Editing Radioteletype (section)

== Early amateur radioteletype history ==
After World War&nbsp;II, [[amateur radio operator]]s in the U.S. started to receive obsolete but usable Teletype Model&nbsp;26 equipment from commercial operators with the understanding that this equipment would not be used for or returned to commercial service. "The Amateur Radioteletype and VHF Society" was founded in 1946 in Woodside, NY. This organization soon changed its name to "The VHF Teletype Society" and started US amateur radio operations on [[2 meter band|2&nbsp;meters]] using [[audio frequency shift keying]] (AFSK). The first two-way amateur radio teletype [[contact (amateur radio)|contact]] ([[Q code|QSO]]) of record took place in May&nbsp;1946 between Dave Winters, W2AUF, Brooklyn, NY, and W2BFD, John Evans Williams, Woodside Long Island, NY.<ref>{{cite magazine |last=Williams |first=John Evans, W2BFD |title=The story of amateur radio teletype |magazine=[[QST|QST Magazine]] |date=October 1948 |page=17}}</ref> On the west coast, amateur RTTY also started on 2&nbsp;meters. Operation on 80&nbsp;meters, 40&nbsp;meters and the other [[High Frequency]] (HF) amateur radio bands was initially accomplished using make and break keying since [[frequency shift keying]] (FSK) was not yet authorized.

In early 1949, the first American transcontinental two-way RTTY [[contact (amateur radio)|contact]] was accomplished on [[11 meter band|11&nbsp;meters]] using [[audio frequency shift keying|AFSK]] between Tom McMullen (W1QVF) operating at [[W1AW]] and Johnny Agalsoff, W6PSW.<ref>{{cite news |title=First transcon TT QSOs realized! |magazine=[[QST|QST Magazine]] |date=March 1949 |page=10}}</ref> The stations effected partial contact on January 30, 1949, and repeated more successfully on January&nbsp;31. On February 1, 1949, the stations exchanged solid print congratulatory message traffic and [[Chew the fat|rag-chewed]]. Earlier, on January 23, 1949, William T. Knott, W2QGH, Larchmont, NY, had been able to make rough copy of W6PSW's test transmissions. While [[Contact (amateur radio)|contacts]] could be accomplished, it was quickly realized that [[frequency shift keying|FSK]] was technically superior to make and break keying. Due to the efforts of Merrill Swan, W6AEE, of "The RTTY Society of Southern California" publisher of ''RTTY'' and Wayne Green, W2NSD, of [[CQ Amateur Radio|''CQ Magazine'']], amateur radio operators successfully petitioned the U.S. [[Federal Communications Commission]] (FCC) to amend Part&nbsp;12 of the Regulations, which was effective on February 20, 1953.<ref name=Kretzman-1962>{{cite book |last=Kretzman |first=Byron H., W2JTP |year=1962 |title=The New RTTY Handbook |page=10}}</ref> The amended Regulations permitted [[frequency shift keying|FSK]] in the non-voice parts of the [[80 meter band|80]], [[40 meter band|40]], and [[20 meter band|20&nbsp;meter bands]] and also specified the use of single channel 60&nbsp;words-per-minute five unit code corresponding to [[ITA2]]. A shift of {{nobr|850 ± 50 [[Hertz|Hz]]}} was specified. Amateur radio operators also had to identify their station callsign at the beginning and the end of each transmission and at ten-minute intervals using [[International Morse code]]. Use of this wide shift proved to be a problem for amateur radio operations. Commercial operators had already discovered that narrow shift worked best on the [[shortwave|HF bands]]. After investigation and a petition to the FCC, Part&nbsp;12 was amended, in March&nbsp;1956, to allow amateur radio operators to use any shift that was 900&nbsp;Hz or less.

The FCC ''Notice of Proposed Rule Making'' (NPRM) that resulted in the authorization of [[frequency shift keying|FSK]] in the amateur high frequency (HF) bands responded to petitions by the [[American Radio Relay League]] (ARRL), the National Amateur Radio Council, and a Mr.&nbsp;Robert Weinstein. The NPRM specifically states this, and this information may be found in its entirety in the December&nbsp;1951 issue of [[QST|''QST Magazine'']]. While ''The New RTTY Handbook''<ref name=Kretzman-1962/> gives ARRL no credit, it was published by [[CQ Amateur Radio|''CQ Magazine'']] and its author was a ''CQ'' columnist (''CQ'' was generally hostile to the ARRL at that time).

The first RTTY Contest was held by the RTTY Society of Southern California from October 31 to November 1, 1953.<ref>{{cite magazine |title=RTTY notes |magazine=[[QST|QST Magazine]] |date=February 1954 |page=62}}</ref> Named the RTTY Sweepstakes Contest, twenty nine participants exchanged messages that contained a serial number, originating station call, check or RST report of two or three numbers, ARRL section of originator, local time (0000-2400 preferred) and date. Example: NR 23 W0BP CK MINN 1325 FEB 15. By the late 1950s, the contest exchange was expanded to include band used. Example: NR 23 W0BP CK MINN 1325 FEB 15 FORTY METERS. The contest was scored as follows: One point for each message sent and received entirely by RTTY and one point for each message received and acknowledged by RTTY. The final score was computed by multiplying the total number of message points by the number of ARRL sections worked. Two stations could exchange messages again on a different band for added points, but the section multiplier did not increase when the same section was reworked on a different band. Each DXCC entity was counted as an additional ARRL section for RTTY multiplier credit.

