The destruction of the AM band started long before IBOC

[Savage]

Pardon my placing the mantle of actual industry experience with Kahn-Hazeltine AM stereo system on my shoulders in public fashion: I worked with the system when it was being used on an experimental basis, where I worked at WWDJ Hacksensack in the early and mid-1970s.

The system sounds Mickey-Mouse to today's technophile industry blog-types, using two radios to tune the separate sidebands. But I can tell you from personal experience that it worked amazingly well. I remember taking a GE tube-type clock radio and a Zenith TransOceanic multiband receiver, tuning them appropriately to 970's 5kw signal arriving from 26 miles away at my house near Harriman State Park.

The stereo image was surprisingly realistic. Tuning was easy, not tricky for the average consumer. Even if the radios weren't particularly well-matched in audio characteristics, it sounded very good. The mono sun was as easily tuned as a conventional AM mono station.

I never actually used a Kahn-licensed AM stereo receiver - just two radios. It worked! And it was fully compatible without the necessity of buying expensive proprietary equipment.

 

[clouseau]

CW-
I agree with most of what you said except:

if KAHN had stuffed his attitude and licensed receivers out the a$$ instead of trying to sell his own design and not allow anyone else to sell them,

I feel you may have been influenced by revisionist propagandists.

The KAHN AM stereo system, from the originator of AM stereo, did not require the purchase of new radios in order to receive KAHN independent sideband full carrier AM stereo. The only requirement was 2 AM radios (that most listeners already had access) each tuned to upper or lower sideband. It was best when both radios were high quality and identical, but this was not required. There was really no licensing or purchase required to receive KAHN AM stereo. Only the KAHN AM system had this capability.

Thanks God. I really don't believe you folks are advocating the "I just need to use two radios" system here. No new equipment needed?

Not to be snide, but how did that Kahn thing work out for us?

Clouseau

 

[Savage]

Aw, c'mon, Inspector - get into the "spirit of the season!"

"Not to be snide," eh? Of course nobody is advocating a return to two-radio DSB stereo here. And you ask, how did Kahn AM stereo "work out?"

Well, let's see.

Kahn-Hazeltine AM stereo didn't succeed. (Neither did the Betamax videocassette, despite its acknowledged superiority to VHS - it became a prevalent professional standard for decades. Neither did Sony's MiniDisc system, a clever, convenient audio storage system still used by hundreds of stations. Add whatever other examples you want here.)

None of this evidence indicates that the innovators involved were stupid, or incompetent, or even wrong. For a variety of reasons, perhaps including misjudging the market conditions prevailing at the time, these concepts simply stiffed or faded away. They were wrong ideas offered at the wrong time.

You know - kind of like HD-AM.

 

[Radioman100]

It seems to me that the Kahn system would have been a bad idea for the reason you cited. If you had a radio slightly out of tune, you would have received just one channel or the other, not a mono sum.

 

[Savage]

Strange thing about that, Radioman - I assumed the same thing when I first heard about it...."here come complaints about half the program being lost." But in practice it worked like this:

As you tuned your analog tuner, you encountered THREE distinct carriers or audio streams associated with a Kahn AM stereo station. There was the main L+R sum channel, which tuned slightly more broadly and was noticeably louder than the L or R sidebands. By gently tuning to the left or right, you encountered a notchy or noticeably centered - and quieted - "side-carrier," for want of a better term.

The system was actually quite intuitive, even for nontechnically-oriented users. It appeared obvious when you were tuned to the mono sum as opposed to one of the sidebands. I never recall getting any complaints about missing program material or anyone's finding WWDJ "difficult to tune." I do remember getting comments about how listeners found it a kick demonstrating the stereo to friends, just using two radios.

I know: it sounds really weird. But the damn thing worked. Nobody was more surprised than me.

 

[rbrucecarter5]

I know: it sounds really weird. But the damn thing worked. Nobody was more surprised than me.

I actually own a radio that could decode Kahn as well as C-Quam (Sony SRF A-1), and for a brief time I was in range of a Kahn station. It sounded at least as good as C-Quam. And it was easy to decode with two radios, just as mentioned above.

