3000 Hz. Average Noise

Transcription

1 PSK-31 Dave, K6AIX , 2007, D. H. Danner 1

2 What is PSK-31? Digital Text, ASCII Narrow Bandwidth, PSK, 31 Hz Low Power, < 25 watts Out Performs Teletype, Packet Low Cost, Simple to Use , 2007, D. H. Danner 2

3 The Normal SSB Signal 3000 Hz Average Noise , 2007, D. H. Danner 3

4 Bandwidth vrs Signal to Noise Narrow receiver bandwidth removes unwanted noise. Increased signal-to-noise ratio 31 Hz Average Noise , 2007, D. H. Danner 4

5 Why Use PSK-31? Usable well into the noise Use available radio and any computer Use low power and normal antenna Uses very little bandwidth Free software on internet All bands and satellite Simple operation, simple set-up , 2007, D. H. Danner 5

6 Simple Set-Up. Uses Standard Soundcard Antenna Transceiver Spkr Sound Card Computer Mic PTT , 2007, D. H. Danner 6

7 What Kind of Signal? PSK-31 uses special CW characters Most used letters use shortest codes Lower case letters type faster Frequency shift keying (FSK) used Only about ± 15 cycles bandwidth About 3 characters per second , 2007, D. H. Danner 7

8 What does it sound like? Each signal sounds like a single tone The tone warbles ± 15 cycles Your SSB receiver can receive many PSK-31 stations all at the same time You hear all the stations at once. Your computer picks out the station you wish to work , 2007, D. H. Danner 8

9 Set and Forget your Radio Set your radio to the established frequency, a fixed - lock your dial Use Upper Sideband, SSB only Turn OFF all filters, compression, and DSP functions. Computer does these jobs. PSK-31 software acts like a digital signal processor (DSP) to compute the incoming and outgoing signals , 2007, D. H. Danner 9

10 Digital Frequencies Band PSK-31 SSTV RTTY ASCII MFSK , 2007, D. H. Danner 10

11 How is PSK-31 Tuned PSK-31 is a continuous carrier signal Spectrum or Waterfall displays for tuning Left mouse click sets receiving frequency Right mouse click sets transmit frequency Computer displays frequency above transceiver setting. Listening is unnecessary , 2007, D. H. Danner 11

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13 Receive Text Here , 2007, D. H. Danner 13

14 Receive Text Here Transmit Text Here , 2007, D. H. Danner 14

15 Receive Text Here Transmit Text Here Control and Mode Settings , 2007, D. H. Danner 15

16 Receive Text Here Transmit Text Here Spectrum Display Control and Mode Settings , 2007, D. H. Danner 16

17 Receive Text Here Transmit Text Here Waterfakk Display Control and Mode Settings , 2007, D. H. Danner 17

18 How Many Stations at Once? 3000 Hz USB Bandwidth Each PSK-31 station needs about 100 Hz. allowing for ample separation. 3000/100 = 30 stations visible , 2007, D. H. Danner 18

19 How is the Tx Signal Generated? The Computer generates an audio tone using your sound card. The audio tone is fed to your SSB rig s microphone input. Your rig produces an RF carrier equal to the tuned frequency plus the audio tone. Adjust the microphone gain down for 25 watts output maximum! , 2007, D. H. Danner 19

20 Why Such Low Power? You are transmitting a CW carrier signal full time. The narrow signal requires very low distortion. Use of high power produces distortion and spurious interference over entire band , 2007, D. H. Danner 20

21 The PSK-31 Display Pentiun II or better, color VGA monitor Standard sound card, mouse Free software DigiPan HamScope WINPSK W1SQLPSK , 2007, D. H. Danner 21

22 The Sound Card Adapter Radio Shack Stereo Patch Cable..(receive only) $4.96 RigBlaster $89.99 Tigertronics $69.95 MFJ $59.99 (Homebrew) about $ , 2007, D. H. Danner 22

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24 Simple Digital Adapter , 2007, D. H. Danner 24

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26 Rig Requirements: 160 through 10 meters USB (even on 40 and below) Under 25 Watts Digital tuning necessary to control frequency stability VHF/UHF uses audio frequency keying (AFSK) , 2007, D. H. Danner 26

27 Other Modes QPSK, BPSK, MFSK PSK-64 RTTY, MMTTY SSTV, MMSSTV Hellscreiber CW Packet , 2007, D. H. Danner 27

28 On the WEB psk31.com/software/software.htm , 2007, D. H. Danner 28

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30 TYPE ON de K6AIX , 2007, D. H. Danner 30

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