DRM (+) DAB (+) FMeXtra, AND IBOC. WHICH IS BEST AND WHY?

[Jay Walker]

I have dealt with IBOC AM/FM as part of my engineering work since the first roll-out, but I've often wondered what the advantages and disadvantages to each system are beyond IBOC compatibility?

Of all the early systems I heard about years ago the Eureka 247 system while allegedly superior, required greater bandwidth and ran afoul of needing additional L-Band spectrum that was unavailable in the US so was never seriously considered or adopted.

FMeXtra seems like a no-brainer but has not had the widespread support of the industry.
Seemed like a perfect use of the under used (in this market at least) of the SCA spectrum.

DRM sounds like a great idea on MW and HF and the demos I've heard sound remarkable.
It sounds like a great idea for medium wave use other than a compatibility issue with existing AM services.. Fairly robust and the ability to down-shift as needed due to QRN/QRM.

So that said, of the Digital systems DRM, DAB, IBOC, FMeXtra, available for over the air, if one could reboot the process which one is the best choice today and why?

If I have any totally wrong assumptions please feel free to educate me as I still find this fascinating.
Any references and links would be appreciated...

Jay Walker

 

[Tom Wells]

If a reboot were possible it still would be a problem if mixed modes were used in standard broadcast bands.

Any movement toward any digital mode pre-supposes a full mastery and reliabiility of the underlying analog, while
leading toward essential misunderstanding of the analog layer, which isn't going to go away.

This is especailly true of any rf connection to digital modes.

All the modes mentioned will have advantages/weaknesses that will be seen differently by different people according to expectations versus actual practice.

For example, the chorus on voice effect in AM iboc is sickening to me, but presumably someone else finds the
light background hiss of even a pure AM bothersome to the point they'd accept any codec artifacts and noises.

I see digital in broadcast as a response to treat the symptom, not the disease.
Further developments of digital modes by rf only raises the general noise level and so furthers the disease.

 

[Jay Walker]

If a reboot were possible it still would be a problem if mixed modes were used in standard broadcast bands.

Any movement toward any digital mode pre-supposes a full mastery and reliabiility of the underlying analog, while
leading toward essential misunderstanding of the analog layer, which isn't going to go away.

This is especailly true of any rf connection to digital modes.

All the modes mentioned will have advantages/weaknesses that will be seen differently by different people according to expectations versus actual practice.

For example, the chorus on voice effect in AM iboc is sickening to me, but presumably someone else finds the
light background hiss of even a pure AM bothersome to the point they'd accept any codec artifacts and noises.

I see digital in broadcast as a response to treat the symptom, not the disease.
Further developments of digital modes by rf only raises the general noise level and so furthers the disease.

Agreed as we are saddled with the "compatibility" issue and lack of available spectrum to re-boot OTA radio to areas of spectrum that would accommodate true uncompressed wide-band digital operation. Since the IBOC roll-out I've been buried in the aspects of keeping many Hd1/2/3/4 services and web streams on the air across multiple frequencies, so I've really never had the time to devote to understanding the options presented before the mandated IBOC roll out.

Since the 70's it's been everything from NRSC 1/2 to Kahn/C-Quam etc etc...
Keeps me employed though...

Appreciate any insight..

Jay Walker

 

[spunker88]

I think adding audio only channels to ATSC would have been a good idea. I'm not sure if they could add it now and have it be compatible with older equipment. It should be possible to fit several decent quality audio channels in the space one SD subchannel uses. With all the DTV boxes out there and TVs with built in ATSC you would already have receivers out there. People wouldn't have to buy a new radio like they do with HD. UHF can be more reliable than VHF in urban areas and a system like this would see most of its initial use in urban areas where FM is crowded.

 

[Jay Walker]

I think adding audio only channels to ATSC would have been a good idea. I'm not sure if they could add it now and have it be compatible with older equipment. It should be possible to fit several decent quality audio channels in the space one SD subchannel uses. With all the DTV boxes out there and TVs with built in ATSC you would already have receivers out there. People wouldn't have to buy a new radio like they do with HD. UHF can be more reliable than VHF in urban areas and a system like this would see most of its initial use in urban areas where FM is crowded.

Of course the only problem now with spectrum management is the appetite created by wireless/common carrier/wi-fi. While a good thing as far as program choices go, coming data charges will neuter to some degree the use of that spectrum for OTA.

Sadly there are no "free all you can eat buffet's" in digital delivery.

 

[kenglish]

I think adding audio only channels to ATSC would have been a good idea. I'm not sure if they could add it now and have it be compatible with older equipment. It should be possible to fit several decent quality audio channels in the space one SD subchannel uses. With all the DTV boxes out there and TVs with built in ATSC you would already have receivers out there. People wouldn't have to buy a new radio like they do with HD. UHF can be more reliable than VHF in urban areas and a system like this would see most of its initial use in urban areas where FM is crowded.

