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#REDIRECT ] |
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FT8 is a popular ] digital mode. The most widely used FT8 software is ]. It is widely used on the ] (high frequency/HF) bands. The exchange consists of ]s, ]s, and ] grid squares. |
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{{rcat shell | |
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] for FT8 signals (bandwidth 50 Hz) in the ] and for JT65 on the right (bandwidth 180 Hz)]] |
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{{R to section}} |
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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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}} |
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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=] (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 ]'s". |
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According to Taylor, the important characteristics of FT8 are — |
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* T/R sequence length: 15 s |
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* Message length: 75 bits + 12-bit ] |
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* FEC code: (174,87) ] |
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* Modulation: 8-FSK, keying rate = 6.25 ]; tone spacing = 6.25 ] |
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* Waveform: Continuous phase, constant envelope |
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* Occupied bandwidth: 50 Hz |
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* Synchronization: three 7x7 ]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 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 ] of amateur radio by making inefficient antennas (which are more feasible for use in apartments and under many other circumstances) and low-power ] (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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==References== |
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