PSK 31 and WSPR May 2010 KWARC Nick

PSK 31 and WSPR May 2010 KWARC Nick Waterman VA 3 NNW & Don Fisher VE 3 ESE

PSK 31 Introduction Still the fastest growing digital mode worldwide Needs: Some software (almost always free) Any computer with a sound card Any reasonably stable transceiver An antenna … and really not a lot else!

PSK 31 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

PSK 31 Introduction Good for ragchews and nets, good for QRP and DX No error correction, so less good for error-free file transfer, mailboxes, etc. PSK 31 category in ARRL Field Day (more points, more mults? )

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

PSK 31 Stands for. . . Phase Shift Keying, 31 Baud Specifically Binary Phase Shift Keying (So sometimes called BPSK 31) 31. 25 baud (so BPSK 31. 25 ? ) There's also a QPSK 31 (Quad Phase shift keying), uses 4 phases instead of 2, some error-correcting, but less common. There's also PSK 63, PSK 500, and some other variants, won't go into too much detail on these.

PSK 31 History Developed by Peter Martinez (G 3 PLX) 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. 25 bps bit rate was chosen as being a nice binary multiple of the sound card clock rate (8 k. Hz/256)

PSK 31 Waveform Unmodulated carrier: CW: BPSK (bad) BPSK (good) In phase Phase changes 180º out

PSK 31 Encoding A “ 0” is sent as a 180º phase shift A “ 1” is sent as no phase shift 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 1 s and 0 s, rare characters are longer (a little like CW) There are never too many long strings of 1 s (difficult to tell how many 1 s belong on a long carrier with no phase changes to sync off). The gap between chars is “ 00”. Long string of 0 s when idling This alphabet is called Varicode

PSK 31 Varicode Alphabet A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 1111101011 1010110101 1110111 11011011 11111101 10101 111111101 1011111010111 1011 1101 10101011 11010101 11101 10101111 1101101 101010111 1101101011101 101110101 101111011 a b c d e f g h i j k l m n o p q r s t u v w x y z 1011111 101101 11 111101 1011011 101011 1101 1111010111111 11011 111111 110111111 10101 10111 101 110111 1111011111 10111010101 SP 1 0 1 2 3 4 5 6 7 8 9 10110111101 11101101 1111 10111 10101101101011 11010110101011 110110111 Worth noting: Really Short Also: Typing ALL IN CAPS will actually slow you down! ☺ ! " # $ % & ' ( ) * + , . / : ; < = > ? @ [ ] ^ _. / { | } ~ 11111 1010111110101 1110110110101011 101111111011 11110111 101101111 1110101 1010111 1101011110101 110111101101 1010101 111010111 101010111101 1010101101 1111101111 111111011 1010111111 1011011011111 1010110111 11011 10101 1011010111 NUL SOH STX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI DLE DC 1 DC 2 DC 3 DC 4 NAK SYN ETB CAN EM SUB ESC FS GS RS US DEL 10101101101101 11011101011 1101011111 1011111101 101111 11101111 11101101111 101101 11111 110101 1110101011110101 1110101111 110101101101101010111 110111110110111 1101011101 11101111101111111 1110110101

PSK 31 - Operating Mic Line out Sound card Line in Audio out

PSK 31 - Operating Mic Line out Sound card Line in 100 k Audio out 1 k Bit of attenuation often helps. Some people do clever stuff with isolation transformers, capacitative DC blocking, opto-isolators, etc.

PSK 31 - Operating Mic Line out Sound card Line in 100 k Audio out 1 k PTT via VOX BUT BEWARE any other sound coming out of your computer (web page audio, MP 3 s, and even windows startup jingle) may be transmitted

PSK 31 - Operating Mic Line out Sound card Line in 100 k Audio out 1 k PTT via regular CAT cable (same one you use for rig control, programming memories etc)

PSK 31 - Operating 2 N 2222 22 k Serial RTS PTT 1 N 4148 Mic Line out Sound card Line in 100 k Audio out 1 k PTT via serial port (RTS, DSR, or similar signal line)

PSK 31 - Operating Mic Audio out Sound Card Interface West Mountain Radio RIGblaster (about 5 types) MFJ make a few Micro. HAM Rig. Expert Signa. Link Many more, inc many homebrew designs starting at about $10

PSK 31 - 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, PSK 31 doesn't sound all that nice anyway!

PSK 31 - Software SOFTWARE! Mix. W - www. mixw. net Multi. PSK http: //f 6 cte. free. fr/index_anglais. htm Digi. Pan www. pavane. net/digipan. htm Fldigi - www. w 1 hkj. com/Fldigi. html Hamscope - www. qsl. net/hamscope Win. PSK, Zakanaka (with Logger 32) 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

PSK 31 - Software This is what we'll be using for the demo SOFTWARE! Mix. W - www. mixw. net Multi. PSK http: //f 6 cte. free. fr/index_anglais. htm Digi. Pan www. pavane. net/digipan. htm Fldigi - www. w 1 hkj. com/Fldigi. html Hamscope - www. qsl. net/hamscope Win. PSK, Zakanaka (with Logger 32) 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

PSK 31 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

PSK 31 Frequencies 1. 83815 MHz 3. 58015 MHz 7. 035 MHz 10. 13715 MHz 14. 07015 MHz 18. 10015 MHz 21. 070 MHz 24. 920 MHz 28. 07015 MHz 50. 290 MHz 7. 07015 MHz 21. 08015 MHz 28. 12015 MHz

PSK 31 - Demo (White with two sugars please!) ; -)

WSPR Pronounced “Whisper” Weak Signal Propagation Reporter, by K 1 JT 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 <1 W, We've seen spots of 13, 000 km on 0. 1 W or less

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 timeslot (actually 110. 6 s) 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.

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 -28 d. B 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 4 mins instead of 2

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.

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

WSPR Software: http: //www. physics. princeton. edu/pulsar/K 1 JT/ Reports: http: //wsprnet. org/olddb? findcall=VE 3 IC&findreporter=VE 3 IC Who's on the air? http: //wsprnet. org/drupal/wsprnet/activity

WSPR - Demo

QUESTIONS? ?

THANKS! This presentation is at: http: //noseynick. net/va 3 nnw/PSK-talk/