NRSC-3? RW article on AM bandwidth

[amfmsw]

Has anyone read that article in the latest Radio World? They report that NRSC "new" tests for AM noise and interference show that a lower 7.5Kc bandwidth is preferred. This ingenious research shows how deeply AM is in trouble. (kc is bad enough, now it apperars we're being prepped for another bandwidth reduction! Why? Hasn't the NRSC done enough damage to American AM Broadcasters.

All this based on a massive research sample of 49 persons! AAND, 9 tests were rejected, leaving a total of 40!

Dear NRSC, this problem was addressed by minds far greater than ours. In fact, this problem was solved in 1932 with a switch, a .01 and .05 capacitor.

It's called a TONE CONTROL. We're not idiots. If the signal is noisy, we can turn the tone control down. We don't need you, or other transparent pushes to limit AM bandwidth to push the AM IBOC agenda.

 

[FFoti1]

Has anyone read that article in the latest Radio World? They report that NRSC "new" tests for AM noise and interference show that a lower 7.5Kc bandwidth is preferred. This ingenious research shows how deeply AM is in trouble. (kc is bad enough, now it apperars we're being prepped for another bandwidth reduction! Why? Hasn't the NRSC done enough damage to American AM Broadcasters.

All this based on a massive research sample of 49 persons! AAND, 9 tests were rejected, leaving a total of 40!

Dear NRSC, this problem was addressed by minds far greater than ours. In fact, this problem was solved in 1932 with a switch, a .01 and .05 capacitor.

It's called a TONE CONTROL. We're not idiots. If the signal is noisy, we can turn the tone control down. We don't need you, or other transparent pushes to limit AM bandwidth to push the AM IBOC agenda.

If you take the time to read the report, you'll see that much of this is based upon interference testing, done with conventional receivers. IBOC seeks AM to use 5kHz BW, and this report shows data that supports 7.5kHz. This is not a suggestion that is driven by IBOC. It was done using data gathered from a well-known researcher. The test facilty was the test labs at NPR.

Subjects were well-chosen to represent a good cross-reference, and the listener's data was compiled without bias. I know full-well, having been the co-chair for the AM Working Group Committee.

-Frank Foti

 

[amfmsw]

With all due respect to you, your professional experience, and education Frank, I feel that 40 persons to represent 300 million Americans is, well, preposterous. And how will limiting transmission bandwidth cut listening interference? And I'm sorry if the suggestion of IBOC interferance on AM as the impetus for the research made anyone uncomfortable. But with recent events allowing legalized IBOC AM splatter on sidebands, I truly see no need for any NRSC band limitations.

If I may suggest, why doesn't the committee work on the manufacturers to make a better radio! A hi-fi hybrid AM with user selectable 7.5 for distant, and full response for local reception. How about automatic blending? We already do it on FM car radios. Force AM manufacturers like Delco to make an AM radio with fidelity standards that are listenable. 9Kc is deficient, but 3.5Kc is totally unacceptable.

Did the 40 compare the audio with 15Kc FM quality? Maybe they would have noticed a preference of 12Kc, of which most every AM station in the US is capable.

Of course there is one other answer, kill all analog AM broadcasting, force Ibiquity to aid in financing the changeover for small operators, or let the government pay for it, and render a billion AM radios useless.

My point is that you have the power to really help the struggeling small AM operators, ALL AM operators. To really make a difference for them. Forcing them to accept crippling audio quality is not the answer. Forcing the manufacturers to assemble decent radios with some sensitivity, develop better high speed noise blanking and user variable filters will.

 

[FFoti1]

With all due respect to you, your professional experience, and education Frank, I feel that 40 persons to represent 300 million Americans is, well, preposterous. And how will limiting transmission bandwidth cut listening interference? And I'm sorry if the suggestion of IBOC interferance on AM as the impetus for the research made anyone uncomfortable. But with recent events allowing legalized IBOC AM splatter on sidebands, I truly see no need for any NRSC band limitations.

