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Presentation on newer digital modes used on HF Amateur bands.Presented to Shefford and District ARS June 2009
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Presentation to Shefford & District ARSGareth Howell – M5KVK
AgendaSome backgroundNew modes to be coveredA couple of odd-balls
Some BackgroundTwo basic families:PSK
(Digital Binary Phase-Shift Keying) PSK 31, 63, 125 etc No error correction Low bandwidth
MFSK (Multi Frequency-Shift Keying) RTTY, Piccolo, Coquelet MFSK 4, 8, 16 (42WPM) Sensitive Good rejection of Doppler
New Modes to be coveredDominoExOlivia
DominoExMurray ZL1BPU18 tone FSKDesigned to overcome limitations in MFSKOptimised for NVIS (80/40/30m)VaricodeIncremental Frequency Keying
Reduces tuning sensitivityAnd drift
CharacteristicsVariants named after Baud rateImproved tolerance to multi-pathImproved rejection of impulse noiseNo need for FEC in normal use
Higher speed than MFSKShorter sync time
i.e. faster turn around in QSO mode
DominoEx 8Used on poorer circuits (50WPM)
DominoEx 16Higher speed, used on better circuits
(100WPM)
OliviaInvented by Pavel SP9vRC64-FSK - sequentialMultiple variants
Tones and BandwidthMultiple Baud ratesVaricode and Forward Error Correction
CharacteristicsHorses for courses
Fewer tones mean higher speedMore tones add robustness
Works over very poor S/N circuitsOften not visible or audibleVoluntary channelisation
Olivia VariantsBandwidth/Tones500/16
19.5 wpmUsed for CQ and QSOs in average conditions
1000/3224.4 wpmUsed for CQ and QSOs in average conditions
500/829.3 WPMQSOs on higher bands
1000/16500/4250/8
Olivia Variants
Olivia 500/16
Olivia 1000/16
A couple of odd-ballsHF-ALEWSJT
HFLINK (ALE)Automatic Link Establishment (ALE)Focused on emergency communicationsPermanent Global network
24x7 on 8 HF bandsMIL-STD-188-141A
SSB/Text/SMS/InternetScanningSounding
WSJTJT65Very slow speedOptimised for very weak signals
Troposcatter/EME/65-MFSK, FECJT65-HF variant for HF
References-1Domino
DominoEX - an IFK Mode for HF http://snurl.com/n7vwv
OliviaWB8ROL Olivia Digital Mode Information
Page http://snurl.com/n7vqzThe International Olivia Digital Mode
Group http://snurl.com/n7vsoOlivia Frequencies http://snurl.com/n7vze
References-2HFLINK
http://snurl.com/n7wdhJT65A and WSJT
The Complete Bozo's Guide to HF JT65A http://snurl.com/n7w4z
Schedshttp://snurl.com/n7vv8
Questions ??