Digital modes will operate your radio at 100% key-down, meaning your radio will be transmitting the maximum power during the duration of the transmission. In contrast to SSB (suppressed carrier) that does not produce output when no audio is present.
Digital should not be operated at more than 50% of the total power output of your radio. It should be operated more in the range of 30% power output or 30 watts which ever is lower. More than 30 watts doesn’t make a difference and considered excessive. Keep an eye on the radio’s temperature monitor when operating more than 30% power.
Never, never, never set the audio interface to your radio (SignaLink, Rigblaster) as the default sound device on your computer (the green check in the playback/recording devices in Windows)!!! Leave the soundcard for your speakers as the default playback and recording device. Every digital program I’ve used has the option to choose the audio interface in the program. Set the audio device in your digital program. If the audio interface is left at default, any audio outputted by the computer will be transmitted by your radio. When your computer plays a system sound or your fish screen saver activates, your radio will transmit every time the fish tank makes the sound of bubbles. In Windows, check “disable all sound effects” in both playback and recording (if applicable) properties under the enhancements tab. Setting the audio input and output levels at 50% in Windows and 100% in Linux eliminates clipping and distortion in general.
Do not over drive your radio with too much audio or you will take up more bandwidth and spatter across the band. To calibrate your audio setup, find an unused frequency, dummy load, or band with poor conditions. You need to know how to access your radio’s transmit power meter and ALC meter (automatic level control). Set a fixed power level such as 30, 50, 100 watts (this is only for calibration) where you can see this output level on the power meter. Generate modulation from the program on the computer (idle PSK tones). Some programs have a ‘tune’ button (Fldigi, WSJT) that accomplishes the same thing. With modulation being generated by the program, and radio transmitting, adjust the audio level on the audio interface device until NO ALC bars are showing on the radio BUT the radio is transmitting the maximum power level you set. Then take it down a smidge from that level. Only adjust your computer’s audio if the output level is minimal when the interface is set at full volume. It is best to get an Elmer or friend familiar with their setup to check your signal on the waterfall (from their station). With a friend on the line, this is a good opportunity to check what happens when levels are too high, too low, and corresponding indicators on your radio.
Search a particular mode for available programs. I recommend Fldigi (free) or DM780 (not free, part of Ham Radio Deluxe) because they have a vast array of digital modes they can operate. Pro Tip: though these programs can operate CW… DON’T. CW ops don’t like people using computer programs for a mode you an learn and work on your own.
Modes that allow free form conversations (PSK, RTTY, CW) use many abbreviations such as BTU, DE, K, KN, PSE. These are called “CW abbreviations” and “prosigns” because they were first used with Morse Code. Good lists are AC6V’s Prosigns and CW Abbreviations (below the prosigns list). There are more condensed and common abbreviations lists. JT65 and JT9 have very limited free form ability (13 characters -beat that Twitter 😉 ) and just exchange contact information, nothing else.
Beginner guides are available. Here are ones for PSK31, RTTY, JT65 – JT9 (search for others) that offer operating techniques, frequencies, conversation exchanges (see previous point for abbreviations and prosigns). Once you get the hang of PSK31 and RTTY conversation exchanges, they carry over to many other modes.