IBOC Installations Not Following Expected Pattern, Says BE

More broadcasters are using lower-power FM transmitters to implement HD Radio, according to Broadcast Electronics, which makes transmitters in those power ranges, said Tim Bealor, VP of RF systems.
“People originally thought the majority of FM stations would have to go with common amplifier combining or high-level combining techniques that called for a higher-priced, full-powered transmitter. But that’s not turning out to be the case at all,” he said in a company statement.
“We’re finding that a lot of those stations can actually combine at the antenna or set up a separate antenna using a lower-powered transmitter.”
Entercom, Greater Media and Clear Channel are among the groups using low-powered FM transmitters to implement IBOC, the supplier said.
Entercom, for example, will be using a new high-level approach that combines analog FM and digital through a shared master antenna. By introducing a separate HD Radio path into one polarity of its existing circularly polarized master antenna, Entercom can broadcast HD Radio at the same time as analog FM, which is radiating from the opposite polarity of the antenna. The approach reduces the injector loss typical of high-level combining (10dB loss in HD Radio and a .45dB loss in analog).
Other stations are using BE’s low-powered FM transmitters in a separate antenna system for the HD Radio path, which also eliminates the 10dB loss and the cost of a high-powered transmitter to handle the loss.