If you were to investigate the criteria used by professional researchers, you'll find their basis that is required for a known successful sampling of subjects. Most research is done using sample sizes that were done here, and I'm not talking about the electronics industry either. Check most research methodologies, and you'll see that the sampling is quite low, based upon the ratio of total persons.

Limiting transmission BW reduces the interference contours in the protection ratios. These tests were done using a 'desired' vs 'desired' signal, and then listening to the effect on consumer radios. Read the test methodology, and you'll be able to see how it effects the scenario.

If I may suggest, why doesn't the committee work on the manufacturers to make a better radio! A hi-fi hybrid AM with user selectable 7.5 for distant, and full response for local reception. How about automatic blending? We already do it on FM car radios. Force AM manufacturers like Delco to make an AM radio with fidelity standards that are listenable. 9Kc is deficient, but 3.5Kc is totally unacceptable.

Did the 40 compare the audio with 15Kc FM quality? Maybe they would have noticed a preference of 12Kc, of which most every AM station in the US is capable.

You are more than welcome to join the NRSC and assist *ALL* of us who would love nothing more than to see the receiver makers offer a wider radio. This has been done *REPEATEDLY* for *DECADES* and nothing has changed. They claim (not my opinion here) that they cannot make an affordable radio within their pricepoint...AND...consumers claim that the wider radio is much more prone to interference. Seems to me, you should take the time, and read the NRSC proceedings, as well as the report.

15kHz BW is not possible in AM, so that's not a valid test case. The FCC mandated NRSC low pass filter does not allow any transmission wider than 10kHz. That's been in effect for 20 years. While AM is capable of 15kHz response, that has not been possible for decades. If you think we have interference issues now, try BW that is wider than 10kHz.

Of course there is one other answer, kill all analog AM broadcasting, force Ibiquity to aid in financing the changeover for small operators, or let the government pay for it, and render a billion AM radios useless.

My point is that you have the power to really help the struggeling small AM operators, ALL AM operators. To really make a difference for them. Forcing them to accept crippling audio quality is not the answer. Forcing the manufacturers to assemble decent radios with some sensitivity, develop better high speed noise blanking and user variable filters will.

BTW: Have you had a look at the response of a 'median' AM radio? It's not much beyond 3kHz! Now, what do you do?

Again, if you'd like to join me, and the 40+ others who were part of this process...AND...care about AM, then please do. All of this work was done by well-known professionals in our industry...AND...on a voluntary basis. (No one gained anything financially through this work.) If I may humbly say, we did this work because we care, were qualified to do the work, and shared the results. This effort was brought forth because there ARE people in our industry who DO care, and we decided to have a real look at this topic with technical testing and research.

Again, I ask that you, and any others whom are interested, to review the posted information, then open a dialog on the topic.

-Frank Foti

 

[dbdigital]

If I understood the article correctly, it stated that listeners were able to tell a quality difference between 5 kHz and 7 kHz but not between 7 kHz and 10 kHz.

So is it possible to extend the analog portion of the signal to 7 kHz and still provide room for digital and keep within the allotted bandwidth for the channel?

db

 

[CW]

If I may suggest, why doesn't the committee work on the manufacturers to make a better radio! A hi-fi hybrid AM with user selectable 7.5 for distant, and full response for local reception. How about automatic blending? We already do it on FM car radios. Force AM manufacturers like Delco to make an AM radio with fidelity standards that are listenable. 9Kc is deficient, but 3.5Kc is totally unacceptable.

Did the 40 compare the audio with 15Kc FM quality? Maybe they would have noticed a preference of 12Kc, of which most every AM station in the US is capable.

You are more than welcome to join the NRSC and assist *ALL* of us who would love nothing more than to see the receiver makers offer a wider radio. This has been done *REPEATEDLY* for *DECADES* and nothing has changed. They claim (not my opinion here) that they cannot make an affordable radio within their pricepoint...AND...consumers claim that the wider radio is much more prone to interference. Seems to me, you should take the time, and read the NRSC proceedings, as well as the report.

