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Open Source WSJT

Open Source WSJT. 12 th International EME Conference. W ü rzburg August 25-27 2006. Joe Taylor K1JT. Open Source WSJT. Motivation, brief history Current status, usage Some EME “politics” Future developments Hardware demonstration. I. Motivation for WSJT.

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Open Source WSJT

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  1. Open Source WSJT 12th International EME Conference Würzburg August 25-27 2006 Joe Taylor K1JT

  2. Open Source WSJT • Motivation, brief history • Current status, usage • Some EME “politics” • Future developments • Hardware demonstration

  3. I. Motivation for WSJT • Study coding and modulation schemes • Enable VHF/UHF QSOs at minimum S/N • Propagation modes: MS, EME, … • Make a convenient, enjoyable, rewarding-to-use program • Establish ultimate limits for weak-signal, real-time QSOs.

  4. EME: Design Goals for JT65 • Work at lowest possible signal levels • Conform to standard operating practices • Exchange all info required for valid QSOs • Good QSO rate for contests, DXpeditions • Very high confidence in copied information • Extremely low probability of false QSOs

  5. WSJT Milestones 2001: FSK441 for meteor scatter 2002: JT44 for EME 2002: JT6M for MS, ionoscatter on 6 m 2003: JT65 for EME, with FEC 2005: JT65 “Deep Search” decoder; Open Source release 2006: Linux and FreeBSD versions; many algorithmic improvements

  6. II. WSJT Status: August 2006 • Total users: >3000 • Nearly all MS uses FSK441 • JT6M popular on 6m • JT65 EME users: 300 – 600 • JT65 EME QSOs: >40,000 • 30% of entries in 2005 ARRL EME contest used JT65 (On 2m, >70%)

  7. JT65 EME, Band-by-Band 6 m: QSOs made almost daily 2 m: 1-yagi to 2-yagi QSOs common 70 cm: usage slowly increasing ? 23 cm: usage increasing With 2.3–3m TVRO dishes, 10 Watts is enough!

  8. VK7MO works G4CCH on 23 cm

  9. G4CCH, 23 cm

  10. G4CCH, 23 cm CW NOW? TNX EASY QSO TNX REX –23 73 RRR VK7MO G4CCH IO93 OOO

  11. First and Last G4CCH transmissions CW NOW? VK7MO G4CCH IO93 OOO

  12. JT65 DXpeditions • VK7MO: VK9XMO, VK9CMO • 3Y0X, Peter I • ZL2RS: to many places • ON4IQ to HI3, FS, J4, … Single yagi or small, transportable array with modest power is enough on 2 m and 70 cm -- and even 23 cm, for working larger stations

  13. Informal Survey (July 2006) • How many EME QSOs have you made using JT65?  On what bands?  Using JT65A, B, or C? • How many QSOs that you originally considered complete, turned out to be invalid? For what reasons? • Has anyone claimed to work you in a JT65 EME QSO that did not occur, or was not valid? • Are the fixed JT65 messages generally reliable, and the formats useful? • Do you make scheduled, or random QSOs?  Call CQ? Answer CQs?  Self-spot when calling CQ? Tailend other QSOs?

  14. Informal Survey, cont’d 50 responses • QSOs by band (round numbers) 6m:2002m:11,80070 cm:40023 cm:100 Total reported QSOs: 12,500 • Bad QSOs considered good by reporting station: 16* • Bad QSOs considered good by other station: 12* • Message structure, reliability: very good • Typical mix: 50% random, 50% skeds *Bad QSOs mostly results of operator errors

  15. JT65: Differences from CW • Structured messages • Error-correcting code • Synchronized transmissions • Transmissions can be averaged • Copy is “all or nothing” • Roughly 10 dB advantage

  16. JT65 Minimal EME QSO • CQ HB9Q JN47 • HB9Q K1JT FN20 • K1JT HB9Q JN47 OOO • RO • RRR • 73

  17. Pileup Situations • CQ 3Y0X EC41 • 3Y0X K2TXB FM29 • K2TXB 3Y0X EC41 OOO • 3Y0X K2TXB RO • K2TXB 3Y0X RRR • 73 Callsign-tagged reports, RRRs

  18. Shorthand Sync DS KV

  19. JT65 Decoding Thresholds Sync limit: –30 dB *Callsign must be in list

  20. III. EME Politics On a web site: “… only two characters need to be decoded to print full EME messages…” Editorial in a respected journal: “… the JT65 mode when using the Deep Search Decoder … needs to ‘recognize’ just only 2 letters but displays a full callsign.” Another web site: “All JT65 QSOs made using the Deep-Search Routine are not complying with long established EME QSO guidelines and are not eligible [for this Top List] due to partial copy.” ✻✻✻ No Nein Non Нет… ✻✻✻ See “How Many Bits” paper near end of Proceedings ! Try the JT65 Hardware Demonstration, yourself !

  21. IV. Future WSJT plans? • Pulsar mode ? • Enhanced meteor scatter mode ? • Connection to Linrad / Winrad ? • New soft-decision RS decoder • EME Echo and Measure modes • 30-bit JT65 messages • Expanded waterfall: 0 – 5 kHz

  22. Expanded waterfall bandwidth WSJT 5.9.6 ✻ ✻

  23. 30-bit Messages Bits • CQ de 3Y0X 30 • de K2TXB 30 • K2TXB 3Y0X OOO 72 • 3Y0X K2TXB RO 72 • TXB de 0X RRR 30 • 73 de K2TXB 30 Notes: • No grid locators • Reports and Rs tagged with callsigns • Numerical reports optional • Messages 5 and 6 can be shorthands • No need for a callsign list

  24. JT65+ Decoding Thresholds *No list required

  25. Programmer’s Information • GNU General Public License (GPL) • Languages: • Pythonfor user interface • Fortranfor number crunching • Cfor A/D, D/A, PTT, … • Compile on Windows, Linux, … • More details in Proceedings • New contributors welcome ! http://developer.berlios.de/projects/wsjt wsjt-devel@lists.berlios.de

  26. V. Hardware Demonstration Generate JT65 (or CW) at any desired S/N A B Audio cables Headphones • A makes “QSOs” with B ? • Send test messages • Listen to the signals • Stress-test the decoders • Play as you wish …

  27. Hardware Demo (cont’d) • Run WSJT on both computers, make “QSOs” Generated S/N in dB (2500 Hz BW) Format: #─26

  28. Hardware Demo (cont’d) 2. Run WSJT on A, SimJT on B; “torture test” the decoders!

  29. Hardware Demo (cont’d) 3. Do the WSJT tutorial using recorded EME signals

  30. TNX 73 GL … de K1JT

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