I'm quite curious (not being a CE or anything of that sort) if and when a few brave soles get the "go ahead" from the FCC to transmit "full-blown" HD radio in non hybrid form, whether or not the usable received coverage would exceed the standard "MPX" stereo reception contours. Would the 30 to 40 miles of non-adjacent channel FM HD mode coverage double without the analog signal hoggin' up 99% of the licenced EARP?
If I'm not mistaken the YD RF output power is equal to 1% of the licenced analog output power and there are two ways of reaching that outcome with the existing antenna setups (speaking of FM only in this case). One way is to "amplify up" a mix of the analog exciter output as well as the digital exciter output with an analog to digital power ration of 100:1.
The other way is to force feed via a directional coupler the output of the main analog signal through the Zero insertion loss side (not it the real world of course!) and then feed in 10 times the assigned digital output power into the attenuated side of the directional coupler thus allowing that brew to mix directly at the antenna feedline.
I'm hoping that (assuming FM IBOC becomes SOVEIGN) if non hybrid broadcast authorization is warranted, it would come into being BECAUSE this system had been struggling to sustain useable signals that were "20dB down" by DECREE!. Try holding down the head of your front-end receiver with a MANDATED 20dB pad attached between your antenna coax and your car radio, then set it afloat in a mobile envoirment to do battle in HD mode with its antiquated analog "Grandpa" Multiplex subcarrier which, 9 times out of 10, gets systematically "BLENDED" to death ( for all of the noise haters). Talk about "Political Correctness" with respect to backwards compatability, it's hard to bend over any more than the IBOC system has; Ooh gotta fit the Narba mask! Yeah now we do, and yet these days the FCC can't wait to give away the store in terms of selling of a portion of the broadcast TV band! Heck, if they can do that thereby effectively slaughtering the direct utlilty millions of NTSC receivers, whose to say that they wouldn't carve up the FM band as well.
I just hope that in preparation for sustaining robust reception in the HD only mode, someone out there has done the math already for what positive impact have a 100 fold signal upgrade would have on today's HD receivers on FM.

Technically, pure digital already exists in the world of seperates. Seperate transmitter, feed line, antenna, etc. Only thing that keeps them sounding alike is the GPS clock time sync. But, unless mandated, analog won't be going anywhere for quite some time. Still gets out about the same as if it was in a hybrid system. (due to the control of only using the ammout of power as if they were in a hybrid setup)

And yes, this is the reason AM IBOC can't be on at night. They're worried about skywave and knocking other stations out. (which happens durring daylight use as well)

Personally i still am in the camp of "wait and see". IBOC is nothing special, and the consumers will dictate it's existance. As shown already (stations have been broadcasting HDR for about 4-5 years already), consumers aren't really aware of it, and nor are they willing to go pop 200-500 bucks on a reciever for their vehicle, let alone the only $1k+ home receivers. This will too go the way of AM stereo.

I'm 48. I MAY live to see "non-hybrid" HD Radio, but I'll be very old. Even Ibiquity is predicting 10-15 years for 50 percent penetration. Give it 20 years or more for anything near enough penetration that the FCC would consider turning off analog broadcasting. Many of us will be "pushin' up daisies". ;)

I'm 48. I MAY live to see "non-hybrid" HD Radio, but I'll be very old. Even Ibiquity is predicting 10-15 years for 50 percent penetration. Give it 20 years or more for anything near enough penetration that the FCC would consider turning off analog broadcasting. Many of us will be "pushin' up daisies". ;)

Hope you're right! I'm 58.

Long way a comin'

The thing is that HD radio receivers are pricey precisely because they have to support 4 different formats. There's nothing state of the art about the hardware involved, if we could suddenly do away with analog radio, HD radio would be much less expensive, and frankly it just isn't good enough to pay top dollar. I may spend $1000 on a Blu-ray player but spend $800 on a home HD radio receiver? No way.

There's no financial incentive for the government to require shutting off analog, as there is with TV (spectrum to sell!) Remember, analog broadcasting will always be the most basic (i.e. affordable, durable, robust) of electronic media. It'a an analog signal that can be received on a wind-up radio after a hurricane, or at considerable distances when all your local stations have been knocked out (as with Hugo in this area...North Carolina...back in '89). Be careful what you wish for! People could actually die from analog being turned off prematurely (older and poor people in isolated areas with no way to receive emergency information when things get rough).

I doubt I'll ever see an end to analog broadcasting. GOOD!