JT4
A weak-signal mode with one-minute turns, used mainly on microwave bands and for Moon bounce.
ModeJT4
FamilyWeak-signal digital
Audio example12.0 s
What does it sound like?
Plate 29Weak-signal digital
Slow, steady tones over nearly a minute.
0 Hz1,0002,0003,000 Hz
12.0-second example. A clean example made by our own signal generator; signals on the air usually sound noisier.
Field marks4 tonesOne-minute cyclesMostly on microwave bands
Who uses it?
Amateur radio operators working very long or difficult paths.
Where and when can I hear it?
Microwave ham bands; rarely heard on HF.