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Spectrum plot of an IBOC AM station
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HD=? Looks like if you got too many of these things splattering all over
there would be lousy reception for sure. Not everybody can afford a $3000 receiver that could knock out either. Il Dolce Far Niente "David" wrote in message ... Thanks to Bob Gonsett http://earthsignals.com/add_CGC/KMXE.PDF |
"Maximus" wrote in message ink.net... HD=? Looks like if you got too many of these things splattering all over there would be lousy reception for sure. Not everybody can afford a $3000 receiver that could knock out either. Il Dolce Far Niente It certainly would be tough to receive adjacent channels. I don't think a $3000 radio would help much, because the IBOC sidebands are right on the adjacent channels. It would be similiar to trying to receive a distant station when a local is on the same frequency. And the local station never gives it's continual noisy modulation a rest. I suppose the best way to receive adjacent channels would be nulling the sideband noise out with the antenna. Frank Dresser |
"David" wrote in message ... Thanks to Bob Gonsett http://earthsignals.com/add_CGC/KMXE.PDF Thanks for the link. That spectrum is consistant with what I heard a few evenings ago around 720 kHz. WGN's engineer said it wasn't them, and I haven't noticed the noise since then. Has anyone heard the sidebands produced by IBOC? The best description I can come up with is something like "digital white noise". Frank Dresser |
Frank Dresser wrote:
That spectrum is consistant with what I heard a few evenings ago around 720 kHz. WGN's engineer said it wasn't them, and I haven't noticed the noise since then. Has anyone heard the sidebands produced by IBOC? The best description I can come up with is something like "digital white noise". It's just a noise rush, but not white exactly. The giveaway is that it's on only one sideband of the station you're trying to hear. If you hear it on the LSB, the offending IBOC station is 10 kHz higher (not lower as you'd expect); and if on USB, then 10 kHz lower. So you need selectable sidebands to tell, or at least a BFO and notice whether the noise pitch goes up as you tune up (in which case the IBOC station is higher) or goes down (in which case the IBOC station is lower), starting from the interfered-with station. -- Ron Hardin On the internet, nobody knows you're a jerk. |
Ron Hardin wrote:
Frank Dresser wrote: That spectrum is consistant with what I heard a few evenings ago around 720 kHz. WGN's engineer said it wasn't them, and I haven't noticed the noise since then. Has anyone heard the sidebands produced by IBOC? The best description I can come up with is something like "digital white noise". It's just a noise rush, but not white exactly. The giveaway is that it's on only one sideband of the station you're trying to hear. If you hear it on the LSB, the offending IBOC station is 10 kHz higher (not lower as you'd expect); and if on USB, then 10 kHz lower. So you need selectable sidebands to tell, or at least a BFO and notice whether the noise pitch goes up as you tune up (in which case the IBOC station is higher) or goes down (in which case the IBOC station is lower), starting from the interfered-with station. [...] All of this destruction of the radio listening hobby -- and destruction of _anyone's_ ability to listen to many of the more distant or weaker stations he can now receive -- is because the money-men of the media monopolies saw a new digital band as a threat to their dominance. So they squelched it -- they hope -- with IBOC. As I've said before, IBOC (In-Band On-Channel) digital -- AM or FM -- is essentially a turkey, technically. It's inferior in almost every way to a dedicated digital system in a dedicated digital band. The main reason IBOC is promoted is because a new dedicated digital band would level the playing field: the present 250-Watt AM daytimer, once ensconced in the new band, would have just as clear and clean a signal as the 50-Kw clear channel or the high-power FM -- just as good fidelity, the same coverage, and 24-hour operation. Just like your Web site is as clear and as easily accessible as NBC's. A dedicated digital band might also be scalable and allow many more channels for the listener -- hundreds, thousands perhaps. Probably enough to allow public access (in which anyone can be a broadcaster for free or nearly free) on an even greater scale than does cable television or Internet radio. And that would mean more competition for the big-money men. And it would mean that competition would now be purely on the basis of programming, not the sheer signal superiority which the money-men have paid for. They want to preserve the _inferiority_ of their smaller competitors. IBOC does that. They want to maintain the high economic hurdle to becoming a broadcaster. IBOC does that. With all good wishes, -- Kevin Alfred Strom. News: http://www.nationalvanguard.org/ The Works of R. P. Oliver: http://www.revilo-oliver.com Personal site: http://www.kevin-strom.com |
