Back to analog stereo AM?

[satech]

Could C-Quam be used on shortwave or longwave? How about HD radio on these bands?

In the '80s there was a planned shortwave station "NDXE" which claimed they would be transmitting in Kahn AM Stereo, but they never got on the air.

Many shortwave stations (and some Longwave/Mediumwave stations) today are using DRM (Digital Radio Mondiale), which is basically the European equivalent of IBOC, except that it is digital-only, and does not provide an intelligible analog signal. People tuning in a DRM signal on an analog receiver will only hear a loud hiss. However, DRM is much more spectrally efficient than IBOC, and fits nicely within the 5 kHz shortwave (or 9 kHz European MW/LW) channel spacing, without causing interference to adjacent stations.

 

[pianoplayer88key]

Many shortwave stations (and some Longwave/Mediumwave stations) today are using DRM (Digital Radio Mondiale), which is basically the European equivalent of IBOC, except that it is digital-only, and does not provide an intelligible analog signal. People tuning in a DRM signal on an analog receiver will only hear a loud hiss. However, DRM is much more spectrally efficient than IBOC, and fits nicely within the 5 kHz shortwave (or 9 kHz European MW/LW) channel spacing, without causing interference to adjacent stations.

Since DRM is more efficient than IBOC, can a listener using a Sony SRF-M37W (one of the widest IF bandwidths I've heard in a radio in a while) get a first-adjacent analog signal a couple dB above atmospheric noise level (or the noise limit sensitivity of the radio) that's "in-the-clear", i.e. without any splatter or desense from the DRM station, even though they may be right next door to the 50+kW DRM signal's transmitter site? I know it can't happen with an IBOC station, but what about a DRM?
Also what's the typical audio quality of the digital signal when using a radio that decodes it?
And how efficient is it for coverage and still being able to resolve a signal compared to an analog signal with the same power and antenna pattern at the same location? For example, if the analog signal was a QRSS CW and was right at the threshold of readability at a particular location, would the DRM audio signal (assuming the sensitivity of the radios are the same, and the same antenna is used) still be fully decodable?

 

[satech]

You can listen for yourself on the handful of daily DRM shortwave broadcasts aimed at North America:

http://www.drm.org/index.php?p=broadcast_schedule#NorthAmerica

DRM has a variety of digital bitrates available, depending on the occupied RF bandwidth, as explained here:

http://en.wikipedia.org/wiki/Digital_Radio_Mondiale

DRM has a 20 kHz mode that would fit our +/-10 kHz NRSC mask, but of course the FCC isn't going to allow U.S. AM broadcasters to use it anytime soon, as long as IBOC is our official standard for digital AM/FM radio.

 

[davideduardo]

Many shortwave stations (and some Longwave/Mediumwave stations) today are using DRM (Digital Radio Mondiale), which is basically the European equivalent of IBOC, except that it is digital-only, and does not provide an intelligible analog signal.

DRM was developed mainly for use on shortwave, where one station may have multiple frequencies (and many used a variety of frequencies at different times of each day) and there is only limited use of DRM, as looking at the 2010 WRTVH will show.

A current list of all the world's DRM broadcasts is at http://www.wwdxc.de/drm.htm and there are not even a dozen fulltime DRM stations in the whole world. There are a bit over 100 DRM segments, many just an hour or even a half hour, out of the several hundred thousand stations in the world.

A big part of the issue with DRM is that shortwave is increasingly irrelevant in today's world and the total number of SW stations is declining rapidly.

 

[davideduardo]

If C-QUAM had become the norm a la FM Stereo, AM might have entered a new era of quality audio. But it was not to be.

We have the brilliant minds at the FCC to thank for that...

Actually, we have Leonard Kahn's legal manipulations to thank for that.

 

[Play Freebird]

A current list of all the world's DRM broadcasts is at http://www.wwdxc.de/drm.htm and there are not even a dozen fulltime DRM stations in the whole world. There are a bit over 100 DRM segments, many just an hour or even a half hour, out of the several hundred thousand stations in the world.

But it appears India is getting quite serious about wide scale adoption of DRM, having already purchased two 1000 kW mediumwave transmitters and requesting bids on another 34:

http://www.drm.org/index.php?p=news_item&uid=212

Needless to say, this is a very large and growing market for equipment, so I hope some American manufacturers get in on the action. You can find All India Radio's bid specs here; note that they're also interested in purchasing a bunch of FM transmitters, and those need to be DRM-capable as well. I didn't see any mention of IBOC in the specs:

http://www.allindiaradio.org/NIT/Tenderenquiry-13/18006010.html

Read more about the DRM system here:

http://www.drmradio.dk/DRM-systemet-en.htm

 

[davideduardo]

But it appears India is getting quite serious about wide scale adoption of DRM, having already purchased two 1000 kW mediumwave transmitters and requesting bids on another 34:

Those are DRM compatible transmitters... the specification indicates operation in analogue mode as well. For the bulk of those units, there are only bid specs, not purchase commitments.

