AM BROADCASTERS - CALL TO ACTION

[rbrucecarter5]

You guys are arguing fidelity when there are hardly any radios that can take advantage of that fidelity.  99% of radios made and probably 100% of radios installed in new cars aren't capable of hearing this wide frequency response you're preaching.

Not again --- GO to Walmart, BUY a radio - OPEN it up.  There's nothing in there but one IC and one el-cheapo ceramic filter.  I'd be surprised if it has less than +/- 30 kHz bandwidth.  I've been inside radio after radio - same story. ALL wideband, but not for fidelity.  To get the cost down.  Cheap junk that happens to have good frequency response.  If you ignore crosstalk from stations 30 kHz away.  Some of these cheap AM radios barely qualify as superhet.  And if they bypass the ceramic filter and use a capacitor instead, they really AREN't superhet.  Technically, they are tuned RF architecture at that point, relying on the Q of the ferrite bar antenna and the leakage of the tuning cap to give acceptable selectivity.  I've seen that more and more.  Great for local 50 kW blowtorches within 30 miles, local 1 kW stations not even receivable.

Don't try to tell me 99% of radios are narrowband.  I can even buy one that is narrowband any more - I've looked.  Cost of manufacture dictates otherwise these days.  Even $100 boom boxes are exactly the same way.  Cheap RF circuitry, bad amp with lots of power overpowering cheap Chinese speakers.  But it has a remote control, lots of flashing lights, and digital tuning.

[rbrucecarter5]

With today's low-cost DSP technology, adaptive wideband AM receiver chips could be developed at a reasonable price.   The circuit could include noise blanking, single-ended hiss reduction, a synchronous

It probably would only be IF somebody at a major IC manfacturer actually had the development done on the FM section of an IC, and was a fan of AM radio themselves and had some extra time and resources to develop the AM section of the chip above bare minimum.

I'm trying to get my hands on the next generation of radio IC's - the ones that have NO external components at all.  One IC, DONE.  Programmable by I2C bus from a cheap microcontroller probably already in the unit.  It won't be long until the microcontroller is on the same silicon as the receiver.  The only thing stopping that now is different semiconductor processes for digital logic and RF IC's.  But the moment the whole masked microcontroller is available as a standard cell in every process, that's it.  No more hardware hacking possible - it will ALL be in silicon.  You won't even be able to bypass the IF with a cap any more, because the IF will be a DSP algorithm.

The AM antenna they recommend for the new IC's?  Not even a ferrite bar.  Just a loop shaped trace on the PC board.  More money saved.

I've got the FM version of these IC's right now.  Antenna in, power supply hook up, stereo audio out.  Period.  Performance?  A little noisy, somewhat sensitive, IF good enough for 400 kHz selectivity.  No possibility of improvement because its all silicon.  No HD, by the way, but RDS.  Available now - Silicon Labs: 

http://www.silabs.com/tgwWebApp/public/web_content/products/Broadcast/Radio_Tuners/en/Si4700-01.htm

In 5 years, this and competing products will BE the majority of all radios made.  Because by then they will be 25 cents in quantity.  NO pesky AM ferrite bar, NO pesky tuning capacitor, NO pesky IF ceramics.  It's coming - cheaper and cheaper circuitry, 99 cent radios at the dollar stores.  Majority of people will be using them.

[hipporadio]

On AM, the hotter and more dense your modulation is - the further your station will go.  If you're not wasting power transmitting a range of frequencies most modern radios can't reproduce, you can modulate the remaining frequencies that much hotter.  It improves coverage and penetration.

Yippee!  A big new bonus courtesy of “HD Radio” – “brutal” audio engineering practices formerly-reserved by AM stations forced to take-on the tundra north of the Artic Circle!

As to transmitters: KNOM runs a Nautel ND-25... Solid as a rock...  Processing is pretty simple and brutal.  There's an Aphex Compellor at the studio... at the transmitter, a CRL-MBL 100 shortwave limiter... This crunches the BW down to [under 5 kHZ] and drives hell outta the Nautel for maximum "reach".  Sounds terrible but it does travel!  Remember, most listeners have bare-minimum receivers and are happy to get any service at all.

What a delightful case-study for major-market corporate AM radio to emulate... ‘Just assume the audience mimics a few-thousand Inuit Eskimos across the Bering Straits from Siberia – straining to hear the “Personals” show on their $40 Eton FR-200 wind-up portable radios.  Since when do engineering practices common to the likes of 680 KNOM—Nome and 720 KOTZ—Kotzebue, Alaska become advantageous to “The Nation’s Station”—700 WLW?  Obviously, since IBOC made its appearance on stage!  Find me ONE competent AM engineer as late as 2000 that would purposely implement such a Draconian directive.  How many of those engineers celebrated their acquisition of a shiny-new Harris DX-50 only to turn it into a screeching “notch-master”?  NONE!  This “5kc shill” is merely another artifact [joining the infamous codec “chorus effect”] of iNiquity IBOC.  Those suddenly singing the praises of telephone-grade audio [allegedly due to “coverage”] coincidentally are simultaneous converts to the new “HD” religion... “Praise our King, Bobby Stubble”... You may call it “getting saved” – I call it “selling out”!