15kHz BW is not possible in AM, so that's not a valid test case. The FCC mandated NRSC low pass filter does not allow any transmission wider than 10kHz. That's been in effect for 20 years. While AM is capable of 15kHz response, that has not been possible for decades. If you think we have interference issues now, try BW that is wider than 10kHz.
BTW: Have you had a look at the response of a 'median' AM radio? It's not much beyond 3kHz! Now, what do you do?

Again, if you'd like to join me, and the 40+ others who were part of this process...AND...care about AM, then please do. All of this work was done by well-known professionals in our industry...AND...on a voluntary basis. (No one gained anything financially through this work.) If I may humbly say, we did this work because we care, were qualified to do the work, and shared the results. This effort was brought forth because there ARE people in our industry who DO care, and we decided to have a real look at this topic with technical testing and research.

Again, I ask that you, and any others whom are interested, to review the posted information, then open a dialog on the topic.

-Frank Foti

Frank,
I respect your opinions and agree with them ..........Its too bad AM rcvrs have never been built to actually hear what WAS being transmitted (well maybe the old TRF versions did ....my Sony XRA-33 FM/AM Stereo receiver made even mono stations sound good with its wide/narrow filter...back in the days when KKBQ Houston was simulcasting the FM on the AM in its top40 days with Kahn and then CQuam on the AM, I actually preferred the AM over the FM for the presence and sound....being an old top40 jock and engineer from the 70s when AMs could transmit as much as 20 kHz (and maybe more in some stations , I guess I am a biased....

However, it seems DIGITAL is the buzz word (pun??)....and I have seen digital in telecom, broadcast, etc....and digital does NOT always mean better....digital cell phones just dont do it for me compared to the analog bag phones of years ago (I find the delay sucks and the chop of the signal OR the clipping on some models is terrible....and I never heard an analog cell sound that bad) and to tell the truth, IBOC doesnt do it for me either....T1s, BRIs, etc are great and my opinion on VoIP is still out on the fence (I run Vonage at home but VoIP in the work place is another issue....including when it is not engineered right....which most companies WONT since they live in cost savings clouds....) Personally I would like to see AM somehow get turned around without going to the digital realm (If the damn FCC had done AM Stereo right...too bad, it was a nice idea and I still like it)....it will take away the easiest mode of reception from the general public....and I have yet to see IBOC Walkmans run on AA batteries worth a flip ..working with digital radios in a 2way radio system, its a PITA to troubleshoot interference issues without an analog rcvr...all it takes is a little carrier or intermod and the decoders studder like a 951 w/a barely readable CD....eeeeewwwwww. While digital does have some advantages, I find this free wheel rush to make EVERYTHING digital as a major problem....as digital is NOT the same for everything..and some thing needs much more improvement before being put on the air OR maybe competition?? (Sorry, had to throw that out there

(I AM REALLY concerned when the aviation service starts to convert to digital mode......that really scares me!)

 

[littlejohn]

You oughta be pleased to note that aviation radios are AM then

 

[FFoti1]

Frank,
I respect your opinions and agree with them ..........Its too bad AM rcvrs have never been built to actually hear what WAS being transmitted (well maybe the old TRF versions did ....my Sony XRA-33 FM/AM Stereo receiver made even mono stations sound good with its wide/narrow filter...back in the days when KKBQ Houston was simulcasting the FM on the AM in its top40 days with Kahn and then CQuam on the AM, I actually preferred the AM over the FM for the presence and sound....being an old top40 jock and engineer from the 70s when AMs could transmit as much as 20 kHz (and maybe more in some stations , I guess I am a biased....