India has infrastructure issues that make large, centralized AM operations the norm for the state broadcaster... thus the high power units. India has 29 languages spoken by 1,000,000 persons or more, and two major languages. That means some cities need three or four transmitters just to provide a single service to each common language. Oh, and there are several hundred mother tongues in use, with about 1500 total dialects. All these are issues not confronted by any other nation in the world (imagine the USA with nearly four times the population and served by only a couple of hundred signals total),

Commercial radio is only about a decade old in India, and only available in certain cities.

 

[Play Freebird]

Those are DRM compatible transmitters... the specification indicates operation in analogue mode as well. For the bulk of those units, there are only bid specs, not purchase commitments.

Commercial radio is only about a decade old in India, and only available in certain cities.

It appears that AIR will initially use the new FM transmitters in analog-only mode (while retaining the ability to convert to DRM several years from now as receivers become available), but my impression is that they want to adopt DRM in the medium wave band much sooner. However, there's no apparent interest in IBOC -- and that says a lot.

A few years ago, I spent a week in India working on audio processing with engineers at a few of the commercial radio groups and had a most interesting experience. I even took a day off to visit the Taj Mahal, but that turned out to be the hottest day of the year!

When the Indian FM band was opened to commercial owners, large group applicants were each granted the same frequencies in the major cities, making promotion much easier. For example, "Radio City" operates on 91.1 in over 20 locations (with plans to add at least 10 more cities next year), "Big FM" is on 92.7 in over 40 cities, "Red FM" (formerly Suryan FM) is on 93.5 in 42 cities, and so on. If they ever make a transition to DRM (digital carriers could be placed on second-adjacent channels which are presently open), this allocation plan might allow for national single-frequency networks. But as you mentioned, India has many regional languages and dialects, so I expect some local origination will always be necessary.

As in the rest of the world, some private owners have experimented with unique formats. When I visited Delhi, I saw billboards all over town for a feline-themed female talk station called "Meow 104.8 FM", whose tagline translated to "Sometimes Sweet, Sometimes Catty":

http://www.radioinfo.com.au/news/6594/

But Kitty never caught the mouse -- 104.8 is now "Oye FM", going up against Big 92.7 --a Bollywood group owned by multi-billionaire Amil Ambani. Here are their websites:

http://oyefm.in/

http://www.big927fm.com/

 

[davideduardo]

However, there's no apparent interest in IBOC -- and that says a lot.

Interestingly, Mexico, which opted for IBOC (perhaps due to having a shared border with the US) tested AM IBOC and DRM in Mexico City. DRM was parallel with analog XEESP 1060 (100 kw) and operated on 1070. IBOC was on XEN 690, also 100 kw.

With Mexico City spacing as close as 20 kHz for same COL, that they approved anything is amazing. Of course, Mexico is trying to migrate as many as 85% of all AMs to FM at this moment, so maybe they decided it did not matter.

When the Indian FM band was opened to commercial owners, large group applicants were each granted the same frequencies in the major cities, making promotion much easier.

National programming is so common outside North America, but perhaps the FCC notion of localism is a deciding factor. When Metromedia put an all news station on in Berlin, they did not realize that German radio was all national and consisted of simulcasts around the country... they lost millions as advertisers did not make local buys. The original design specs of RDS had to include the ability to have a radio pick the best possible signal of a network for people on the move and where not all stations shared a channel.

If they ever make a transition to DRM (digital carriers could be placed on second-adjacent channels which are presently open), this allocation plan might allow for national single-frequency networks.

They have a unique ability to make the change... low numbers of radios, and uncrowded bands. Unless you are in Elko, NV, I doubt you could do that in the US... which is why we got in band on channel.

As in the rest of the world, some private owners have experimented with unique formats.

I assisted with some aspects of music testing (and the eventual training of a local research team) for that Murdock fellow... it's amazing how the Bollywood/Tollywood/Lollywood music has such appeal. There are obviously so many different format options there based on language, social stratification and such. I was never on site, so I am a bit envious of your experiences and hope you can relate some of them here.