As for the interestingly-timed discovery that “honkish” audio equals a fantastic propagation breakthrough, consider a genuine non-iNiquity-assisted AM-undertaking I had personal experience with at the whopping 1kw level:

...we brought in NBC AM engineer John Bailie from WMAQ... Jim Loupas at WCFL... along with the greatest AM antenna engineer of all time, Harv Rees...

You’ve just tagged the “Trinity” of AM engineering, Cary!  All TOO often, TOO many marvel at their Star Trek-ish Omnia AM box firing a reasonably-modern rig – and think they have all the bases covered... [Recalling a political statement regarding the economy] “IT’S THE ANTENNA, STUPID!”  I was fortunate to have a contract engineer [a Harv Rees “disciple”] who worked with me on an AM upgrade in the early-90s... NO transmission hardware [with circuit boards] changed... NOT our stack of CRL components fed via carefully-equalized Telco by an Aphex Compellor – NOT our impeccably-maintained decade-old 1kw Harris MW-1 rig.  Save the original steel on the tower, the antenna was completely rebuilt... New Andrew line; a custom-designed folded uni-pole skirt designed to achieve “flat” system impedance/bandwidth and low J-factor...; and a HOME-BREWED antenna ATU in a new Kintronics box – literally built on the floor of our AM control room.  Oh what a beautiful sight that finished box with its shiny-new Delta base-current meter was to behold!  ‘Shame it lived behind an eight-foot stockade fence to keep people and grazing cattle at bay.  While the prior facility sounded good and coverage was a bit beyond the norm – we were entertained by the challenge to [increase quality and coverage]... The result was MUCH BETTER!  Audio quality, density, and “impact” were off-the-scale... The 180-watt [ND] night signal bettered the heritage AM in town with 500-watts [DA] at night... It WAS the ANTENNA, stupid!

...And fortunately, those audio improvements and coverage were NOT mutually-exclusive... And note that I did NOT direct my engineer to re-jumper the CRL limiter to a 5 kHz bandwidth – we used EVERY kilohertz allowed by law to modulate that Oldies format!  Gains weren’t the result of some mythical RF projection due to an alternative antenna design – they were the result of “hot ‘n nasty sidebands” – a rip-roaring “here’s my turf” audio signature that was unavoidable on radios 40-miles away.  So goes your “convenient” coverage inducement. I test-drove that 5kc highway on another 250-watt AM station where coverage WAS a consideration [and demands of the Perry Como music genre were fewer] – BUST!  Purposely-choking audio provided NO significant increase in the size of the ameba – ‘just an undesirable decrease in intelligibility [which no-doubt hindered the former].

...I can pick out a chopped down analog signal on some radios from quiet casual listening... In the car, it's so obvious that I am appalled that others claim there is no difference.  I can only assume you have bad hearing or an awful radio.  Or both!

I own no-less than a dozen radios priced from $40-140 where the difference is apparent – and I’m not including my ownership of several “niche” receivers [such as the CCRadio, Carver TX-11b, and ICOM R71a] which might suggest my flirtation with the “lunatic fringe”    The difference is telling – even on the notorious Delco radio in my GM SUV.  SAD, considering the enhanced state of AM processing and transmission gear in this era – enhanced, that is, before that rotten IBOC egg was hatched.   

...Consider the implication: a system so flawed that, before you're allowed to use it, you have to pledge undying allegiance to it!  Unless my broadcasting/media/electronics history has a glaring defect, I remember no such iron-lung provision for NTSC color TV, HDTV, stereo FM, C-QUAM AM, VHS v. Beta, 8-tracks, cassettes or LP vs. 45 rpm.  Nice system.  So valid, so terrific, its perpetrators have to legally muzzle anyone who might have a bad experience with it.

EVEN SADDER – but chilling proof that surreptitious corporate interests that cherish “fine print” are displaying their real agendas with billboard-sized letters.

[TheRover]

The published AM MW specs on my Radio Shack DX-440 (Sangean ATS-803A) (I still have it, and I will be holding on to it...  ) are:

AM Sensitivity for 20dB S/N Ratio:

300 kHz  560 uV/m

600 kHz  320 uV/m

1.4 MHz  280 uV/m

AM Image Rejection Ratio:

300 kHz  65dB

600 kHz  65dB

1.4 MHz  60dB

AM Selectivity:

               -6dB     -50dB

Wide    +- 3 kHz    7kHz

Narrow +- 2kHz     4kHz

[Savage]

Radioman can't hear the IBOC sidebands in analog reception?  He's either delusional, lacks candor or has a car radio with 1 kHz AM bandpass.  Or maybe all three.  Perhaps this is a special perspective which possesses you when "the success of radio means far more to (me) that it does to you."