A new magazine named ''RTTY'', later renamed ''RTTY Journal'', also published the first listing of stations, mostly located in the continental US, that were interested in RTTY in 1956.<ref>{{cite report |title=RTTY Call Book |year=1956 |url=http://www.seas.upenn.edu/~uparc/documents/RTTY%20Call%20Book%201956.pdf |access-date=2010-09-03 |via=[[University of Pennsylvania|U Penn]]}}</ref> Amateur radio operators used this callbook information to contact other operators both inside and outside the United States. For example, the first recorded USA to New Zealand two-way RTTY [[contact (amateur radio)|contact]] took place in 1956 between W0BP and ZL1WB.

By the late 1950s, new organizations focused on amateur radioteletype started to appear. The "British Amateur Radio Teletype Group", BARTG, now known as the "British Amateur Radio Teledata Group"<ref>{{cite web |title=British Amateur Teledata Group |url=http://www.bartg.org.uk/ |access-date=2010-09-03}}</ref> was formed in June 1959. The Florida RTTY Society was formed in September&nbsp;1959.<ref>{{cite magazine |title=British Amateur Radio Teletype Group and Florida RTTY Society |magazine=RTTY Journal |date=September 1959 |pages=12–13}}</ref> Amateur radio operators outside of Canada and the U.S. began to acquire surplus teleprinter and receive permission to get on the air. The first recorded RTTY [[contact (amateur radio)|contact]] in the U.K. occurred in September&nbsp;1959 between G2UK and G3CQE. A few weeks later, G3CQE had the first G/VE RTTY QSO with VE7KX.<ref>{{cite magazine |title={{grey|[no title cited]}} |date=January 1960 |magazine=RTTY Journal |volume=8 |number=1 |page=9}}</ref> This was quickly followed up by G3CQE QSOs with VK3KF and ZL3HJ.<ref>{{cite magazine |last=Schultz |first=Bud, W6CG |date=January 1960 |title=RTTY DX |magazine=RTTY Journal |volume=8 |number=1 |page=11}}</ref> Information on how to acquire surplus teleprinter equipment continued to spread and before long it was possible to work all continents on RTTY.

Amateur radio operators used various equipment designs to get on the air using RTTY in the 1950s and 1960s. Amateurs used their existing receivers for RTTY operation but needed to add a terminal unit, sometimes called a demodulator, to convert the received audio signals to DC signals for the teleprinter.

Most of the terminal unit equipment used for receiving RTTY signals was home built, using designs published in amateur radio publications. These original designs can be divided into two classes of terminal units: audio-type and intermediate frequency converters. The audio-type converters proved to be more popular with amateur radio operators. The Twin City, W2JAV and W2PAT designs were examples of typical terminal units that were used into the middle 1960s. The late 1960s and early 1970s saw the emergence of terminal units designed by W6FFC, such as the TT/L, ST-3, ST-5, and ST-6. These designs were first published in ''RTTY Journal'' starting in September&nbsp;1967 and ending in 1970.

An adaptation of the W6FFC TT/L terminal unit was developed by Keith Petersen, W8SDZ, and it was first published in the ''RTTY Journal'' in September&nbsp;1967.  The drafting of the schematic in the article was done by Ralph Leland, W8DLT.

Amateur radio operators needed to modify their transmitters to allow for HF RTTY operation. This was accomplished by adding a frequency shift keyer that used a diode to switch a capacitor in and out of the circuit, shifting the transmitter’s frequency in synchronism with the teleprinter signal changing from mark to space to mark. A very stable transmitter was required for RTTY. The typical frequency multiplication type transmitter that was popular in the 1950s and 1960s would be relatively stable on [[80 meter band|80&nbsp;meters]] but become progressively less stable on [[40 meter band|40&nbsp;meters]], [[20 meter band|20&nbsp;meters]], and [[meter band|15&nbsp;meters]]. By the middle 1960s, transmitter designs were updated, mixing a crystal-controlled high frequency oscillator with a variable low frequency oscillator, resulting in better frequency stability across all amateur radio HF bands.

During the early days of Amateur RTTY, the RTTY [[Worked All Continents]] Award was conceived by the RTTY Society of Southern California and issued by RTTY Journal.<ref>{{cite magazine |title={{grey|[no title cited]}} |date=October 1973 |magazine=RTTY Journal |volume=21 |number=8 |page=11}}</ref> The first amateur radio station to achieve this WAC – RTTY Award was VE7KX.<ref>{{cite magazine |title={{grey|[no title cited]}} |date=December 1968 |magazine=RTTY Journal |volume=16 |number=11 |page=12}}</ref> The first stations recognized as having achieved single band WAC RTTY were W1MX ([[80 meter band|3.5&nbsp;MHz]]); DL0TD ([[40 meter band|7.0&nbsp;MHz]]); K3SWZ ([[20 meter band|14.0&nbsp;MHz]]); W0MT ([[15 meter band|21.0&nbsp;MHz]]) and FG7XT ([[10 meter band|28.0&nbsp;MHz]]).<ref>{{cite magazine |title={{grey|[no title cited]}} |date=February 1977 |magazine=RTTY Journal |volume=25 |number=2 |page=10}}</ref> The ARRL began issuing [[Worked All Continents|WAC]] RTTY certificates in 1969.

