A Possible AM Radio Solution

[radiowizard101]

AM radio needs to take a step back and re-evaluate traditional Engineering Standards. Used to be my GE Superadio sounded very good on Music stations. However, some chucklehead in Engineering thought it would be a grand idea to limit the bandwidth with the NRSC standard. That means no audio frequencies past the 10K threshold with a rapid decline after 8K. Well, that killed audio quality (that already had limitations) and most music formats. Combine this with the rejection of the C-Quam stereo standard and you get really poor audio quality for a music format. By the way, when selling the NRSC limited bandwidth standard, AM broadcasters were told that there would be AM radios manufactured to compensate for the NRSC restricted bandwidth, much like the frequency compensation in FM receivers.

Then the same genius's gave us IBOC (In Band On Channel) digital audio that not only further limits audio bandwidth, but hasn't had widespread acceptance and offers some serious sideband interference. Some IBOC broadcasters limit analog as low as 5K. Very bad for music and very bad for the analog listener that comprises 99% of available listenership.

What is needed now, (and this could be done immediately), is an AM Radio Organization that that would get rid of the NRSC AM Standard as well as all IBOC broadcasting, embrace the C-Quam Stereo Standard that has been a success elsewhere around the world, and come up with some creative content that the listeners actually want.

These are very simple solutions that could be implemented quickly. The quagmire that AM Radio is currently in has been brought upon itself. Is it too late? Maybe not.

 

[johnbasalla]

I agree with doing whatever is necessary to increase the audio quality of AM radio. I flipped between an AM and FM station airing the President's speech and noticed how on FM, he almost sounded like I was in the same room with him, on AM, the sound seemed "smashed" a bit. I can see how solving the technical issues on AM could bring about a renaissance for the band. I base that thought on the knowledge of how many new FM stations have gone on the air over just the past 5 years or so. In my market I count five. There's no shortage of people who want to own over the air radio stations. Having a viable AM band might give more people/potential owners an opportunity to have a real radio station, while stopping this cluttering up (particularly in the non-comm part) of the FM band.

 

[davideduardo]

Used to be my GE Superadio sounded very good on Music stations.

There are so few radios made or in service today with that kind of quality of design that it does not matter how good the transmitted product is; the receivers out there today generally have poor AM sections.

However, some chucklehead in Engineering thought it would be a grand idea to limit the bandwidth with the NRSC standard.

The NRSC standard came from the growing complaints and evidence of severe interference between stations on adjacent channels as the band filled up with more and more stations. You can only roll back to pre-NRSC days if you thin the herd. And that still does not resolve the issue that nearly no receiver out there today would produce noticeably improved fidelity.

That means no audio frequencies past the 10K threshold with a rapid decline after 8K.

No, it means a brick wall at 10 k and a rapid drop curve above 9500 k. In any case, the NRSC study group headed by Bob Orban concluded that most consumer radios today were off so much by 5 k that worrying about anything above about 7 k was useless (my interpretation of the findings... which were worded in a less direct fashion)

Well, that killed audio quality (that already had limitations) and most music formats.

Most music formats on AM were dead by the very early 80's... even earlier in some markets. FM sounded better, FM stations covered the local market better, and the band was immune to the noise and static and RIF that was a growing problem for AM.

Combine this with the rejection of the C-Quam stereo standard and you get really poor audio quality for a music format.

C-Quam or any form of analog AM stereo came too late to help AM music formats. There was no rejection of C-Quam... it was tried, did not make a difference with consumers, and it gradually was dropped from stations that had adopted it.

...embrace the C-Quam Stereo Standard that has been a success elsewhere around the world

Where else in the world is C-Quam successful? It certainly is not in this Hemisphere, and in much of the rest of the world, AM operations are being phased out with many countries now having no AM stations or a reduced number designated for specific types of service.

and come up with some creative content that the listeners actually want.

It does not matter what you put on the signals since the two biggest problems are inadequate signals and increasing RFI that makes previously usable signal areas now useless for listening. In the top 100 markets, there are only around 170 stations that cover 80% or more of the market day and night; the rest do not have good enough coverage to compete due.

As to relaxing NRSC, that's not likely: the laws of physics, not FCC regulations, are in play there. In any case, the trend is towards distribution of content via streaming, not OTA radio. Nobody is going to invest in new radio designs that nobody will buy, much less spending of money to put C Quam back on the air.

 

[bossbill]

This whole discussion is so 1950. Inherent in the relative bandwidth of AM, the laws of physics don't allow for AM audio bandwidth to compete with FM. You simply can't do with 8 kHz, 10 kHz, or even 20 kHz, the same thing you can do with 200 kHz. All possible methods of measurement, including harmonic distortion, intermodulation distortion, audio bandwidth, show over and over that the laws of physics just can't be violated. Move on, AM-lovers.

 

[PTBoardOp94]

Very few of my complaints about AM radio have to do with spectral content (with the exception of the telephone quality analog audio on IBOC AM stations). 9500 Hz is more than sufficient for talk and not that bad for music if you have a strong signal.

If you have a really strong signal.

 

[Kmagrill]

IMHO, the receiver audio quality is the key problem. Lack of content didn't drive listeners to FM. Rather, lack of bandwidth & impulse noise limited AM's format choices. 9kHz audio is noticably inferior to 15khz audio. To make matters worse, AM has always had problems with noise, which has gotten far worse in the past 20 years. These two quality issues rule out most music formats on AM. Any format done on AM can be done on FM, but sounds better.

Any form of stereo without improved bandwidth is just doubling the listening agony. I put several C-quam stations on the air in years past and had a Delco C-quam radio in my car. It was marginally better than mono and far more susceptible to noise. I found most of my listening done in the narrow BW mode.

I do think NRSC was a mistake, and if one were to look at the FCC's Report & Order, my name appears on a petition for reconsideration, however, NRSC did not kill AM. The lack of receiver quality had firmly nailed the coffin lid shut long before NRSC came along.

Much of this discussion has been hashed here and elsewhere. For example see:
http://radiodiscussions.com/showthread.php?639758-If-not-AM-HD-then

 

[a6intruderdriver]

FCC's answer to everything...IBOC, jamming more signal into already crowded bands, requiring new hardware, proprietary licensing, a 1% listener base and another investment by listeners. DRM and DRM+, use less bandwidth, carry more information, isn't proprietary, can use some existing transmitter hardware and doesn't require you to sacrifice your first born child to iBiquity. It's also the choice of the ITU and is easy to implement with bandwidth options from 4.5 kHz to 100 kHz that may be used up to 174mHz. Not a bad deal considering you can get very close to the same propagation on AM with DRM that you can get with an old Gate Blowtorch that can kill the weeds within a 1/2 mile of your tower, and still have excellent fidelity.

Given the rate at which the FCC implements anything for terrestrial broadcasting you can bet the entire planet will be on DRM+ while the US is still powering old Collins transmitters with a monkey on a treadmill.

Content is another matter, but one thing that would help is rescinding the ownership rules and breaking up these 700 station chains that spew out the same pablum across the dial from coast to coast. Corporations have turned broadcasting into the pay-toilet of technology, making entrance onto a top 100 impossible and sucking up medium and small stations that had some character and turning them into Coke Machines that emit radiation.

 

[a6intruderdriver]

Interesting. This whole moderation bit is as annoying as Russian Heavy Metal.

 

[Tom Wells]

The notion that music on FM could ever sound as good as music on AM is absurd. Yes, I'm crazy, I know.

I've also accquired radios that sound wonderful, so I never have suffer modern AM radios with "designed-in" frequency distortion.

I have the ability to modulate any way I like, and I would never suffer to listen to my own music on a system using FM.
Instead of a directly proportional analog repesentation in terms of power, FM takes the representation into terms of frequency.

While it does reject amplitude noises, it's like food you can smell but never eat.
It's sizzle but no steak.

When AM is done properly it's much more "transparent sounding " than FM.

FM reminds me of seeing a flower pressed under glass, as opposed to touching and smelling an actual uncut living flower.

Bad sounding radios should be thrown away, regardless of whatever demodulation scheme they use.
Unless they are kept around as bad examples.

 

[bossbill]

No way can AM radio drink itself pretty.

 

[Kmagrill]

The notion that music on FM could ever sound as good as music on AM is absurd. Yes, I'm crazy, I know.

It's not crazy. Audio from a mod monitor or crystal detector in proximity to the transmitter is excellent. Unfortunately, the inherent limitations of the medium make this impractical for personal use.

Bad sounding radios should be thrown away, regardless of whatever demodulation scheme they use.
Unless they are kept around as bad examples.

Perhaps, in a perfect world, that is true, but even this is arguable. Receiver manufacturers say that they design low bandwidth radios partly to limit objectionable impulse noise. Others argue that this decision is based on economics. In previous years, it was cheaper to design a poor radio, however new techniques mean that this might not be true anymore. Either way, the problem is that bad radios are here to stay and there's nothing to be done about that at this stage.

When AM is done properly it's much more "transparent sounding " than FM.

FM reminds me of seeing a flower pressed under glass, as opposed to touching and smelling an actual uncut living flower.

I would have to disagree, but what we think is not important. The problem is that the public also thinks FM is a better choice than AM for most formats. If you could demonstrate to 1000 people that AM could sound as good or better than FM, 997 of them would never lift a finger to buy a good AM radio because they're happy with FM audio.

The only way I can see people going back to the AM band (en masse) is if the AM noise and bandwidth problems are solved and the radios that do it are so cheaply made that there's financial incentive for companies to prefer making that type of receiver.

 

[radiowizard101]

Thank you Dave Eduardo for admitting that the GE SuperadioII is a quality receiver. It is. Also, it was mentioned that Bob Orban had his input regarding the NRSC standard adopted by the FCC in the early 90's.

It's no small wonder that Bob would deight in contributing to the lousy quality of the NRSC standard that is required by AM broadcasters. Being the owner of an FM Processing Giant,(well put 2+2 together), and you could conclude that Orban would prefer that AM radios sound like garbage. It sells more FM!!!

One of the facts regarding the NRSC standard was the FCC REQUIREMENT for manufacturers to offer QUALITY AM RADIOS. It never happened. AM Radios just got cheaper with narrow band chips and even cheaper antennas.

It's probably too late to save the senior band. The damage has been done. The future is here now with internet streaming. I listen to net radio 90% of the time. The programming on AM radio has an odor. It's so bad that I don't even dx as much anymore.

Oh well... (By the way, I have a lot of respect for Bob Orban.)

 

[chriscollins]

Thank you Dave Eduardo for admitting that the GE SuperadioII is a quality receiver. It is. Also, it was mentioned that Bob Orban had his input regarding the NRSC standard adopted by the FCC in the early 90's.

It's no small wonder that Bob would deight in contributing to the lousy quality of the NRSC standard that is required by AM broadcasters. Being the owner of an FM Processing Giant,(well put 2+2 together), and you could conclude that Orban would prefer that AM radios sound like garbage. It sells more FM!!!

One of the facts regarding the NRSC standard was the FCC REQUIREMENT for manufacturers to offer QUALITY AM RADIOS. It never happened. AM Radios just got cheaper with narrow band chips and even cheaper antennas.

It's probably too late to save the senior band. The damage has been done. The future is here now with internet streaming. I listen to net radio 90% of the time. The programming on AM radio has an odor. It's so bad that I don't even dx as much anymore.

Oh well... (By the way, I have a lot of respect for Bob Orban.)

I tend to agree that streaming is a big future. More cars are getting to the point of having Internet in the dash than IBOC. Thing is, the little guy needs a way to get his streams in there as well. Right now, outside of the big boys, you or I can't get on that dashboard.

I hate compression (bit reduction). If you view my posts, you will see that a lot. HOWEVER, I do think 48Khz AAC2 sounds very good and is 'listenable' to me. Although 32Khz has become the AAC Streaming 'Standard'.

 

[okcradioguy!]

Agreed Chris. 32 AAC+ still has a gritty sound to it. 48 and above seems to not. Guys, quietly, more and more HD factory car radios are coming out in normal peoples' cars. Go down to the local car dealer and do some research. The tide is changing. I've never been a big fanboy of HD radio, but the fact is that, in the car/truck, HD is actually gaining some ground. If enough of them get out there to build an audience, it may be time, in a few more years, to switch off the loser analog AM stations in clusters and use that channel for a pure digital simulcast of the king-kong AM that still has some life in it. It's pretty obvious that hybrid mode AM is a laughing stock. Pure digital sure isn't. The recent tests look pretty darn good. With some radios out there to hear it, AM might be salvageable.

