> But I was thinking to first encode it with MPEG1 layer 3. (See another mail
> in the list) So i get an enormous datareduction.

That you do.. Just try restoring it.
MPEG is lossy compression, so you won't be able to use any files that
you compress.
With sound and pictures, all that matters is that the end product be a
lot like the original.  Programs are a bit more picky.

You'll have to compress, but lossless (ZIP type) compression is your
only choice. You'll also need forward error correction, and lots of it,
since dropouts are expected in the media. This will further cut the
available bandwidth.