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Where available how is AM-HD configured for listeners?...
- Thread starter thezak
- Start date
HD AM is not capable of side channels. Not enough bandwidth there.
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rbrucecarter5
Guest
The last time I heard it - was before power lines were installed on the one road without them and made further reception impossible. The magnetic field lines of power lines seems to disrupt HD AM even if there is no interference from the power line. I used to notice this over and over again - the high tension lines with hundreds of thousands of volts disrupt HD AM for about 1/4 mile. The ordinary 1700 volt three phase distribution lines disrupt for about 50 feet. Unfortunately most roads have power lines along them. What I heard was very good. It was just a sports station about 60 miles away, but when it decoded it sounded great. If you are into that sort of format it probably would be exciting enough. That is what HD AM is good at - talk and sports. The last time I heard music on HD AM - aliasing was taking percussion instruments like triangles and frequency shifting them way down in frequency for a surreal effect, very fatiguing to listen to. Definitely NOT delivering on the promise of AM sounding as good as FM! The only technology that did that was C-Quam coulpled with AMAX. I had heard the same song on the same station weeks earlier before the conversion from C-Quam to HD. The same triangle was crisp, clear, on frequency. Station - KMKI. Distance from towers 10 miles. Receivers - Radio Shack TM-152 C-Quam, Sangean HDT-1 HD. Song - Beautiful Soul by Jesse McCartney. I wish I had video captures but youtube didn't exist and my video skills were not great.
There are fewer and fewer AM-HD stations around, but depending on where you live, this is a good time of the season to hear the remaining ones at a distance.
Beyond Bruce's gibberish, the quality of AM-HD essentially equals that of FM analog with less noise. In my view the quality is actually quite good. Far better than analog AM. Some have been critical of music on AM HD, mainly because the station uses MP3 files, where the compression of the audio file isn't compatible with the compression used for HD. It's a shame that the industry never got behind AM HD, or some sort of transition plan, because its definitely an aural improvement.
Beyond Bruce's gibberish, the quality of AM-HD essentially equals that of FM analog with less noise. In my view the quality is actually quite good. Far better than analog AM. Some have been critical of music on AM HD, mainly because the station uses MP3 files, where the compression of the audio file isn't compatible with the compression used for HD. It's a shame that the industry never got behind AM HD, or some sort of transition plan, because its definitely an aural improvement.
AM HD required a wider transmit antenna bandwidth of approximately 40 kHz, which many AM antennas were not capable of. After all, AM antennas were designed for 20-30 kHz bandwidth. I recall reading years ago that directional phasors in particular were a major impedance (haha, electronics joke) to sufficiently broadband AM antennas.
Probably not an insurmountable challenge, but the other big problem with AM HD was the very narrow analog bandwidth presented to listeners on ordinary radios, with the audio bandwidth reduced to 5kHz.
With all the AM stations becoming second class citizens to puny little 99 watt FM translators, I think it'd be nice if they could just go all-digital on the AM side. They all say "no one listens to the AM anyway" so why not go all out with digital and be done with it? I understand the HD-only broadcasts aren't really wide like the hybrid digital-analog version we are saddled with (heh) now. And allegedly-reportedly it works even better.
Who's gonna listen? How many IBOC receivers are out in the field? Can they work with just a digital signal, without the analog carrier? Does anybody really give a flying...?
No one gives a flying… about the AM stations now. They're just a waste of electricity for stations who concentrate on the FM. I know of several that have cut power and directional antennas in an attempt to save money after they got on FM. So I'm saying it seems like a good way to extend coverage and drive digital radio sales by converting these useless AMs into a digital signal.
And as far as I know all the AM HD capable radios can do digital-only reception.
Yes, existing AM HD receivers can operate with digital-only operation. I'm not sure of the technical details, but the NAB, iBiquity and CBS Radio performed some tests on this in North Carolina a few years back:
http://www.nab.org/xert/scitech/pdfs/rd050613a.pdf
I'm also unsure if this mode of HD operation reduces the bandwidth, and therefore allows an all-digital station to operate with a standard bandwidth antenna system. If so, it would also reduce the digital "Hash" that DXers pick up from HD+Analog stations.