By the early 1970s, amateur radio RTTY had spread around the world and it was finally possible to work more than 100&nbsp;countries via RTTY. FG7XT was the first amateur radio station to claim to achieve this honor. However, Jean did not submit his [[contact (amateur radio)|QSL]] cards for independent review. ON4BX, in 1971, was the first amateur radio station to submit his cards to the DX editor of ''RTTY Journal'' and to achieve this honor.<ref>{{cite magazine |title={{grey|[no title cited]}} |date=October 1971 |magazine=RTTY Journal |volume=19 |number=9 |page=15}}</ref> The ARRL began issuing [[DXCC]] RTTY Awards on November 1, 1976.<ref>{{cite magazine |title={{grey|[no title cited]}} |date=September 1976 |magazine=RTTY Journal |volume=24 |number=7 |page=11}}</ref> Prior to that date, an award for working 100 countries on RTTY was only available via RTTY Journal.

In the 1950s through the 1970s, "[[ASCII art#History|RTTY art]]" was a popular on-air activity. This consisted of (sometimes very elaborate and artistic) pictures sent over RTTY through the use of lengthy punched tape transmissions and then printed by the receiving station on paper.

On January 7, 1972, the FCC amended Part&nbsp;97 to allow faster RTTY speeds. Four standard RTTY speeds were authorized, namely, 60&nbsp;[[words per minute]] ({{sc|wpm}}) (45&nbsp;[[baud]]), 67&nbsp;{{sc|wpm}} (50&nbsp;baud), 75&nbsp;{{sc|wpm}} (56.25&nbsp;baud), and 100&nbsp;{{sc|wpm}} (75&nbsp;baud). Many amateur radio operators had equipment that was capable of being upgraded to 75 and 100&nbsp;words per minute by changing teleprinter gears. While there was an initial interest in 100&nbsp;{{sc|wpm}} operation, many amateur radio operators moved back to 60&nbsp;{{sc|wpm}}. Some of the reasons for the failure of 100&nbsp;{{sc|wpm}} HF RTTY included poor operation of improperly maintained mechanical teleprinters, narrow bandwidth terminal units, continued use of 170&nbsp;Hz shift at 100&nbsp;{{sc|wpm}}, and excessive error rates due to multipath distortion and the nature of ionospheric propagation.

The FCC approved the use of [[ASCII]] by amateur radio stations on March 17, 1980 with speeds up to 300&nbsp;[[baud]] from [[80 meter band|3.5&nbsp;MHz]] to [[15 meter band|21.25&nbsp;MHz]] and 1200&nbsp;baud between [[10 meter band|28&nbsp;MHz]] and [[1.25 meter band|225&nbsp;MHz]]. Speeds up to 19.2&nbsp;kilobaud was authorized on amateur frequencies above [[70 centimeter band|420&nbsp;MHz]].<ref>{{cite magazine |title={{grey|[no title cited]}} |date=April 1980 |magazine=RTTY Journal |volume=28 |number=3 |page=3}}</ref>

These symbol rates were later modified:<ref>{{cite report |title=Authorized emission types |id=47 CFR § 97.305 |publisher=U.S. [[Federal Communications Commission]] |type=regulations |url=https://www.law.cornell.edu/cfr/text/47/97.305#c |via=[[Cornell University|Cornell U]] Law}}</ref>
::{|
! nominal [[amateur radio band|band]]<br/>[[wavelength]] !! [[symbol rate|symbol<br/>rate]] !! [[Federal Communications Commission|FCC]]<br/>regulation
|-
| [[12 meter band|12&nbsp;m]] and below || {{center|300 [[baud]]}} || 47 CFR § 97.307 (f)(3)
|-
| [[10 meter band|10&nbsp;m]] || {{center|1200 [[baud]]}} || 47 CFR § 97.307 (f)(4)
|-
| [[6 meter band|6&nbsp;m]] & [[2 meter band|2&nbsp;m]] || {{center|19.6 kilo[[baud]]}} || 47 CFR § 97.307 (f)(5)
|-
| [[1.25 meter band|1.25&nbsp;m]] & [[70 centimeter band|70&nbsp;cm]] &emsp; || {{center|56 kilo[[baud]]}} || 47 CFR § 97.307 (f)(6)
|-
| [[33 centimeter band|33&nbsp;cm]] and above || {{center|&emsp;{{grey|[not specified]}}&emsp;}} || 47 CFR § 97.307 (f)(7)
|}

The requirement for amateur radio operators in the U.S. to identify their station [[callsign]] at the beginning and the end of each digital transmission, and at ten-minute intervals using International Morse code, was finally lifted by the FCC on June 15, 1983.