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Digital Signals Spark Static From AM Radio
Carl Bialik writes "Digital radio is touted as broadcast radio's golden ticket, but the transition to digital broadcasts is creating static and interference for many smaller AM stations that are still analog-only, the Wall Street Journal reports: 'The AM stations most affected are those whose neighboring stations -- nearby on the dial -- add a digital signal.' The WSJ adds, 'For some small AM operators, it adds insult to injury that the only company licensing the digital broadcast technology is one backed by the small stations' deep-pocketed competitors.' Critics question why the FCC only approved the technology from that big radio-backed company, Ibiquity."
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It is unfortunate that different types of media are conflicting this way, but I'm not sure there's anything that can be done about it.
"I lie right back and turn the radio on..."
Not everyone wants to shell out money to upgrade their car radio to satellite. Out here in Sask. AM stations rule because of our vast geographical distances. The AM dial is not crowded, and some nights you can pick up stations that are more than 400 miles away.
I wonder though, is this digital signal the stuff that identifies a radio station for new car radio displays?
Saskboy's blog is good. 9 out of 10 dentists agree.
The AM stations most affected are those whose neighboring stations -- nearby on the dial -- add a digital signal...Critics question why the FCC only approved the technology from that big radio-backed company, Ibiquity.
Man, that Ibiquity seems to be all over the place these days.
He who knows best knows how little he knows. - Thomas Jefferson
Critics question why the FCC only approved the technology from that big radio-backed company, Ibiquity.
What about: 'Because they payed the most money and the FCC does not mind creating monopolies when properly greased.'
Once again, I am happy not to live over there, my middle of the road ideas would be considered ultra left wing in over there.
This space is intentionally staring blankly at you
Can someone explain why I need to by a $300 radio to listen to something that is not perceptibly different?
At any rate it seems like another way to fleece the public.
Anyway analog broadcasting should be preserved as they are easy to implment and use in the event of an emergency.
to listen to AM radio, usually the morning shows are the Howard Sterns & I'm rushing to get to work. Now PM radio tends to be more informative.
Oddly enough, I have one of those "emergency" flashlights that would also change the channels on yet another ancient TV.
And in yet another case, we had an ancient answering machine that would randomly pick up other people's conversations for seemingly no reason. Technologies clash more often than we realize.
This will be a tough call for some of you. Lots of small AM radio stations are Christian stations. Prejudice against big business or prejudice against religion -- which prejudice will win?
And for those who are going to say "silly, AM isn't hi-fi," just listen to a GE Super Radio or Tivoli sometime.
Sounds like an awful idea. It's annoying when the station you're tuned into starts to fade as you drive along; I can't imagine being interrupted by all those sharp chirps and clicks that digital feeds make when they're interrupted.
Interesting article but it doesn't really establish a cause and effect for the interference. Wonder if this is this is caused by a limit in the digital protocol, a design problem with the transmitters, or if the problem can be solved by improvements in receivers?
A simple 4 step process:
1. Buy radio station neighbouring a competitor's band.
2. Broadcast FCC legal digital interference.
3. ???
4. Profit!
Major lawsuits coming? Anyone?
Saskboy's blog is good. 9 out of 10 dentists agree.
Yeah, I'm in Calgary and I can pick up CBC 540 from Regina which is, what, 600 miles away?
I miss Saskatchewan, that's why I listen.
When I was younger in Saskatoon, I used to listen to CFUN in Vancouver (over a thousand miles away).
I believe the digital signal to which you are referring is the Radio Data System. It's nice when you don't know the name of a song or the artist and some stations allow you to keep your radio's clock sync'd.
Mr. Universe: "They can't stop the signal, Mal. They can never stop the signal."
Do you need a napkin to clean up all that spittle?
"I lie right back and turn the radio on..."
I recently purchased a car stereo with digital support and can say that the AM digital stuff sounds absolutely terrible! You really hear the digital artifacts... tinny, cellphone-ish sounds. Also, the analog signals aren't in sync with the digital ones so that when the stereo goes from one to the other, you either miss something, or hear the same thing over again... typically around 4 seconds worth. Get into an area where the AM signal isn't too great, and the stereo repeately goes back and forth between analog to digital. It's enough to drive you insane.
Hopefully digital AM will get dropped as people realize how terrible it sounds.
FM, on the other hand, sounds great and doesn't have the sync problem.
If I can only figure out how to turn off the digital AM support in my stereo!!!
In case this is just a fluke, here are the details:
AM 740 in San Francisco.
Headunit: Kenwood KDC-890
Digital Box: Kenwood KTC-HR100
You mean the early 1900's AM started up in 1906, at least thats what wikipedia says anyway.
I am a broadcast engineer.
This "HD Radio" is actually called IBOC (in-band, on-channel). Radio works by changing the amplitude (AM) or the frequency (FM). You're only permitted to change it by a certain amount--your bandwidth--otherwise it will interfere with adjacent stations. By adding more information, the digital data stream, you're using increased bandwidth.
The other big issue with AM is overnight. Most AMs power down or sign off at sunset because the atomosphere changes overnight and AM travels much farther--for example, I get ESPN 1000 out of Chicago 1,200 miles away and the 1000khz station here shuts off overnight. The sky is already being polluted with IBOC hiss (sound just like a modem) and it's DEFINITELY hurting the smaller AM stations who have special authorizations to stay on overnight, but at a significantly reduced power.
Surf the spectrum and you'll see. This has been a HUGE issue in the broadcasting community and it's about time it gets mainstream attention.
It's not that anybody paid the FCC commissioners directly, or even made campaign contributions or anything like that.
The big stations have more listeners. The big stations have more lobbyists. That's because the ones funding digital radio (and its concordant mind control capabilities) only pay attention to the big players.
The problem is moving to digital radio in the first place. It's a scam to sell radios, to control our minds even more than before.
Lucky for me, my hat keeps out all the signals anyway. Damned aliens can't get me!
540 is broadcast in Saskatoon and Regina, and possibly elsewhere. I could pick up Calgary country AM in the 900 range when in the Wood Mountain hills of SK, late at night only. It's about a 7 hour drive to Calgary.
I see the digital broadcast can be simul-cast with analogue, but that it still interferes with neighbouring analogue signals. They can't even transmit digital at night legally.
Saskboy's blog is good. 9 out of 10 dentists agree.
I am not a radio-frequency broadcasting expert, but here in the UK, the word 'digital' can describe three types of receiver. Those that have a digital tuning system, those that can decode the digital information broadcast alongside some analogue stations (RDS - it allows enabled sets to switch to relevant traffic information at the right time, and so forth) and those that pick up digital audio broadcasting (DAB - proper digital signals running on multiplexes that would seem to need better transmitters than are available; probably much the same as the US satellite system, but without the satellites).
DAB is supposedly the future and I'd be willing to bet a small amount of money that RDS is the stuff causing the interference. In other words, TFA is indeed both inaccurate and poorly written.
So, the FCC was happy to approve IBOC AM radio and not a competing technology, D-CAM but more than happy to let the market decide which digital cell phone standard should apply? If the broadcast standard a station wants to use does not cause adjacent channel interference why does the FCC care what technolog a station wants to use? In the case of IBOC, it does cause interference and shouldn't have been approved in the first place, but that's what happens when you have money and lobbyting power.
I really do not see the issue here, AM should have been killed off 20 years, sounded like ass then, Sounds like ass now, all i can see is a few of those Religous stations are mad because they are trying to reclaim those frequencies for hopefully something useful. Yes i realize AM was the FIRST sucessful broadcast radio technology with that said, put an exhibit in the smithsonian and call it done.
Still, I enjoy fiddling with crystal radios etc and would hate to see the AM stations lost completely.
Engineering is the art of compromise.
I love it, another untested closed standard.
l e
The AM MW mode should be left alone. The band that it is used in the US is not that reliable for digital modes, but it is very reliable for AM transmision to local areas.
This band/mode is essential for emergencies. Everyone in the US has an "AM" radio somewhere in the house or their car. It will just work.
Has the FCC rated this HD radio as an actual mode?
I have started to experiment with drm on my HF equipment and in fact i am upgrading to a SDR-1000 in a month or so.
With my existing equipment, I have heard a few of the DRM broadcasts on HF Shortwave and they are impressive. I have heard that you can broadcast it with a SDR-1000.
DRM is an open standard based on mpeg4. In fact this is the standard for european countries. There is GPL code for both listening and transmitting it.
http://en.wikipedia.org/wiki/Digital_Radio_Mondia
KB0FHF
I used to listen to an alternative station, WBER (wber.monroe.edu) on the way to work but recently a local NPR station added HD radio. These stations are 90.5 and 90.3 respectively. I can't get squat from WBER anymore. Lots of cross fading to the NPR station. I just thought it was because they were so close, not because of HD.
If Grove Enterprises doesn't have it, it probably is no longer on the market
http://www.grove-ent.com/
I design radio test equipment for a living - so welcome to Modulation Theory 101.
Amplitude modulation, or more correctly double-sideband non-suppressed carrier amplitude modulation (FCC emission type A3E), results in an RF spectrum that is twice as wide as the highest frequency component of the modulating signal. In other words, if the signal you are modulating has as its highest frequency component 3kHz (normal voice signals), then the resulting AM signal will occupy 6 kHz of RF spectrum - from 3kHz below the nominal carrier frequency to 3 kHz above the nominal carrier.
