Probably all amateurs recognize QSB as the q-code to represent 'fading'.

I recently encountered the terms

  • Shallow QSB
  • Deep QSB

A quick google search failed to yield fruit; What do the above terms mean?


1 Answer 1


Deepness of QSB refers to the magnitude of fading. A very deep fade-out can make the received signal so weak that it becomes unreadable.

A shallow fade-out would be one where the signal level drops only slightly, not affecting readability.

Radio propagation conditions often change quite quickly over time. For example, QSB might start in the middle of a longer QSO, being quite shallow in the beginning. It'd be noticeable on the signal meter. On FM you'd hear a little noise on top of the carrier from time to time, on SSB the audible volume of the received signal would go down temporarily. If conditions would continue to go worse, the QSB could soon become too deep for successful communications - you would start to miss words, then whole sentences.

shallow: of little depth


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .