introduction to digital modes creede lambard wa7kpk introduction to digital modes creede lambard,...

Introduction to Digital ModesCreede Lambard WA7KPK

INTRODUCTION TO DIGITAL MODES

Creede Lambard, WA7KPKMercury Northwest

November 2012


What is a digital mode?


What is a digital mode?

● Any amateur radio mode that can or must be received, presented, encoded and transmitted by the use of a computer or other dedicated digital device.


The first digital mode



● Morse code!



● Morse code● CW



● Morse code● CW● Frequency-Shift Keying (FSK)


Radioteletype (RTTY)



● Developed when AM was king



● Developed when AM was king● War surplus Teletype machines



● Developed when AM was king● War surplus Teletype machines● Uses FSK on both sidebands



● Developed when AM was king● War surplus Teletype machines● Uses FSK on both sidebands● Uses Baudot encoding (5 bits)


Packet Radio


Packet Radio

● Sort of an “internet via amateur radio”


Packet Radio

● Sort of an “internet via amateur radio”● First became feasible in 1980 when the

FCC allowed transmission of ASCII via ham radio


Packet Radio



● Primarily uses dedicated equipment for communication (TNC)


Packet Radio



● Primarily uses dedicated equipment for communication (TNC)

● Does error correcting


Personal Computers & Sound Cards



● RTTY modem software developed for PC



● RTTY modem software developed for PC● PC software emulating a TNC is available



● RTTY modem software developed for PC● PC software emulating a TNC is available● Research on creating narrow-bandwidth

PC-based modes




PC-based modes● FCC allows ASCII transmission




PC-based modes● FCC allows ASCII transmission● FCC allows other encodings provided they

are published into the public domain


PSK-31


PSK-31

● Created by Peter Martinez (G3PLX) in 1998


PSK-31


● Stands for “phase shift keying”


PSK-31


● Stands for “phase shift keying”● Bandwidth: 31 hz


PSK-31


● Stands for “phase shift keying”● Bandwidth: 31 hz● 80-90 QSOs in the width of a typical SSB

signal


PSK-31


PSK-31


● Stands for “phase shift keying”● Bandwidth: 31 hz● 80-90 QSOs in the width of a typical SSB

signal● Does not do error correcting


Other Digital Modes


Other Digital Modes

● Drinking from the firehose!


Other Digital Modes

● Olivia MFSK


Other Digital Modes

● Olivia MFSK● Developed by Pavel Jalocha (SP9VRC), 2003● Named after his daughter


Other Digital Modes

● Olivia MFSK


Other Digital Modes

● Olivia MFSK● Developed by Pavel Jalocha (SP9VRC), 2003● Named after his daughter● FEC enabled


Other Digital Modes

● Olivia MFSK● Developed by Pavel Jalocha (SP9VRC), 2003● Named after his daughter● FEC enabled● Can be decoded even when below the noise

floor


Other Digital Modes

● MT63


Other Digital Modes

● MT63● Also developed by Jalocha● Similar in some ways to Olivia


Other Digital Modes

● MT63● Also developed by Jalocha● Similar in some ways to Olivia● Used for emergency communications due to

robust FEC


Other Digital Modes

● Several other modes● DominoEX● Thor● Throb● Hellschreiber


JT65


JT65

● “Music Box” mode


JT65

● Developed by Joe Taylor, K1JT


JT65

● Developed by Joe Taylor, K1JT● Also chair of astrophysics department at

Princeton


JT65


Princeton● Also Nobel Prize laureate in physics


JT65



● Based in meteor scatter and EME


JT65



● Based in meteor scatter and EME● Not a keyboard-to-keyboard mode● Based on the minimal information

necessary to conduct a QSO


JT65


A typical JT65 QSO


A typical JT65 QSO

● CQ WA7KPK CN87● (each transmission is one minute long)● (CQ was sent on an even minute)


A typical JT65 QSO

● CQ WA7KPK CN87● WA7KPK JH1KYA PM95

● (reply was sent on an odd minute)


A typical JT65 QSO

● CQ WA7KPK CN87● WA7KPK JH1KYA PM95● JH1KYA WA7KPK -15


A typical JT65 QSO

● CQ WA7KPK CN87● WA7KPK JH1KYA PM95● JH1KYA WA7KPK -15● WA7KPK JH1KYA R-10


A typical JT65 QSO

● CQ WA7KPK CN87● WA7KPK JH1KYA PM95● JH1KYA WA7KPK -15● WA7KPK JH1KYA R-10● JH1KYA WA7KPK RRR


A typical JT65 QSO

● CQ WA7KPK CN87● WA7KPK JH1KYA PM95● JH1KYA WA7KPK -15● WA7KPK JH1KYA R-10● JH1KYA WA7KPK RRR● WA7KPK JH1KYA 73


A typical JT65 QSO

● CQ WA7KPK CN87● WA7KPK JH1KYA PM95● JH1KYA WA7KPK -15● WA7KPK JH1KYA R-10● JH1KYA WA7KPK RRR● WA7KPK JH1KYA 73● 30W DPL TU 73


Hardware requirements



● Transceiver (of course)



● Transceiver (of course)● Computer (the faster the better, especially

for higher-latency modes like JT65 or Olivia)





● Sound card or dedicated USB device (e.g. Signalink or Rigblaster)





● Sound card or dedicated USB device (e.g. Signalink or Rigblaster)

● Cables to connect radio to computer


Software


Software

● Ham Radio Deluxe● Very comprehensive (read: steep learning

curve)● Includes most digital modes● Current version (5.0) is donationware; next

version (6.0) will be $60● Numerous other bells and whistles● Windows only


Software

● Fldigi● Reasonably fast● Keyboard-to-keyboard modes only (no JT65)● Developer is very responsive● Associated utilities: flrig (rig control), flmsg, etc.● Windows/Linux/Mac


Software

● JT65-HF● JT65 and similar modes only (no keyboard-to-

keyboard)● IMO much superior to the original JT65

software for HF use● Developer in poor health● Windows only; Linux version does not work on

recent distributions


Software

● Others


Software

● Your favorite browser● Useful for propagation maps, callsign lookups,

help with your program, etc.● Logging program (your preference)


My digital software setup


Comments/questions?


This deck will be available at

http://www.lambard.net/radio/

digitalmodes.ppt


Thank you!!

73 ES GUD DXDE WA7KPK!!

introduction to digital modes creede lambard wa7kpk introduction to digital modes creede lambard,...

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