Is it possible to have HD-4-5-6 and so on? I heard someone talking about it on the radio this morrning, if they happen to launch those with in time, will my HD Radio now be able to pick it up?

From what I've heard, they might be able to slip in another 32K channel if stations are allowed to broadcast more subcarriers. At this point they're not using as many as they could because stations aren't convinced that they won't cause interference. A local station C.E. told me they're going to consider doing this later this year. I think some stations are already.

That would mean a station could have analog FM plus two 48K channels and a 32K channel. A fully digital station could have something like twice that. You'd hope HD Radio manufacturers test all these difference configurations.

iBiquity Digital has sucessfully broadcast up to 7 sub carriers for a single station. They are able to create up to 8, but with too many problems.

I know the Sangean HD Radio's have the full multicast capability and also believe the other ones can as well, but I am not 100% sure about the others.

Currently, I believe there are a half dozen stations throught the US broadcasting HD3, but only NPR is actually preparing and planning 4 that I know of. But that will be seen with the newest HD Radio thing. . . Conditional Access. . .

Currently, I believe there are a half dozen stations throught the US broadcasting HD3, but only NPR is actually preparing and planning 4 that I know of.
Is this with two 48K channels plus a 32K channel? The C.E. at the local classical station is talking about adding a 32K HD2 channel to their stunning 96K main channel but he's waiting for approval from someone or something.

I'm not against adding new substations but if they add more I hope they change the ability to save a subchannel as a preset...otherwise it will be a chore to go though some of them...nearly half mine have two and that's fine....

I'm not against adding new substations but if they add more I hope they change the ability to save a subchannel as a preset...otherwise it will be a chore to go though some of them...nearly half mine have two and that's fine....

The Sangean HDT-1 and the Accurian CAN save a subchannel as a preset.

The Sangean HDT-1 and the Accurian CAN save a subchannel as a preset.

I got the Accurian radio its great, I'm waiting for the Sangean to get a little cheaper, I want to get a home unit HD radio also.

We looked around at possibilities for KSL-FM's HD sub-channels. I was told it was possible to make several lower-fidelity mono channels (we were investigating foreign news/features channels like WRN, Radio Netherlands, Deutsche Welle).

My biggest concern would be, like with the HDTV options, how many receivers meet all the specs for doing the various options? (Like, Dolby Digital allows a separate center channel for second-languages, so you don't have to send two full 5.1 feeds....but many receivers don't meet the specs).

Ken, you can use HD Radio modes MP2-MP7 for additional channels without lowering the bit rate of the 96-kb primary channel (as multicasting will do). However, this will cause additional noise in analog home receivers (but not car radios). See http://users.tns.net/~bb/iboc.htm for details about the impairment. I think current HD Radio receivers will decode MP2-MP7 but I'm not sure.

Brian

Is any additional FCC paperwork required, to expand MP1 HD to MP2-7 ?

However, this will cause additional noise in analog home receivers (but not car radios). See http://users.tns.net/~bb/iboc.htm for details about the impairment.
This sounds a lot like what happened to some B&W televisions when they started broadcasting in color -- introduce a new signal and it's inevitable that it will mess up some receivers. It's weird that a signal much weaker than the main carrier way above the FM audio can cause audio problems. It's like the manufacturers were counting on every station's 102-198 Khz spectrum to be completely silent forever.

Let's see if I can sum up Ibiquity's document right. There are three main hybrid modes with their sidebands are MP1 = 96 Kbps (129.3-198.4 Khz), MP2 = 108 Kbps (122.4-198.4 Khz) , and MP3 = 120 Kbps (115.5-198.4 Khz). BTW thank you, Ibiquity, for using the common term "MP3" to confuse people.

There are also four extended hybrid modes which use still more bandwidth (136 Kbps 101.7-198.4 Khz) for more robust audio or new data services.

MP4 is like the MP1 we listen to today but uses the extra bandwidth to support a bunch of data services (PDS, AAS) which I have no clue about.

MP5 is the first mode that can be used without analog FM (but doesn't have to) and has two identical audio channels at different rates (24 Kpbs "core" and when added to the "enhanced" channel gives you 96 Kbps total) which are combined to make one robust stream with the 24 Kbps channel being the most robust of all, more than HD stations today. I think the receiver falls back to the "core" channel if it gets too many errors on the "enhanced" channel, just like it falls back to analog with hybrid systems. It also gives you audio from the "core" channel sooner before switching to the "enhanced" channel. The last 24 Kbps is used for data services.

