WSJT (amateur radio software)

"JT9" redirects here. For the jet engine, see Pratt & Whitney JT9D.
WSJT, WSJT-X
Developer(s)Joe Taylor, K1JT
Initial release2005
Stable release
2.4.0 / 24 May 2021
Written inPython (GUI), C++ (Qt GUI), Fortran, C [1]
Operating system32-bit Windows NT or later, Unix, Unix-like
Available inSoftware: English
Documentation: English, Dutch, Finnish, French, German, Hungarian, Italian, Japanese, Portuguese, Russian, Serbian, Slovak, Spanish
TypeAmateur radio and DSP
LicenseGPL
Websitephysics.princeton.edu/pulsar/K1JT/

WSJT is a computer program used for weak-signal radio communication between amateur radio operators. The program was initially written by Joe Taylor, K1JT, but is now open source and is developed by a small team. The digital signal processing techniques in WSJT make it substantially easier for amateur radio operators to employ esoteric propagation modes, such as high-speed meteor scatter and moonbounce.[2]

History

WSJT was originally released in 2001 and has undergone several major revisions. Communication modes have been both added and removed from the software over the course of its development. Since 2005, the software has been released as open source software under the GNU General Public License. This licensing change required substantial rewrites and took several months to complete. Although Joe Taylor was the original developer (and still acts as maintainer), several programmers are currently involved in writing the software. Currently, the program is written in Python and C, with several utilities written in Fortran.[3]

WSJT versions up through 7.06 r1933 (referred to as colloquially as WSJT7) and earlier were aggregations of previous versions, and as such WSJT7 contained 16 different modes (FSK441, JT6M, JT65 variants A - C, JT2, JT4 variants A - G, WSPR, and a preview of JT64A). As of version 8.0 (referred to as colloquially as WSJT8) the available modes changed completely such that WSJT8 now offers 5 different modes (JTMS, ISCAT, JT64A, JT8, and Echo) -- none of which are back-compatible with WSJT7 or earlier releases.[4] This backwards-incompatibility includes JT64A, such that the preview release of JT64A in WSJT7 cannot communicate with the stable release of JT64A in WSJT8. As of May 2018, the latest WSJT version is WSJT10.

통신 모드 제공

소프트웨어는 약한 신호 작동과 고급 DSP 기법을 일반적으로 강조하지만, 통신 모드는 서로 다른 전리권 전파 모드에 의존하며 많은 다른 대역에서 사용될 수 있다.[5]

WSJT의 통신 모드는 고속 모드와 저속 모드로 나눌 수 있다. 고속 모드는 오류 수정 없이 문자별로 전송되는 반면, 저속 모드는 최소한의 QRO(고출력) 사용을 위해 최적화하는 것을 목표로 한다. WSJT10 현재 지원되는 고속 모드는 JTMS, FSK441, ISCAT, JT6M이며, 저속 모드는 JT65, JT4이다.[6]: 6 WSJT-X 1.8은 "느린" JT9, FT8, QRA64를 추가로 구현한다. 일부 모드에서는 톤 간격이 큰 하위 모드가 파생된다.[7]: 17 다른 두 가지 모드인 WSPR과 Echo는 전파 측정 및 달 바운스 에코 테스트에 포함된다.[7]: 1

FSK441

2001년 WSJT에 포함된 최초의 통신모드로 도입된 FSK441은 지구 대기로 진입하는 유성의 궤도에 의해 전리층에 생성된 무선반사 이온 줄기를 이용한 통신을 지원하도록 설계됐다.[3][2] 이러한 탐방로에 의해 생성되는 신호의 버스트(burst)는 특징적인 소리 때문에 흔히 "ping(ping)"이라고 한다. 이러한 핑은 10분의 1초 정도로 짧을 수 있으며, 적어도 한 단계의 접촉을 완료하기에 충분한 정보를 전달할 수 있다.[8] FSK441은 데이터 전송 속도 441에서 4톤을 사용하는 다중 주파수 시프트 키잉을 사용한다. 프로토콜의 문자 코드의 선택 때문에, 그것은 자가 동기화되며 명시적인 동기화 톤이 필요하지 않다.[2] FSK441은 일반적으로 2m와 70cm의 아마추어 밴드에 사용된다. 접촉은 거의 언제든지(즉, 유성우가 진행 중일 필요는 없다) 최대 1400마일(2,250km)의 거리에서 이루어질 수 있다.[8]

