Should IBOC Rollout Be Stopped?

[rwagoner]

I was not around when any claims of no interference were made. I cannot understand how anyone could state so, at least on AM ... it is rather obvious. Not the "self jamming" some mention, but the adjacent and 2nd adjacent. I have heard of FM's HD interference in the way that it prevents some tuners from picking up stations that were once available. I once thought that I could not get KRUZ from Ventura at times when I could occasionally in the past. However, it was so rare that I could get them anyway I could never verify any problems. Adjacent stations to LA HD FM stations from San Diego and Santa Barbara seem to come in as good as they ever did.

One thing I have never quite understood: Since AM HD does indeed cause interference, why aren't analog stations allowed to go back to 20,000 hertz again? I'd love to hear good analog again on my Carver. That is if anything in Los Angeles AM were worth tuning in.

Is that being on the fence enough?

Richard

 

[FredRichards]

Richard, it's a matter of perspective when discussing interference.

According to the "pro" digital guys, the IBOC is within the bandwidth, and if set up correctly, it does carry most of the energy inside the station's carrier. Where the truth hits home is that most analog radios receive outside the normal 10 kHz bandwidth in some form. So while you may be tuned to 1400, your radio does have some ability to hear down to 1392.5 and up to 1407.5, which is technically inside the other station's (the one running IBOC) spectrum. So your analog tuner hears the noise generate.

And because digital is more constant, in contrast to the analog occasional peaks normally called "splatter", you're more likely to hear it.

IMHO, IBOC should have been placed on another band segment. Mixing digital and analog together is like mixing Bengal and Browns fans in the stands. You know a fight will break out. And unfortunately, while most think it's just the two warring parties that are affected, those within earshot of the bru-ha who are completely innocent get dragged into it.

 

[Powell]

I would love to SHOW you, but we are not in the business of trading secrets about how we make our radios better. All I can do is reccomend you try out the HDT-1X and see for yourself. It has the function and capability to turn off HD Radio so you can use the tuner as an analog only tuner. . . Plug it in, turn HD off and play with it. You will likely find that it makes an exceptional tuner in analog, as well as HD.
[/quote]

Are you going to institute the changes that Brian Beezley suggested when he tested an early model for you? I guess IF I get one of those, I should get him to align it properly! ;D ;D ;D ;D ;D


Powell

 

[MasterTheseus]

I would love to SHOW you, but we are not in the business of trading secrets about how we make our radios better. All I can do is reccomend you try out the HDT-1X and see for yourself. It has the function and capability to turn off HD Radio so you can use the tuner as an analog only tuner. . . Plug it in, turn HD off and play with it. You will likely find that it makes an exceptional tuner in analog, as well as HD.

Are you going to institute the changes that Brian Beezley suggested when he tested an early model for you? I guess IF I get one of those, I should get him to align it properly! ;D ;D ;D ;D ;D


Powell
[/quote]

I am in constant contact with Brian and am working closely with him to resolve the issues he sees in the units.

 

[dbdigital]

I'm sure I've missed some posts on this, but was it ever determined if the HDT-1X can decode AM stereo? What is the overall analog AM performance of this unit?

It might be worth buying one just for the analog section.

db

 

[Len14043]

SUPERCASTER WROTE: "Your "Duh" just detracts from your ability to project your image as a serious, intelligent, knowledgeable poster. It's much more a reflection on you then on anyone else. At the Radio Shacks I visited neither the BA Receptor or the Accurian could pick up any AM or FM HD signals. So I would have to say both are stone deaf."


[EDIT] If someone went to a store and heard both radios playing the same station, would it be very bright to assume that both radios have excellent sensivity? [EDIT]


[EDIT-inflammatory]

 

[SUPERCASTER]

SUPERCASTER WROTE: "Your "Duh" just detracts from your ability to project your image as a serious, intelligent, knowledgeable poster. It's much more a reflection on you then on anyone else. At the Radio Shacks I visited neither the BA Receptor or the Accurian could pick up any AM or FM HD signals. So I would have to say both are stone deaf."