A couple years ago, several other stations field tested full-digital mode and submitted their test results to the NAB and FCC. I tested full digital mode before HD radio for AM was even approved. It worked well then too, even with a prototype receiver.
Honestly, given the small percentage of AM DX'ers left in the world, the industry shouldn't care whether these folks are bothered by the sideband hash effecting analog stations. Tests have proven, going all digital not only increases the amount of available bandwidth for the data by eliminating the analog portion and increasing coverage, but it naturally reduces the amount of sideband noise by narrowing up the mask. It confounds me how the shortsightedness of squeaky wheel DX'ers who just can't seem to understand they can DX full digital stations almost better than analog ones, (RMS vs. peak). AM station owners should be looking for ways to generate interest in what could possibly be the reintroduction of their medium to a new generation who's cars already have the ability to receive HD, rather than going down with a sinking ship of staying analog until AM fades into the history books.
Regarding who would listen? HD-capable radios in cars has become pretty available, even as standard equipment. There will come a time when the waning numbers of AM analog, and the amount of available HD radios will be at a crossing point. The question at that point will be; will owners 'stuck' with AM stations take the plunge and lobby to convert to all digital mode, or will they shut the station down and turn in the license?
An all digital AM band might be very interesting. Since there is no analogue signal being broadcast, the sidebands aren't an issue, because they're not being used. With IBOC, AM signals are only using 10% of the power of the analogue signal. A full powered digital signal has the same coverage as the analogue signal. DXing a digital signal would introduce a new element into the hobby, and could be a lot of fun. Imagine the clarity and the distance. I've never heard HD AM, but I wouldn't mind so I could make up my own mind about it. From what I have read, the issues plaguing the hybrid model in use now would go away. It would be less susceptible to interference and dropouts. Building penetration is supposed to be very good in full digital mode.
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rbrucecarter5
Guest
Here we go again with an insulting post about DX'ers - attempting to marginalize them and their influence. What the advocates of HD fail to realize is - that according to the laws of debate, they have just lost! The moment you have to resort to insulting your opponent, the debate goes to that opponent. Look it up! Now - as far as DX'ing is concerned, I may be a DX'er, but I was one of the first people to post on here how excited I was about the prospects of DX'ing full digital AM. A full TEN YEARS AGO - when I heard HD sidebands from the Chicago clears, during the day, at a rest stop near Clayton NM. That has to be a good 1000 miles away! Not just a fluke, either, I did the same thing again 6 months later at the exact same location. The AM noise floor was very low, there was only one local station, and the big stations in Denver and Amarillo were all but absent. Yet - using a very ordinary Delco car radio, with a very ordinary windshield antenna - there were sidebands on 660, 680, 710 (obliterating what was left of KGNC), 730, 770 (destroying KKOB), 790, 880, 900. The frequency pairs were too much of a coincidence. There was no trace of analog from Chicago. Just the faint sideband pairs. That car was not HD equipped. If it had been, I am almost certain I would have gotten a lock on at least a couple of them! Full digital has the potential of 1000 mile daytime range. I said it then, I am saying it now. But - in the intervening ten years - the industry has changed. AM stations, including some of those Chicago clears, have abandoned HD for the FM band on translators or "full" power FM stations. Building penetration is the new mantra, with lemmings jumping over a cliff to get it. Building penetration on AM is not the problem. The problem is flourescent lights and network equipment. At least the network equipment interferes worse with FM, so penetration is not going to happen with an FM translator. It used to be - the opinions and observations of careful, scientifically oriented DX'ers were a valuable resource to station engineers, because it was early warning that something was wrong at the transmitter site. But - when HD radio came along - it was more of a religion than anything else. If anybody - station engineer or DX'er - had anything bad to say about HD radio, they were treated as heretics and burned at the stake in technical forums. That continues today. I will not be deterred. The emperor has no clothes. AM's problems started decades ago when they started putting formats on the air that were not compelling to listeners. And the do-nothing politically oriented FCC operates the same regardless of the party in charge - they did not act on AM stereo when it could