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[[File:FT8+JT65.png|thumb|FT8 being used on the 40 meter band.]] |
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FT8 is a popular [[amateur radio]] digital mode. The most widely used FT8 software is [[WSJT-X]]. It is widely used on the [[shortwave]] (high frequency/HF) bands. The exchange consists of [[call sign]]s, [[signal-to-noise ratio]]s, and [[Maidenhead Locator System]] grid squares. |
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'''FT8 '''or '''Franke & Taylor 8''' is a [[Frequency-shift keying|frequency shift keying]] digital mode which was released on June 29, 2017, by the creators Joe Taylor, K1JT and Steve Franke, K9AN along with the software package [[WSJT (amateur radio software)|WSJT]].<ref name=":0">Burmester, Dale March 12, 2019. Amateur Radio Digital Communications Mode FT8. http://site.ieee.org/msn/files/2019/04/FT8-KA9SWE.pdf</ref> FT8 is a popular form of digital weak signal communication used primarily by amateur radio operators to communicate on [[amateur radio bands]] with a majority of traffic occurring on the [[High frequency|HF]] amateur bands.<ref>{{Cite web |last=Luscre |first=Anthony |date=2019-10-11 |title=FT8—What Is It and How Can I Get Started? |url=https://www.onallbands.com/ft8-what-is-it-and-how-can-i-get-started/ |access-date=2022-08-17 |website=OnAllBands |language=en-US}}</ref> It is currently the most popular digital mode on spotting networks such as [[PSK Reporter]]..<ref>{{Cite web |last=Barron |first=Robert |date=2020-02-08 |title=PSK Reporter |url=http://www.ka5wss.com/posts/psk-reporter/ |access-date=2022-10-06 |website=KA5WSS |language=en-US}}</ref> The mode offers operators the ability to communicate in unfavorable environments such as during low [[Solar cycle|sun spot numbers]], high RF noise, or during [[QRP operation|low power operations]].<ref>{{Cite web |title=FT8 – Signal Identification Wiki |url=https://www.sigidwiki.com/wiki/FT8 |access-date=2022-08-17 |website=www.sigidwiki.com}}</ref> With advances in signal processing technology FT8 is able to decode signals down to −20 dB, which is significantly lower than [[Continuous wave|CW]] or [[Sideband|SSB]] transmissions.<ref>{{Cite web |title=FT8 Mode is Latest Bright Shiny Object in Amateur Radio Digital World |url=http://www.arrl.org/news/ft8-mode-is-latest-bright-shiny-object-in-amateur-radio-digital-world |access-date=2022-08-17 |website=www.arrl.org |language=en}}</ref> The mode works by sending signals in 15-second-blocks with 12.64 seconds of transmission time and 2.36 seconds of decode time, this gives the mode five words per minutes effective transmission.<ref name=":0" /> The mode requires each computer to be synced up in time with each other with most users making use of either [[Network Time Protocol|NTP]] or [[Global Positioning System|GPS]] to ensure transmissions fall in the proper window. This allows FT8 transmission to support up to 13 characters, the mode uses [[Forward Error Correction|forward error correction]] to ensure proper transmission and decoding. As the mode is quite limited in the number of words that it can send, it only sends enough information to ensure a contact with each station. There are multiple uses for FT8 including contesting,<ref>{{Cite web |title=FT8/FT4 from a contester's perspective – VA7ST.ca |url=https://va7st.ca/2020/10/ft8-ft4-from-a-contesters-perspective/ |access-date=2022-08-17 |language=en-US}}</ref><ref>{{Cite web |title=ARRL Surveying Field Day Participants |url=http://www.arrl.org/news/arrl-surveying-field-day-participants |access-date=2022-08-17 |website=www.arrl.org |language=en}}</ref> testing antennas,<ref>{{Cite web |title=FT8 |url=https://www.rtl-sdr.com/tag/ft8/ |access-date=2022-08-17 |website=www.rtl-sdr.com}}</ref> and for scientific research.<ref>{{Cite web |last1=Erickson |first1=P. |last2=Liles |first2=W. |last3=Miller |first3=E. |last4=Miller |first4=E. |date=2020 |title=Amateur digital mode based remote sensing: FT8 use as a radar signal of opportunity for ionospheric characterization |url=https://hamsci.org/publications/amateur-digital-mode-based-remote-sensing-ft8-use-radar-signal-opportunity-ionospheric |access-date=2022-08-17 |website=hamsci.org}}</ref> |
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[[File:20 meter FT8.jpg|thumb|FT8 Blocks on 20 Meters]] |
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[[File:FT8 Video.ogg|thumb|Recording of FT8 Transmissions on 20 Meters]] |
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[[File:FT8+JT65.png|thumb|A [[waterfall plot]] for FT8 signals (bandwidth 50 Hz) in the [[40-meter band]] and for JT65 on the right (bandwidth 180 Hz)]] |
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{{reflist}} |
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Joe Taylor, K1JT, announced on June 29, 2017, the availability of FT8 in WSJT-X.<ref>{{cite web |
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| title=FT8 Mode is Latest Bright Shiny Object in Amateur Radio Digital World |
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| url=http://www.arrl.org/news/ft8-mode-is-latest-bright-shiny-object-in-amateur-radio-digital-world |
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| publisher=[[American Radio Relay League]] (ARRL) |
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| date=2017-08-01 |
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}}</ref> FT8 stands for "Franke-Taylor design, 8-FSK modulation" and was created by Joe Taylor, K1JT and Steve Franke, K9AN. It is described as being designed for "multi-hop Es where signals may be weak and fading, openings may be short, and you want fast completion of reliable, confirmable [[Contact (amateur radio)|QSO]]'s". |