As far as the consumer only being able to hear one channel - that scenario is infinitely preferable to the IBOC situation, where if you aren't perfectly tuned, you get loud IBOC self-jamming. Don't take my word for it. Try it yourself on a cheap AM radio with poor tuning mechanism and see how much trouble it is to get a clear signal.

I have the schematic for the Sony - you would be surprised how simple it was to switch between C-Quam and Kahn. The only difference was some phase shift on a quad op-amp. I ought to simulate that thing in Spice to see how they are doing it. But - the important thing here: the decode circuitry is one inexpensive chip, and it was low power. Contrast that with the expensive, power hungry IBOC chips - and you can see the fallacy of the IBOC system. Too expensive, too power hungry, too complex, and too much interference if you aren't on frequency. Let alone the problem with skywave interference at night. Bottom line - IBOC is the wrong solution to the problem of making AM sound better. As for the problem with formats - that isn't a technical problem. That is indicative of poor management and poor programming decisions that turned off millions of listeners decades ago. Add interference from IBOC to the AM band, and yes, you may really kill it off.

I was the one suggesting segregating the AM band into digital and analog segments. Digital allocated 30 kHz apart, super power OK to cover metro areas, no protection outside of the area served. The ___ with the rest of the world when we put million watt transmitters to cover vast metro areas like LA. But the damage would be confined to one portion of the band. Everything else - interference free. C-Quam, Kahn, whatever people want to use as long as its not IBOC. The AM band has undergone massive frequency swaps in the past, it wouldn't hurt it any more that it already is hurt to do another one.

Another thing we could do is use longwave for IBOC. Kick the antiquated aircraft beacons off of there - they are outmoded since the advent of GPS. People need new radios to get IBOC anyway - give every station that cares a longwave frequency - no protection - superpowered, serving their metro area only. Leave the AM band analog.

 

[dbdigital]

But I think AM could have a renewed life as a mostly local service (with the exception of retaining the clear channels) with programming that is unique to the community.

Localism that is not entertaining is not listened to.

Then the problem would lay with whoever programmed the station, not the concept. Actually, what I was proposing closely mirrors the LPAM initiative which calls for community stations on the X-band.

db

 

[CW]

CW-
I agree with most of what you said except:

if KAHN had stuffed his attitude and licensed receivers out the a$$ instead of trying to sell his own design and not allow anyone else to sell them,

I feel you may have been influenced by revisionist propagandists.

The KAHN AM stereo system, from the originator of AM stereo, did not require the purchase of new radios in order to receive KAHN independent sideband full carrier AM stereo. The only requirement was 2 AM radios (that most listeners already had access) each tuned to upper or lower sideband. It was best when both radios were high quality and identical, but this was not required. There was really no licensing or purchase required to receive KAHN AM stereo. Only the KAHN AM system had this capability.

Ok I'll give you that...I did that BUT those kind of radios were a hindrance..
1) You needed TWO radios....cmon
2) The freq response out of such was 3-4kHz at most..so much for best resposne

a TRUE Kahn ISB rcvr would have had 10kHz or more response and was in ONE radio...that was Kahns downfall. To get his decoder design which made it sound GREAT, not good, you needed HIS decoder which he refused to license..end of story.

 

[SUPERCASTER]

CW-
I agree with most of what you said except:

if KAHN had stuffed his attitude and licensed receivers out the a$$ instead of trying to sell his own design and not allow anyone else to sell them,

I feel you may have been influenced by revisionist propagandists.

The KAHN AM stereo system, from the originator of AM stereo, did not require the purchase of new radios in order to receive KAHN independent sideband full carrier AM stereo. The only requirement was 2 AM radios (that most listeners already had access) each tuned to upper or lower sideband. It was best when both radios were high quality and identical, but this was not required. There was really no licensing or purchase required to receive KAHN AM stereo. Only the KAHN AM system had this capability.