전송된 메시지에 적어도 하나의 공간이 포함된 경우, FSK441 디코딩 알고리즘은 오버헤드 제로 동기화를 위한 동기 워드로 이 공간 문자를 사용한다.[2]: 30 [6]: 12.2

이 모드는 더 이상 wsjt-x v.2.1.2의 일부가 아니다.

JT6M

JT6M, introduced in late 2002,[3] is intended for meteor scatter and other ionospheric scattering of signals, and is especially optimized for the 6-meter band. The mode also employs multiple frequency-shift keying, but at 44 tones. One of the tones is a synchronization tone, leaving 43 tones to carry data (one tone per character in the character set, which includes alphanumerics and some punctuation). The symbol rate is 21.53 baud; the actual data rate as encoded for transmit is 14.4 characters per second. The mode is known for sounding "a bit like piccolo music".[2]

This mode is no longer part of wsjt-x v.2.1.2.

JT65

JT65, developed and released in late 2003,[3] is intended for extremely weak but slowly varying signals, such as those found on troposcatter or Earth-Moon-Earth (EME, or "moonbounce") paths.[2] It can decode signals many decibels below the noise floor in a 2500 Hz band (note that SNR in a 2500 Hz band is approximately 28 dB lower than SNR in a 4 Hz band, which is closer to the channel bandwidth of an individual JT65 tone), and can often allow amateurs to successfully exchange contact information without signals being audible to the human ear. Like the other modes, multiple-frequency shift keying is employed; unlike the other modes, messages are transmitted as atomic units after being compressed and then encoded with a process known as forward error correction (or "FEC"). The FEC adds redundancy to the data, such that all of a message may be successfully recovered even if some bits are not received by the receiver. (The particular code used for JT65 is Reed-Solomon.) Because of this FEC process, messages are either decoded correctly or not decoded at all, with very high probability. After messages are encoded, they are transmitted using MFSK with 65 tones.[9]

Operators have also begun using the JT65 mode for contacts on the HF bands, often using QRP (very low transmit power);[10] while the mode was not originally intended for such use, its popularity has resulted in several new features being added to WSJT in order to facilitate HF operation.[11]

JT9

JT9, intended for MF and HF use, was introduced in an experimental version of WSJT, known as WSJT-X.[12] It uses the same logical encoding as JT65, but modulates to a 9-FSK signal. With 1-minute transmission intervals, JT9 occupies less than 16 Hz bandwidth. JT9 also has versions designed for longer transmission intervals of 2 minutes, 5 minutes, 10 minutes or 30 minutes. These extended versions take increasingly less bandwidth and permit reception of even weaker signals.[13]

FT8

A waterfall plot for FT8 signals (bandwidth 50 Hz) in the 40-meter band and for JT65 on the right (bandwidth 180 Hz)

Joe Taylor, K1JT, announced on June 29, 2017, the availability of a new mode in the WSJT-X software, FT8.[14] 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 QSO's".

According to Taylor, the important characteristics of FT8 are —

  • T/R sequence length: 15 s
  • Message length: 75 bits + 12-bit CRC
  • FEC code: (174,87) LDPC
  • Modulation: 8-FSK, keying rate = tone spacing = 6.25 Hz
  • Waveform: Continuous phase, constant envelope
  • Occupied bandwidth: 50 Hz
  • Synchronization: three 7x7 Costas arrays (start, middle, end of transmission)
  • Transmission duration: 79*1920/12000 = 12.64 s
  • Decoding threshold: -20 dB (perhaps -24 dB with a priori decoding, TBD)
  • Operational behavior: similar to HF usage of JT9, JT65
  • Multi-decoder: finds and decodes all FT8 signals in passband
  • Auto-sequencing after manual start of QSO

