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Soundcard Digital Modes

Soundcard Digital Modes. Tyler Griffiths N7UWX. Evolution of Acronyms. Human transmitted digital CW – Operator determines performance Machine sent digital RTTY – Baudot 5-bit code Machine sent corrected data packets Packet – APRS – TCP/IP High noise immunity RTTY replacements

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Soundcard Digital Modes

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  1. Soundcard Digital Modes Tyler Griffiths N7UWX

  2. Evolution of Acronyms • Human transmitted digital • CW – Operator determines performance • Machine sent digital • RTTY – Baudot 5-bit code • Machine sent corrected data packets • Packet – APRS – TCP/IP • High noise immunity RTTY replacements • PSK31 – QPSK – MFSK – MT63 • Intermittent channel weak-signal modes • HSCW – FSK441 (WSJT) • Extreme weak signal mode • JT44 (WSJT) Tyler Griffiths - N7UWX

  3. Sound Card Digital Modes Connecting your Radio to your Computer You can purchase an interface to connect your transceiver to your computer, OR you can make your own for a few $.

  4. 144.390 Computer/Radio Interfacing Line or Speaker Output Line or Mike Input Interface COM Port COM Port Push-to-talk (PTT) Receive Audio Transmit Audio Computer ControlCI-V or CAT Tyler Griffiths - N7UWX

  5. Sound Card Digital Modes Connecting your Radio to your Computer Receive Audio Connection: Connect an audio cable between the transceiver audio output and the soundcard LINE IN jack.

  6. Sound Card Digital Modes Connecting your Radio to your Computer Transmit Audio Connection: Connect a shielded audio cable between the transceiver MIC input and the soundcard LINE OUT jack through a 40 db attenuator. If your transceiver has a LINE input, no attenuation is required. (eliminate the 2 resistors)

  7. Sound Card Digital Modes CW PSK31 RTTY PACKET APRS FSK411 JT44 EME Connecting your Radio to your Computer T/R Connection: http://www.sv2agw.com/downloads/ PTT is controlled via the RTS and/or DTR outputs of the computer’s RS-232 serial port.

  8. Sound Card Digital Modes CW PSK31 RTTY PACKET APRS FSK411 JT44 EME Connecting your Radio to your Computer T/R Connection: http://www.sv2agw.com/downloads/ PTT is controlled via the RTS and/or DTR outputs of the computer’s RS-232 serial port.

  9. Soundcard Packet • AGW Packet Engine for 1200 or 9600 • Supports Terminal, TCP/IP, DX Cluster, Digipeater • APRS Software support via APRSPoint, UI View and WinAPRS • Supports multiple simultaneous connections • Allows remote use over a network/Internet Tyler Griffiths - N7UWX

  10. PSK 31 • Designed by Peter G3PLX • Based on the RTTY mode of operation useful for live keyboard to keyboard QSO • Works at 31.25 bauds • Uses varicode character coding providing 50wpm • Give very good copy under low Eb/No numbers and is thus suitable for QRP • That instead of using FSK or on/off keying uses BPSK or QPSK with a Viterbi decoder • Uses advanced DSP and narrow band (31 Hz!!) techniques Tyler Griffiths - N7UWX

  11. PSK 31 Frequencies Tyler Griffiths - N7UWX

  12. QPSK • Quadernary Phase-Shift Keying • Four phases instead of 2 for PSK • Extra capacity used for error-correction • Improvements of up to 5 fold in error-rate • Not as good for QRP (3dB hit) • Extra transmission delay • More frequency sensitive (within 4Hz) • Must use correct sideband • Start BPSK and switch to QPSK Tyler Griffiths - N7UWX

  13. MFSK 16 • Multiple frequency-shift keying (MFSK) is a variation of frequency-shift keying (FSK) that uses more than two frequencies. • Sixteen tone carriers, ~16Hz apart • 42 WPM in 316Hz with FEC • High rejection of pulse and broadband noise due to narrow bandwidth per tone • Low baud rate for sensitivity and multi-path rejection - data bit rate higher than symbol baud rate • Tolerance of ionospheric effects such as doppler, fading and multi-path Tyler Griffiths - N7UWX

