Radio/Digital Modes

Radio modem for a microcontroller: PSK31, RTTY, APRS: https://github.com/zenmetsu/radioModem

HF voice: speech codec for 3200 bps and lower: https://github.com/freedv/codec2

• comes with FDMDV modem, PSK modem, and api for embedding in other programs

Overview

In ham radio, digital modes are ways of communicating digital information using radios. Normally, with analog communications, the operator and/or receiver radios will be operated by a human. The information being transmitted is human voice data, or some other information a human can understand (CW). With digital modes, the data being transferred is digital data, and the transmitting and receiving radios are operated by computers. These computers are able to translate analog signals to digital signals, or vice versa, using a modem (a modem modulates and demodulates signals).

Exploring digital modes can be done with a Linux or Windows computer, or with a phone. A radio helps, but is not necessary to get your feet wet.

Listed below are a few different digital modes, how they work, and what software to use.

Digital modes:

• SSTV
• PSK31/PSK63
• MFSK
• Olivia
• RTTY
• APRS
• D-Star
• GSM
• GPRS
• TCP/IP over Packet

Slow Scan TV

Slow scan TV turns images into audio signals that can be transmitted over long ranges. Software can translate images into sounds, and sounds into images. QSOs are made by exchanging a series of images. More notes on the SSTV page.

To do slow scan television, you can use Qsstv on Linux, or Robot36 on Android.