Sounds like it's about 50 baud, but so far I've been unable to make sense of it. I've tried 45.45, 50, 56, and 75 bauds in both normal and inverted mark/space senses and get nothing but gobbledygook.
I'm beginning to suspect it's something military from somewhere, and thus encrypted. Maybe I'll give ASCII an whirl (been trying to parse it as Baudot). Would be neat to find a RTTY pirate!