1 / 31

PSK31 and WSPR

May 2010 KWARC Nick Waterman VA3NNW & Don Fisher VE3ESE. PSK31 and WSPR. PSK31 Introduction. Still the fastest growing digital mode worldwide

kiefer
Download Presentation

PSK31 and WSPR

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. May 2010 KWARC Nick Waterman VA3NNW & Don Fisher VE3ESE PSK31and WSPR

  2. PSK31 Introduction • Still the fastest growing digital mode worldwide • Needs:Some software (almost always free)Any computer with a sound cardAny reasonably stable transceiverAn antenna… and really not a lot else!

  3. PSK31 Introduction • Very narrow bandwidth, much narrower than RTTY, comparable with CW • Gets through like CW (OR BETTER) at comparable power and S/N ratio • Manages about 50 wpm

  4. PSK31 Introduction • Good for ragchews and nets, good for QRP and DX • No error correction, so less good for error-free file transfer, mailboxes, etc. • PSK31 category in ARRL Field Day (more points, more mults?)

  5. PSK31 Error Rate RTTY Error Rate PSK-31 Signal to Noise Ratio (dB) 100W SSB ≈ 8W RTTY ≈ 1W PSK31 –You WILL NOT NEED a lot of power ! (Chart borrowed from YCARS, with thanks)

  6. PSK31 Stands for... • Phase Shift Keying, 31 Baud • Specifically Binary Phase Shift Keying (So sometimes called BPSK31) • 31.25 baud (so BPSK31.25 ?) • There's also a QPSK31 (Quad Phase shift keying), uses 4 phases instead of 2, some error-correcting, but less common. There's also PSK63, PSK500, and some other variants, won't go into too much detail on these.

  7. PSK31 History • Developed by Peter Martinez (G3PLX) and introduced to the wider amateur radio community in December 1998. • Martinez initially called his creation "varicode", because it uses variable length encodings (Huffman codes) to represent characters (more on that later) • The slightly obscure 31.25bps bit rate was chosen as being a nice binary multiple of the sound card clock rate (8kHz/256)

  8. PSK31 Waveform • Unmodulated carrier: • CW: Phase changes • BPSK (bad) Phase changes • BPSK (good) 180º out In phase

  9. PSK31 Encoding • A “0” is sent as a 180º phase shift • A “1” is sent as no phase shift 0 1 1 0 0 0 0 0 1 1 0 0 0 • The “alphabet” is then designed to make sure that commonly-sent characters are made up of a small sequence of 1s and 0s, rare characters are longer (a little like CW) • There are never too many long strings of 1s (difficult to tell how many 1s belong on a long carrier with no phase changes to sync off). • The gap between chars is “00”. Long string of 0s when idling • This alphabet is called Varicode

  10. PSK31 Varicode Alphabet A 1111101 B 11101011 C 10101101 D 10110101 E 1110111 F 11011011 G 11111101 H 101010101 I 1111111 J 111111101 K 101111101 L 11010111 M 10111011 N 11011101 O 10101011 P 11010101 Q 111011101 R 10101111 S 1101111 T 1101101 U 101010111 V 110110101 W 101011101 X 101011101 Y 101110101 Z 101111011 a 1011 b 1011111 c 101111 d 101101 e 11 f 111101 g 1011011 h 101011 i 1101 j 111101011 k 10111111 l 11011 m 111011 n 1111 o 111 p 111111 q 110111111 r 10101 s 10111 t 101 u 110111 v 1111011 w 1101011 x 11011111 y 1011101 z 111010101 SP 1 0 10110111 1 10111101 2 11101101 3 11111111 4 101110111 5 101011011 6 101101011 7 110101101 8 110101011 9 110110111 ! 111111111 " 101011111 # 111110101 $ 111011011 % 1011010101 & 1010111011 ' 101111111 ( 11111011 ) 11110111 * 101101111 + 111011111 , 1110101 - 110101 . 1010111 / 110101111 : 11110101 ; 110111101 < 111101101 = 1010101 > 111010111 ? 1010101111 @ 1010111101 [ 1010101101 \ 111110111 ] 111101111 ^ 111111011 _ 1010111111 . 101101101 / 1011011111 { 1010110111 | 110111011 } 1010110101 ~ 1011010111 NUL 1010101011 SOH 1011011011 STX 1011101101 ETX 1101110111 EOT 1011101011 ENQ 1101011111 ACK 1011101111 BEL 1011111101 BS 1011111111 HT 11101111 LF 11101 VT 1101101111 FF 1011011101 CR 11111 SO 1101110101 SI 1110101011 DLE 1011110111 DC1 1011110101 DC2 1110101101 DC3 1110101111 DC4 1101011011 NAK 1101101011 SYN 1101101101 ETB 1101010111 CAN 1101111011 EM 1101111101 SUB 1110110111 ESC 1101010101 FS 1101011101 GS 1110111011 RS 1011111011 US 1101111111 DEL 1110110101 Worth noting: Really Short Also: Typing ALL IN CAPS will actually slow you down! ☺

  11. PSK31 - Operating Mic Audio out Line out Sound card Line in

  12. PSK31 - Operating Mic Audio out Line out Sound card Line in 100k 1k Bit of attenuation often helps. Some people do clever stuff with isolation transformers, capacitative DC blocking, opto-isolators, etc.

