Soundcard Digital Modes

Name: Soundcard Digital Modes
Uploaded: 2017-08-16T22:34:24+00:00
Duration: PTM30S25
Channel: Kory Basil Blankenship
Description: Soundcard Digital Modes

Soundcard Digital Modes
Soundcard Digital Communications Soundcard Digital Modes Tyler Griffiths N7UWX Scott Honaker- N7WLO

Soundcard Digital Communications
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) CW is the first and oldest digital mode, sent and received by humans. Performance is determined by the skill of the operator. RTTY provides basic text but is wide bandwidth, uncorrected, slow and limited in characters Packet provides full 8-bit ASCII data to be sent in corrected packets APRS is an application that runs on packet and provides position and message transfer capabilities ( ) TCP/IP is also implemented over a packet connection for Internet connectivity over radio at 1200 or 9600 baud (half duplex) PSK31 provides keyboard to keyboard chat functionality like RTTY but very narrow bandwidth (31Hz vs. 350Hz) with high noise immunity QPSK error-corrected version of PSK MFSK error-corrected with a slightly wider bandwidth MT63? High Speed CW at WPM used for meteor scatter contacts but machine-inefficient FSK441 very efficient high speed with many repetitions for meteor scatter contacts JT44 very slow speed data sent repeatedly to create a signal that can be copied 26dB+ BELOW the noise floor Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 $.

Computer/Radio Interfacing
Soundcard Digital Communications Computer/Radio Interfacing Line or Speaker Output Line or Mike Input Interface COM Port COM Port The Rascal interface shown here is not necessary. There needs to be an audio connection and some method for PTT. This is normally done via a simple transistor switch off the serial port. Some packages also support switching via the computer control port for some radios. You have a laptop with no real COM port. There are USB to serial adapters that can be used. This is occasionally tricky because they may not support the RTS and DTR lines properly to handle the switching. Push-to-talk (PTT) Receive Audio Transmit Audio Computer Control CI-V or CAT Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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

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)

Connecting your Radio to your Computer T/R Connection: CW PSK31 RTTY PACKET APRS FSK411 JT44 EME PTT is controlled via the RTS and/or DTR outputs of the computer’s RS-232 serial port.

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 The software was written by SV2AGW. The basic features are free and he charges a small registration fee for more advanced features and higher speed (still a fraction of the cost of a hardware TNC). Tyler Griffiths - N7UWX Scott Honaker- N7WLO

PSK 31 Designed by Peter G3PLX Based on the RTTY mode of operation useful for live keyboard to keyboard QSO Works at 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 PSK31 is not a digital mode that will make Pactor, Pactor-2, Clover-II or Gtor obsolete, offers error free links, can be used to transmit files or access mailboxes... Tyler Griffiths - N7UWX Scott Honaker- N7WLO

PSK 31 Frequencies HF Band Frequency VHF Band 160 M 1807 KHz 6 M MHz 80 M 3580 KHz 2 M MHz 40 M 7070 KHz 1.25 MHz 30 M 10140 KHz 70 cm MHz 20 M 14070 KHz 33 cm MHz 17M 18100 KHz 15M 21080 KHz 12M 28120 KHz Most PSK 31 is USB Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 PSK31 operators find QPSK can be very good but is sometimes disappointing. In bench tests with white noise, it is actually worse than BPSK, but in real band conditions with fading and interference, improvements of up to 5 times in the character error-rate have been recorded. This doesn't come free, however. Apart from the transmission delay, which can be a bit off-putting, QPSK with four phases instead of two, is twice as critical in tuning as BPSK, and needs to be within 4Hz. This could be a problem with some older radios. What tends to happen is that contacts start on BPSK and change to QPSK if both stations agree. There is one aspect of QPSK that has to be kept in mind - it is important for both stations to be using the correct sideband - on BPSK it doesn't matter. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 MFSK is a technique for transmitting digital data using multiple tones, extending the RTTY two-tone technique to many tones, usually, but not always, one tone at a time. MFSK means Multi - Frequency Shift Keying, and should not be confused with MSK (Minimum Shift Keying). There are a number of different techniques, using concurrent (or parallel) tones, sequential (one after another) tones, and combinations of tones. MT-Hell can be either concurrent or sequential, DTMF tones used for telephone signaling are concurrent tone pairs, while Piccolo and Coquelet, although using tone pairs, are decidedly sequential. MFSK transmissions have a unique sound, almost musical, which is why Piccolo and Coquelet received their names (Coquelet means rooster). MFSK uses relatively narrow tone spacing, so remarkable data rates are achieved for a given bandwidth - 64 bps in a signal bandwidth of 316 Hz is typical. The following picture is a waterfall display of an MFSK16 signal (16 carriers) with a spacing of Hz and operating at baud. The transmission operates at 62.5 bps (about 80 words per minute!) and occupies about 316 Hz of bandwidth. MFSK16 is always operated with FEC, so the text throughput is actually only about 42 WPM (31.25 bps). Let's be fair - there are disadvantages to MFSK! The main disadvantages are related to the narrow spacing and narrow bandwidth of the individual tone detectors - drift can be a problem and accurate tuning is essential. Good tuning indicators and AFC are necessary at the slower speeds. It is important that the radio transceiver be very stable, and also that it has very small frequency offset between transmit and receive (preferably less than 5 Hz). MFSK also uses more bandwidth for a given text speed than a 2FSK or PSK system, but by the same token it is therefore more robust. This wider bandwidth means that you will not have the same QRP performance advantages as an extremely narrow band mode like PSK31. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