have made a difference, they did not act when new devices appeared with huge interference levels on AM. AM was virtually finished off when CFL lightbulbs became law - the AM owners said NOTHING in protest to the introduction of hundreds of millions of interference sources mandated in homes. And they said nothing when cheap Chinese switching supplies - with a design defect that produces high levels of interference were also mandated into law. Now interference is not only limited to the home - even one of those defective power supplies can radiate hundreds of feet. And there are now hundreds of millions of them in use. The AM station owners said NOTHING. AM owners said NOTHING when some models of new cars and other devices do not even have an AM band. They said NOTHING when iPod docking ports charging a device are pumping out so much inteference that the AM band on those devices is jammed. DX'ers KNEW about every one of these problems. If the AM station owners, engineers, and the FCC had LISTENED to DX'ers and worked to solve these problems - instead of insulting and marginalizing DX'ers - then it might have made a difference. As for AM's prospects now - get ready for more and more irrelevant, un-listened to brokered stuff because that is now the only future AM has. And the FM band? It is being re-made in the image of the AM band. Defective Chinese supplies jam FM to a lesser degree, and cheap networking equipment, cell phones, and other devices are going to keep FM from penetrating buildings and eventually homes - just like AM. The ones who know - DX'ers - we are still ignored, insulted, and marginalized. As far as I am concerned - I haven't bothered to DX in years. Not because it isn't a great hobby - there is just no station out there - anywhere - that plays a format I care to hear. I still DX - to hear those FM translators that are supposed to have massive penetration of buildings. Yeah - right - whatever. Good luck with that business model. Keep playing boring corporate lawyer approved music, talk, sports, and foreign. I've got 10,000 songs on my iPhone - guess what I am listening to.
I'm an avid HF DXer and still regularly spin the dial on the Ancient Modulation band, and I did not perceive anything in this thread that I'd consider insulting to DXers. So I don't know where you're getting off with that accusation. DXers are a dying breeed; weare a minority of listeners; skywave is not a major draw for stations or advertisers anymore and hasn't been for decades. This is simply the reality of our existence.
I've been a member off and on of this site for eons and I remember all the back and forth when HD was getting rolled out. DXers and engineers alike acknowledged the issue with AM's sidebands affecting long distance reception at night. DXers were also in a panic over FM sidebands but that quickly died down because very few stations had their coverage affected adversely by someone else's sidebands. The whole anti-HD thing is, frankly, overblown fear of the future, wrapped in a reality that the technology is not that great.
In reality, DXers have adapted to dealing with sidebands on AM, and stations have pretty much abandoned the concept in favor of little pea shooter FM translators. So, all this complaining is pretty much for nothing at this point.
I've been a member off and on of this site for eons and I remember all the back and forth when HD was getting rolled out. DXers and engineers alike acknowledged the issue with AM's sidebands affecting long distance reception at night. DXers were also in a panic over FM sidebands but that quickly died down because very few stations had their coverage affected adversely by someone else's sidebands. The whole anti-HD thing is, frankly, overblown fear of the future, wrapped in a reality that the technology is not that great.
In reality, DXers have adapted to dealing with sidebands on AM, and stations have pretty much abandoned the concept in favor of little pea shooter FM translators. So, all this complaining is pretty much for nothing at this point.
Well alrighty then! Creating your own playlist would be a good choice.
DX hobbyists are conservatively .0001% of the total radio listening audience, and hardly a factor. I also (surprisingly) do agree with one thing in your latest War and Peace-length rambling rant; that is the owners of AM stations need to take responsibility for the decline in their business by ignoring the trends and options. DX'er's, in spite of being such a tiny group, were the ones who stepped up to complain, becoming the lone squeaky wheel. Did many broadcasters speak up in much higher numbers to override the naysayers? Nope!
That said, I still argue there is a chance for AM stations to at least try to reverse the trend. It will take time, but if someone doesn't try, it's over for the AM band.
Please tell me none of you are actually suggesting that if you put a popular format like CHR or contemporary country on a good AM sans translator that it would even get three listeners. Except for people of my father's generation, no one associates AM with music anymore.