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. Features not yet implemented include signal subtraction, two-pass decoding, and use of a priori (already known) information as it accumulates during a QSO."[15]

FT4

테일러 등은 2019년 FT8과 비슷하지만 T/R 시퀀스 길이가 짧은 실험 프로토콜인 FT4를 선보여 대회 교류가 빨라졌다.[16]

JT65용 대체 소프트웨어

JT65에는 MultiPSK(F6CTE가 개발한 상용 패키지)[17]와 JT65-HF HB9HQX Edition(W6CQZ가 개발한 JT65-HF 프로젝트에서 착수한 무료 소프트웨어 패키지) 등 대체 소프트웨어 패키지가 있다.[18] JT65-HF HB9HQX Edition 소프트웨어는 소스 코드와 함께 SourceForge에서 얻을 수 있다.[19]

원본 JT65-HF 소프트웨어 사용에 관한 기사 시리즈가 CQ 아마추어 라디오의 2010년[21] 10월[20] 11월호에 실렸다. 그리고 LZ2의 MSHVHV는 Linux와 Windows OS용 GUI 구현이 서로 다른 WSJT-X의 소스 코드에서 재구성되었다.

참조

  1. ^ "WSJT Program Development".
  2. ^ a b c d e f Joe Taylor, K1JT (2006-08-10). "WSJT6 User Guide & Reference Manual" (PDF).
  3. ^ a b c d Joe Taylor, K1JT (August 25–27, 2006). Open Source WSJT: Status, Capabilities, and Future Evolution (PDF). 12th International EME Conference. Würzburg, Germany.
  4. ^ "WSJT Overview".
  5. ^ Joe Taylor, K1JT; Steve Franke, K9AN; Bill Sommerville, G4WJS (August 2017). "Work the World with WSJT-X. Part 2: Codes, modes and cooperative software development". RadCom. Radio Society of Great Britain. 93 (8): 58–59. ISSN 1367-1499.
  6. ^ a b Joseph H Taylor Jr. K1JT. "WSJT 사용자 설명서".
  7. ^ a b K1JT. "WSJT-X User Guide".
  8. ^ a b Joe Taylor, K1JT (December 2001). "WSJT: New Software for VHF Meteor-Scatter Communication" (PDF). QST: 36–41.
  9. ^ Joe Taylor, K1JT (September–October 2005). "The JT65 Communications Protocol" (PDF). QEX: A Forum for Communications Experimenters: 3–12.
  10. ^ Steve Ford, WB8IMY (July 2007). "JT65A on the HF Bands". QST: 85.
  11. ^ "WSJT revision history and release notes".
  12. ^ Joe Taylor, K1JT; Steve Franke, K9AN; Bill Sommerville, G4WJS (July 2017). "Work the World with WSJT-X. Part 1: Operating capabilities". RadCom. Radio Society of Great Britain. 93 (7): 40–45. ISSN 1367-1499.
  13. ^ AC4M. "JT9".
  14. ^ "FT8 Mode is Latest Bright Shiny Object in Amateur Radio Digital World". American Radio Relay League (ARRL). 2017-08-01.
  15. ^ Joe Taylor, K1JT. "FT8".
  16. ^ 2019년 4월 FT4 디지털 콘테스트 프로토콜
  17. ^ "MultiPSK - Ham Radio Software from F6CTE".
  18. ^ "Google Group for JT65-HF HB9HQX Edition".
  19. ^ "Download site for JT65-HF HB9HQX Edition".
  20. ^ David Witkowski, W6DTW & Tomas Hood, NW7US (October 2010). "Communicating Under The Noise". CQ Amateur Radio.CS1 maint: 여러 이름: 작성자 목록(링크)
  21. ^ David Witkowski, W6DTW & Tomas Hood, NW7US (November 2010). "Communicating Under The Noise". CQ Amateur Radio.CS1 maint: 여러 이름: 작성자 목록(링크)
  22. ^ "MSHV Amateur Radio Software LZ2HV Amateur Radio Website". lz2hv.org. Retrieved 2018-09-10.

외부 링크