Ok I'll give you that...I did that BUT those kind of radios were a hindrance..
1) You needed TWO radios....cmon
2) The freq response out of such was 3-4kHz at most..so much for best resposne

a TRUE Kahn ISB rcvr would have had 10kHz or more response and was in ONE radio...that was Kahns downfall. To get his decoder design which made it sound GREAT, not good, you needed HIS decoder which he refused to license..end of story.

Kahn did allow manufacturers such as Sony to include decoding of his AM stereo system in receivers. In fact many, if not most of the c-Quam AM stereo receivers could also decode Kahn AM stereo. Many manufacturers did not promote the fact that their radios could also decode the Kahn system once c-Quam became the standard. The only difference was that c-Quam sidebands were phase shifted.

For proof read rbrucecarter5 's reply above.
Here is the link:

http://www.radio-info.com/smf/index.php/topic,86930.msg654243.html#msg654243

 

[rbrucecarter5]

For proof read rbrucecarter5 's reply above.
Here is the link:

http://www.radio-info.com/smf/index.php/topic,86930.msg654243.html#msg654243

I've still got TWO SRF A-1's. One got drenched in a pool, I replaced it, but got the original one working again. I'll post the schematic for unbelievers if you want ---- it clearly shows the phase shift network in a quad op amp.

 

[CW]

CW-
I agree with most of what you said except:

if KAHN had stuffed his attitude and licensed receivers out the a$$ instead of trying to sell his own design and not allow anyone else to sell them,

I feel you may have been influenced by revisionist propagandists.

The KAHN AM stereo system, from the originator of AM stereo, did not require the purchase of new radios in order to receive KAHN independent sideband full carrier AM stereo. The only requirement was 2 AM radios (that most listeners already had access) each tuned to upper or lower sideband. It was best when both radios were high quality and identical, but this was not required. There was really no licensing or purchase required to receive KAHN AM stereo. Only the KAHN AM system had this capability.

Ok I'll give you that...I did that BUT those kind of radios were a hindrance..
1) You needed TWO radios....cmon
2) The freq response out of such was 3-4kHz at most..so much for best resposne

a TRUE Kahn ISB rcvr would have had 10kHz or more response and was in ONE radio...that was Kahns downfall. To get his decoder design which made it sound GREAT, not good, you needed HIS decoder which he refused to license..end of story.

Kahn did allow manufacturers such as Sony to include decoding of his AM stereo system in receivers. In fact many, if not most of the c-Quam AM stereo receivers could also decode Kahn AM stereo. Many manufacturers did not promote the fact that their radios could also decode the Kahn system once c-Quam became the standard. The only difference was that c-Quam sidebands were phase shifted.

For proof read rbrucecarter5 's reply above.
Here is the link:

http://www.radio-info.com/smf/index.php/topic,86930.msg654243.html#msg654243

NO, Sony used a 3rd party multi mode decoder..it was NOT done by Kahn...his own decoder, he would NOT license to any manufacturers...CQUAM decode KAHN?? Technically impossible....Kahn is ISB (independant sideband), CQUAM involves L-R Phase modulating the carrier with L+R Amplitude modulating the carrier...NO, they are totally different and CQUAM receivers NEVER decoded KAHN...you are terribly misinformed....IBOC receivers can decode CQUAM it seems but flips the channels....however one maker has stopped this feature (this is because of DSP decoding not available 10-15 years ago when Kahn was still around)

As to rbrucecarter's post, yes it was a SONY (I have a SONY XRA-33 which decoded all 4 AM stereos, HARRIS, MAGNAVOX, KAHN and CQUAM.....) SONY cheated on their decode scheme and was NOT fully correct..the mutli deocde chip they used was made overseas (Ahhh hell who made that)...but the "simple" phase shift mentioned in his post was to allow the signal to present itself to the decoder chip SONY used...it was NOT just a simple mod to allow a CQUAM to decode KAHN...if you knew anything abou the various systems (as in engineering), you would understand...but they are NOT similar....the DECODE chip which was a one time shot on the market which DID decode the 4 formats is what did it..NO other CQUAM receiver can do that and the SONY method was a compromise...a true KAHN receiver would have been better but again, KAHN NEVER licensed his design to manufacturers.