Group,

Something I failed to mention in earlier responses. My involvement was as one who could assist with crafting the test proceedures. Especially the audio, and processing portion. As stated (numerous times) on this list and others, my desire is for our industry to hopefully do what's best for radio. If it includes digital or not, I'm honestly still undecided. While my company stands to gain by the implementation of digital, my personal feelings are in the middle of the debate. I'm still a 'kid' radio engineer, like the rest of you. (Yes, still a kid at 51.)

-Frank Foti

 

[carlvenorden]

I just posted my "new" opinion about IBOC above, but this discussion featuring Frank Foti (yes I read the referenced article in RW). is also interesting.

If there was an all-out effort by Mc Donalds to promote an "all worm" hamburger, and the idea didn't catch on, that meal would be discontinued.

Fact is: I've heard a couple of AM stations which may not have actually been using 5 kHz bandwidth, but may have indeed been broadcasting audio from the internet (yep, it's done; worked for a station that did and.......well, it's gone now), or from over the telephone.
It sounds just that bad, and this programming never lasts long. Supply and demand: if there is no demand for a product, it simply goes away.

Back to at least the late 70's there were AM's out there using full 10kHz bandwidth, and although they weren't in stereo, the quality of the broadcast was definately there. I was fortunate to first work at my hometown station. Truth: this station had very very outdated equipment; the studio was a sorry thing to see; however, everything worked very well because the engineer(s) were simply terrific. I have at least 100 hours of tape of this station recorded off air.....(remember, we played records back then...scrachy dirty records). The audio is impeccable despite the fact that the equipment was old and fixed/refixed. This station made you proud to work there, but it was the People that made it happen.

Those were also the days when "local stations" were 1,000 watts days/250 nights, "regionals" had 5,000 watts or less.....and there were hardly any other stations licenced on clear channels but one or two. The only places you could find florescent lights were stores, and no one had computers, or RF generating appliances in their houses other than a TV (I mean one TV, not 4).

The NSRC, NAB....Frank Foti et al, have no interest in destroying the AM band. Ibiquity has no interest in destroying it either (IIRC, that would be about 50% of their business out the window).
Their main interest is in improving the band by ways that they 'can' in the real world as it exists today. Like Republicans and Democrats, there is always someone on the other side.................lets' take this as an example:

The AM expanded band was 'supposed' to help clean up the standard band by reducing interfering stations (stations that should never had been assigned in the first place, or should have been moved to accomodate additional stations). It took a long time to happen, but it happened and would have helped interference issues. Sunset has come for stations that elected to move to the expanded band, BUT they had a CHOICE: keep the x-band frequency and give up the original, OR vise versa. Now, lets suppose that all 58 stations that gravitated to the X-band decided to keep their original frequency (and they Could Have!....they had a Choice!)....what does the X-band exist for then?

One station (which I will not name) was chosen to go from 550 with 5,000 watts to 1700 with 10k/1k. If I were that owner, I would stay where I was; and in fact he did just that.
However, many more stations were located between 1250-1600 on the dial, had 5,000 watts or less and operated expensive DA's. They chose to move up the band, knock a couple towers down, increase power and now they have excellent night signals.......but......what about their original frequency????????????????????????

Sunset has arrived for nearly all the x-band stations; and now the new news:
Minds are changing because it appears as though the x-band stations will be able to retain their original frequencies by agreeing to program them separately, or, by selling them to a minority concern for 75% of it's value. If this is the case, why the idea of reducing interference by expanding the AM band?

Case(s) in point; both of these are happening in New Jersey:
1530 WJDM in Elizabeth was the first station granted a X-band frequency. In the past 5 years it was agreed that WJDM could keep both stations "because" Elizabeth was the largest city in the U.S. without a primary station. They also got a power boost!...and kept their X-band assignment, albeit with separate programming. Here's the kicker: Soon after that WJDM moved to studios and offices in New York City. A New Jersey station, eh?...not really.

