While Fldigi does include RTTY, the suite offers a wide variety of the new sound card modes.
The yellow window is the receive text window.
The blue window is the transmit text window.
The row of buttons are the macro buttons.
The black strip of numbers represents audio frequency. (I normally set this to read out in Radio Frequency).
The window below the frequencies is the waterfall display. The blue is air noise and the yellow traces are psk 31 signals.
Fldigi, the Fast Light Digital modem application is a free and open-source program which allows an ordinary computer's sound card to be used as a simple two-way data modem. The software is mostly used by amateur radio operators who connect the microphone and headphone connections of an amateur radio SSB transceiver or an FM two way radio to the computer's headphone and microphone connections, respectively.
This interconnection creates a "sound card defined radio" whose available bandwidth is limited by the soundcard's sample rate and the external radio's bandwidth.
Such communications are normally done on the shortwave amateur radio bands in modes such as PSK31, MFSK, RTTY, Olivia, and CW (morse code). Increasingly the software is also being used for data on VHF and UHF frequencies.
Using this software, it is possible for amateur radio operators to communicate worldwide while using only a few watts of RF power.
Fldigi software is also used for amateur radio emergency communications when other communication systems fail due to natural disaster or power outage. Transfer of small files, emails, and ICS forms are possible using inexpensive radio hardware.
Download Links
FlDigi is available at DOWNLOAD FLDIGI
Simply select the version for your computer's operating system and down load it
FlDIgi users manual ONLINE USER MANUAL
FlDigi WIKI FLDIGI WIKI
BEGINNERS GUIDE
Getting Started With FlDigi
EQUIPMENT REQUIRED
A MODERN RADIO
While flDigi will run on most computer platforms the radio should be drift free. Most people like to use a cable to route the audio to and from the computer to the audio in /out jack on the back of the radio as these inputs/outputs are not variable and maintain a constant level and preserve your use of the radio AF gain control.
The ALC meter becomes important in setting up the radio output. More on this later.
EXTERNAL SOUND CARD
The computer sound card can be used but many find an external sound card easier to adjust.
I use and recommend the signal link sound card interface.
When you order the signal link you order it for the specific radio that you are going to use for Data modes.
Signal Link at DX Engineering
FlRig
FLRIG is a transceiver control program designed to be used either stand alone or as an adjunct to FLDIGI. The supported transceivers all have some degree of CAT. The FLRIG user interface changes to accommodate the degree of CAT support available for the transceiver in use.Three different main dialog aspect ratios can be selected to suit the computer screen dimensions and operator preferences. The wide aspect ratio can be resized horizontally. The narrow aspect ratios are fixed in width and height.
Download Link
Download FlRig
FlRig USER GUIDE
To take advantage of all the features of FlRig you will need a CAT control cable from the rig to the computer. This will allow you to run the rig from the screen of the computer.
