Introduction to Digital Radio & PSK31 Josh KD8SLQ Chris AB3YS

Agenda What is Digital Radio? Advantages of Digital Radio Hardware Requirements Software Requirements Digital Calling Frequencies Operating Procedures Control Interface Features Comparing Operating Modes Other Features Notable Contacts Conclusion

What is digital radio? Radio communication via computer. PSK31 is one of the most popular methods PSK31 stands for Phase Shift Keying and will transmit a signal 31 Hz wide.

Advantages of digital radio Fast data exchange Messages can be sent in a matter of seconds High degree of error correction Small bandwidth Exchanges can be automated using macros for fast response. Lower power requirements compared to voice Resistant to interference Can be done with desktop computers and base station radios or with laptops and mobile radios for portable operation. Does not require listening. Good for the hard of hearing or places with noise constraints.

Hardware Requirements TNC to Radio Connection Dedicated DATA port Custom interface RX audio from speaker or headphones TX audio from computer soundcard PTT control Recommend isolation transformers and audio limiters to protect equipment. Radio Controller (Optional) RT Systems Direct Connection via USB or Serial Port Computer Must have sound card or ports for external sound card Radio Interface Radio Sound Interface SignaLink Terminal Node Controller (TNC) West Mountain Radio MFJ TNC’s

Hardware Setup Signalink USB Popular radio interface. ~$100 new with interface cable of your choice. Specify when ordering. Powered by computer’s USB, no external power needed. Wide variety of radio interface cables available (~$20), or make your own. Easy setup in Windows computers.

Hardware Setup System setup With Signalink USB Radio Control Cable (Optional) USB Cable Transmit Audio Receive Audio PTT Control Feedline to antenna Commonly one cable.

Software Requirements Windows DigiPan FLDigi Free & Open Source Ham Radio Deluxe with Digital Master 780 Version 5.24 free to download. Later versions must be purchased. Packet Engine Pro Linux FLDigi Mac cocoaModel Multimode

Operating Procedures Select base frequency via VFO. PSK31 requires USB, even below 10 MHz. Multiple stations are clustered around one frequency, with varying modulation to separate signals. Once tuned, do not change VFO. Suggest locking VFO, if possible, to prevent bumping. Setup your call sign in software. Used as part of communication packet. Set output power to max 50% of radio or amp. Digital radio is 100% usage and may damage the radio if used at higher power. Select modulation on the waterfall display. Will decode any messages on that modulation. Type in message or select macro. Hit send/Auto. Call sign is included at the start of each message sent, so regular ID’ing is not required, only when you end a conversation.

Popular Digital Calling Frequencies 160 meters: 1.383 MHz 80 meters: 3.580 MHz 40 meters: 7.07015 MHz 30 meters: 10.142 MHz 20 meters: 14.070 MHz Most popular PSK31 location 17 meters: 18.100 MHz 15 meters: 21.080 MHz 12 meters: 24.920 MHz 10 meters: 28.120 MHz 6 meters: 50.290 MHz 2 meters: 144.140 or 144.144 MHz Normally horizontally polarized 160 to 12 meters require General or Extra 10, 6, & 2 meters allow Technician license

Operating procedures Calling CQ audio in various modes PSK31 PSK63 OLIVIA RTTY

Operating Interface Features Overview Logging Info Macro Menu Text Interface Waterfall

Operating Interface Features Text Interface Received data window Send, leaves PTT closed until canceled. Auto, opens PTT when finished with text in window Macro Quick Keys Transmission text window

Operating Interface Features Waterfall

Operator Interface Features Transmitting Progress of transmission. Text being sent struck-through as transmitted. Audio being transmitted shown on waterfall.

Operator Interface Features Other Functions

Operator Interface Features Supersweeper Vertical waterfall Decodes multiple signals simultaneously. Allows you to pick which signal you want to interact with.

Operator Interface Features Software Most software can decode multiple types of digital signals PSK63 RTTY Contestia CW Some software can decode SSTV (Slow scan TV)

Comparing operating modes PSK31 Very popular Narrow bandwidth Effective Good for contests, rag chewing, etc. PSK63 Faster than PSK31 Larger bandwidth Not as popular

Comparing operating modes, Con’t. JT-65 Created by Nobel Prize winner Joe Taylor, K1JT. Very accurate because of error correction built in. Can sometimes work even if not audible to the ear. Popular Olivia Good during bad band conditions. Wider Bandwidth. Not very popular.

Comparing operating modes, Con’t. RTTY (Radio TeleTYpe) Old mode, created in 1922. Popular, especially in Europe. Popular with Contests. Slower than PSK31 Very regimented contacts. Watch a lot of QSOs to learn expected procedures. CW People tend to have mixed feeling about computer generated CW. Computer decoding not always accurate. Other modes Hellschreiber Domino

Operator Interface Features Radio Control via HRD

Other Features HRD Remote Radio Control HRD enables radio computer control of your radio via CAT interface. Depending on the radio, this can allow for full radio control by computer. Remote operation of a radio via two computers connected over a network.

Other Features PSK Reporter Stations heard on DM780 & FLDigi can be sent to share what stations are heard with an online tracking system. See real time digital activity Track your receiving and transmission capability. https://www.pskreporter.info/pskmap.h tml

Other Features PSK Reporter See all stations that you hear See all stations that can hear you See details on individual contacts.

Notable contacts by Chris AB3YS

Conclusion Thank you for attending. Questions? Live Demo