Mark Roberts wrote:

If AM IBOC is such hot stuff, why is it restricted to daytime hours only?

Because the group delay that is the result of the uneven ionosphere prevents
it from being decoded properly when the signal is received on skip, and the
amount of stuff coming over the horizon on skip prevents it from being
properly received when it's being received on groundwave at night.

I can now hear the damage it does to the analog signal on KCBS. The
effect varies from radio to radio, but on almost all of them, the
noise floor goes up when IBOC is on.

I wouldn't be bothered by this so much if the digital system actually
sounded good. But the audio quality of the digital carrier is actually
a lot worse than good analogue AM. It's like listening to Cylon Warriors.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."