 

[rbrucecarter5]

As to rbrucecarter's post, yes it was a SONY (I have a SONY XRA-33 which decoded all 4 AM stereos, HARRIS, MAGNAVOX, KAHN and CQUAM.....) SONY cheated on their decode scheme and was NOT fully correct..the mutli deocde chip they used was made overseas (Ahhh hell who made that)...but the "simple" phase shift mentioned in his post was to allow the signal to present itself to the decoder chip SONY used...it was NOT just a simple mod to allow a CQUAM to decode KAHN...if you knew anything abou the various systems (as in engineering), you would understand...but they are NOT similar....the DECODE chip which was a one time shot on the market which DID decode the 4 formats is what did it..NO other CQUAM receiver can do that and the SONY method was a compromise...a true KAHN receiver would have been better but again, KAHN NEVER licensed his design to manufacturers.

I agree - what Sony did was vastly oversimplify the decode scheme required. You got two channels and a stereo sound out of C-Quam. You got two channels and a stereo sound out of Kahn - I heard a Kahn station in stereo with it back in the 80's. But was it compliant with either spec? Probably C-Quam, probably not Kahn. But there was some degree of stereo separation on both.

 

[Play Freebird]

Another thing we could do is use longwave for IBOC. Kick the antiquated aircraft beacons off of there - they are outmoded since the advent of GPS. People need new radios to get IBOC anyway - give every station that cares a longwave frequency - no protection - superpowered, serving their metro area only. Leave the AM band analog.

Or else, let the AM licensees use TV Channels 5 and 6 for digital. What do you think of Jack Mullaney's recent comments to the FCC? :

http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6519744377

 

[clouseau]

What do you think of Jack Mullaney's recent comments to the FCC? :

http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6519744377

I think
...presumably because the Audio Division fears the potential misuse
of that information could “undermine the war effort in Iraq” - - why else keep that
mundane information about the NCE apps “top secret” within the FCC - - which
as we all know, willingly leaks like a sieve to the select people it wants to have this
insider information).

And ...

However, we all know that an FCC deadline is not really a deadline that one can count on.

Is probably NOT the way to get taken seriously at the FCC.

YMMV.

Clouseau

 

[rbrucecarter5]

Is probably NOT the way to get taken seriously at the FCC.

Its good for a laugh, though. The only way to make it funnier would be to add extraterrestrial coverup conspiracy to it.

NOTHING will make the FCC money grubbers give up channels 2-6: for sale to the highest bidder. You got the money? You got the spectrum. The ____ with what is best for the public.

 

[KeithE4]

NOTHING will make the FCC money grubbers give up channels 2-6: for sale to the highest bidder. You got the money? You got the spectrum. The ____ with what is best for the public.

Blame Bill Clinton and the Congress-critters of the mid '90s, not the FCC. They just do as they're told.

The Omnibus Budget Reconciliation Act of 1993 authorized this whole cluster**** and the Balanced Budget Act of 1997 extended it. These laws in-effect made the Federal Government the owner of the entire electromagnetic spectrum and all frequencies that are allocated for commercial services are for sale to the highest bidder.

 

[Savage]

KeithE4 and Clouseau, thanks for the reminder.

Congressman John Dingell's House Subcommittee, an arm of the Commerce Committee, is launching an investigation of the FCC. This is an excellent opportunity for all of us who opposed HD Radio to weigh in on the corrupt process by which this mess was allowed to happen in the first place.

Absolutely no meaningful interference studies, monopoly granted in summary fashion to iBiquity, extortionate business practices, warnings of adverse effects from virtually all objective experts ignored by the Commission, and so forth.

Talk about clueless: I remember remember reading in some trade a year or so ago, Chairman "Doogie Howser" Martin actually being quoted on how he had just had a cozy one-on-one with Bob Struble and how, as a result of that little chat, he felt that "AM radio needs digitial, and it needs it at night as well as during the day, and as soon as possible." (From personal experience I can confirm that the FCC accepts checks and credit card payments. Not sure about the Chairman. Aw, lighten up, just kidding!!)