[EDIT] If someone went to a store and heard both radios playing the same station, would it be very bright to assume that both radios have excellent sensivity? [EDIT]
[EDIT-inflammatory]

"DUH" = from a no brainer.
After visiting several Radio Shack stores within sight of HD stations broadcasting towers and still not being able to hear even one HD AM or FM station on either the BA Receptor or Radio Shack Accurian, I would confidently and accurately say that both radios at the several locations are stone deaf to HD signals. The analog AM and FM reception was clear and fine from the local towers at these Radio Shack locations. Distant reception from out of sight AM and FM analog towers was somewhat noisy, but no HD signals were received from those stations either.
HD reception in the suburbs was also absent at all but one suburban retail store (Best Buy) but only one of the several local HD AM stations (50kw former FCC class 1b, 2 miles from transmitter site) was receivable at all, but it was in mono only and intermittent (failure to hold HD lock). The HD AM had a buzzy, annoying high frequency resonance, had more highs then the same stations 5kHz limited analog audio, but the HD AM audio was somewhat worse then High Fidelity analog AM stations on the same radios. The Sony HD radio could only lock on to 1 HD FM station (Class B FM HD at about 5 miles) reliably using the supplied AM loop and FM antennas. Tests at the suburban Best Buy included JVC, Visteon, and Sony HD radios, all with similar results.
Conclusion:
Where you get a very strong, clear high fidelity analog signal you might be able to occasionally lock on and hold the stations HD signal.

 

[MasterTheseus]

I'm sure I've missed some posts on this, but was it ever determined if the HDT-1X can decode AM stereo? What is the overall analog AM performance of this unit?

It might be worth buying one just for the analog section.

db

HD AM is in stereo if the station chooses to use it. From my understanding they can either allocate all bandwidth to AM mono, or use some of the bandwidth to allow stereo. I am a little confused as to exactly how that works, but I quess it does. As for AM Stereo, only if the bradcaster is broadcasting in C-Quam standard. Although the units are not designed specifically for C-Quam, since the C-Quam and HD Radio AM technology is similar the units will decode C-Quam.

As for analog performance, at the beginning we were selling many of the tuners BECAUSE of the analog side and inspite of the HD offering. Since then we have found that the ones that bought because of the analog have become lovers of the HD signals and that now more are buying for that benefit.

 

[SUPERCASTER]

I'm sure I've missed some posts on this, but was it ever determined if the HDT-1X can decode AM stereo? What is the overall analog AM performance of this unit?

It might be worth buying one just for the analog section.

db

1-HD AM is in stereo if the station chooses to use it. From my understanding they can either allocate all bandwidth to AM mono, or use some of the bandwidth to allow stereo. I am a little confused as to exactly how that works, but I quess it does. As for AM Stereo, only if the bradcaster is broadcasting in C-Quam standard. Although the units are not designed specifically for C-Quam, since the C-Quam and HD Radio AM technology is similar the units will decode C-Quam.

1-Incorrect.
The mono 20 kbps HD digital signal is transmitted on adjacent channels, while the stereo left minus right digital signal optionally transmitted by the HD station, is transmitted at much less power and has even less coverage then the HD mono signal.

But the weak, fragile, secondary HD radio stereo signal coverage is much smaller then the already small and problematic mono AM HD signal coverage.

HD AM radio coverage is mostly 20kBps mono, unless you are extremely near a powerful HD station's transmitter site.

Another fact about AM IBOC that seems to be uncommon knowledge is that the hybrid system has two audio streams, a 20 kilobits-per-second "core" stream and a 16 kbps "enhanced" stream. Stereo audio is only available when the less-robust enhanced stream kicks in. When talking about the digital coverage they're obtaining, AM IBOC enthusiasts invariably neglect to mention whether they're achieving stereo audio.

Source for last quote:
http://www.rwonline.com/pages/s.0044/t.4050.html

C-Quam may have been inadvertently included because some of the pre-HD (legacy) receiver chips used already had C-Quam capability. C-Quam is analog and not very similar to the digital HD radio signals.