Open Open SourceSource WSJT WSJT

Joe Taylor K1JT

12th International EME Conference

WürzburgAugust 25-27

2006

Open Source WSJTOpen Source WSJT

I.I. Motivation, brief historyMotivation, brief history

II.II. Current status, usageCurrent status, usage

III.III. Some EME “politics”Some EME “politics”

IV.IV. Future developmentsFuture developments

V.V. Hardware demonstrationHardware demonstration

I. Motivation for WSJTI. Motivation for WSJT

Study coding and modulation schemes Study coding and modulation schemes Enable VHF/UHF QSOs at minimum S/NEnable VHF/UHF QSOs at minimum S/N Propagation modes: MS, EME, …Propagation modes: MS, EME, … Make a convenient, enjoyable, rewarding-Make a convenient, enjoyable, rewarding-

to-use programto-use program Establish ultimate limits for weak-signal, Establish ultimate limits for weak-signal,

real-time QSOs.real-time QSOs.

EME: Design Goals for JT65EME: Design Goals for JT65

Work at lowest possible signal levelsWork at lowest possible signal levels Conform to standard operating practicesConform to standard operating practices Exchange all info required for valid QSOsExchange all info required for valid QSOs Good QSO rate for contests, DXpeditionsGood QSO rate for contests, DXpeditions Very high confidence in copied informationVery high confidence in copied information Extremely low probability of false QSOsExtremely low probability of false QSOs

WSJT MilestonesWSJT Milestones

2001:2001: FSK441 for meteor scatter FSK441 for meteor scatter

2002:2002: JT44 for EME JT44 for EME

2002:2002: JT6M for MS, ionoscatter on 6 m JT6M for MS, ionoscatter on 6 m

2003:2003: JT65 for EME, with FEC JT65 for EME, with FEC

2005:2005: JT65 “Deep Search” decoder; JT65 “Deep Search” decoder; Open Source release Open Source release

2006:2006: Linux and FreeBSD versions; Linux and FreeBSD versions; many algorithmic improvementsmany algorithmic improvements

II. WSJT Status: August 2006II. WSJT Status: August 2006

Total users: >3000Total users: >3000 Nearly all MS uses FSK441Nearly all MS uses FSK441 JT6M popular on 6mJT6M popular on 6m JT65 EME users: 300 – 600 JT65 EME users: 300 – 600 JT65 EME QSOs: >40,000JT65 EME QSOs: >40,000 30% of entries in 2005 ARRL 30% of entries in 2005 ARRL

EME contest used JT65 EME contest used JT65 (On 2m, >70%)(On 2m, >70%)

JT65 EME, Band-by-BandJT65 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!

VK7MO works G4CCH on 23 cmVK7MO works G4CCH on 23 cm

G4CCH, 23 cmG4CCH, 23 cm

G4CCH, 23 cmG4CCH, 23 cm

VK7MO G4CCH IO93 OOO

RRR

73

TNX REX –23

TNX EASY QSO

CW NOW?

First and Last G4CCH transmissionsFirst and Last G4CCH transmissions

VK7MO G4CCH IO93 OOO

CW NOW?

JT65 DXpeditionsJT65 DXpeditions

1.1. VK7MO: VK9XMO, VK9CMOVK7MO: VK9XMO, VK9CMO

2.2. 3Y0X, Peter I3Y0X, Peter I

3.3. ZL2RS: to many placesZL2RS: to many places

4.4. ON4IQ to HI3, FS, J4, …ON4IQ to HI3, FS, J4, …

Single yagi or small, transportable array Single yagi or small, transportable array with modest power is enough on 2 m with modest power is enough on 2 m and 70 cm -- and even 23 cm, for and 70 cm -- and even 23 cm, for working larger stationsworking larger stations

Informal Survey (July 2006)Informal Survey (July 2006)

1.1. How many EME QSOs have you made using How many EME QSOs have you made using JT65?  On what bands?  Using JT65A, B, or C?JT65?  On what bands?  Using JT65A, B, or C?

2.2. How many QSOs that you originally considered How many QSOs that you originally considered complete, turned out to be invalid? For what complete, turned out to be invalid? For what reasons?reasons?

3.3. Has anyone claimed to work you in a JT65 EME Has anyone claimed to work you in a JT65 EME QSO that did QSO that did notnot occur, or was not valid? occur, or was not valid?

