FSQ (Fast Simple QSO)
A text chat mode built for reliable short-range shortwave contacts, with automatic messaging features.
What does it sound like?
A soft, stepping sequence of tones.
Who uses it?
Amateur radio operators, including emergency groups.
Where and when can I hear it?
Lower HF ham bands, for example 3.5 and 7 MHz.
The science
FSQ uses 33 tones spaced 8.8 Hz apart and, like DominoEX, carries data in the step between successive tones, with a rotating offset so the same tone never repeats. Its receiver needs no timing synchronization at all, and it decodes any sending speed from 2 to 6 tones per second (about 20 to 60 words per minute) in about 290 Hz. Every lowercase letter and common punctuation mark takes a single tone step, and text is sent a line at a time when the operator presses Enter.
Why use it?
Without synchronization to lose, FSQ copes unusually well with the timing smear of near-vertical skywave paths on the lower bands, locks on almost immediately, and its designers found it robust enough to need no error correction. Its directed mode lets stations address messages, files and queries to one another automatically, which suits nets and emergency groups.
Lore
FSQ grew out of WSQ2, a very slow weak-signal mode for low frequencies; the developers realized that with enough computing power it could be sped up into an HF chat mode. It was developed by Con Wassilieff with help from Murray Greenman, and the first FSQ contact between the two took place on November 28, 2014.
Easily confused with
- Olivia, from the same family
- Contestia, from the same family
- MFSK (MFSK16/32), from the same family