  14. HamScope Software Tyler Griffiths - N7UWX

  15. DigiPan Software Tyler Griffiths - N7UWX

  16. Tyler Griffiths - N7UWX

  17. fldigi Software Tyler Griffiths - N7UWX

  18. Winmor (Winlink 2000) Tyler Griffiths - N7UWX

  19. APRS Software

  20. Digital ModesWaterfall’s CW PSK-31 QSPK PACKET RTTY

  21. Interesting Waterfall!

  22. FSK 441 - WSJT • Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave.[ • 100% duty cycle, so no extra energy wasted by On/Off keying • More user-friendly interface--like RTTY or PSK31 modes • Much better S/N than HSCW at same speed • Each character takes about 2.3ms to send with four tones. That’s 441 baud. Tyler Griffiths - N7UWX

  23. JT 44 - WSJT • Uses long term signal averaging to recover a signal that is up to 30dB below the noise floor! • Humans have “short ears” limited by their sensory memory—they can only analyze a signal in a small timeframe • Computers can analyze in relatively large timeframes • Inspired by the PUA43 mode (with dedicated hardware) • Uses 44 tones, one for each character in the PUA43 alphabet (same as FSK441), plus a synchronization tone. Each character is assigned a unique frequency • Slow transmission speed: 5.38 baud • Highly redundant (FEC) Tyler Griffiths - N7UWX

  24. JT44 – Terrestrial Use • JT44 works well on troposcatter paths that are too short for MS enhancement • Several operators have used it on 6m for borderline TE, and marginal Es openings. • Microwave non-line-of-sight paths • Could be a good way of overcoming atmospheric absorption above 10GHz • Contest stations can make otherwise impossible contacts Tyler Griffiths - N7UWX

  25. JT44 – EME Use • JT44’s ability to recover extremely weak signals makes it ideal for EME • Most activity by arranged schedule. • 144MHz is the most popular band. • Also operation on 50 MHz, 432MHz, and 1296 MHz so far…. • A pair of single-yagi stations should be able to work each other, with QRO power • Portable EME operation can be a reality Tyler Griffiths - N7UWX

  26. What Does It Take? • Windows PC • Windows 98 or higher recommended • Pentium 150MHz or better • SoundBlaster compatible soundcard • Most laptop sound systems work • More expensive cards have less noise and are more frequency stable/accurate • Interface cabling • RigBlaster or Rascal interfaces not necessary Tyler Griffiths - N7UWX

  27. Soundcard Interfacing • Most radios have audio in/out PTT on back via a Data or AUX port • These line level in/outs are best • Mike/speaker levels can be used with appropriate attenuation • PTT support generally via transistor or optoisolator switch • PTT can be done with CAT port but requires radio-specific software Tyler Griffiths - N7UWX

  28. PTT Switching Tyler Griffiths - N7UWX

  29. Soundcard Interface Tyler Griffiths - N7UWX

  30. Soundcard Interface Tyler Griffiths - N7UWX

  31. Built-in SoundcardInterface West Mountain RIGblaster Advantage $189.95 Tigertronics SignaLink USB $99.99 microHAM USB Interface III $155.00 Tyler Griffiths - N7UWX

  32. Remote Control • Radio tuning, antenna rotation, transmission and reception are all computer controllable • This software is easily remote controlled via Terminal Server, Team Viewer or NetMeeting • Using Skype to talk on the radio • Access can be via LAN or Internet • There are shared radios on the Internet Tyler Griffiths - N7UWX

  33. Resources • DigiPan: http://www.digipan.net/ • Fldigi: http://www.w1hkj.com/Fldigi.html • Ham Radio Deluxe: http://www.ham-radio-deluxe.com/ • Winlink 2000: http://www.winlink.org • Signal link USB: http://www.tigertronics.com/slusbmain.htm • West Mt. Radio: http://www.westmountainradio.com/rigblaster.php • microHAM • http://www.microham.com/contents/en-us/d158_U3.html • Rascal: http://www.packetradio.com • Rig Expert • http://www.arraysolutions.com/Products/rig_expert_standard.htm • AGW Packet Engine: http://www.sv2agw.com/downloads/ • KB3KAO Sound card TNC: http://www.kb3kai.com/sound-card-tnc • Sound Card Packet: http://www.soundcardpacket.org/ • Web Radios http://www.websdr.org/ Tyler Griffiths - N7UWX

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