4.4. Are the fixed JT65 messages generally reliable, Are the fixed JT65 messages generally reliable, and the formats useful?and the formats useful?

5.5. Do you make scheduled, or random QSOs?  Call Do you make scheduled, or random QSOs?  Call CQ? Answer CQs?  Self-spot when calling CQ? CQ? Answer CQs?  Self-spot when calling CQ? Tailend other QSOs?Tailend other QSOs?

Informal Survey, cont’dInformal Survey, cont’d

1. QSOs by band (round numbers)6m: 200 2m: 11,800 70 cm: 400 23 cm: 100Total reported QSOs: 12,500

2. Bad QSOs considered good by reporting station: 16*

3. Bad QSOs considered good by other station: 12*

4. Message structure, reliability: very good

5. Typical mix: 50% random, 50% skeds

*Bad QSOs mostly results of operator errors

50 responses

JT65: Differences from CWJT65: Differences from CW

Structured messages Error-correcting code Synchronized transmissions Transmissions can be averaged Copy is “all or nothing” Roughly 10 dB advantage

JT65 Minimal EME QSOJT65 Minimal EME QSO

1. CQ HB9Q JN472. HB9Q K1JT FN203. K1JT HB9Q JN47 OOO4. RO5. RRR6. 73

Pileup SituationsPileup Situations

1. CQ 3Y0X EC412. 3Y0X K2TXB

FM293. K2TXB 3Y0X EC41 OOO4. 3Y0X K2TXB RO5. K2TXB 3Y0X RRR6. 73

Callsign-tagged reports, RRRsCallsign-tagged reports, RRRs

Measured JT65 Performance

0

20

40

60

80

100

-35 -30 -25 -20

S/N in 2500 Hz BW (dB)

Per

cen

t o

f tr

ansm

issi

on

s co

pie

d

KV

DS

Sync

Shorthand

JT65 Decoding ThresholdsJT65 Decoding Thresholds

Message typeKV (dB)

KV Avg (dB)

DS (dB)

Short65 (dB)

Arbitrary –24 –28

BC + Grid/Rpt –24 –28 –28*

Shorthand –32

Sync limit: Sync limit: ––30 dB30 dB *Callsign must be in list

III. EME PoliticsIII. EME PoliticsOn 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 !

IV. Future WSJT plans?IV. Future WSJT plans?

Pulsar mode ?Enhanced meteor scatter mode ?Connection to Linrad / Winrad ?New soft-decision RS decoderEME Echo and Measure modes30-bit JT65 messagesExpanded waterfall: 0 – 5 kHz

Expanded waterfall bandwidthExpanded waterfall bandwidth

✻ ✻

WSJT 5.9.6

30-bit Messages30-bit Messages Bits1. CQ de 3Y0X 302. de K2TXB 303. K2TXB 3Y0X OOO 724. 3Y0X K2TXB RO 725. TXB de 0X RRR 306. 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

JT65JT65+ Decoding Thresholds Decoding Thresholds

Message type KV (dB)

KV Avg (dB)

DS (dB)

Short65 (dB)

Arbitrary –24 –28

BC + Grid/Rpt –24 –28 –28*

Shorthand –32

30-bit –27

*No list required

Programmer’s InformationProgrammer’s InformationGNU General Public License

(GPL)Languages:

Python for user interfaceFortran for number crunchingC for A/D, D/A, PTT, …

Compile on Windows, Linux, …More details in ProceedingsNew contributors welcome !

http://developer.berlios.de/projects/wsjt wsjt-devel@lists.berlios.de

V. Hardware DemonstrationV. Hardware Demonstration

Generate JT65 (or CW) at any desired S/N

Audio cablesA B

1. A makes “QSOs” with B ?2. Send test messages3. Listen to the signals4. Stress-test the decoders5. Play as you wish …

Headphones

Hardware Demo (cont’d)Hardware Demo (cont’d)

1.Run WSJT on both computers, make “QSOs”

Generated S/N in dB (2500 Hz BW)Format: #─26

Hardware Demo (cont’d)Hardware Demo (cont’d)

2. Run WSJT on A, SimJT on B; “torture test” the decoders!

Hardware Demo (cont’d)Hardware Demo (cont’d)

3. Do the WSJT tutorial using recorded EME signals

TNX 73 GL TNX 73 GL … de K1JT… de K1JT