Another New Jersey station to get a X-band assignment was WHWH in Princeton.
It's sunset came last year and WHWH signed off.
It's x-band station, located in central NJ recently moved it's transmitter and tower just outside of Philadelphia......another "NJ radio station huh?" Now, it can't be heard in a lot of NJ, but Philly hears it just fine. Kicker: WHWH re-signed on last week; it is testing as of this writing. By my count that is two frequencies within 100 miles of themselves that were slated to be cleaned up, but they won't be. How many more instances can we expect?

I'm not saying this is right, nor wrong, but I am saying that the fixes to the AM dial have to be addressed knowing full well that someone is not working along with you.
When we make rules (such as the x-band rules) and we don't adhere to them, the goal of the rule goes by the wayside.
When we 'don't' make a rule (such as selecting an AM Stereo Standard), expecting the market to make a decision, and the market fails to make one, we live with the results.

Here, we have a decision on a system some believe to be great, others believe to be flawed. The market will choose to listen or not listen.
But at least there are people out there that are "trying" with what they have to work with, to improve the AM band for us.

 

[OKCRadioGuy]

Pull the 10kc filters and let it fly to 15kc.... Save thousands and actually sound better. The interference is the same or less, so my question is (as someone else mentioned), are we just going digital so we're digital? The real problem is at the receiver end anyway.

 

[rfry]

Pull the 10kc filters and let it fly to 15kc.... Save thousands and actually sound better. The interference is the same or less, so my question is (as someone else mentioned), are we just going digital so we're digital? The real problem is at the receiver end anyway.

OTOH, what is the point of transmitting more bandwidth than receivers can demodulate and reproduce from that transmission, while at the same time causing interference to receivers tuned to adjacent channels?
//

 

[jammerdave]

*exactly*. Most AM radios barely pass 3 or 4 khz, if we are lucky. The tests probably showed a difference for the 7khz signals, as there was enough higher frequency energy left to still be perceptible that far down the I.F. filter curve.. Those cheap/crap filters that are usually in consumer radios are pretty narrow up top, but check the curves out at 5 khz or so. They flatten out some. Great filters cost big bucks, so I'm sure that's why we don't see them in the garbage they market to joe consumer.

 

[FFoti1]

Pull the 10kc filters and let it fly to 15kc.... Save thousands and actually sound better. The interference is the same or less, so my question is (as someone else mentioned), are we just going digital so we're digital? The real problem is at the receiver end anyway.

10kHz BW existed 20 years ago, long before the inkling of anything 'digital.' You cannot pull the filters, as first and second adjacent channel inteference grows exponentially. What is lost in this discussion, is that the NRSC made the decision to have a look at AM BW, 20 years later, and see if the existing NRSC restriction was viable, or did it require a change.

-Frank Foti

 

[rbrucecarter5]

I don't know where the people doing the study got their radios, but it had to be at garage sales or flea markets, because virtually every new radio has wideband AM. Why? It has absolutely nothing to do with the manufacturer wanting "high fidelity" sound out of AM - it is to make the cost of manufacturing the radio as cheap as possible. I have half a dozen schematics for "single chip" AM-FM radios. Here is the list of materials for them:
(item)
(1) IC - single chip AM FM
(2) Ferrite bar antenna
(3) tuning capacitor
(4) AM ceramic filter
(5) FM ceramic filter
(6) FM discriminator coil

Done. And you can bet the ceramic filters are the cheapest things they can find. I measured one such radio as having an AM bandwidth of +/- 40 kHz!!!

People buy these things because they are cheap - $5 to $10. Or they are part of a boom box without much more attention to quality (although my daughter's "Mary Kate and Ashley" boom box actually uses good quality ceramic filters, a decent ferrite bar antenna - and is a really decent radio). Even though it is the 6 part reference design ---

Now - if people buy them and listen to local AM, they hear really great sounding audio. No different than they would hear on an expensive wideband AM tuner - if it were played through a small speaker. Small speakers work terrifically well as tweeters, by the way, so the high end of the audio is really good. Even on AM - it sounds impressive! Wideband audio response - quite unintentional, but also quite real.

