The Radio Advertising Bureau has reported its latest revenue numbers, and, it looks “bleak” for the future of traditional radio.

On-air revenue dropped 7 percent in the first half of 2008. While other revenues, from the Internet and other sources, are growing at a healthy rate, they are not enough to balance plummeting broadcast revenues.

Here’s the radio revenue breakdown:

Total revenues are down 5 percent in the first half of 2008.

“The industry’s larger groups do not appear ready to institute revolutionary changes yet in sales, programming, promotion or station clusters. There is a notable sense of denial of how harsh the prospects have been and continue to be for radio,” said analyst Jim Boyle. “The classic CEO reply is radio is not bleeding as badly as newspapers,” Boyle wrote.

It looks like radio is still unprepared to deal with portable media players, podcasting and Internet radio. Here are a few trends that traditional broadcasters are facing:

• The audience for podcasts has grown steadily since the technologies’ emergence, growing at a rate between 12-40% annually.
• Portable media players listen to less radio.
• Online advertising is set to overtake radio this year, and magazines by 2012.
• Podcasting and Internet radio have killed off HD radio, are working on satellite radio, and broadcast radio looks like it may be next.