HSMS med WSJT OZ1PIF, Peter Frenning EDR Roskilde Afd. Torsdag den 29. November 2001

Hvad er WSJT? Weak Signal by k1JT K1JT = Joe Taylor, Professor i Astrofysik ved Princeton Universitetet i USA. Nobelpris i Fysik 1993 for opdagelsen af Pulsarer ved hjælp af Radioteleskopet i Arecaibo.

Hvorfor køre HSMS? På 144MHz: Tropo op til ca 8-900Km ES sjældent under 2000Km AU sjældent over 1200Km MS Km! På 50MHz: Uinteressant, afstande allerede dækket ind af ES På 432Hz: Nye muligheder at udforske!

Hvorfor køre HSMS? (Størrelsen GØR en forskel!)

JUST HOW FAST IS HSCW? IS IT MUCH FASTER THAN SSB? Here are some examples: (lpm = wpm x 5) [lpm, letters per minute; wpm, words per minute]. Typical CW 25 wpm 125 lpm Fast CW 50 wpm 250 lpm (Limit of most "regular speed" MS operation) SSB 250 wpm 1250 lpm Slow HSCW 300 wpm 1500 lpm Kinda slow HSCW 400 wpm 2000 lpm (used for CQ's in North America) Faster HSCW 800 wpm 4000 lpm (common schedule speed in North America) Still faster HSCW 1200 wpm 6000 lpm (used for many skeds now) Very fast HSCW 1600 wpm 8000 lpm Ultra fast HSCW 3200 wpm 16,000 lpm (not recommended, S/N Ratio bad. But has been done!) You can see that even slow HSCW is as fast as most SSB operators can talk, except maybe for those whose occupation is auctioneering! And receiver tuning and signal strength requirements are not as tight.

SO JUST HOW SHORT CAN THESE PINGS BE AND STILL GET USABLE INFORMATION ACROSS? Very short! In fact, for HSCW, pings or bursts longer than two or three seconds are exciting but are almost a nuisance! We'll leave it up to you do the actual math. But a 1/10th second ping can propagate a complete set of calls at the medium or higher speeds! This might produce a full syllable on SSB! YOU CAN'T COPY THAT BY EAR! AND THE CW DECODERS I'VE SEEN COULDN'T HANDLE ANYTHING LIKE THIS. HOW DO YOU DO IT? Right. The idea is simple. Use a device to slow the code down to something readable. Then copy by ear what has come through.

FSK441 Frequency shift 441BAUD 4 Toner: –882, 1323, 1764 og 2205 Hz Hvert tegn kræver 3 toneintervaller, dvs. 3/441sek. (Ca 2.3ms) for afsendelse Max 48 forskellige tegn, 43 i brug, samme som i PUA-43 alfabetet.

Indkodning The present encoding of each character is defined in the table below. The four tones are labeled 0-3 for the tones 882 through 2205 Hz, in increasing order. The four possible "single-tone" encodings, namely 000, 111, 222, and 333, are reserved in WSJT for special use as shorthand messages. (These characters sent repeatedly amount to pure single-frequency carriers, and their pings are easily recognized by the software and by the human ear.) The present definition of the shorthand messages is respectively "R26", "R27", "RRR", and "73". These messages are very widely used in North American HSMS communications.

Character Tones Number sent Character [reserved] , ? / # $ A B C D [reserved] F G H I J K L M N O P Q R S T U V W X Y [reserved] E Z [reserved]

En random QSO IK1MTZ CQ CY IK1MTZ TZ CQ IK1MTZ K1MTZ R26 R26 OZ1PIF IK1MTZ OZ1PIF IK1MTS OZ1PIF?IK PIF IK1MTU R OZ1PIG R26 OZ1PIF IK1MTZ R263R26 OZ1PIF II1/E Z1PIF IK1M OZ PIF IK1MTZ R26 R26 OZ1XIF F IK1MTZ R26# IK1MTZ R26 R26 OZ1PIF IK1MTZ R26 R26 OZ IF IK1MTZ Z1PIF IK1MTZ R26 R26 OZ1PIF IK1 TZ R OZ1PIF Z R26 R26 OZ1PIF IH IF IK1MTZ R26 R26 OZ1XIF IK1MTQ RRR JN35UB GZ/ IK1MTZ 7 OZ GQ 3XOF Z1PIF IK1MTZ 73 OZ1PIF HK1MTZ

Krævede signal niveauer The first column gives the necessary signal level in dB, relative to the noise power in a 2500 Hz passband, for communication or signal detection by each mode. The entries are ordered by increasing sensitivity of the mode: the farther down this list, the better the mode is, in terms of signal-to- noise ratio. (Actual communication throughput rates vary rather widely, of course.)

Krævede signal niveauer Signal Level (dB) Mode Other details HSCW Single dit at 10k LPM +7.0 HSCW Single dit at 6k LPM +6.0 SSB Voice, very weak but readable +5.2 HSCW Single dah at 10k LPM +4.1 HSCW Single dah at 6k LPM +1.5 FSK441 Multi-tone WSJT message 0.0 FSK441 Multi-tone WSJT folded message, 160 ms ping, 12 characters -1.5 HSMS Underdense ping, 20 ms, detected in full BW -3.1 WSJT Single-tone message, 20 ms ping, v0.92 decoder -5.0 HSMS Underdense ping, 100 ms, detected in full BW -5.9 CW 20 WPM, single dit, Rx bandwidth 500 Hz -6.6 WSJT Single-tone message, 20 ms ping, v1.0 decoder CW 20 WPM, single dit, Rx bandwidth 50 Hz FSK441 Multi-tone WSJT 12 character message, whole 30 s file averaged (not implemented in present decoder) WSJT Single-tone message, 100 ms ping (not implemented) PUA-43 One minute transmission, 28-char msg EME-2 One minute of alternating TX/RX intervals, detection only PUA-43 One hour, alternating TX/RX, 14 character message decoded EME-2 One hour of alternating TX/RX intervals, detection only

Internet Ressourcer WSJT Home pagehttp://pulsar.princeton.edu/~joe/K1JT EU spejlhttp:// Shelby Ennis FAQhttp:// Shelby’s generelle MS siderhttp://