"Kevin Alfred Strom" wrote in message ... All of this destruction of the radio listening hobby -- and destruction of _anyone's_ ability to listen to many of the more distant or weaker stations he can now receive -- is because the money-men of the media monopolies saw a new digital band as a threat to their dominance. So they squelched it -- they hope -- with IBOC. As far as I know, the FCC has stopped all IBOC testing at night in order to reduce interference with other stations. As I've said before, IBOC (In-Band On-Channel) digital -- AM or FM -- is essentially a turkey, technically. It's inferior in almost every way to a dedicated digital system in a dedicated digital band. The main reason IBOC is promoted is because a new dedicated digital band would level the playing field: the present 250-Watt AM daytimer, once ensconced in the new band, would have just as clear and clean a signal as the 50-Kw clear channel or the high-power FM -- just as good fidelity, the same coverage, and 24-hour operation. Just like your Web site is as clear and as easily accessible as NBC's. Didn't the Canadians establish a new digital band? Is it being heard much? A dedicated digital band might also be scalable and allow many more channels for the listener -- hundreds, thousands perhaps. Probably enough to allow public access (in which anyone can be a broadcaster for free or nearly free) on an even greater scale than does cable television or Internet radio. And that would mean more competition for the big-money men. And it would mean that competition would now be purely on the basis of programming, not the sheer signal superiority which the money-men have paid for. They want to preserve the _inferiority_ of their smaller competitors. IBOC does that. They want to maintain the high economic hurdle to becoming a broadcaster. IBOC does that. With all good wishes, -- Kevin Alfred Strom. Well, maybe, but I don't see the entire broadcast industry rushing to IBOC. The night time ban puts a big crimp on IBOC. IBOC reduces the bandwidth and fidelity of the main channel. Also, putting all that power into sideband noise reduces the power and signal to noise ratio of the main channel. People who are annoyed by bad sounding AM radio and have yet to buy an IBOC radio are more likely to tune out. People who don't much care about fidelity, and I think that's the majority of casual listeners, won't much care for IBOC, either. Frank Dresser |
Frank Dresser wrote:
It's just a noise rush, but not white exactly. The giveaway is that it's on only one sideband of the station you're trying to hear. If you hear it on the LSB, the offending IBOC station is 10 kHz higher (not lower as you'd expect); and if on USB, then 10 kHz lower. I'm not sure I understand. The spectrum plot shows two symmetrical peaks off the carrier frequency. The noise I observed was consistant with that. It's not symmetric around the adjacent channel station being interfered with. If IBOC is on 700 and you're listening to 710, the the IBOC noise is at 713, which is the upper sideband of 710. If you listen to 710 LSB, the noise disappears. -- Ron Hardin On the internet, nobody knows you're a jerk. |
"Ron Hardin" wrote in message ... It's not symmetric around the adjacent channel station being interfered with. OK. The noise was symmetrical around 720, and I was trying to catch 710. If IBOC is on 700 and you're listening to 710, the the IBOC noise is at 713, which is the upper sideband of 710. If you listen to 710 LSB, the noise disappears. -- Ron Hardin I live a few miles from WGN's transmitter, and the normal sideband splatter makes WOR almost unlistenable. I was just curious about propagation that night. A station ID was all I wanted. If I ever hear the noise again, I'll listen to it more carefully. Frank Dresser |
Holy crap, look at those spurs +/- 15kc!
Oh, yeah, IBAC (In Band Adjacent Channel) is going to save AM! 73, Steve Lawrence Burnsville, MN "David" wrote in message ... | Thanks to Bob Gonsett | | http://earthsignals.com/add_CGC/KMXE.PDF --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.576 / Virus Database: 365 - Release Date: 1/30/04 |
Canada uses Eureka 147 DAB. It is slowly gaining an audience.
