2. Digital Communications  El Paso Amateur Radio Club  August 22, 2003  Tom, WB5QLR

3. Repeat Offender – 8/9/00

4. Digital Modes  RTTY  PSK31  PSK63  MFSK  WSJT

5. Computer Based  Hardware requirements  SoundBlaster compatible sound card  PC capable of running Win95/98  PTT switching mechanism

6. Computer Based  Software  Software for mode of operation  Might have multiple mode in same program

7. What is NOT Necessary  Heavy teletype  TNC  Special tuning scopes

8. Main Point #1  Digital modes can be implemented totally with:  Computer  Sound Card  Software  Simple PTT circuit from serial port

9. Connections  Receiver audio out into Computer line in  Preferable if audio out is independent of AF gain  Could also run through a 1:1 audio transformer to help isolate grounds

10. Connections  Computer speaker in Transmitter audio  Use a resistor and 1:1 audio transformer  Optional trimmer pot to control audio level

11. Audio Connection

12. Connections  Computer serial port to Transmitter PTT  Circuit includes:  1 resistor  2 diodes  1 transistor  Optional DPST to switch between 2 inputs from serial port

13. PTT Connection

14. RigBlaster Interface

15. RigBlaster Interface - Back

16. RTTY  Convention is LSB  Been around for a long time

17. RTTY

18. PSK and sound  Convention is USB  Most around 14.070 MHz and up  Phase shifted  Variable code – combination of Baudot and Morse  Band width is 31.25 cycles wide  Efficiency ranks with CW  Implemented completely with sound card and software

19. PSK Tuning – Old Style

20. PSK Tuning – New Style

22. PSK Frequencies  3.580 MHz  7.080 MHz  10.140 MHz  14.070 MHz  18.100 MHz  21.080 MHz  28.120 MHz

23. PSK 63  100 wpm character transmission speed for contest exchanges and macro transmission versus RTTY at 60 wpm  Only 1/5 the bandwidth of RTTY - capable of displaying 24 signals simultaneously on a waterfall or spectrum display  Capable of color thumbnail portrait transmission in less than 2 minutes  Faster sync recovery than RTTY, resulting in fewer errors

24. PSK 63  Requires much less power than RTTY for the same communications performance  Identical to PSK31 except for a wider bandwidth of 63 Hz  Improved polar path performance compared to PSK31  Works with any soundcard-equipped Windows computer and SSB transceiver  High-speed transmission of macros and brag files

25. MFSK – Mutiple Frequency Shift Keying  A Weak signal digital mode  Advantages  High rejection of pulse and broadband noise due to narrow receiver bandwidth per tone  Low baud rate for sensitivity and multi-path rejection - data bit rate higher than symbol baud rate  Constant transmitter power  Tolerance of ionospheric effects such as doppler, fading and multi-path

26. MFSK  Disadvantages  Narrow spacing and narrow bandwidth of the individual tone detectors  Drift can be a problem and accurate tuning is essential.

27. WSJT – Weak Signal by W1JT  Four Modes  FSK441 – Meteor Scatter  JT6M – Meteor Scatter for 6M  JT44 – Tropo and EME  EME Echo – Listening to your EME return  Competitive with 50 watts and 10-11 element beam

28. Bandpass Comparisons

29. Resources  RTTY/PSK software  TrueTTY - www.dxsoft.comwww.dxsoft.com  3KHz band pass  On RTTY, both FSK and AFSK  RigBlaster Interface  www.westmountainradio.com/RIGblaster.ht m

30. Resources  PSK Home Page  www.aintel.bi.ehu.es/psk31.html www.aintel.bi.ehu.es/psk31  PSK only software  DigiPan – www.digipan.netwww.digipan.net  WinPSKse - www.winpskse.com  Other Sites  Great overview - www.qsl.net/kk7lk/psk31.htmwww.qsl.net/kk7lk/psk31  Interface details - www.w5bbr.com/psk31.html

31. Resources  MSFK  http://www.qsl.net/zl1bpu/MFSK/ http://www.qsl.net/zl1bpu/MFSK/  Software – Stream - http://iz8bly.sysonline.it/Stream/index.htm  WSJT  http://pulsar.princeton.edu/~joe/K1JT/ http://pulsar.princeton.edu/~joe/K1JT/  http://www.qsl.net/wa5ufh/WSJTGROUP/WSJTG ROUP.htm http://www.qsl.net/wa5ufh/WSJTGROUP/WSJTG ROUP.htm  Ping Jockey - http://www.pingjockey.net/cgi- bin/pingtalk

32. Resources  Articles  QST May, 1999 pg 41-44  QST May, 2000 pg 42-45  Book  ARRL’s HFDigital Handbook

33. Non Digital Resources  Logging software  XMLog - www.xmlog.comwww.xmlog.com  Multiple logs books  Easy reference to notes  Logger - www.qsl.net/kc4elo/  Little higher level  Includes PSK  Contesting Software – www.writelog.comwww.writelog.com  Includes RTTY and PSK

34. Main Point #2  Fun  Easy  On air demonstration  Slides and references at www.striplingdata.com/w5es