It is understandable that the subchannels cant have an analog backup, as the digital system is a piggyback of the analog system, where would the analog backups go, on top of someone elses frequency? What, are you new?
"The FM hybrid digital/analog mode offers four options which can carry approximately 100, 112, 125, or 150 kbit/s of lossy data depending upon the Station Manager's power budget and/or desired range of signal (achieving perceived quality equal to a 1400 kbit/s CD). If in the future the FCC decides to discontinue analog radio, as they have done with analog television, the HD Radio provides several pure digital modes. In these modes broadcasts can be made at 270 or 300 kbit/s maximum, with extra features like surround sound. Like AM, pure digital FM provides a "fall back" condition where it reverts to a low-quality 25 kbit/s signal in the event of interference."
The station is the one who determines its own signal strength, not the technology. Of course there is a delay! Its digital! Do you have an HDTV? pfffst. Is your analog system free of dropouts and interference? Let me answer that for you, NO. Analog systems are prone to such instances. Get out of my thread if you cant contribute anything meaningful to my current issue. No bashing allowed.