STANAG 4285 (NATO modem)
A NATO standard for sending data over shortwave with a single wide tone.
ModeSTANAG 4285
FamilyUtility data
Audio example12 s
What does it sound like?
Plate 61Utility data
A steady, rough hiss about 3 kHz wide, like a waterfall of static.
0 Hz1,0002,0003,000 Hz
12-second example. A clean example made by our own signal generator; signals on the air usually sound noisier.
Field marksA continuous, dense digital hissAbout 3 kHz wide2,400 symbols per second
Who uses it?
Military and naval stations.
Where and when can I hear it?
Various HF frequencies, often continuous for long periods.