08/15/14 HM01 9333 kHz 08:00 UTC Tuned in to open carrier then it started at 8. Newbie question: I always hear a sound like a plane engine running (like a propeller plane) on one or two frequencies at night. I've checked sound clips on N&O and UDXF, but I can't find it. Can someone tell me what this is? Thanks! Ashley Dugan Sapulpa, OK