Now, we have to consider the concept of "receiver bandwidth". A properly designed radio receiver will only pick up signals within a given frequency difference of where it is tuned (the "tuned frequency" or TF) - this is the receiver bandwidth (sometimes referred to as "IF bandwidth" since in modern superheterodyne receivers it is the bandwidth of the narrowest intermediate frequency section that determines the overall receiver bandwidth).
Now, consider the case of 2 radio stations spaced such that their carriers are 10 kHz apart - the normal spacing for AM radio stations. Assume your radio is tuned to one of the stations. If your radio has a receiver bandwidth of 20 kHz (in other words receiving signals from 10 kHz below tuned frequency to 10 kHz above tuned frequency), you would hear the station you *weren't* tuned to as a 10 kHz whine on your radio (the carrier of the other station, 10 kHz off your tuned frequency), plus the audio of the other station inverted in frequency (low tones become high tones and vise versa).
So, your radio has to have a narrow filter to receive only those signals within 5 kHz of tuned frequency (total 10 kHz). Now, a perfect "brick wall" filter would allow, say, 4 kHz through, but stop 4.00001 kHz dead. Now, filters are not perfect, and so if your filter allows signals from, say, 4 kHz away from TF, then it will not totally block signals until they are, say, 6 kHz from TF. So, radios are designed to allow signals +/- 3kHz from TF in (receiver bandwidth of 6kHz), and block signals more than 5 kHz from TF.
OK, now, how do we add any new signals to the A3E signal so that we can put the digital signal in place? We cannot place those signals within 3kHz of the carrier without going to a LOT of trouble, otherwise analog radios will "hear" the digital signal as noise. So what IBOC does is exploit that "no man's land" from 3kHz away from carrier to 5kHz away from carrier to put the digital signal in. Now, your old analog radio will still "hear" these signals to an extent, but between the attenuation of the receiver bandwidth and the attenuation of the audio chain, this noise will not be very perceptible.
HOWEVER - remember how I said there were no perfect "brick wall" filters? Well, that applies to transmitters too. The transmitter may be putting signal into the 3 kHz to 5 kHz region, but it will put some unwanted signals beyond 5kHz (they will just be very weak compared to the desired signals) - and that means into the frequency band of the next guy on the dial. However, if the next guy is far enough away in space, your signals that are in his band (which are already weak) will be weakened further by distance, and won't be perceptible by the other guy's listeners. Also, your signals that are in the 3kHz to 5kHz area will be weakened by distance, and attenuated by the receiver's filters, and so they, too, won't be very objectionable.
Except in the fringes between where your spatial region stops and his starts. That's what is happening here - if you are close to "the other guy" you won't hear the interference, but if you are far from him, and close to the digital station - you get noise where there was none before.
Add to this the fact that the stations that are going digital are the stations with money - and how do you get money? By having lots of listeners. How do you get lots of listeners? Among other things, by having lots of POWER <Tim Allen Grunt>. The little station
www.eFax.com are spammers
Digital radio sounds MUCH better then the old AM and FM. And the bit rate is also much higher than the Satellite providers XM and Sirius. It is CD quality audio on most stations.
So I can see why the radio stations, large and small, are rushing to push a free service that sounds much better than anything out there.
Most HD stations are still without commercials!! And from what I hear, they should be that way for at least the next year or two.
By the way, doesn't Ibiquity have a patent on the HD technology?
AM radio sucks up interference easily. When I want to listen to sports radio instead of the iPod, I can tell every time someone within 10 feet of me gets a text message or call. It's a nice discreet REAACHACHAHHEHRTAHAHHAHAHACHHCHCCCT noise.
Bury me in mashed potatoes.
AM radio is unlistenable even without this new interference. It is static-laden, low-fi and intolerable, given any other option. That other option is satellite, of course. $0.33 per day plus a $50 radio is enough to get you set you up with a Sirius or XM satellite radio with terrific digital fidelity and static-free reception from coast-to-coast. On top of that, you get to hear people talk like human beings, not watered-down, pussified, 'G'-rated, FCC-compliant clones. I don't know anyone who can afford to drive a car that could not afford the above. I have Sirius, and I can tell you that once you start listening, you simply don't listen to FM radio anymore, let alone AM radio.
In any case, the right wing speech, expecially hate speech, in relegated to the ghettos of the AM dial. Which means that nything that interferes with the AM stations is a point for the liberal media. I mean what self respecting conservative is going to work under the kind of conditions that typify the average liberal FM radio station.
Ethernet interferes with AM 560 kHz - I can vouch for that. My dad listens to AM 560, and started getting interference with it when their computer was hooked up to a cable modem. I did all sorts of troubleshooting to isolate the problem, and got it down to an Ethernet cable from the modem to the network card. I looked for, but couldn't find, a shielded cable with RJ-45 connectors. (If anyone knows of one - let me know!) I ended up connecting to it via USB instead, which took care of the problem.
