How is the HD Radio rollout going? The statistics say there are currently 1,867 stations transmitting an HD Radio signal, with 2,817 total digital streams available. It seems the 2,000-station mark is in sight, but the rate at which stations are activating HD Radio signals has slowed. (In case you're wondering, the 1,000th station to implement HD Radio was WIYY-FM Baltimore on Sept. 18, 2006.) One reason is the looming decision to allow increased power of the digital sidebands.

HD Radio adoption started in larger markets, and two years ago we provided a list of the top 10 HD Radio markets. These 10 markets boasted 271 stations. Of those, 149 were also transmitting multicast signals for a grand total of 420 digital streams.

Two years later, the list of markets hasn't changed much. Two cities have been replaced: Miami and Boston are out and Seattle-Tacoma, Philadelphia and Houston-Galveston are in. (There is a three-way tie for the last slot, so we have 11 stations this time). The remaining order has changed just a little.

Counting only the top 10, the new list accounts for 300 stations transmitting an HD Radio signal, with 193 multicast signals, for a grand total of 493 digital streams.

Data Source: Ibiquity Digital station finder. Numbers in parenthesis indicate current Arbitron market ranking.