Time to reconsider AM stereo?

[Play Freebird]

Thanks to everyone for the interesting and informative responses to my post. I would love to see AM stereo make a comeback! It would be a vast improvement over IBOC. "What's old is new again"!

If one or two of the major networks would switch off their IBOC jammers and put AM stereo back on the air and promote it, that would be a major step toward revitalizing the AM band.

Your ideas are good and I agree that DSP would really help to improve AM Stereo receiver quality.  The only thing I would add is an optional, non-proprietary, low speed data subcarrier, similar to RDS but using the spectrum below the pilot tone.    It would not need to carry more than the station's callsign or "handle", two lines of text for title and artist info, website/stream URL, and alternate frequencies (to facilitate automatic retuning to translators).

[midatlanticengineer]

Yes, iBquity should bite the bullet and reprogram their HD generators to broadcast in "C-QuamII" aka AMHiFi or AMAX.  It would be compatible with all the Ford, Delco and Chrysler CQuam receivers out there, but on the HD tuners, it not only would decode the CQuam stereo audio, but also add the data with station ID.
I'm game, and the time is now.

What?
Continue to pay iBiquity's royalties?

Why not just buy a new C-Quam generator?
Link:
http://www.deltaelectronics.com/amprod.htm

Or....upgrade that old tube transmitter with a BE transmitter and be sure to get the stereo cards to go with it.


Google Groups "AM Stereo (AM Broadcast Radio)" group.
http://groups.google.com/group/amstereo

[midatlanticengineer]

BTW...does anyone know for certain which HD radios are capable of decoding C-Quam? I know it seems that the good old analog C-Quam receivers are getting harder and harder to find unless you go to special websites or buy an older receiver and vehicle.

I'm doing a bit of probing into this, as should everyone else. There -are- some stations out there that would start operating in C-Quam right now - IF - they knew for certain that the receivers were easy to get/find and readily available at decent prices.

Without the receivers, it's almost pointless.

AM owners/operators also need to provide something of worth to listen to. AM radio doesn't  - HAVE - to be talk radio. I know of several music AM stations that do quite a good job at it.




Google Groups "AM Stereo (AM Broadcast Radio)" group.
http://groups.google.com/group/amstereo

[radioskeptic]

If you're looking for a C-Quam receiver, you might consider the Meduci AMX-2000, which is only an AM tuner -- but what a tuner!  Unfortunately, it costs $150, direct from the manufacture.  That's an awful lot for a tuner, but it's an extraordinarily well-designed and well-built AM-only tuner.

You can see the owner's manual here: http://meduci.com/amx2000.pdf

And here's an interesting excerpt from the manual's Q & A section:

Q: I saw your AM Stereo radio on the Internet and it looks like a well designed unit. I am wondering if
you will ever decide to produce an IBOC unit, since all the stations in this area have turned off their
stereo encoders in favor of IBOC. I believe your receiver will be a good RF section for an IBOC receiver.

A: There are at least two chips developed by Texas Instruments (TI) for decoding the iBiquity HD Radio
bit stream. When we contacted Texas Instruments about purchasing engineering samples of their chipsets,
TI said that we first needed to obtain a manufacturing license from iBiquity. When subsequently
contacting iBiquity, we were notified that a $25,000 up-front payment was required to license their
proprietary HD Radio technology; we also would need to make royalty payments to iBiquity for each
tuner sale. Given the negligible profit margin, we would have to sell many, many AMX2000 tuners to be
able to afford the up-front manufacturing license and other costs.

What?  $25,000 to license the technology before you can even buy a chipset just to try it out?  Before you finalize your design, never mind your marketing plan?

[midatlanticengineer]

Yeah I've seen the radio...but for general all around purposes like for automotive use and so forth...its not very practical. If C-Quam is to make a return in the market, receivers have to be out there for the consumer to buy.

Look at IBOC radio ....aside from the analog audio quality, digital audio quality in many cases and the "noise" pollution that some hear on their radios, how many stores can you go into right now and purchase an IBOC radio....portable or automotive?

Broadcasters can transmit all the digital streams and or C-Quam platforms all they want...all day long, but if the general practical receivers are not out there, forget it.

[audioguy]

I have read that some of the HD radios can also decode C-QUAM, although I have no personal experience with this. The question is really more about whether AM broadcasters would be willing to get behind AM stereo and promote it. Or, would they rather continue to shell out licensing fees to iBiquity for an "HD" system that doesn't work? Alternatively, is AM radio going to be satisfied staying with monophonic transmission when every other audio device you can buy delivers a stereo listening experience?