MP6 cranks up the super-robust "core" channel to 48 Kbps with the "enhanced" channel still adding up to 96 Kbps but you lose the data services. I can't imagine a station wasting what are effectively two separate quality channels on the same audio (or three if they simulcast analog FM), especially if the data services become popular. Maybe some areas with bad reception would benefit from the higher quality "core" channel. The "enhanced" channel is as robust as our HD stations today.

MP7 sounds like MP4 with even less bandwidth for audio than we get from HD Radio stations today with the extra devoted to robust transmission of the data services. I think it can only send one 48 Kbps or two 24 Kbps channels audio channels. Let's hope this one doesn't get popular.

Note that all of the hybrid modes stay out of the analog FM spectrum so there's no way to add digital channels by removing SCA or analog stereo. That wasn't even a consideration for them.

Then there are four all-digital modes MS1-MS4 which I haven't figured out because they don't seem to have any advantages in the document, so I must not understand it right.

Brian asked me to visit here, since I just put on two stations running extended hybrid mode last week.

Thus far, we have not found any HD Radios that cannot see the extended hybrid programs. The Day Sequerra M4 makes you go through some odd button pushes to get to it, but will go there as well.

We are currently running 96k on the main, and 24k on the extended hybrid...this is mode MP3 (NOT to be confused with the coding/compression algorythm!).

Brian calculates that we will be giving up a few db of signal to noise on our analog, but these stations seldom have any zero modulation time, so we don't think it will be noticeable. I have however asked everyone at the station who might answer a complaint call to please let me know about it. So far, nothing.

I'm not sure I'd suggest this mode for a Classical music station however...where that difference in noise-floor might be noticeable. I have not made any formal measurements of changes to the analog noise-floor, but will try to do that shortly.

I believe the proceedure with the FCC is the same as adding multicast HD channels...you must get an STA to do it. This is supposed to be fixed if the commission ever gets around to finishing the update of the HD rules.

I checked the coverage of the programming in the extended hybrid mode, and found it to be nearly the same as the HD main. I was expecting that there would be some interference to the HD carriers, since they are in closer to the main channel modulation...but my seat-of-the-pants evaluation is that the extended hybrid coverage is at least 90% of the main HD coverage.

I'll try to watch for any questions you folks might have about this.

Dave O.

To add to my long post about the MP1-7 service modes, I've finally figured out the all-digital modes.

First you have to pick service mode MP5, MP6, or MP7 for the sidebands. These are the only ones designed to work with the all-digital modes. Then you can pick from four digital modes.

MS1 only lets you replace your analog with new 96 Kbps and 5 Kbps data channels, no audio. MS2 gives you two new audio channels, 72 Kbps and 24 Kbps plus a 24 Kbps data channel and a slow 5 Kbps data channel. MS3 gives you a robust 48 Kbps audio channel and another slightly less robust 48 Kbps audio channel plus a slow 5 Kbps data channel. MS4 gives you just one 24 Kbps audio channel and three not-very-robust data channels (96 Kbps, 24 Kbps and 5 Kbps).

These all digital modes are not really intended to deliver another high-quality audio channel. They're mostly for data services. Ibiquity recommends using their audio channels to enhance the audio in the MP modes. They mention surround sound but it's not clear if their bits can be "added" to the bits in other audio streams.

The channels in the MS modes are much less robust than the ones in the MP modes. I think that's because they intend to broadcast these at full power so less error correction will be needed.

The Sangean HDT-1 can readout the transmission mode. All stations in my area (Portland and one Eugene station) show "MP1" ... has anybody observed a higher numbered mode? If so, any comments on number of channels being transmitted, sound quality etc?

I'm presently running hybrid service mode MP3 (NOT to be confused with the compression / coding algorithm) at a couple of my stations in Missouri.

Please read my earlier post from 2/7/07.

I assume other stations will slowly begin to add services from the other service modes.

Service mode MP3 allows an additional 24kbps HD-3 to be run in the extended hybrid portion of the usable spectrum. This is in addition to the normal, 96k main HD channel.

Dave O.

I'm presently running hybrid service mode MP3 (NOT to be confused with the compression / coding algorithm) at a couple of my stations in Missouri.
Dave O.
Does a Sangean HDT-1 indicate this higher mode properly?

As far as I know, it does.

Dave O.

In Las Vegas, every station is in MP1 mode except for KSTJ 102.7. They are broadcasting in MP2 and feature HD-1,2 and 3. The HD-3 is a mono weather channel.