General Motors has produced more than three million vehicles with factory-installed XM satellite radios. GM offers more than 50 vehicle models that feature the services of the satcaster. In model-year 2006, nearly 90% of GM’s U.S. retail models will offer factory-installed XM satellite radios as either an option or as standard equipment.
Roots of Radio
The Development of the Directional AM Broadcast Antenna
The advent of the directional antenna made it possible for co-channel stations to operate in close proximity