That's already possible under the ATSC standards. At least one of our local stations, KUEN at the University of Utah, runs an audio-only channel of KUER-FM. On some receivers, it is married to the same video as the main channel. On others, it runs with just a "screen-saver" that bounces around saying "Audio Only".

A station still has to run one video channel on there to be legal, but it could be something as simple as an animated logo. The rest of the channel could be devoted to many, many DD audios....from mono. all the way to 5.1.

Problem is, the copyright issues are different between a radio-only channel and a radio-over-TV channel. Something to clear up within the legal system, I guess.

(I wish I could get one of the local LD Spanish stations to add a few dozen ethnic-radio channels to his SDTV channel. But, his one-man-band operation is already stretching him too thin.)

 

[diymedia]

Agreed as we are saddled with the "compatibility" issue and lack of available spectrum to re-boot OTA radio to areas of spectrum that would accommodate true uncompressed wide-band digital operation. Since the IBOC roll-out I've been buried in the aspects of keeping many Hd1/2/3/4 services and web streams on the air across multiple frequencies, so I've really never had the time to devote to understanding the options presented before the mandated IBOC roll out.

There were no options presented before the IBOC roll-out. The NAB originally endorsed Eureka 147 but backed away right quick when the Pentagon would not free the spectrum necessary to implement it. This led directly to the development of IBOC...and proponents worked mightily during the FCC approval process to make sure the rules said IBOC would be the *only* digital broadcast technology adopted for the U.S., and when the FCC blessed it it said specifically that it would not consider any other technology going forward. Plans for a comparative analysis of Eureka 147 and the various flavors of IBOC (this is the mid-to-late '90s, prior to FCC consideration) fell apart when the various IBOC developers couldn't agree on a testing regime.

Of course, IBOC's approval in the U.S. took place before DRM took the stage, but from a regulatory perspective IBOC is the only game in town and always will be. At the same time, the proprietary nature of IBOC stopped the FCC short of mandating conversion, instead relying on faith in "marketplace forces" to make the transition happen. The market has not been kind to IBOC.

If radio wants to do the transition right - and hold onto its spectrum real-estate - it needs a widespread, uniform transition to a technology which provides a qualitative improvement from the perspective of both broadcasters and listeners. No technology seems to cover those bases...though I would like to learn more about DRM, which would allow digitalization-in-place.

(Then there is expanding "radio" to venues off the AM/FM band, which incumbent broadcasters are also still struggling with...but that's another story, right?)

Short of an act of Congress that mandates conversion, similar to the one for TV found in the Telecom Act of '96, I have a hard time thinking radio's digital transition will play itself this decade...or even next. Even if, by some miraculous change in perspective, other technologies were given consideration.

 

[iyiyi]

Best I can tell; DAB requires a separate frequency. FMeXtra and DRM are both IBOC systems, as is iBiquity. Except (AFIK) the iBiquity system is capable of twice the data rate of both DRM and FM eXtra. I believe that FMeXtra may also have some compatibility issues with it's hybrid vs. pure digital modes.

Canada has had DAB for a while but is going to go iBiquity. Nobody cares what Europe does. There are more iBiquity IBOC broadcasters than all the others combined, worldwide.

Stick with iBiquity and the good old U.S.A.!

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[Ai4i]

Whenever a technology is required to be backward compatible, there will be compromises.
Any system starting from scratch will be better than a hybrid one.
My favorite examples are adding color to TV and adding stereo to FM.

Many CATV systems locate their digital music bouquets (Music Choice, etc) within single ATSC channels.
Ludwig, LLC will use similar technology, but OTA.

 

[Jay Walker]

Good points everyone. As I mentioned I've been involved in the Dallas roll-out since day one. I was the first commercial station to lite up in Dallas, the first to add SPS and am up to SPS-3 on several stations with SPS 4 in the pipeline. I've had good success running enhanced mode as it allows a higher bit rate on the SPS-3 and makes it usable for music. Haven't had issues with the digital carriers bashing the analog but the processing is state of the art as well as the transmitters.

The concept is noble, however without a mandate (which will never happen because of the volume of receivers it would orphan IMHO), the set penetration will take a long time.

Thanks again for the input.

Jay Walker

 

[pqgeorge]

FMeXtra allows you to simply use the SCA spectrum without requiring a new transmitter. Just simply install the FMeXtra connecting the server/composite modulator on the SCA input and there you have it. Unlike IBOC-FM which causes interference to the first and second adjacents, FMeXtra simply uses the SCA composite spectrum that FM has had all-along. No adjacent splatter whatsoever. Full quality Stereo with several subs available. iBiquity requires you to get a new transmitter, new antenna (depending upon how brandband your antenna is) and a full-replacement of your audio chain. The coverage on FMeXtra is almost equal to that of FM Stereo. IBOC, on the other hand..... well, you know the story on that. FMeXtra, had it been made the standard for DAB, would have allowed even the smallest of FM stations to go digital for about $25,000, with no licensing fees. The cost of IBOC, on the other hand, is exorbitant. It's at least $75,000 for just the transmitter alone, not to mention the licensing fees for $5000 for each stream. Of course on AM, IBOC is a disaster. It's splatter city and ruins the analog audio to less than 4 or 5 kHz (max).