 

[tomservo]

The original design specs of RDS had to include the ability to have a radio pick the best possible signal of a network for people on the move and where not all stations shared a channel.
of your experiences and hope you can relate some of them here.

Kinda OT but one of the things that makes me mad about HD implementation is that none of my HD radios (which decode RDS) support most of the useful RDS features like the AF-auto frequency or CT-clock time.

Moving up to a new platform should not entail losing features. Maybe some of the car radios support AF and HD, but I haven't found any yet. AF was pretty useful when I lived in Mississippi and traveled a lot, since the public radio network supported it. They were also the only HD stations in the state for the most part. So I could have one or the other, but not both.

 

[davideduardo]

Maybe some of the car radios support AF and HD, but I haven't found any yet. AF was pretty useful when I lived in Mississippi and traveled a lot, since the public radio network supported it.

I am somewhat associated with KRCD/KRCV in LA, a simulcast. We use RDS for the AF function, and my car's factory radio can be seen switching from 98.3 to 103.9 as I drive around the market area... of course, I have the HD part turned off so it may be either/or, and maybe I'll check that over the holidays.

 

[Play Freebird]

I am somewhat associated with KRCD/KRCV in LA, a simulcast. We use RDS for the AF function, and my car's factory radio can be seen switching from 98.3 to 103.9 as I drive around the market area... of course, I have the HD part turned off so it may be either/or, and maybe I'll check that over the holidays.

David, do you know if anyone keeps a list of car models sold in the US that come equipped with AF-enabled RDS radios? I was told by one of our translator listeners that the 2009 Buick Lucerne is among them, but would also like to know which model you have. Anyone else with factory RDS/AF, please chime in. My aftermarket Blaupunkt "Alaska" had this feature, but developed other problems, so I had to put the old factory radio back in.

I became an early believer in RDS after reading a paper that Dietmar Kopitz of the EBU presented at the 1986 NAB show, then saw an RDS encoder on display at the 1991 AES show and decided it was time to get on board. Funny story:

In 1992, I took an attractive offer to work for a locally-owned FM station, and shortly after taking the new job, the manufacturer whom I had met at AES loaned me an RDS box for a long-term demo, which became an outright gift. Our station owner (who hadn't seen RDS before) loved the concept of displaying the station name and PAD on a radio --although, in those days, there were very few receivers in the US market. However, we left the RDS signal on the air through the '90s (why not?) and we were the first local station to send dynamic title and artist data by radiotext, beginning around 1995. We were also first station in our market with a local website, as well as the first to stream -- so we added a "now playing" box on the home page.

In 2000, a "consolidator" bought the station -- a publicly-traded company which at that time had very little experience with the Internet -- and as far as I know, none of their other stations were running RDS. I offered to help in both areas and asked if the corporate office would like to "borrow" our webmaster for a few days -- but, no -- they were our new bosses and didn't want help from underlings at the local level. Fortunately, they let us do our thing for a while -- but a few years later, as the company sunk into financial hardship, they cut the budget for maintenance of the web site, killed the streaming, and told me to take off the RDS. I objected to that (after all, the RDS encoder didn't cost anything to run) and managed to leave it on until I left the company in 2005.

So about four years ago, someone at a high corporate level finally realized that RDS and the web stream might be valuable to listeners, then suddenly there was a big rush to get all the stations on line and become "interactive". And now, if RDS goes off the air, it's a big deal! Hey, I tried to tell them...

It costs so little these days to buy (or build) an RDS box that stations of any size should be able to afford one. Unlike HD Radio, there are no licensing fees, no interference issues, and receiver penetration is significantly greater (it's even supported by the iPod Nano). And, the RDS PS display allows for eight alphanumeric characters, rather than the four-letter limit imposed by HD.

 

[Play Freebird]

I assisted with some aspects of music testing (and the eventual training of a local research team) for that Murdock fellow... it's amazing how the Bollywood/Tollywood/Lollywood music has such appeal. There are obviously so many different format options there based on language, social stratification and such. I was never on site, so I am a bit envious of your experiences and hope you can relate some of them here.

A few impressions of India from the brief time I was there:

• Since very few Indian citizens own a car (I recall it's just 1 or 2 percent, but rapidly increasing), the majority travel on foot, by transit, or hire a rickshaw -- so most FM listening is done on cell phones or portables. I saw many billboards advertising FM-capable mobile phones, which are in high demand. The wired phone network is a mess, so India has invested heavily in mobile. My GSM phone worked better there that it does in Pennsylvania.
  
