Originally Posted by trotterdotpom
PS My theory is fading fast, but something tells me that 500 kcs wouldn't be much use for mobile phones.
No, but some of the frequency bands allocated for marine radar and marine satellite communications have been targeted for some years now. The MF W/T band is a target for aerobeacons and other navaids, the MF R/T band for the broadcasters. It is only a matter of time.