I had this also on the SDR recording, from 0301 until 0350 sign off.
I am pretty sure this was SSB and not AM, there was a carrier on 6930 AM, but it was there before this started, and stayed on well after it ended, so I think that was someone else.
I am not sure what the exact frequency was, I tried a range from 6930 USB to 6931 USB, nothing sounded right. I also tried 6933 LSB.