Congressman Dingell wrote a little Christmas card to Martin including some festive nuggets such as "a trend appears to be emerging of short-circuiting procedural norms" and "I am rapidly losing confidence that the Commission has been conducting its affairs in an appropriate manner." Here's hoping that visions of many other similar sugar-plums are dancing in the commissioners' heads this season.

Anyway, RIGHT NOW would be an appropriate time for the IBOC critics who populate this board to speak up. Don't just blogify. Tell Congress - during one of the rare opportunities when key players might actually be listening - how you feel about the AM band IBOC morass:

Rep. Hon. John D. Dingell
Michigan 15th Congressional District Office
2328 Rayburn House Office Building
Washington, DC 20515

Don't put it off, friends! Write today!

 

[hipporadio]

Congressman John Dingell's House Subcommittee, an arm of the Commerce Committee, is launching an investigation of the FCC... Congressman Dingell wrote a little Christmas card to Martin including some festive nuggets such as "a trend appears to be emerging of short-circuiting procedural norms" and "I am rapidly losing confidence that the Commission has been conducting its affairs in an appropriate manner." Here's hoping that visions of many other similar sugar-plums are dancing in the commissioners' heads this season.

While being FAAAR from a card-carrying member of the John Dingell Fan Club, I’m with the Dem on this one!!! “Chairman” Doogie Martin [kudos Mr. Savage for that little nugget] is a downright EMBARRASSMENT to the regulatory process and a sterling example of the oxymoron in “public servant”—not to mention, a perfectly-consummated LAP-DOG in tail-wagging want to the pathetic corporate radio lobby... ‘But then consider the “Dumber-than-the-Average Jellystone Bear” [flush with Malaise Family campaingn cash] who appointed him in the first place! Think of two obese serial abusers careening out of control and you have “My Favorite Martin” of the FCC AND the industry he’s charged and allegedly-trusted to regulate.

 

[CW]

Congressman John Dingell's House Subcommittee, an arm of the Commerce Committee, is launching an investigation of the FCC... Congressman Dingell wrote a little Christmas card to Martin including some festive nuggets such as "a trend appears to be emerging of short-circuiting procedural norms" and "I am rapidly losing confidence that the Commission has been conducting its affairs in an appropriate manner." Here's hoping that visions of many other similar sugar-plums are dancing in the commissioners' heads this season.

While being FAAAR from a card-carrying member of the John Dingell Fan Club, I’m with the Dem on this one!!! “Chairman” Doogie Martin [kudos Mr. Savage for that little nugget] is a downright EMBARRASSMENT to the regulatory process and a sterling example of the oxymoron in “public servant”—not to mention, a perfectly-consummated LAP-DOG in tail-wagging want to the pathetic corporate radio lobby... ‘But then consider the “Dumber-than-the-Average Jellystone Bear” [flush with Malaise Family campaingn cash] who appointed him in the first place! Think of two obese serial abusers careening out of control and you have “My Favorite Martin” of the FCC AND the industry he’s charged and allegedly-trusted to regulate.

IF "Doogie and company" allow XM and Sirius to merge, then protecting and serving the public interests is definitely gone the way of the dolar bill....I thought government was supposed to prevent monopolies (OH wait a minute, THEY are one

 

[rbrucecarter5]

IF "Doogie and company" allow XM and Sirius to merge, then protecting and serving the public interests is definitely gone the way of the dolar bill....I thought government was supposed to prevent monopolies (OH wait a minute, THEY are one

My 2 cents on the merger - it might actually allow some creativity and niche formats - because they can eliminate duplication. Who needs 20 rock channels when 10 are enough? So maybe those polka fans might get a low bandwidth channel or something.

Another good aspect of this is those of us who want just some of the programming can opt-out of things we don't want, like perverts Howard Stern / Opie and Antony. A-la-carte choices are good for dealing those morons a well deserved financial slap in the face. Hopefully TV cable will be next to offer al-la-carte so we don't have to pay for things we don't want and don't believe in.