On Tue, 24 Feb 2004 22:38:00 GMT, "Frank Dresser" wrote: "Kevin Alfred Strom" wrote in message ... All of this destruction of the radio listening hobby -- and destruction of _anyone's_ ability to listen to many of the more distant or weaker stations he can now receive -- is because the money-men of the media monopolies saw a new digital band as a threat to their dominance. So they squelched it -- they hope -- with IBOC. As far as I know, the FCC has stopped all IBOC testing at night in order to reduce interference with other stations. As I've said before, IBOC (In-Band On-Channel) digital -- AM or FM -- is essentially a turkey, technically. It's inferior in almost every way to a dedicated digital system in a dedicated digital band. The main reason IBOC is promoted is because a new dedicated digital band would level the playing field: the present 250-Watt AM daytimer, once ensconced in the new band, would have just as clear and clean a signal as the 50-Kw clear channel or the high-power FM -- just as good fidelity, the same coverage, and 24-hour operation. Just like your Web site is as clear and as easily accessible as NBC's. Didn't the Canadians establish a new digital band? Is it being heard much? A dedicated digital band might also be scalable and allow many more channels for the listener -- hundreds, thousands perhaps. Probably enough to allow public access (in which anyone can be a broadcaster for free or nearly free) on an even greater scale than does cable television or Internet radio. And that would mean more competition for the big-money men. And it would mean that competition would now be purely on the basis of programming, not the sheer signal superiority which the money-men have paid for. They want to preserve the _inferiority_ of their smaller competitors. IBOC does that. They want to maintain the high economic hurdle to becoming a broadcaster. IBOC does that. With all good wishes, -- Kevin Alfred Strom. Well, maybe, but I don't see the entire broadcast industry rushing to IBOC. The night time ban puts a big crimp on IBOC. IBOC reduces the bandwidth and fidelity of the main channel. Also, putting all that power into sideband noise reduces the power and signal to noise ratio of the main channel. People who are annoyed by bad sounding AM radio and have yet to buy an IBOC radio are more likely to tune out. People who don't much care about fidelity, and I think that's the majority of casual listeners, won't much care for IBOC, either. Frank Dresser |
"David" wrote in message ... Canada uses Eureka 147 DAB. It is slowly gaining an audience. I thought so. A seperate band makes sense. If some entrepeneur thinks the public really wants the presumed advantages of digital broadcasting, let him be a pioneer on a new band. Frank Dresser |
Frank Dresser wrote:
[...] Well, maybe, but I don't see the entire broadcast industry rushing to IBOC. The night time ban puts a big crimp on IBOC. IBOC reduces the bandwidth and fidelity of the main channel. Also, putting all that power into sideband noise reduces the power and signal to noise ratio of the main channel. People who are annoyed by bad sounding AM radio and have yet to buy an IBOC radio are more likely to tune out. People who don't much care about fidelity, and I think that's the majority of casual listeners, won't much care for IBOC, either. Frank Dresser All very true. But the owners of the media monopolies don't care a great deal about the success of IBOC or even its widespread implementation. Their main concern is to _prevent_ the creation of a new digital band wherein all existing broadcasters would have an even playing field. IBOC does that -- at least so far. With every good wish, Kevin. -- Kevin Alfred Strom. News: http://www.nationalvanguard.org/ The Works of R. P. Oliver: http://www.revilo-oliver.com Personal site: http://www.kevin-strom.com |
"Kevin Alfred Strom" wrote in message ... All very true. But the owners of the media monopolies don't care a great deal about the success of IBOC or even its widespread implementation. Their main concern is to _prevent_ the creation of a new digital band wherein all existing broadcasters would have an even playing field. IBOC does that -- at least so far. With every good wish, Kevin. We don't have a seperate band for digital radio, but the time brokered domestic shortwave stations are allowing much of the programming the networks don't. Although there isn't any local content. Anyway, the radio establishment doesn't seem much bothered by independant broadcasting. I think the bigger reason there wasn't a seperate digital band established is the government plans to auction off spectrum, and setting aside a band in a prime VHF/UHF region puts a crimp in their budget estimates. Frank Dresser |
Kevin Alfred Strom wrote:
Frank Dresser wrote: [...] Well, maybe, but I don't see the entire broadcast industry rushing to IBOC. The night time ban puts a big crimp on IBOC. IBOC reduces the bandwidth and fidelity of the main channel. Also, putting all that power into sideband noise reduces the power and signal to noise ratio of the main channel. People who are annoyed by bad sounding AM radio and have yet to buy an IBOC radio are more likely to tune out. People who don't much care about fidelity, and I think that's the majority of casual listeners, won't much care for IBOC, either. Frank Dresser All very true. But the owners of the media monopolies don't care a great deal about the success of IBOC or even its widespread implementation. Their main concern is to _prevent_ the creation of a new digital band wherein all existing broadcasters would have an even playing field. IBOC does that -- at least so far. With every good wish, Kevin. It's actually more insidious than that. A little background. Meetings I attended when I worked at CBS discussed the future of radio, and for that matter, TV broadcasting revenues, and it was clear that advertising revenue streams were not the future. Technological innovations, at that time limited to VCR's with black sensing self editing capability which allowed automatic deletion of commercials, and later the first generation of TiVo which openly promoted commercial free TV viewing, made it clear that advertising revenues were under extreme fire. Though Radio lagged behind TV in this capability, it was only a matter of time before radio caught up, and radio advertising revenues, too, were threatened. Karmazin said at one staff breakfast that I atteneded, that the only way to insure the long term viability of broadcast media was through the generation of multiple revenue streams for each freqency allocation. He described several ways that advertising could be sold, and incorporated into the programming so that additional non-traditional revenue could be harvested outside of spot sales. Other products could be tied to each broadcast facility generating further non-traditional revenue. This is where the ubiquitous "Dateline" your favorite radio station promotes. That software was invented by three guys at Northwestern in Evanston. We turned into the Dateline at US99, and my GM created the company, DMI, which was later spun off into Spark International, which installs, maintains and operates the datelines worldwide. But non traditional revenue sources all require some form of advertising to work. Karmazin was looking for more direct revenue streams, not based in advertising. And when he got to digital broadcasting, he outlined several future scenarios...all of which involve stealing small amounts of bandwidth from the digital stream, which would be converted to alternative programming, or informational streams. He actually said the words....that we will not be broadcasting full bandwidth digital programming beyond the resolution we currently enjoy in analog, in fact, maybe even a little less, so that alternative revenue producing streams can be incorporated onto each frequency. Not unlike SAP channels do now for television. These would also be subscription based, further generating addtional revenue. This would be necessary because of the erosion of advertising revenue caused by both technological innovation, and the public's growing distaste for the spot load. He then cited cable tv and it's subscription based business model as an example of how the future of broadcasting may be shaped. Noting the pervasive nature of cable, and the spread of subscription based dish networks, he said there is clearly no major objection to subscription based broadcasting among the population. And as the XM and Sirius models clearly demonstrate, subscription based reception for radio is a viable business model. Karmazin said that the real benefit of digital broadcasting, whether DAB, or IBOC, because of the interactive potential of digital distribution, as currently demonstrated with digital cable, will be the capture of the holy grail of broadcasting since the media were first blown into the air--absolutely accurate counts of who's listening, and when. It will also mean the ultimate in usage sensitive pricing.... Subscription radio. When asked if this was his goal, he said not at first. But eventually, yes. There followed a lot of mumbling in the room. Now, whether IBOC, especially on AM, proves itself as a practicality before something else comes along to obsolete it will be determined in the next few years. XM growth, and expansion of accessibility, demonstrates it to be a viable contender on the horizon. And the availability of internet radio through cell phones and PDA's is proving to be a surprise, although certainly not a current threat. In the meantime, the larger broadcasters retain their investment, their profitability, and their competitive advantages of both scale and strategy over smaller operators. While preparing to take full advantage of all the media at their disposal. Something that smaller operators will have to struggle to achieve. But the ultimate losers with IBOC will not be the smaller operators. The ultimate loss will be on our side of the grille cloth. |