- Bill
"Can someone explain why I need to by a $300 radio to listen to something that is not perceptibly different? At any rate it seems like another way to fleece the public." I totally agree. Until sometime as I NEED a digital radio (ie, when/if AM stations are slowly phased out), I think I'll stick to a regular radio receiver. The supposed increase in quality is negligible, and in my opinion, definitely not worth the money. I'll hold out for as long as I can.
Would be saved by turning into what satellite radio already is. Until they cut the commercials, stop censoring music, and get some variety they will continue to watch their audience get smaller.
That's RDS, something that's been available for years but only recently switched on at some stations. The audio is still analog though.
HD Radio has that feature too, and can show Artist/Song/Station info and also possibly things like weather or traffic too, depending on how the station programs it.
Sad part is that the same Azzhats (clear channel etc) will still own the bulk of the AM stations, The bulk of AM digital will be higher fidelity garbage, but it will still be garbage.
There are a few good AM stations, but they are a small minority.
I'm fascinated by your comments because my views are similar to the grand parent.
So you have killer OTA HDTV.
But I don't see what's so *great* about having more when it generally means a plethora of re-runs, mundane cooking shows, and an automatic nipple of crap for kids to suck on.
Is it the whole watercooler, "Did you see show XYZ last night?" thing?
I pay $40/month for vaguely improved internet connection. If you put the difference between my 40/month bill and your total cable bill in the bank at the end of a few years, the savings look pretty good.
Where's the value for you?
http://www.maxineudall.com/2010/02/should-economists-be-sued-for-malpractice.html
It's worth noting that the "digital" radio referred to is the In Band On Channel (IBOC) system used only by the U.S., and manufactured by Ibiquity.
The rest of the planet wisely chose a system that was entirely digital, and which consequently does not have these problems, while the Americans, defending the inalienable right to own radio stations using 1930s technology, or some such thing, fought for a system which sqeezes a digital audio stream into their existing AM or FM signals.
An all round bad idea, and yet another demonstration why engineering decisions shouldn't be the province of politicians and lobbyists.
Blah blah.. politics and big money... blah blah...
Three Squirrels
How about prejudice against misuing the public radio frequencies?
I couldn't care less if it's Christian programming being stomped on, or Howard Stern. Of it Howard Stern was getting stomped on by Christian programming.
They should bloody well keep the radio waves working correctly without spilling over onto other frequencies.
But, I'm sure when the FCC mandates an all digital world and sells off the bandwidth, that argument will no longer apply. Of course, should they ever need plain old modulated, analog radio in an emergency they'll be screwed.
Lost at C:>. Found at C.
Here in Vancouver, I listen to AM 810 KGO out of San Francisco, which has to be what, 1000 miles away? I guess no one in Canada actually listens to thie stations in their town :)
My parents flipped out after they built their new house because the fireplace would suddenly come on when they weren't home. Turns out the neighbor's garage door opener was the same frequency/channel as the remote to the gas fireplace.
Han shot first.
A remote control for a fire? Now that's lazy.
This should be obvious, but the WSJ is not an expert on radio technology or legality.
If a station is interfering with an adjacent's signal, then they have to figure out how to fix it. It's not allowed by the FCC. Seriously. Maybe they need some bandpass filters or to lower their modulation to a sane level.
"Anonymous"
Radio Engineer
C. Crane has a nice selection of antennas for AM, FM broadcast, SW and Wi-Fi.
The Boston Acoustics Recepter is worth a look as a first generation HD Radio. If you are serious about AM, this is the place to begin.
Without directly answering your questions (I'm not the OP), I have a few questions for you:
1. Instead of buying CDs, buying MP3s, or even downloading music illegally, do you choose to tape your music on audio cassettes off of AM broadcasts?
2. Assuming the type of music you like is never played on the radio, do you get your music by hand-recording live shows on cassette tapes?
3. Do you prefer the sound of music on record players, because the natural filters and background scratch are how "music is supposed to be heard"?
4. If you do download music illegally, do you mind if you get versions that are 48 kbps, full of compression errors, or are missing one of the sound channels?
Nothing necessarily wrong with you if you do. But many folks don't like dirty, scratchy music. And I will argue that there are people out there who consider all music to be a grand waste of time, when the only real spiritual relaxation is ( enter alternate hobby X ).
It doesn't hurt to be nice.
In my experience, it also degrades the analog FM signal (of the IBOC broadcaster) with additional multipath.
It's sad that the FCC will go after 2 watt pirate broadcasters, but not care about interference on a much larger scale. And, as mentioned elsewhere, the codec is proprietary, and widely considered to sound like crap.
For me, the value has nothing to with getting more of anything, in fact my OTA HDTV gives me much less than cable, and generally nothing additional than I already have on my cable. The value is that I personally enjoy watching the shows I like with a better picture and digital suround sound. Call me nuts, but after spending ~12 hours on the computer at work with my mind racing to create hardware designs, I typically enjoy a couple hours zoning out in front of a TV. That said, I like my experience to be the best it can, especially if it's free or for a small one-time cost (the cost of the HDTV tuner rolled into the price of my TV)
As far as the savings, I really don't give a shit. I could also spend my entire evening with no lights nor heat and save money that way. But, I choose to endulge in the modern luxuries, and am even willing to pay for it.
Maybe I am a bit paranoid since the news of paid advertising shills posting positive reviews/reponses in forums has become common knowlege, but that response right there sounds like the sales pitch from a stereo saleman I heard the other day -- almost verbatim. Also, it goes against what I have found in my research -- and why I decided that the technology was not worth adopting. If I want "digital radio" I can get it much better from a podcast and an FM transmitter for my iPod. I hope /. is keeping an eye out for posts like this, considering they are a ripe target for the shills -- I am sure companies would love to "modify" your average reader's opinions. My $.02.
Ehren Goldberg
"First they ignore you, then they laugh at you, then they fight you, then you win."
-Gandhi
"First they ignore you, then they laugh at you, then they fight you, then you win."
-Gandhi
Boeing only handles the right wing.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
The top and middle levels of bureaucracy in the government is RIFE with corruption and payoffs, even if a lot of it is indirect and delayed, witness all the drones who get to retire with a fat and full pension and then go into private business as "consultants" in the same industry they were over seeing. They scratch corporations back while "in service", then get the favor returned after they get out. Both civil and military. It's corrupt beyond belief. Been that way for a long time. It's called "business as usual".
The whole business is a failure. It was started as a nice experiment in people governing themselves, but it has failed, obvious to see. We are in the decline of the grand american experiment, and like all failed civilizations it will go out with a bluster of military might as it rots from within. Similar has happened throughout history, I don't understand why US citizens are still in denial over this, maybe contemlating the failure of empire and relatively cushy and easy livfes is something just too terrible to consider so they have gone into denial or something. The rest of the planet sees it clearly.
We peaked immediately following WW2. It cruised on inertia until the 70s, then started a slow decline. By the mid 90s it became a rout, so the conmen at the top went into overdrive with the boom and bust cycle business manipulations, mostly based on bluster and lies. Soon you will see a huge flight from financing our debt. Just last week Japan has closed up a huge debt financing loophole in the currencies markets, unprecedented in scope and scale and it *barely* made the news in the US,because the movie watching music listening sports worshipping and gaming folks never see this stuff as a general rule, mesmerised by bread and circuses. Once this really starts to hit, then even the dullest of the non sharp will have to admit how utterly rotten and inefficient and corrupt it has become.
It's like global warming, no need to point fingers or try to assign blame, it is IRRELEVANT, what is important is that it is happening. The earth is getting warmer and it will lead to mass climate change then mass geopoliticaland social change. Peak oil is a reality, it is going to hurt. The US became rotten years ago and it has lead to it becoming a rampaging imperialistic global has-been.
The only thing keeping us afloat now is nukes, aircraft carriers, and inertia in the currencies market, which is just about to change. Rome was at their height just before they collapsed. Internally they were rotten, but still had huge militaries, but they found out it takes more than military might to make a viable civilization.
Now, to more directly answer your question, I find that I'm actually watching a few new-to-air series this year, which I find quite enjoyable:
Lost
Battlestar Galactica
Drawn Together
Rollergirls
Monk
Perhaps I'm wasting all my time doing this. Perhaps. But for the first time in 4-5 years I'm not playing an MMORPG or indeed any PC games (except ones released more than 20 years ago). Maybe watching TV is less stimulating for my brain, but then again I used my "free time" last night while watching TV to research the newest ideas in city zoning, with the idea that I can influence my city's new zoning ordinances to stop suburban sprawl and encourage modern, pedestrian-friendly, town-center styled development.
And I would consider that to be more socially and intellectually stimulating that any computer game I could be playing instead.
It doesn't hurt to be nice.
Actually, it's super common in new houses these days, and the whole thing makes a lot of sense. Since the fireplace is gas instead of wood-burning, there's just an IR sensor that turns on the gas. The fireplace can be sealed too (glass or whatever), instead of open to the room. Plus, there's no chimney all the way to the top of the house, only a vent that goes directly out the back of the fireplace to the outside.
I almost defy you to show me a house $200k around here that doesn't have one. Plus, this is Louisiana. The winter gets to about 50 degrees for about 3 weeks.
Han shot first.
I think that the highway contractors are in with Big Radio... Every time I go under an overpass my AM radio goes completely dead
Where's my tin foil hat!
I don't listen to FCC stations, I'm in Canada [CRTC stations instead]. I don't enjoy listening to a bunch of swearing or watered down crud, and my AM dial is pretty much just how I like it. It'd be nice to have a dozen more options like in most markets, but the ~10 AM stations cover most genres pretty well here. CBS and Crap Channel programming does make me wretch by the way.
Saskboy's blog is good. 9 out of 10 dentists agree.
Heads need to roll at the FCC, they are not doing their job.
-- Bob
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
A guy working at a radio station once told me that the large networks pretty much own the market. It used to be small independent radio stations, but not anymore. Like record labels. There are some small ones, but they occupy such a small marketshare that they are almost neligable.
I'm not sure why any of the broadcast stations are bothering with it. If they really cared about audio quality, they wouldn't have an Optimod cranked up to 11 in their audio chain. Most people wouldn't believe how good a properly run AM or FM station can sound, they've never heard one.
Mea navis aericumbens anguillis abundat
IThe worst source of noise in the AM, FM, VHF, and UHF spectrum comes from the poorly designed and shielded switching power supplies that are now almost universally used. I use the HF spectrum for communication, and my power supply for my laptop wipes it out. It even interferes with my TV. I know its the supply as I am an electrical engineer who has done some design work for these types of power supplies. Plus, as soon as I turn off the supply, the interference goes away. Unfortunately, it is very hard to filter and shield power supply noise without creating a very bulkiy power supply. It is not quite as bad for entertainment components as there is more space for the needed circuitry. But laptop power supplies can only be so big before they are unwieldy.
The large cylindrical objects that are part of computer power supply cables are attempts at filtering the noise, but they really only work for very high frequencies. Plus, ethernet cables and the AC line cord also contribute to the problem.
Another potential huge source of noise is the BPL internet access networks that radiate RF energy like a huge antenna because the power lines on the poles act like huge antennas.
I think it is only going to get worse. All of these devices have to meet FCC requirements for emitted radiation, but they really can't go too far without drastically increasing the cost of power supplies. I guess for now, there really isn't a good solution to the whole problem.
FYI, Monk is several years old now. It's been bounced around various networks, which gives it the appearance of being new.
Good luck on your changes to planning/zoning ordinances.
Actually, it's super common in new houses these days
Just because it's common doesn't mean it's not lazy.
Since the fireplace is gas instead of wood-burning, there's just an IR sensor that turns on the gas.
See, lazy. You don't even have to chop and haul wood. What's the point? You don't get the wonderful smells of burning wood. You don't get a nice bed of coals for roasting marshmallows. You don't even get the satisfaction of starting a fire yourself. Starting the fire is more than half the fun of having a fireplace anyway. Gas fireplaces just suck.
Give me Classic Slashdot or give me death!
Have you tried one of those new furnaces that heats your home with the power of self-righteousness? It could save you a bundle on heating costs.
This is not unusual in the US, in any area of technology. I've seen USians build major roads with nothing more than sand for a foundation - 2000AD cars running on 2000BC infrastructure. Sure, the roads break up badly, and I'm certain there are many accidents and deaths on US roads as a result, but cheap & quick seems to be the in-thing. Thomas Telford these guys are not.
Having said all that, is there any fundamental reason why a digital signal over AM should cause any interference at all? After all, it's simply a matter of signal spread and drift. If you're in a narrow enough band and have no drift, then it makes no difference if your technology is analog, digital or purple.
It would seem to follow that the digital layer is inferior in design. Of course, this does beg a question - in order to receive a digital signal and decode it, you need a radio capable of decoding digital data, which means a 1930s radio isn't going to work. Given that the consumer is going to use a new radio anyway, it makes no sense to use AM for the modulation. AM works great for analog, but NASA doesn't use AM for digital signals, and I'd rather trust them for radio design than Clear Channel.
There may be others I'm not thinking of, but the modulation schemes I know of are: Amplitude Modulation (AM), Frequency Modulation (FM) - but isn't good for long range, Phase Modulation, Pulse Modulation and Polarity Modulation. NASA, IIRC, uses Pulse Modulation for digital signals, which seem to work just fine over long distances and variations in velocity, requiring relatively simple, power-efficient decoders.
The other benefit of using a different modulation scheme is that you should get less interference and it should be easier to filter that interference out. Of course, filtering interference would be a non-issue if the FCC mandated that anyone generating such interference had to pay all analog radio manufacturers 100% of the cost of upgrading all equiptment in production and in use with the necessary additional filters. Hey, if you generate the pollution, you should pay to clean it up.