HamScope Software HamScope is a FREE multi-mode communications interface for amateur radio that supports: PSK31 (BPSK and QPSK, see PSK31 Home Page ) RTTY (HamScope uses Makoto Mori's MMTTY Engine) ASCII (both 7 bit and 8 bit protocols using MMTTY) MFSK16 (see MFSK16 Home Page ) PACKET (HamScope uses George Rossopoulos' AGWPE Engine) CW Hamscope also offers an advanced user interface with a multitude of features to provide optimal control and convenience during operation: a wide, multifunction panoramic display a radio control interface for several ICOM, TenTec, Kenwood, and Yaesu transceivers 42 user-programmable macro buttons user definable function key mappings HamScope 1.51 has added data links to several logging and/or radio control programs: DXbase LOGic 6 RYLogit TRX-Manager YPLOG HamScope also supplies a DDE server for users who wish to connect to the program HamScope is designed to run under Windows 95, 98, and NT, and requires a 133 MHz Pentium-class or better machine. 16 bit SVGA color (or greater) is also necessary for the panoramic waterfall display to function correctly. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

DigiPan Software DigiPan stands for "Digital Panoramic Tuning" and brings the ease and simplicity of PANORAMIC reception and transmission to PSK31and PSK63 operation. DigiPan provides a panoramic display of the frequency spectrum in the form of an active dial scale extending the full width of the computer screen. Depending upon the transceiver IF bandwidth, it is possible to "see" as many as 40 to 50 PSK31 stations at one time. DigiPan1.0 forever changed how PSK31 tuning was done, from manually tuning the transceiver, to "point-and-click" mouse tuning, in which a signal on the waterfall is clicked with the mouse button to find out the station's callsign and decide whether or not to contact that station.. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Tyler Griffiths - N7UWX

fldigi Software Fldigi - Digital modem program runs on many different flavors of operating system Linux, Free-BSD, OS X, Windows XP, NT, W2K, Vista and Win7. flarq - Automatic Repeat reQuest program. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Winmor (Winlink 2000) Tyler Griffiths - N7UWX

APRS Software Using programs like UI-View and APRSISCE along with AGWpe you can run APRS. Scott Honaker- N7WLO

Digital Modes Waterfall’s
Soundcard Digital Communications Digital Modes Waterfall’s CW PSK QSPK PACKET RTTY Scott Honaker- N7WLO

Interesting Waterfall!
Soundcard Digital Communications Interesting Waterfall! Scott Honaker- N7WLO