• Ambient noise level is very high due to constant blaring of horns (not to mention the noisy rickshaw and cycle engines) so dense audio processing is needed. As in the US, stations also overmodulate. Here's how driving is done in that part of the world -- I will never complain about East Coast traffic again:
  http://www.youtube.com/watch?v=RjrEQaG5jPM
  http://www.youtube.com/watch?v=0cdUPOvSXOo&feature=related
  
  
• The owner of Big 92.7 FM also owns Reliance Mobile, a cell phone carrier -- as well as the Adlabs film studio, Bollywood movie theatres, a petroleum company -- oh, did I mention he also runs a financial services company. So there's plenty of opportunity for cross promotion within that organization. I saw billboards for Reliance Mobile with the phone tuned to 92.7
  
• Wages remain very low by US standards. Most of the big-city FM stations still have engineers on duty around the clock at each transmitter site.
  
• The broadcast engineers I met were well-educated and a pleasure to work with. They had many questions about the way we do things here in the US. For example, they saw "SCA INPUT" on an audio processor and wanted to know "what's SCA?", because that term isn't commonly used in India
  
• Utility power is unstable, so a backup generator is a must. I noticed many billboards advertising UPS equipment, especially in rural areas. Infrastructure is very substandard to what's found in the US and Europe. They're catching up, but it will take years. Great export market for the US, hopefully Obama's recent visit will pay off.
  
• A German friend of mine who works for a broadcast software company offered to manage the Mumbai office, but quickly moved back to Frankfurt after experiencing these problems. India is a fascinating place to visit, but takes some getting used to!

 

[satech]

So about four years ago, someone at a high corporate level finally realized that RDS and the web stream might be valuable to listeners, then suddenly there was a big rush to get all the stations on line and become "interactive". And now, if RDS goes off the air, it's a big deal! Hey, I tried to tell them...

RDS was pretty much dead in the USA until the emergence of IBOC brought with it renewed interest in offering text data to listeners, and the necessary station equipment upgrades to make this possible. And ironically almost every HD Radio receiver decodes RDS, and many even do C-Quam AM Stereo as well!

 

[davideduardo]

David, do you know if anyone keeps a list of car models sold in the US that come equipped with AF-enabled RDS radios? I was told by one of our translator listeners that the 2009 Buick Lucerne is among them, but would also like to know which model you have.

I don't know of any list; my discovery was by accident. The radio is the standard, not upgraded, one in the 2010 BMW X5d.

I became an early believer in RDS after reading a paper that Dietmar Kopitz of the EBU presented at the 1986 NAB show, then saw an RDS encoder on display at the 1991 AES show and decided it was time to get on board.

I've worked outside the US where multi-station networks are common as well as in Puerto Rico where every significant commercial FM operation is a set of two or three stations in near total simulcast. The ability to at least get a portion of receivers to track the best signal is very valuable. I've also traveled in Europe and been fascinated each time a car radio did a frequency switch... I know what the system is, but seeing it actually do it is kind of a thrill (the same kind of thrill a tall tower flashing in the night causes) that non-radio types don't get.

And, the RDS PS display allows for eight alphanumeric characters, rather than the four-letter limit imposed by HD.

That was a good an familiar story. :'( I increasingly find that HD really has a single digit limitation, and that digit is the middle one on either hand...

 

[tomservo]

Cars with RDS that I've observed... New Volkswagens, certain Lexuses (Lexii?), most Dodges and Pontiacs, um... Several other GM vehicles I think. Audis. Probably all the German marques. The Asians are the ones lagging behind.

 

[KB1OKL]

Cars with RDS that I've observed... New Volkswagens, certain Lexuses (Lexii?), most Dodges and Pontiacs, um... Several other GM vehicles I think. Audis. Probably all the German marques. The Asians are the ones lagging behind.

I have an 09 Pontiac (G8) and there is no RDS.

 

[Savage]

That's weird. I had an 06 Pontiac Vibe (traded it a couple years ago) which is a lot cheaper car than a G-8 and it had RDS.

 

[tomservo]

I was stuck into a G6 rental in LA and it had RDS and a pretty damn good FM section to boot. They may only offer RDS in the lower end radios or something.

I seem to recall Chrysler and Toyota only put AM stereo in their mid-level radios. Seemed like an odd move to me.

 

[KB1OKL]

That's weird. I had an 06 Pontiac Vibe (traded it a couple years ago) which is a lot cheaper car than a G-8 and it had RDS.

You may be right, if it has it it's not enabled, I'll check it out.