Using a dedicated band for digital radio would work too, and would be the best solution if the net range of frequencies in use does not grow significantly or shrinks as a result. I'm a little concerned that the spectrum is getting very cluttered with not a whole lot of gain. Of course, if the tax payer wants to put Aricebo and Jodrel Bank's Lovell Telescope into space, then it wouldn't be a big problem. However, it seems to me that Clear Channel and Sirius Radio would rather generate the problem than fix it.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Does raving about something that matters diminsh your cognitive ability to understand the problems in the illegal and corrupt Republican Federation of Former America? It is time to stop pretending the Constitution is a napkin for your bum. If you don't like what I have to say, that's your problem, not mine. But we all have to deal with the Republican culture of corruption that is pervading the government of the country that is supposed to be the world's superpower. Or you can keep your head in the hand. Just watch out for the weather. Storm clouds are predicted ahead. Even if you claim after the fact nobody ever expected them.
The real question is - why is it only in the US that these odd technology hacks are being used - the rest of the world is using DAB for digital broacast radio. It seems like the US is the only place that WON'T be using DAB.
Oolite: Elite-like game. For Mac, Linux and Windows
All you have to do is look at the AM stereo fiasco.
You're using a computer! LAZY!!!!!
Back in my day you had to make the pen and paper out of twigs and papyrus, and if you ran out of ink you'd just jab it into your arm and use blood, and we liked it!
Cars? Don't get me started on cards.
These posts express my own personal views, not those of my employer
FYI, Monk is several years old now. It's been bounced around various networks, which gives it the appearance of being new.
I meant "new" in that there are new episodes airing. I don't actually watch it "new new", because it is on at the same time as Battlestar Galactica, and my DVR only has one tuner. I just recorded all the episodes on USA's New Year's Day marathon, and finished watching them last night.
Good luck on your changes to planning/zoning ordinances.
Thanks. Of course being on the city planning and zoning commission, and being tasked with developing more pedestrian-friendly codes, makes it more likely someone will listen to me. =p
It doesn't hurt to be nice.
You know, the slashdot uproar when industries fail to standardize is matched only by the uproar when they do standardize. Why did they only approve one? The stakeholders (manufacturers, stations, govenment) got together and made a decision to go with an established technology. The last thing we needed was a radio format war.
People who think they know everything really piss off those of us that actually do.
My research was checking the online forums for various radio enthusiast groups, discussing the technology with a few of my friends and classmates that are audiophiles, and looking at the websites of those who make the hardware.
However, I did say the wording of your post sounded very similar to the sales pitch a salesman at a local A.V. retailer ran by me (a high-end retailer, mind you). Having worked in retail, I know that most new products are accompanied by a video and/or documentation that tells the sales staff what the product is, and how great it is. These promotional materials are commonly full of statements that are small and quite usefull to the salespeople when they are talking with a customer about said product. The salesman I spoke to used what I suspect is one of these "statements" when trying to sell me on the product, and the content of you post tells me that you might have been exposed to this "statement" as well, either in the capacity of a customer and consumer, or as a paid shill for a member of the industry.
You can say good things about large companys on Slashdot, just be prepared to have them challenged, especially when your main argument against my post is a simple central route emotionally based attack on me, without any intellectual, factual based counters to my post. Also, I noticed that you fail to address the primary point of my post, which was the integrity of your post, not the viability/accuracy of your claims about the technology under discussion. The phrase, "Doth protest too much" springs to mind.
I have heard HD radio. I was not impressed with it -- simple as that. Thus, I did not purchase equipment to take advantage of the technology. As for your belief that HD radio is "free" I would argue that there is no free radio, since as a listener you are exposed to sales pitches, ie I am exchanging some of my time for the opportunity to listen to the other content of the station. Also, the hardware to listen to HD costs money. Both these points effectively dispute your claim of "free". Apperently it is you who does not understand.
I agree fully, it doesn't matter, unless your vehicle is of sufficient quality to reduce engine/wind noise to a neglible amount. In this situation the quality of the sound system is worthy of note. As to your opinion on HD's quality in the home setting, I feel I already addressed my opinion on the supposed superior quality of HD technology.
You are correct, my iPod's FM transmitter is not digital or FM, however the iPod is a digital storage device, which was the "digital" I was referring to. The statement about the iPod was my attempt at humor. I am sorry you didn't enjoy it.
"First they ignore you, then they laugh at you, then they fight you, then you win."
-Gandhi
1.Design of a good SELECTIVE output filter for D.R. amplifier is very expensive.
..but if you want to get it cheap with long range...
2. LINEAR hf high power amplifier - same
it's nothing wrong with technology
They all just want money !!
Sadly, co-channel interferance isn't something that is new.
If you goto a larger city and scope the NTSC/DTV spectrum you will see interferance on every channel. A friend just did a large job in chicago and told me all about it. This in theory, wasn't supposed to be as a big of a problem as it is. The good news, DTV receivers handle it quite well and it's only temporary.
All I can say to the AM folk...
At least they didn't force the upgrades on you and force you to pay for their "work in progress" digital signal requirements.