Unfortunately, iBiquity and the almighty dollar beat the system. Now, how many people actually have IBOC radios today? It's a dead issue.

 

[Jay Walker]

It was a pricy venture at launch, now years later all my stuff is at MTBF and is basically obsolete (IMO)
But it is what it is. I'd often wondered the story since I was too busy executing the plan LOL...

 

[RadioEngnr]

I have the FMeXtra system (now sitting unconnected on a shelf), a few years ago on one of my stations I had my FMeXtra and iBiguity system on the air at the same time, My only problem running the 2 systems was in the extended hybrid mode for HD, but that problem was fixed changing the bandwidth used by FMeXtra.

I ended up using the FMeXtra as a backup STL for my other analog FM, it had great sound when I put it on the air, now I am using a DSL with Winamps Shoutcast audio encoder as my emergency STL

now what was interesting, when I was testing the actual FMeXtra signal strength with "The Radio Doctor" we drove 70 miles away and we had a perfect FMeXtra signal and we lost the HD signal 30 miles earlier, gotta love a digital (FMeXtra) signal being nestled in the SCA

If I had a choice..... FMeXtra

 

[Chuck]

now what was interesting, when I was testing the actual FMeXtra signal strength with "The Radio Doctor" we drove 70 miles away and we had a perfect FMeXtra signal and we lost the HD signal 30 miles earlier, gotta love a digital (FMeXtra) signal being nestled in the SCA

If I had a choice..... FMeXtra

I had exactly the same experience. As usual, we have made the wrong choice. I suspect it was all about money and not much else.

 

[RadioEngnr]

and here is what FMeXtra is today

http://www.vucast.com/

 

[diymedia]

Canada has had DAB for a while but is going to go iBiquity. Nobody cares what Europe does. There are more iBiquity IBOC broadcasters than all the others combined, worldwide.

Stick with iBiquity and the good old U.S.A.!

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Interesting. Canada bailed from IBOC when the Canadian Association of Broadcasters disbanded in 2010. Has something changed since then?

 

[DavidEduardo]

I had exactly the same experience. As usual, we have made the wrong choice. I suspect it was all about money and not much else.

I think the biggest amount of blame comes from broadcasters and the FCC wanting a solution that was usable on both AM and FM.

 

[tomservo]

The coverage on FMeXtra is almost equal to that of FM Stereo. IBOC, on the other hand..... well, you know the story on that.

I know that in real world applications, I get a good lock on IBOC as far or further out than I do a quiet stereo signal. Considering the aggressive blend that most OEM car radios use today, I doubt anyone further than 15-40 miles out is getting even a hint of stereo on most stations. That's about the range of IBOC on equivalent facilities.

After spending years listening to (and getting used to) those harsh metallic digital codecs used in streaming and satellite broadcasting, that quiet noise floor has spoiled me. I can't stand static on FM any more. I can't even get good quieting on some of my local 100 kW stations and I'm only about 10-15 miles from their TX sites because of man made electrical noise in my own house. IBOC fixes that, at least somewhat. It's certainly far from a perfect solution.

Broadcasters are the reason the band is in the mess its in. Greed and fear of change kept them from endorsing finding a new, clean band to start on digitally. Me personally, I would have loved to see a chunk of 700 MHz set aside that could accommodate the entire broadcast band as it stands today, plus room for expansion. I'd have given every licensed broadcaster the right to use the spectrum, in a digital only mode. What they chose to do with it would have been up to them. A new service, a repeater of their existing service, whatever. A single high quality feed, a multiplex, whatever. No cellular style network like DAB, but individual transmitters just like we have now. AM & FM on equal footing.

But that would never happen because of corporate greed. Regular radio is fine for most people - that's why it broadcasts mass appeal programming. But niche stuff has been festering away on low fi satellite radio and (expensive) online streaming instead of getting the mass broadcast outlet it might should have had in the first place.

 

[kenglish]

Broadcasters I talked to (including Corporate where I work) did not want additional spectrum, because we would have had to buy that spectrum, and pay FCC regulatory fees on it, in addition to what we already had. So, they went with in-band and on-channel.

 

[iyiyi]

Canada has had DAB for a while but is going to go iBiquity. Nobody cares what Europe does. There are more iBiquity IBOC broadcasters than all the others combined, worldwide.

Stick with iBiquity and the good old U.S.A.!

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Interesting. Canada bailed from IBOC when the Canadian Association of Broadcasters disbanded in 2010. Has something changed since then?

So you say there is NO IBOC for Canada. Eh?

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