I don't think it would be very expensive for most stations to switch to AM stereo. Some of them already have the gear; it's probably just sitting in an equipment closet collecting dust. As far as I know it doesn't cost any more to operate an AM stereo transmitter than a mono transmitter, and the audio can sound very good in mono or stereo (and much better than an HD station received in analog). C-QUAM doesn't create any additional interference. So what is the downside, even if in the near term there were no more stereo listeners than there are currently HD AM listeners?

It's a chicken-and-egg thing: nobody wants to make receivers if there are no stations to listen to, and nobody wants to broadcast if there are no receivers out there. But in this case, it seems that the cost of "priming the pump" on the broadcast side should be quite low in comparison to HD AM. If a number of key stations were to switch to AM stereo and promote it, new receivers would eventually be introduced, because this is fairly simple to do now that more and more of them are becoming, in effect, software defined radios.

I don't think AM radio has a lot of other possibilities left. The bandwidth is too small to support more advanced modulation schemes.

[KB1OKL]

BTW...does anyone know for certain which HD radios are capable of decoding C-Quam? I know it seems that the good old analog C-Quam receivers are getting harder and harder to find unless you go to special websites or buy an older receiver and vehicle.

I'm doing a bit of probing into this, as should everyone else. There -are- some stations out there that would start operating in C-Quam right now - IF - they knew for certain that the receivers were easy to get/find and readily available at decent prices.

Without the receivers, it's almost pointless.

AM owners/operators also need to provide something of worth to listen to. AM radio doesn't  - HAVE - to be talk radio. I know of several music AM stations that do quite a good job at it.




Google Groups "AM Stereo (AM Broadcast Radio)" group.
http://groups.google.com/group/amstereo

I just went to the website you posted and found that it has turned into an IBOC-DRM discussion group!
If you want an AM stereo website try

http://www.amstereoradio.com/

[strangelove]

If i had to choose between the 1996-webstream-quality of IBOC on AM and this: http://www.youtube.com/watch?v=Wm_iYK-ctiQ I think I know which one I'd prefer.

[Savage]

Thanks strangelove - a great link and a sobering thing to listen to.  When I listen to "what could have been" - as opposed to where we are now, with the AM band a complete interference-choked mess - it absolutely breaks my heart.

I grew up in this business with managers who constantly juggled the "quality-versus-loudness/coverage" issues.  A station's technical sound was a point of pride.  But not today, thanks for engineering cretins willing to dial back audio quality to the equivalent of bad 78rpm records in order to accomodate IBOC.  You can't even make the claim HD forces AM back to 1920s sound.  Even crystal sets sounded better than today's HD-strangled AM signals.

Yep: THIS is where we COULD be today.  But for a corrupt government and a handful of "expert" jerks and crooks.

And you know who you are, Dan, Glynn, Cris, Tom, Peter, et al.

[ddsparxx]

If you're looking for a C-Quam receiver, you might consider the Meduci AMX-2000, which is only an AM tuner -- but what a tuner!  Unfortunately, it costs $150, direct from the manufacture.  That's an awful lot for a tuner, but it's an extraordinarily well-designed and well-built AM-only tuner.

You can see the owner's manual here: http://meduci.com/amx2000.pdf

And here's an interesting excerpt from the manual's Q & A section:

Q: I saw your AM Stereo radio on the Internet and it looks like a well designed unit. I am wondering if
you will ever decide to produce an IBOC unit, since all the stations in this area have turned off their
stereo encoders in favor of IBOC. I believe your receiver will be a good RF section for an IBOC receiver.

A: There are at least two chips developed by Texas Instruments (TI) for decoding the iBiquity HD Radio
bit stream. When we contacted Texas Instruments about purchasing engineering samples of their chipsets,
TI said that we first needed to obtain a manufacturing license from iBiquity. When subsequently
contacting iBiquity, we were notified that a $25,000 up-front payment was required to license their
proprietary HD Radio technology; we also would need to make royalty payments to iBiquity for each
tuner sale. Given the negligible profit margin, we would have to sell many, many AMX2000 tuners to be
able to afford the up-front manufacturing license and other costs.

What?  $25,000 to license the technology before you can even buy a chipset just to try it out?  Before you finalize your design, never mind your marketing plan?

I have the AMX2000 tuner; sounds great though I normally don't use it for AM DX.