In article , Bob Radil wrote:

I wouldn't presume that. Most ATUs and phasors are designed for the carrier
frequency. The fact that a transmitter may also transmit audio sidebands is a
secondary issue.

This is unfortunately true, and it's also one of the more important sources
of lousy sound for AM broadcasters. Low group delay across the antenna system
really _is_ important for good clean analogue audio.

IBOC splatter was certainly not taken into consideration in
the design of nearly, if not all, of the phasors in use today.

IBOC now requires low group delay across an even wider frequency range. My
hope personally is that stations will be forced to upgrade their phasing
networks and antenna systems in order to implement IBOC-AM, which will then
fail, leaving them with wider band antenna systems that result in higher
analogue audio quality.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."