Maybe — maybe — if you were the only station around AND on AM you could be successful playing a contemporary music format as a standalone AM. But the dial is so saturated and high speed internet has reached many small towns, so there is almost nowhere outside of some barren Indian reservation out west where the dial is even remotely empty anymore.
Maybe — maybe — if you were the only station around AND on AM you could be successful playing a contemporary music format as a standalone AM. But the dial is so saturated and high speed internet has reached many small towns, so there is almost nowhere outside of some barren Indian reservation out west where the dial is even remotely empty anymore.
That one sentence (in the most ill-constructed, rambling paragraph I think I have ever read) says everything about what you fail to understand about radio.
First, corporate lawyers don't have anything to do with the approval of music (unless a station is fined for broadcasting a song with indecent lyrics). Programmers program music for listeners, not lawyers.
Two, talk and sports have proven themselves to be viable AM formats (as long as they don't get FM competitors) and were among the surviving formats on the band when music listening moved to FM... despite some good and noble efforts by heritage AM music stations to survive.
Three, foreign language stations have been around since the band started "filling up" right after WW II. They provide a needed service, often on stations that don't have signals that can compete in the general market.
Fourth: bully for you for having 10,000 songs. When the average user of MP3s is surveyed, they are found to be playing around 200 to 300 songs at the most. The trend is to on-demand streaming, where very few songs get most of the listening. In other words, you are not typical and should not think that your "eclectic" (meaning "bizarre" in this case) taste is common to anyone else.
Finally, and in reference to your comments about DXers, please recognize that DXers are hobbyists who want to log stations. They are not listeners to those station's content, but seekers of signals. They do nothing useful for a radio station and haven't for the last 50 years or so since stations for the most part stopped caring about listening in distant locations. I caution you on this in my role as a 60-year AM DXer who has even been on the BoD of one of the leading MW DX clubs... so, I can tell you, in the immortal words of Archie Bunker, "stifle yourself".
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rbrucecarter5
Guest
(1) Corporate lawyers were a constant enemy of KZEW Dallas. A fact they occasionally mentioned on air.
(2) Talk and sports are not a good thing when you can receive the exact same program on half a dozen frequencies. Where is localism or diversity in that? How does the sports format - or the talk format for that matter meet the mandate of operating in the public interest? Just asking, because it seems that money and ratings long ago supplanted stations operating in the public interest. Making a profit for somebody does NOT necessarily mean that the station is operating in the public interest. The reverse is true - they might be operating in the public interest - if ratings show they are providing a service people want.
(3) Foreign language may meet the serving the public interest criteria - but NOT the way it happens locally. Two competing Spanish religious broadcasters snatch frequencies so the other church can't. That doesn't serve the public interest. Once church has what - 100 members tops while the other has about 80 members? Really a "good" use of a dozen frequencies. The only justification - they can afford to do it / they can pay the highest price at frequency auctions. The auctions themselves do not serve the public interest. They only insure that the group with the most money gets the frequency. Which doesn't serve diversity at all.
(4) I could call your taste in music bizarre. Or anybody else's taste in music bizarre. Given that we are all unique individuals, I think everybody's taste at one point or another will be bizarre to somebody.
(5) As you point out - some people DX to log stations. Others DX for content and I am clearly in the latter category. If it doesn't play music I like, I don't listen. And I went to some extreme lengths to get the music I want. Broadening this a bit - in the days of football blackouts there were a LOT of TV DX'ers who wanted to get the games on out of town TV stations. I still have the articles - one of which talks about how to cut an antenna exactly for a VHF channel. Another how to make a (really good) pre-amp for each VHF channel. Some really sophisticated stuff. All for football fanatics who happened to have electronics knowledge. I am probably a music fanatic that has electronics knowledge. The speed at which I adopted HD radio for oldies / smooth jazz / indie rock / dance HD-2's here demonstrates that. No matter how flawed the technology is - it provides the formats I want so I use it. Same with streaming, satellite. DX - I don't even bother because every decent frequency here is covered by warring Spanish language churches. Great use of frequencies - guys. Somebody give each church ONE really good frequency so they can give up the rest! PLEASE!
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