The Morse letter "A" repeated many times, then a single 5-figure group repeated for a minute, then the sequence repeats with another 5-figure group. Was very uncommon, heard once in a few months, and operated on 6571 and 7928 kHz between 7:00 and 13:00 UTC in USB mode.

Derived from Langley Pierce's 1994 book "Intercepting Numbers Stations"