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[[Category:Amateur radio]] |
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According to Taylor, the important characteristics of FT8 are — |
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[[Category:Quantized radio modulation modes]] |
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* T/R sequence length: 15 s |
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[[Category:Data transmission]] |
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* Message length: 75 bits + 12-bit [[Cyclic redundancy check|CRC]] |
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* FEC code: (174,87) [[Low-density parity-check code|LDPC]] |
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* Modulation: 8-FSK, keying rate = 6.25 [[baud]]; tone spacing = 6.25 [[Hertz|Hz]] |
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* Waveform: Continuous phase, constant envelope |
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* Occupied bandwidth: 50 Hz |
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* Synchronization: three 7x7 [[Costas array]]s (start, middle, end of transmission) |
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* Transmission duration: 79*1920/12000 = 12.64 s |
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* Decoding threshold: -24 dB (with [[a priori probability|''a priori''] decoding) |
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* Operational behavior: similar to HF usage of JT9, JT65 |
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* Multi-decoder: finds and decodes all FT8 signals in passband |
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* Auto-sequencing after manual start of QSO |
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Compared to the so-called "slow modes" (JT9, JT65, QRA64), FT8 is a few decibels less sensitive, but allows completion of QSOs four times faster. Bandwidth is greater than JT9, but about one-quarter of JT65A and less than one-half of QRA64. Compared with the "fast modes" (JT9E-H), FT8 is significantly more sensitive, has much narrower bandwidth, uses the vertical waterfall, and offers multi-decoding over the full displayed passband. <ref>{{cite web|url=http://physics.princeton.edu/pulsar/K1JT/Release_Notes_1.8.0.txt|title=FT8|author=Joe Taylor, K1JT}}</ref> |
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== Controversy == |
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{{unsourced section|date=January 2022}} |
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FT8 is somewhat controversial, with some amateur radio operators having strong opinions either for or against its use. Some common claims in favor of its use are that it reduces the [[barrier to entry]] of amateur radio by making inefficient antennas (which are more feasible for use in apartments and under many other circumstances) and low-power [[transceivers]] (which are often less expensive than higher-power transceivers), while its opponents often claim that it is "ruining ham radio" or other phrases expressing a belief that use of FT8 is contrary to the purposes of amateur radio. |
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Revision as of 20:48, 6 October 2022
FT8 or Franke & Taylor 8 is a frequency shift keying digital mode which was released on June 29, 2017, by the creators Joe Taylor, K1JT and Steve Franke, K9AN along with the software package WSJT.[1] FT8 is a popular form of digital weak signal communication used primarily by amateur radio operators to communicate on amateur radio bands with a majority of traffic occurring on the HF amateur bands.[2] It is currently the most popular digital mode on spotting networks such as PSK Reporter..[3] The mode offers operators the ability to communicate in unfavorable environments such as during low sun spot numbers, high RF noise, or during low power operations.[4] With advances in signal processing technology FT8 is able to decode signals down to −20 dB, which is significantly lower than CW or SSB transmissions.[5] The mode works by sending signals in 15-second-blocks with 12.64 seconds of transmission time and 2.36 seconds of decode time, this gives the mode five words per minutes effective transmission.[1] The mode requires each computer to be synced up in time with each other with most users making use of either NTP or GPS to ensure transmissions fall in the proper window. This allows FT8 transmission to support up to 13 characters, the mode uses forward error correction to ensure proper transmission and decoding. As the mode is quite limited in the number of words that it can send, it only sends enough information to ensure a contact with each station. There are multiple uses for FT8 including contesting,[6][7] testing antennas,[8] and for scientific research.[9]
References
- ^ a b Burmester, Dale March 12, 2019. Amateur Radio Digital Communications Mode FT8. http://site.ieee.org/msn/files/2019/04/FT8-KA9SWE.pdf
- ^ Luscre, Anthony (2019-10-11). "FT8—What Is It and How Can I Get Started?". OnAllBands. Retrieved 2022-08-17.
- ^ Barron, Robert (2020-02-08). "PSK Reporter". KA5WSS. Retrieved 2022-10-06.
- ^ "FT8 – Signal Identification Wiki". www.sigidwiki.com. Retrieved 2022-08-17.
- ^ "FT8 Mode is Latest Bright Shiny Object in Amateur Radio Digital World". www.arrl.org. Retrieved 2022-08-17.
- ^ "FT8/FT4 from a contester's perspective – VA7ST.ca". Retrieved 2022-08-17.
- ^ "ARRL Surveying Field Day Participants". www.arrl.org. Retrieved 2022-08-17.
- ^ "FT8". www.rtl-sdr.com. Retrieved 2022-08-17.
- ^ Erickson, P.; Liles, W.; Miller, E.; Miller, E. (2020). "Amateur digital mode based remote sensing: FT8 use as a radar signal of opportunity for ionospheric characterization". hamsci.org. Retrieved 2022-08-17.