FSK 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. WSJT was created by Joe Taylor – K1JT, Nobel Prize winning Astronomer. Most popular bands are 144 and 50MHz. There is growing activity on 222MHz, and a few 432 MHz QSO’s have been made. More is better, but “brick and yagi” are sufficient on 144 and 222 any time of year. Brick and yagi has worked on 432, but more operation is needed to draw conclusions. Preamp—you don’t know what you’re missing! On 144MHz, the average “brick and yagi” station should be able to work a similar station in the mi range fairly consistently, any time of year. Geometric limit of ~1400mi (based on the height at which meteors ionize sufficiently) Limits, schlimits! Records are meant to be broken! Rovers can stray to distant grids and still make contacts—that means new grids and more multipliers. “Big guns” should be able to work anyone within 1200mi on 144Mhz. Fills the “dead time” in the small hours of the morning with valuable mulipliers. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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) Bandwidth of 485Hz Tones spaced at 10.8Hz Sync tone 32.3Hz below data. Allows for frequency error and EME Doppler shift with and 2.7 KHz passband. Transmission lasts about 25 s, with a gap at the beginning and end to allow for timing error and EME delay. (Like FSK441, operators use alternating 30-second periods) 135 intervals (bits) 69 are devoted to sending the sync tone Other 66 intervals are used to send the 22-char message three times. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 It can take some time but is perfect for otherwise impossible Field Day and contest shots. There’s usually some down-time during a contest that is perfect for these contacts. TE – Transequatorial Es – Sporadic E Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 DXpedtions can afford to bring gear W5UN has been copied with a “Ringo-Ranger” vertical on 2m! A couple of people have copied him locally via EME for the first time in just the last couple weeks (December 2002). The stations had 13 element yagis in 2m with watts. One didn’t even have elevation control. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 Some software has higher DSP requirements than others. These requirements will vary. Most packages will work with this. Interfacing can be simply the audio lines from the back of the radio into the soundcard with a simple RS-232 PTT switch. The Rascal interface adds isolation on the PTT and audio lines. The RigBlaster adds level conversions and mike switches to allow use of mike/speaker connections on radio. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Soundcard Interfacing
Soundcard Digital Communications 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 I would recommend ALWAYS using AUX connections on the back of the radio, rather than speaker/mike if available. The audio is cleaner, no level/impedance conversion necessary, level adjustments are limited to the computer side because they never change on the radio. Virtually all packages expect PTT switch to be on the serial port. Some can use the computer control (CAT) port to tell the radio to transmit but this is software and radio specific. MixW can also do the CAT PTT switching for most radio Icom/Kenwood/Yaesu radios. The FT-817 Commander supports CAT switching for its PSK31 mode. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

PTT Switching This is the simplest and cheapest PTT switches available. With a little effort, it can be built into a DB-9 hood so no external box is required for an interface (unless audio isolation is desired/required). Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Soundcard Interface This is the Rascal interface. It has an optoisolator (4N33) for the PTT line and 1:1 audio transformers on both audio leads. It also has ferrite cores on the audio leads to eliminate RF feedback. This is one of the best designed interfaces available. Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Built-in Soundcard Interface
Soundcard Digital Communications Built-in Soundcard Interface West Mountain RIGblaster Advantage $189.95 Tigertronics SignaLink USB $99.99 microHAM USB Interface III $155.00 Tyler Griffiths - N7UWX Scott Honaker- N7WLO

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 The soundcard modes are ideally suited for remote control because the audio doesn’t need to be sent over the network – it’s all processed locally. There are currently radios on the Internet that allow radio tuning and reception via NetMeeting. Some even allow transmission via an application that handles PTT. This is all simply software, after this basic hardware is in place. Imagine sitting in the living room watching TV with the laptop and wireless network card. You have terminal services installed on the computer (running Windows 2000 or Windows XP) in the radio room and the Remote Desktop client on the laptop. You connect to the machine in the radio room via Remote Desktop, run HamScope and tune to look for some PSK31 activity. You make a few contacts and then tune to and look for some CW. You see a CW signal on the waterfall display, click on it and make a CW QSO. You can do all this while sitting in the chair watching TV Perhaps from your office at work or a friend’s house… Now see what a computer hooked to a radio can do? Unplug the mike and plug in the computer and no more noise about computers and the Internet killing ham radio! Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Resources DigiPan: Fldigi: Ham Radio Deluxe: Winlink 2000: Signal link USB: West Mt. Radio: microHAM Rascal: Rig Expert AGW Packet Engine: KB3KAO Sound card TNC: Sound Card Packet: Web Radios Digipan PSK software West Mountain Radio carries the original RigBlaster interfaces at MFJ also carries RigBlaster style interfaces at Tyler Griffiths - N7UWX Scott Honaker- N7WLO

Soundcard Digital Modes

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