And spare us the snide suggestion that anyone hearing IBOC sideband noise must be driving "a 1975 Monte Carlo."  Everyone knows there are loud steady-state sidebands which cause first, and in some cases, second-adjacent channel interference, regardless of what kind of car your're driving (like the Jeep Liberty, Pontiac Vibe, Ford F-150 pickup and Hudson Commodore currently parked in the WYSL lot - all of 'em.)  If what you claim were true, there wouldn't be a debate about IBOC.

If you want credibility for your cause, you and other IBOC-boosters need to lose the arrogance and be straight with people.  The smug attitude and lack of candor (beginning with Ibiquity's misleading claims for HD-AM and refusal to release complete and accurate technical standards) are much of what turns people off to consideration of the system.  To say nothing of the cavalier disregard shown a significant number of existing AM broadcasters who will be negatively impacted.

[amfmsw]

Mr.100,

Let me show my agreement with the others with a statement that an engineer that mentored me had on his office door.  It was a poster with a lighning bolt, and the words:

"Thunder is good.  Thunder is impressive.  But it's lightning that does the work."
Albert Einstein.

Can you think of a better engineer?

It was to keep the PD's at bay before they complained "W--- is louder than us.  Can you turn us up.  Instead, the transmitters were always locked at 105% output, the max.

[SUPERCASTER]

With today's low-cost DSP technology, adaptive wideband AM receiver chips could be developed at a reasonable price.   The circuit could include noise blanking, single-ended hiss reduction, a synchronous detector, and the ability to automatically demodulate the sideband with the least adjacent channel interference, all defined in software.   The complexity would be less than an HD receiver (have you seen how much DSP horsepower goes into those?), and without iBiquity's royalty payments, a radio using this design should cost less too.   And once developed, it could be marketed worldwide.  No, it would not eliminate the lightning crashes, but neither does IBOC.

Could this be the solution?  No need for broadcasters to spend money on digital exciters and expensive modifications to their antenna systems, no need to pollute the band with hash, no lawsuits, and listeners would probably prefer the end result.


   

You are right. The modern software defined radios should be capable of all of the above (and much more) with proper programming.

[dumber than a box of hair]

Mandate C-QUAM AM stereo.  Most stations already have it installed.

In precisely whose fantasy?  Most stations NEVER installed it, and of those who did nearly all have abandoned it.  It was too little, too late, on a band where it wasn't necessary (music stations had gone from AM to FM, and talk radio doesn't need stereo).  I've been in and out of transmitter sites for the best part of 40 years, and I've seen exactly one C-QUAM exciter...sitting in a corner, overgrown with spider webs.  Stick a fork in it...it's done.

[LinoNYC]

In precisely whose fantasy?  Most stations NEVER installed it

I don't know the situation up where you are,  here in New York we had AM stereo on the following:

660 WNBC/WFAN disc 2002

930 WPAT Disc when they tried iboc.

1010 WINS News in stereo!?

1050 WEVD (A-amax also) 1988- till sold to ESPN


1560 WQEW 1992-98 Great sounding pop standards, Radio Disney should turn it back on.

1600 WWRL 1997 Installed w/new TX. Truely awesome sounding, an example of what AM could have sounded like even with an ancient studio.

For awhile I also heard the characteristic "split" carrier and phasey-ness on 620, and was told of one graveyard station that was C-quam, don't recall which.

Most AM stereo receivers were only marginally better than average in bandwidth and the system required strong signals or the standard noise problems prevailed.

Did any of your company's stations employ C-Quam or was this another thing you opposed?

Lino

[LinoNYC]

Find me ONE competent AM engineer as late as 2000 that would purposely implement such a Draconian directive.  How many of those engineers celebrated their acquisition of a shiny-new Harris DX-50 only to turn it into a screeching “notch-master”?  NONE!

Anyone who writes this wasn't in the NY metro area during the loudness wars of the 1970's or has convenient amnesia.

Flatline dynamics often to the point of envelope inversion, piercing eq, lopped-off bass and highs and the coup de'gras..sped up records. Not just the subtle kind such as practiced by WABC, but the 50rpm "chipmunk style of such "greats" as WAVZ, WWDJ and WPTR.

As for "killer sidebands" there were so many splashing complaints that  we ended up the hi-fi ending 10K NRSC imposition.

No doubt that some of the engineers who are so indignant about the admittedly trashy 5K limit of iboc, also have alot of dirt on their hands from past offenses to audio.

I know, I know, "I was just following orders".

Lino