Multiple Frequency-Shift Keying and Mysterious Olivia — Trans-Polar Fun and More
If you have taken the leap into using your shortwave transceiver as a digital mode communication tool, perhaps with the highly popular FT8 mode, or with another mode that uses a computer rather than with your voice or by using a Morse code key, then you understand the effectiveness of digital communication. If you have only heard the glowing reports from others who have tried digital modes, then you are a candidate for a new journey that can be rewarding in many ways.
Olivia MFSK is an amateur radioteletype protocol that uses multiple frequency-shift keying (MFSK) and is designed to work in difficult (low signal-to-noise ratio plus multipath propagation) conditions on shortwave bands. The signal can be received accurately even if the surrounding noise is 10 dB stronger. It is commonly used by Amateur Radio operators to reliably transmit ASCII characters over noisy channels using the high-frequency (3 MHz to 30 MHz) spectrum. The effective data rate of the Olivia MFSK protocol varies but is typically around 150 characters per minute.
Frequency-shift keying (FSK) is a modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier signal. The technology is used for communication systems such as telemetry, weather balloon radiosondes, caller ID, garage door openers, and low-frequency radio transmission in the VLF and ELF bands. The simplest FSK is binary FSK (BFSK). BFSK uses a pair of discrete frequencies to transmit binary information, “0s” and “1s.” With this scheme, the “1” is called the mark frequency and the “0” is called the space frequency. RTTY is an example of a BFSK radio signal modulation scheme.
Come meet Olivia and the digital chat mode that makes FT8 obsolete for social radio enthusiasts.
— Tomas Hood, NW7US