AM radio and Max (Mac?) Richmond

[Jim Hall]

Did FM stations originally broadcast only in the horizontal plane, and then added the vertical plane for cars and their whip antennas?  When WGBH-FM used to sign off at midnight, they would include "WGBH broadcasts at 89.7 MHz, with an effective radiated power of 100,000 watts in the horizontal plane, and 96,000 watts in the vertical".


"I always wondered why it took so long to get FM into cars.  Some people told me that FM reception wouldn't work in cars, but I couldn't see why not.  Obviously, once we got FM in cars, it worked fine."