  13. PSK31 - Operating Mic Audio out Line out Sound card Line in 100k 1k PTT via VOX BUT BEWARE any other sound coming out of your computer (web page audio, MP3s, and even windows startup jingle) may be transmitted

  14. PSK31 - Operating Mic Audio out Line out Sound card Line in 100k 1k PTT via regular CAT cable (same one you use for rig control, programming memories etc)

  15. PSK31 - Operating 2N2222 22k PTT Serial RTS 1N4148 Mic Audio out Line out Sound card Line in 100k 1k PTT via serial port (RTS, DSR, or similar signal line)

  16. PSK31 - Operating Mic Audio out Sound Card Interface • West Mountain Radio RIGblaster (about 5 types) • MFJ make a few • MicroHAM • RigExpert • SignaLink • Many more, inc many homebrew designs starting at about $10

  17. PSK31 - Operating If you're feeling REALLY cheap, some people get away with simply putting their rig mic near their computer speaker and vice-versa! This provides good electrical isolation, but it's tricky to get the audio levels right, ambient noise can ruin your transmitting or receiving, and besides, PSK31 doesn't sound all that nice anyway!

  18. PSK31 - Software • MixW - www.mixw.net • MultiPSK - http://f6cte.free.fr/index_anglais.htm • DigiPan - www.pavane.net/digipan/digipan.htm • Fldigi - www.w1hkj.com/Fldigi.html • Hamscope - www.qsl.net/hamscope • WinPSK, Zakanaka (with Logger32) • Plenty of others. • Almost always FREE • Usually includes multiple other digital modes (RTTY, Olivia, Hell, sometimes packet, SSTV) • Often includes logging software, some level of CAT, rotor control SOFT- WARE!

  19. PSK31 - Software This is what we'll be using for the demo • MixW - www.mixw.net • MultiPSK - http://f6cte.free.fr/index_anglais.htm • DigiPan - www.pavane.net/digipan/digipan.htm • Fldigi - www.w1hkj.com/Fldigi.html • Hamscope - www.qsl.net/hamscope • WinPSK, Zakanaka (with Logger32) • Plenty of others. • Almost always FREE • Usually includes multiple other digital modes (RTTY, Olivia, Hell, sometimes packet, SSTV) • Often includes logging software, some level of CAT, rotor control SOFT- WARE!

  20. PSK31 Audio Settings • Windows audio mixer or equivalent • Adjust “Line In” volume until the waterfall looks nice or until the stronger signals are using about 50% of the available range. • Adjust “Line Out”, “Headphone”, or “Wave” (and make sure you're using the right one) until your rig ALC is barely deflecting and flat, and again about 50% power output is probably ideal • Make sure you're not overdriving or clipping in either direction – will cause bad IMD (inter modulation distortion). Vol DOWN if you are. • Compression OFF on your rig

  21. PSK31 Frequencies • 1.83815 MHz • 3.58015 MHz • 7.035 MHz 7.07015MHz • 10.13715 MHz • 14.07015 MHz • 18.10015 MHz • 21.070 MHz 21.08015MHz • 24.920 MHz • 28.07015MHz 28.12015 MHz • 50.290 MHz

  22. PSK31 - Demo (White with two sugars please!) ;-)

  23. WSPR • Pronounced “Whisper” • Weak Signal Propagation Reporter, by K1JT • Definitely NOT for ragchews • Not even really QSOs • This mode effectively turns your PC+Rig into a beacon, but also monitors for, and reports, other people's WSPR beacons. • Good use of your Rig when you're not using it! • You can be heard WORLDWIDE on <1W, We've seen spots of 13,000km on 0.1W or less

  24. WSPR - timing • Time is divided into 2-minute slots (it helps to have your PC sync'ed over the net using NTP, any of the free atomic clock tools or just Windows time sync) • You will occasionally transmit for a 2 min time-slot (actually 110.6s) • You will usually receive in all other 2-minute time-slots, and automatically report any “spots” to the wsprnet.org website, assuming you have “always on” internet.

  25. WSPR - Encoding • VERY slow data rate (1.4648 baud) – you take 2 minutes to transmit just your callsign, your 4-digit Maidenhead locator, and your power level. • Tonnes of error-correction to ensure you can be heard at -28dB • If you want to use a callsign with prefixes or suffixes, or a 6-digit locator, there are special ways to send it, and you end up taking 4mins instead of 2

  26. WSPR - Encoding • 4-FSK, tone separation 1.4648 Hz • Occupied bandwidth: about 6 Hz • Not going to go into all the details of the error-correcting codes, there's some complex coding theory there... • … but for operating it really doesn't matter, the software is trivial to run, you just set it up and leave it running.

  27. WSPR - Operating Mic Audio out Line out Sound card Line in 100k 1k EXACTLY THE SAME AS PSK-31!* *(Just different software)

  28. WSPR • Software:http://www.physics.princeton.edu/pulsar/K1JT/ • Reports:http://wsprnet.org/http://wsprnet.org/olddb?findcall=VE3IC&findreporter=VE3IC • Who's on the air?http://wsprnet.org/drupal/wsprnet/activity

  29. WSPR - Demo

  30. QUESTIONS? ?

  31. THANKS! • This presentation is at:http://noseynick.net/va3nnw/PSK-talk/

More Related