PSK-31 and MT-PSK-31 and MT-6363

Digital ModesDigital Modes

Al Duncan VE3RRDAl Duncan VE3RRD

PSK-31PSK-31 Was created by Peter Martinez G3PLXWas created by Peter Martinez G3PLX Based on RTTY style of communications, Based on RTTY style of communications,

and is useful for keyboard-to-keyboard and is useful for keyboard-to-keyboard QSO’sQSO’s

Data rate of 31.25 baud or about 50 wpmData rate of 31.25 baud or about 50 wpm Total bandwidth of about 50 Hz (with Total bandwidth of about 50 Hz (with

proper equipment setup and adjustment)proper equipment setup and adjustment) Can fit at least fifteen PSK-31 QSO’s into Can fit at least fifteen PSK-31 QSO’s into

the bandwidth occupied by one SSB QSOthe bandwidth occupied by one SSB QSO Uses an SSB transceiver connected to a Uses an SSB transceiver connected to a

computer soundcard and free softwarecomputer soundcard and free software

PSK-31PSK-31 The PSK31 station consists of a The PSK31 station consists of a

combination of Software, PC, Sound Card, combination of Software, PC, Sound Card, SSB transceiver & interface hardwareSSB transceiver & interface hardware

Software: DigiPan, FLdigi, Ham Radio Software: DigiPan, FLdigi, Ham Radio Deluxe, or many other free programsDeluxe, or many other free programs- Encodes and Decodes PSK signal tones- Encodes and Decodes PSK signal tones- Controls TX PTT via the serial port- Controls TX PTT via the serial port

PC:PC:Laptop or desktop preferably running Laptop or desktop preferably running Windows 2000 or later operating systemWindows 2000 or later operating system

PSK-31PSK-31

Basic transceiver to computer soundcard interfaceBasic transceiver to computer soundcard interface

PSK-31PSK-31 Many commercially made interfaces are Many commercially made interfaces are

availableavailable One of the best is the SignaLink USB which One of the best is the SignaLink USB which

includes its own soundcard and transceiver includes its own soundcard and transceiver keying and only needs a USB cable to the keying and only needs a USB cable to the computer (powered by the USB cable)computer (powered by the USB cable)

PSK-31 on 7035KHz using PSK-31 on 7035KHz using DigiPanDigiPan

Adjust your equipment Adjust your equipment properlyproperly

Don’t overdrive the Don’t overdrive the transmittertransmitter

Signal at 1000 is overdriven with multiples of 31 Hz on either side of center – about 185 Hz wide

WWaterfall screen shotaterfall screen shot    below is an example of a below is an example of a badly overdriven badly overdriven sound cardsound card. Notice . Notice that you can count out that you can count out to the to the 15th harmonic15th harmonic and it is and it is splatteringsplattering over over 500Hz500Hz taking out taking out at least at least 6 PSK31 6 PSK31 QSO'sQSO's

A good PSK-31 signalA good PSK-31 signal

PSK-31 audio clip

PSK-31 QRPPSK-31 QRPThe Small Wonder Labs PSK80 Warbler is a small The Small Wonder Labs PSK80 Warbler is a small

3W 80m QRP transceiver that covers 3580 to 3W 80m QRP transceiver that covers 3580 to 3581 KHz uses computer soundcard, and serial 3581 KHz uses computer soundcard, and serial port to key TXport to key TX

MT-63MT-63 Uses up to 64 separate tonesUses up to 64 separate tones Uses FEC (Forward Error Correction) giving Uses FEC (Forward Error Correction) giving

it an advantage in poor signal conditionsit an advantage in poor signal conditions Not really useful for a keyboard-to-keyboard Not really useful for a keyboard-to-keyboard

QSO due to long FEC decode time (several QSO due to long FEC decode time (several seconds)seconds)

Three bandwidths used: 500 Hz for HF, Three bandwidths used: 500 Hz for HF, 1000 Hz for HF under excellent conditions, 1000 Hz for HF under excellent conditions, 2000 Hz often used for VHF/UHF FM2000 Hz often used for VHF/UHF FM

Speeds vary: 50 wpm for MT63-500, 100 Speeds vary: 50 wpm for MT63-500, 100 wpm for MT63-1000, and 200 wpm for wpm for MT63-1000, and 200 wpm for MT63-2000MT63-2000

MT-63MT-63 Computer and audio interface requirements Computer and audio interface requirements

are the same as mentioned for PSK-31are the same as mentioned for PSK-31 Best free software for MT-63 use is FLdigiBest free software for MT-63 use is FLdigi FLdigi includes additional modules FLdigi includes additional modules

optimized for the error free transfer of text optimized for the error free transfer of text message filesmessage files

Error free message transfer ability makes it Error free message transfer ability makes it an excellent choice for emergency an excellent choice for emergency communicationscommunications

MT63-2000 works very well over 2m FM MT63-2000 works very well over 2m FM simplex and also through a repeatersimplex and also through a repeater

FM radio interfacing can be done FM radio interfacing can be done acoustically!! A real bonus for emergency acoustically!! A real bonus for emergency communicationscommunications

MT-63MT-63MT63-1000 signal on 20mMT63-1000 signal on 20m

To fit within the audio pass band of an SSB transmitter, an MT63-2000 signal uses tones from 500 Hz to 2500 Hz

MT63-2000 audio clip

MT63-2000 received via a MT63-2000 received via a microphonemicrophone

The “wrap” function includes a checksum for the message enclosed by commands that allow FLdigi to recognize the message and automatically save it

ICS-213 message received in the ICS-213 message received in the previous slide using a microphone previous slide using a microphone

held close to the speakerheld close to the speaker

FLmsg is used to open the received message. It puts all the text back into the proper fields so that the received message is a duplicate of the message created by the originator who also used FLmsg.

Where to get the Where to get the softwaresoftware

Download FLdigi and associated Download FLdigi and associated modulesmodules

FLmsg and FLwrap from:FLmsg and FLwrap from:

http://www.w1hkj.com/downloadhttp://www.w1hkj.com/download.html.html

And now for a demonstration of PSK-31 and

MT-63