 

[Kmagrill]

... it was mentioned that Bob Orban had his input regarding the NRSC standard adopted by the FCC in the early 90's.

It's no small wonder that Bob would deight in contributing to the lousy quality of the NRSC standard that is required by AM broadcasters. Being the owner of an FM Processing Giant,(well put 2+2 together), and you could conclude that Orban would prefer that AM radios sound like garbage. It sells more FM!!!

Oh well... (By the way, I have a lot of respect for Bob Orban.)

Well, I'm quite sure that Bob was as concerned about AM as everyone else. You may recall that Orban sold a long line of multiband AM processors starting with the inovative 9000 with analog look-ahead limiting. The industry standard for AM processing at the time was the 9100. Orban is not going to sell any additional FM processors by pushing AM under the bus. All he would have done is hurt AM sales and the 9100 was very expensive compared to the 8100.

Basically, Orban and the rest of the NRSC committee looked at the terrible frequency response curves of the radios and developed a pre-emphasis suggestion to make the audio sound more flat. The 10kHz cutoff was not some plan to devastate AM radio. Radio receiver manufacturers had, for years, claimed that they would happily make high quality AM tuners if there wasn't an adjacent channel splatter problem. They claimed that this spaltter or hetrodyning caused customers to complain that the radios didn't work properly so the bandwidth was reduced. Many Am stations in the Northeast and midwest also loudly complained of adjacent channel spaltter, even on narrow receivers, so the NRSC called the radio receiver makers' bluff and appeased the big AM stations at the same time. Of course, the receiver makers were just blowing smoke. They had no intention of spending one extra dime to improve their AM receivers. So, was the spaltter problem big enough to merit crippling the AM frequency response? Well, that depends on your point of view. If you were being killed by spaltter, then maybe yes. If you were among the majority of stations not struggling with spaltter, then probably not. However, since widebanded AM radios were (and remain) rare, it really was a difference that made no difference.

 

[kevtronics]

No, it means a brick wall at 10 k and a rapid drop curve above 9500 k. In any case, the NRSC study group headed by Bob Orban concluded that most consumer radios today were off so much by 5 k that worrying about anything above about 7 k was useless (my interpretation of the findings... which were worded in a less direct fashion)

A majority of listeners in the test found 10 kHz bandwidth to be preferable for music, even when heard through typical narrowband receivers. For talk formats 7 kHz was slightly preferred over 10 kHz but it was pretty close. 5 kHz was only ever preferred in situations of severe adjacent-channel interference, in which case most people wouldn't have been listening to that station anyway, in the real world.

In any event, AM IBOC does not pass the NRSC "noise" test, and therefore should've been declared unacceptable. The NRSC 10 kHz bandwidth mask was designed for normal program material, such as talk or music. In cases of using constant pink noise to test the transmitted bandwidth, however, the NRSC rules specify a sharper cutoff above 10 kHz. The AM IBOC system does not meet this stricter bandwidth requirement despite the IBOC digital sidebands most certainly being constant noise and not anything like normal amplitude-modulated program material! But the NRSC looked the other way and let iBiquity get away with a system which does not abide by the rules according to how they were intended to be applied. And then IBOC proponents had the gall to demand that all analog AM stations should restrict their bandwidth to 5 kHz to protect the digital sidebands of IBOC stations!!

 

[Grounded Grid]

FM will never be threatened by anything-AM, at least not in my lifetime. I would suggest, however, that broadcasters created the "irritating" sound of FM by insisting that everything below 700Hz hit 100% as hard as 5,000Hz and above. No matter how creatively you want to describe it, all that clipping does have an effect. Sad, that the "get our signal out farther" loudness wars got somehow translated to FM, where that kind of thing makes no difference at all.

But... if you want to turn back the clock, return FM to the days when the FCC insisted "only light processing" be used. Fat chance of that, though.

I think I still have an old Gates stereo (tube-type) limiter around somewhere... I'm ready!!

 

[chriscollins]

But... if you want to turn back the clock, return FM to the days when the FCC insisted "only light processing" be used. Fat chance of that, though.

Sad thing is, if you were in a mainstream format, light processing wouldn't help, as the content we get is already smashed to hell and back.