Onstar uses AMPS cell phone freqs and GPS freqs.
Cell phones: 824 to 849 megahertz
Global Positioning System: 1,227 and 1,575 megahertz
Also see:
http://electronics.howstuffworks.com/cell-phone5.htm
http://electronics.howstuffworks.com...-spectrum1.htm
Klaus
Rare 2003 H2 with UM8 Integrated Navigation Radio
Skull & Bones Member since 2003