"You should always go to other people's funerals; otherwise, they won't come to yours." -- Yogi Berra
Clear Channel will own the bulk of the AMs? Ummm NO. Are you aware that Clear Channel only owne 10% of the stations out there? That is far from a monopoly my friend.
Why do you have such an issue with Clear Channel? Dont give me the crap that others spew about hwo they hold back music ya da ya da, because it isnt true. All stations have local control.
If you dont like what is on teh air, I suggest you get your own show and show us how it is done!
Have a nice day.
AM: 32K bit
They use a codec similar to AAC.Aww. It's a shill. /pet
I, too, am a radio engineer -- in my case, with almost 30 years of experience. See what the other engineers here have said about bandwidth; I won't add to that. Instead, let's address this Evil Money Thing. I get SO tired of this ... it's SO easy for smug, self-righteous people to whine cynically that it's "all just money" and ignore basic economic realities.
... until new buildings and trees grow up around their "rimshot" billboards. Now they're unhappy, because no one's renting space from them anymore.
Imagine that you run a billboard company. You pay the big bucks and fees to put billboards on the major interstates in a large metro area. You have to charge more just to make a living, don't you? But now some little company figures out a way to put the billboards off the main road, but still visible from the interstate, for a lot less money. They're happy
My market is Birmingham, AL. Our company spent MILLIONS buying and upgrading a 50KW AM to serve this metro. Our expenses are much higher than, say, a little guy 30 miles out with a 1KW AM. At present, he puts a halfway-decent signal into Birmingham and is able to sell there. But whoa, now things are changing, and yes, he just might lose some of that coverage. And you better believe, yep, these little guys are whining about it.
Here's the key: instead of targeting his actual market -- which is the little town that he's actually licensed to -- he's trying to "rimshot" his way into Birmingham. Hey, that's understandable; there's more money here than in his little podunk town, but he can't complain when "the trees grow up" and he can no longer serve an area THAT HE WAS NEVER GUARANTEED in the first place. He has basically been enjoying a freebie all these years.
Don't miss that: the GUARANTEED COVERAGE AREA will not be harmed by HD AM. The fact is, if you were granted a license to build an 1KW AM 30 miles from Birmingham, you were never guaranteed Birmingham to start with.
You're cute, you astro turfer, I think I'll keep you.
The large cylindrical objects that are part of computer power supply cables are attempts at filtering the noise, but they really only work for very high frequencies.
No. The large cylindrical objects (most people call them capacitors) are for smoothing the rectified AC supply. It's the small ones that filter the high frequency noise - large electrolytic caps aren't good at that. Oh, and they're not usually cylindrical either. Other than that, you're spot on.
Reading from the other posts, seems the digital broadcasts wern't much better, full of artifacts.
Change is certain; progress is not obligatory.
Heck, we don't even close the bathroom window until it's about 20 degrees here!
Yes, you can use phase modulation of the carrier to carry information - that's the "...a lot of trouble...." that I spoke of in my previous post. There are tricks, such as using a quadrature modulated carrier (carrier at 90 degrees phase shift to the main carrier).
www.eFax.com are spammers
When the transition from CW (Morse radiotelegraphy) to voice was made, there were obvious, undeniable advantages to voice transmissions over CW. Anyone could "decode" such transmissions without Morse training. The data rate was higher, too - Morse tops out (for the vast majority of people, anyway) at about 40 WPM (words per minute), at least for by-ear decoding. The spoken word can easily exceed that (at the price of higher bandwidth, of course).
But the real answer to your question is, "The difference is that the FCC didn't license voice transmissions only to huge, billion-dollar corporations."
The FCC rules have been there for many years. Like them or not, stations are given a certain protect range, beyond that you have "extra" coverage. Let me tell you, when a station moves into our area and limits our "extra" coverage, I am not happy about it, but because of the rules there is nothing I can do about it. There have been a bunch of lower power FMs moving closer and closer, limiting some of the FMs I work at. All I can do is make sure my "Protected coverage" IS protected. In regards to AM, there are rules that keep stations seperated by distance and frequency. By this THEORY, HD Radio should work just fine. Of course there are always exceptions. Yes HD radio (on AM) appears broad. It apperas broader than the analog splash because the digital signal is always at 100% modulation, where analog is quite a bit lower. But it is still there. In regards to FM, the FM HD signal is only 1%..... thats right ONE PERCENT of the analog power. So a station that broadcasts 6000 watts, has an HD signal of 60 watts. I dont know about you but I can easily null out a 60w station on FM. I know I listen to a number of stations beyond their "protected coverage". And if they go away I will be quite disappointed. The FCCs attitude is that stations should only cover certain areas. To me it appears that the argument is with Congress and the FCC. But good luck in changing these rules as they have been in force for many years. Now onto the NPR issue...... NPR is the big force beind HD Radio. They are the ones implementing HD radio faster than anyone else. Why is no one going after NPR???? (sound of crickets.....)