"Peter Maus" wrote in message ... [snip] Karmazin said that the real benefit of digital broadcasting, whether DAB, or IBOC, because of the interactive potential of digital distribution, as currently demonstrated with digital cable, will be the capture of the holy grail of broadcasting since the media were first blown into the air--absolutely accurate counts of who's listening, and when. I can imagine how they might get a sense of which radios are tuned to which program. But how can they know who, if anyone, is listening? It will also mean the ultimate in usage sensitive pricing.... Subscription radio. When asked if this was his goal, he said not at first. But eventually, yes. There followed a lot of mumbling in the room. Now, whether IBOC, especially on AM, proves itself as a practicality before something else comes along to obsolete it will be determined in the next few years. XM growth, and expansion of accessibility, demonstrates it to be a viable contender on the horizon. And the availability of internet radio through cell phones and PDA's is proving to be a surprise, although certainly not a current threat. In the meantime, the larger broadcasters retain their investment, their profitability, and their competitive advantages of both scale and strategy over smaller operators. While preparing to take full advantage of all the media at their disposal. Of course, free radio has a competitive advantage over pay radio. It would be up to the networks to somehow come up with programming people will pay for. Anyway, pay programming now seems to be low cost. No multimilllion talk show hosts and such. Something that smaller operators will have to struggle to achieve. But the ultimate losers with IBOC will not be the smaller operators. The ultimate loss will be on our side of the grille cloth. It might, but the loss would depend on the number of people willing to pay for radio. There's a hard core who won't pay for cable, and I'd guess the hard core who won't pay for radio is even larger. Frank Dresser |
= = = Ron Hardin
= = = wrote in message ... Frank Dresser wrote: It's just a noise rush, but not white exactly. The giveaway is that it's on only one sideband of the station you're trying to hear. If you hear it on the LSB, the offending IBOC station is 10 kHz higher (not lower as you'd expect); and if on USB, then 10 kHz lower. I'm not sure I understand. The spectrum plot shows two symmetrical peaks off the carrier frequency. The noise I observed was consistant with that. It's not symmetric around the adjacent channel station being interfered with. If IBOC is on 700 and you're listening to 710, the the IBOC noise is at 713, which is the upper sideband of 710. If you listen to 710 LSB, the noise disappears. .. RH, I thought that basic AM and SSB technology were different from IBOC Digital Technology. A 13kHz IBOC (@713kHz) off-set from 700kHz is NOT a 3kHz SSB (@713kHz) off-set from 710kHz. IBOC and SSB are not produced in the same manner and do not decipher in the same manner. Please Correct Me - If I Am Wrong ? ~ RHF .. |
"RHF" wrote in message om... If IBOC is on 700 and you're listening to 710, the the IBOC noise is at 713, which is the upper sideband of 710. If you listen to 710 LSB, the noise disappears. . RH, I thought that basic AM and SSB technology were different from IBOC Digital Technology. A 13kHz IBOC (@713kHz) off-set from 700kHz is NOT a 3kHz SSB (@713kHz) off-set from 710kHz. IBOC and SSB are not produced in the same manner and do not decipher in the same manner. Please Correct Me - If I Am Wrong ? ~ RHF . I don't think Ron's is using SSB in the sense of a modulation method, but rather as a reception method. There's a couple of troughs in the spectrum plot in the splits between the main analog channel and the digital sidebands. One sideband of each adjacent channel will be in those troughs. http://earthsignals.com/add_CGC/KMXE.PDF Listening SSB mode will limit the interference. Unfortunately, the sideband with the least amount of interference will be the sideband closest to the carrier of the unwanted station. Normally, it would be preferable to listen to the sideband farthest away from the carrier of the unwanted station. I was able to tune in an actual IBOC transmission on WSAI 1530 kHz, yesterday evening. WSAI is strong here, but I've never tuned them in before they turned off their IBOC noisemaker. I was also able to tune in KXEL 1540kHz inbetween WSAI's main channel and their upper IBOC noiseband. There was splatter from the main channel and noise from the digital channel, but it was readable. I don't have the selectivity to listen in true sideband mode, but I think even that wouldn't totally eliminate the interference. If the IBOC station is local, I think there would still enough noise and splatter to overwhelm an otherwise listenable near adjacent channel. The current split digital/analog system is intended to be temporary. The IBOC standard is designed to go full digital. Frank Dresser |