Unfortunately if you add IBOC into the mix, you can really hear the sideband noise on radios like these, precise tuning is really hard given the cheap construction.

OK - now the people doing the study can crawl back into their bed with Ibiquity - I've BUSTED their MYTH yet again. The only reason these studies exist is to justify the self-serving interests of people who want to limit AM bandwidth - so EVERY AM station sounds as muffled as IBOC (levels the playing field) - and coincidentally the low bandwidth is just what is necessary for conversion to IBOC. What a coincidence.

 

[FFoti1]

I don't know where the people doing the study got their radios, but it had to be at garage sales or flea markets, because virtually every new radio has wideband AM. Why? It has absolutely nothing to do with the manufacturer wanting "high fidelity" sound out of AM - it is to make the cost of manufacturing the radio as cheap as possible. I have half a dozen schematics for "single chip" AM-FM radios. Here is the list of materials for them:
(item)
(1) IC - single chip AM FM
(2) Ferrite bar antenna
(3) tuning capacitor
(4) AM ceramic filter
(5) FM ceramic filter
(6) FM discriminator coil

Done. And you can bet the ceramic filters are the cheapest things they can find. I measured one such radio as having an AM bandwidth of +/- 40 kHz!!!

People buy these things because they are cheap - $5 to $10. Or they are part of a boom box without much more attention to quality (although my daughter's "Mary Kate and Ashley" boom box actually uses good quality ceramic filters, a decent ferrite bar antenna - and is a really decent radio). Even though it is the 6 part reference design ---

Now - if people buy them and listen to local AM, they hear really great sounding audio. No different than they would hear on an expensive wideband AM tuner - if it were played through a small speaker. Small speakers work terrifically well as tweeters, by the way, so the high end of the audio is really good. Even on AM - it sounds impressive! Wideband audio response - quite unintentional, but also quite real.

Unfortunately if you add IBOC into the mix, you can really hear the sideband noise on radios like these, precise tuning is really hard given the cheap construction.

OK - now the people doing the study can crawl back into their bed with Ibiquity - I've BUSTED their MYTH yet again. The only reason these studies exist is to justify the self-serving interests of people who want to limit AM bandwidth - so EVERY AM station sounds as muffled as IBOC (levels the playing field) - and coincidentally the low bandwidth is just what is necessary for conversion to IBOC. What a coincidence.

You've busted no myth. Where is YOUR test data to support your claim? Anyone can make idle chat about tech-specs. I saw the test results, as well as the test bed. Some of the best broadcast engineers in the business were involved, and they did so without bias.

Since you asked...The radios, all current common models, were obtained from CEA, who represent the receiver manufacturers. Please provide for the group, a list of common known radios that perform to the specifications you claim, as well as a *verifiable* test methodology and test results. BTW: I'm not talking of the one-off, or 'few-off' models that offer better-than-average performance, but the common models that consumers purchase on a daily basis.

I can tell you, since all 40+ radios sat in my office for a year, that there were many top-of-the-line models included. All receivers were measured, and broken into three groups, based upon performance. From there, further testing, and research was performed.

If you wish to criticize, please get *ALL* the facts straight, before hitting your <return> key.

-Frank Foti

 

[boiseengineer]

FWIW: (AM) IBOC can operate with 7 khz analog audio with a couple taps on the exciter's menu and setting the processing for 7. The secondary IBOC carriers aren't there so the HD is not nearly as "robust". Know of a couple stations running it this way.

 

[EasyPeazy]

You've busted no myth. Where is YOUR test data to support your claim? Anyone can make idle chat about tech-specs. I saw the test results, as well as the test bed. Some of the best broadcast engineers in the business were involved, and they did so without bias.

Since you asked...The radios, all current common models, were obtained from CEA, who represent the receiver manufacturers. Please provide for the group, a list of common known radios that perform to the specifications you claim, as well as a *verifiable* test methodology and test results. BTW: I'm not talking of the one-off, or 'few-off' models that offer better-than-average performance, but the common models that consumers purchase on a daily basis.

