookbook.Newnes.ISBN 978-0-7506-5214-8– via Google Books.
^ Weiss, Adrian.The Five-Watt QRP Movement in the US, 1968-1981(PDF)(Report). Miliwatt QRP Books.Retrieved24 November2019– via n5dux.com/ham/files.
^ "QRP – what, why, and how".ARRL.org.Newington, CT:American Radio Relay League.Archived fromthe originalon 27 September 2007.Retrieved4 April2007.

[3] The opposite ofQRPisQRO,or increased power operation.^[2]

[13] QRSSis an exaggerated version ofQRS,the standardQ codeused in radio communications. "QRS?"asks"Shall I send more slowly?".^[2]

[16] Dr.Joseph Hooton Taylor Jr.is an astrophysicist who won theNobel Prize in Physicsin 1993 for discovery of a new type ofpulsarwhich is useful for the study ofGeneral Relativitybyradio astronomy.He is anamateur radiooperator (currently K1JT), and has generously contributed his technical expertise to the development of successful transmission of weak signals over otherwise rarely usable propagation paths.

[QRP-1] "Why QRP?".arrl.org.American Radio Relay League.Retrieved10 December2019.

[Marchant-2] Marchant, William Henry (1914).Wireless Telegraphy: A handbook for the use of operators and students.Whittaker. p.220– via Archive.org.

[4] The ARRL General Class License Manual.American Radio Relay League.1998. pp.3.ISBN 978-0-87259-676-4– via Archive.org.The maximum power output from most amateur transceivers is about 100 W.

[Wells-5] Wells, Bradley (April 1984)."QRP: More than a state of mind".QST Magazine.Newington, CT:American Radio Relay League.p. 52.Retrieved24 November2019.

[Arland2007-6] Arland, Richard H. (2007).ARRL's Low Power Communication: The art and science of QRP.American Radio Relay League.ISBN 978-0-87259-104-2– via Google Books.

[Dobbs2012-7] Dobbs, George (1 September 2012).QRP Basics.Radio Society of Great Britain(RSGB).ISBN 978-1-905086-84-9– via Google Books.

[Silver2018-8] H. Ward Silver (25 February 2011).Ham Radio For Dummies.John Wiley & Sons. p. 218.ISBN 978-1-118-05419-2– via Google Books.

[HistoryOfQRP-9] Weiss, Adrian (1987).History of QRP in the U.S., 1924-1960.Vermillion, SD: Milliwatt Books.ISBN 978-0-9614139-1-0.OL 2411449M.

[10] Rutledge, David(1999).The Electronics of Radio.Cambridge University Press. p. 312.ISBN 978-1-107-39366-0– via Google Books.

[DeMaw1991-11] DeMaw, Doug (1991).W1FB's QRP Notebook.American Radio Relay League.ISBN 978-0-87259-365-7– via Google Books.

[WSM-12] "Weak signal modes".ARRL.org.American Radio Relay League.Retrieved24 November2019.

[DennisonFielding2007-14] Dennison, Mike; Fielding, John (2007).Radio Communication Handbook.Radio Society of Great Britain(RSGB).ISBN 978-1-905086-33-7– via Google Books.

[15] "Grabber compendium".QRSS Knights.digilander.libero.it.Bergamo, IT: I2NDT.

[17] Chaffin, Kenny A. (February 1990)."Why QRP?".QST magazine.Newington, CT:ARRL.p. 43.Retrieved24 November2019.

[18] Brown, George (2001)."CW QRP transmitter for 80 meters".Radio and Electronics Cookbook.Newnes.ISBN 978-0-7506-5214-8– via Google Books.

[Weiss-19] Weiss, Adrian.The Five-Watt QRP Movement in the US, 1968-1981(PDF)(Report). Miliwatt QRP Books.Retrieved24 November2019– via n5dux.com/ham/files.

[20] "QRP – what, why, and how".ARRL.org.Newington, CT:American Radio Relay League.Archived fromthe originalon 27 September 2007.Retrieved4 April2007.

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