fldigi is a program for Windows that supports a wide array of digital modes commonly used by radio enthusiasts. Its primary functions revolve around conducting frequency measurement tests and calibrating a sound card to a signal.

Setup and configuration

The app relies on the system sound card for both input and output of audio signals. It seamlessly integrates with a standard HF SSB radio transceiver. At the same time, you can manage and control the device via serial port connections. To send Morse code messages, you may use Morse Code Tools.

Upon initial launch, the configuration wizard is available to lead you through all the necessary steps for selecting the operational settings. This includes entering operator information, setting up audio devices, and choosing tabular data sources. You also have the option to tweak these parameters later on.

Advanced radio capabilities

The receiver and transmitter panes allow you to view encrypted and sent messages. The main interface also has a section dedicated to identifying and tuning the signal. Depending on the chosen method, you can access a spectrogram display showcasing signal strength versus frequency or an oscilloscope.

The program has an integrated signal browser, mode detection, tuning, text capturing functionalities, data logging, and more. You can automate routine tasks using macros as well as generate reports in text, CSV, or Cabrillo formats.

Features

free to download and use;
compatible with modern Windows versions;
allows you to transform PC into a radio station;
you can decrypt and send custom messages;
it is possible to customize the UI appearance.