I can tell you, since all 40+ radios sat in my office for a year, that there were many top-of-the-line models included. All receivers were measured, and broken into three groups, based upon performance. From there, further testing, and research was performed.

If you wish to criticize, please get *ALL* the facts straight, before hitting your <return> key.

-Frank Foti

You clearly haven't spent much time reading the HD Radio forum here Frank. Logic is completely irrelevant and unnecessary. In the last week IBOC has evolved into a government conspiracy to keep the populace dumb. No, I'm not kidding.

I for one found the article interesting and informative. Thanks for taking the time and thanks for defending your work and the work of your fellow engineers.

 

[SML]

Well, OK. Here is what I wrote a day or two ago on pubtech about this:

Please go take a look at the test results:

http://www.rwonline.com/pages/s.0044/t.4031.html

In reality, the radios being tested are worse than 3 db down at 5khz. The worst case is 25 db down at 5 khz. Heck, at 3 khz, the worst case is 10 db down.
Looking at this data, I could not figure out how they got any objective, usable results. Please read the paragraph where it plainly
stated that:

"the majority of current analog AM receivers have audio bandwidths of less than 5 khz. In fact, with only a few exceptions, the frequency
response of individual receivers falls off above 1 or 2 khz".

and

"As shown in Fig. 1, the combined frequency response of all receivers through the test bed (the middle curve, in blue) was –3 dB at 2450
Hz and –10 dB at 4100 Hz".

I am really unable to comprehend how anyone can fairly judge the upper frequency response of a AM broadcast station with this
kind of roll-off of frequencies above 3 or 4 khz, built-in to the test receivers. I really want to know how one does that.

That is a physics lesson I'd like to sit in on sometime.

 

[BofH]

Guys,

The *cheap* radio's in the chain outlets *are* the design that Bruce speaks of. (no doubt the most popular radios sold these days - considering that the average Joe buys on price alone)

Take a walk into your local $2 store and buy ever one of these cheap radios and you'll be amazed at the WIDE AM bandwidth.

The latest trend I've noticed is analogue knob-tuned "digital" displays, effectively instead of an expensive PLL circuit they are using an analogue circuit to tune the station. Needless to say, the digital frequency display never stays right on channel - they drift.. normally 1-3hz off after the radio has warmed up!

I'll bet the vast majority of radio's you find in the average supermarket to be this exact design.

I've seen it most commonly in handheld pocket radios, and cheap boom boxes etc, although its crept into seeminly decent mini systems as well!

Of course most Sony, Panasonic, Sanyo etc radios make the grade... reputable japanese brand names. However, even brand name radio's are rapidly becoming VERY hit and miss as the manufacturers try to reduce costs.

The sad thing is that even FM sounds terrible on these radios.. many of them don't even bother with FM stereo to save a few cents!

Matt

 

[FFoti1]

You clearly haven't spent much time reading the HD Radio forum here Frank. Logic is completely irrelevant and unnecessary. In the last week IBOC has evolved into a government conspiracy to keep the populace dumb. No, I'm not kidding.

I for one found the article interesting and informative. Thanks for taking the time and thanks for defending your work and the work of your fellow engineers.

Thank you.

Yes, you're right, I've not spent any time in the HD Forum. If that 'arena' is like some of the other broadcast list-serves, I have a good idea how those discussions are proceeding. One would think that "The Man From U.N.C.L.E." will be called in to rescue radio from the evil "THRUSH". That should jog some memories.

Seems this topic is following our general social disciplines, by allowing it to become too political, conspiratorial, and lacking sense. I'm not talking about the tech, but referring to those whom have turned any of these discussions into self-proclaimed soap-box sessions.

My comments are meant to support the work that was done. If others wish to challenge the effort, I welcome that, but please do it with comprehensive technical data, that one can support, and save the rhetoric.

-Frank Foti