Interference or noise
Unwanted radio noise from electrical equipment or natural sources rather than a transmission.
ModeInterference or noise
FamilySignal structure
Audio exampleComing
What does it sound like?
Plate 27Signal structure
Buzzing, hissing, crackling, whining or ticking.
Field marksSpread across many frequencies at onceChanges when nearby devices switch on or off
Who uses it?
Not a station: power lines, electronics, appliances, lightning and so on.
Where and when can I hear it?
Anywhere; man-made noise is usually worst at the lower frequencies and near homes.
Easily confused with
- Steady carrier, from the same family