That makes no sense. Xm and Sirius each have 100 channels on 12.5 MHz
of spectrum. The current FM and AM bands have 21.4 mHz of spectrum. They could migrate everyone to a new band then auction off the old FM channels for a billion dollars. On Wed, 25 Feb 2004 19:49:19 GMT, "Frank Dresser" wrote: "Kevin Alfred Strom" wrote in message ... All very true. But the owners of the media monopolies don't care a great deal about the success of IBOC or even its widespread implementation. Their main concern is to _prevent_ the creation of a new digital band wherein all existing broadcasters would have an even playing field. IBOC does that -- at least so far. With every good wish, Kevin. We don't have a seperate band for digital radio, but the time brokered domestic shortwave stations are allowing much of the programming the networks don't. Although there isn't any local content. Anyway, the radio establishment doesn't seem much bothered by independant broadcasting. I think the bigger reason there wasn't a seperate digital band established is the government plans to auction off spectrum, and setting aside a band in a prime VHF/UHF region puts a crimp in their budget estimates. Frank Dresser |
"David" wrote in message ... That makes no sense. Xm and Sirius each have 100 channels on 12.5 MHz of spectrum. The current FM and AM bands have 21.4 mHz of spectrum. They could migrate everyone to a new band then auction off the old FM channels for a billion dollars. This is your lucky year. You can run for President! Run on the "I'll make you replace your radios" platform. Don't forget to do all your campaigning from the sattelite. Dunno about the billion bucks, though. I suppose that's good for the government budget estimate, but reality may be different. Frank Dresser |
"Frank Dresser" wrote in message ...
"RHF" wrote in message om... If IBOC is on 700 and you're listening to 710, the the IBOC noise is at 713, which is the upper sideband of 710. If you listen to 710 LSB, the noise disappears. . RH, I thought that basic AM and SSB technology were different from IBOC Digital Technology. A 13kHz IBOC (@713kHz) off-set from 700kHz is NOT a 3kHz SSB (@713kHz) off-set from 710kHz. IBOC and SSB are not produced in the same manner and do not decipher in the same manner. Please Correct Me - If I Am Wrong ? ~ RHF . I don't think Ron's is using SSB in the sense of a modulation method, but rather as a reception method. There's a couple of troughs in the spectrum plot in the splits between the main analog channel and the digital sidebands. One sideband of each adjacent channel will be in those troughs. http://earthsignals.com/add_CGC/KMXE.PDF Listening SSB mode will limit the interference. Unfortunately, the sideband with the least amount of interference will be the sideband closest to the carrier of the unwanted station. Normally, it would be preferable to listen to the sideband farthest away from the carrier of the unwanted station. I was able to tune in an actual IBOC transmission on WSAI 1530 kHz, yesterday evening. WSAI is strong here, but I've never tuned them in before they turned off their IBOC noisemaker. I was also able to tune in KXEL 1540kHz inbetween WSAI's main channel and their upper IBOC noiseband. There was splatter from the main channel and noise from the digital channel, but it was readable. I don't have the selectivity to listen in true sideband mode, but I think even that wouldn't totally eliminate the interference. If the IBOC station is local, I think there would still enough noise and splatter to overwhelm an otherwise listenable near adjacent channel. The current split digital/analog system is intended to be temporary. The IBOC standard is designed to go full digital. Frank Dresser .. FD, If the IBOC Signal is a 'broadcast' as "Digital Encoded Algorithm". Either as Dual IBOC Signals (Stereo) or as 'separate' Voice and Data/Information Channels. Then, how do you 'decode' it and Listen to it simply using standard "Analog" SSB ? ~ RHF .. |
"RHF" wrote in message om... . FD, If the IBOC Signal is a 'broadcast' as "Digital Encoded Algorithm". Either as Dual IBOC Signals (Stereo) or as 'separate' Voice and Data/Information Channels. Then, how do you 'decode' it and Listen to it simply using standard "Analog" SSB ? ~ RHF . I didn't take it as a method of decoding the IBOC signal. I took to mean a way to minimize the interference from a IBOC station on a close adjacent channel signal. Let's say a station at 830 kHz is using IBOC and you want to hear a station on 840 kHz. There's interference to the station at 840 from the splatter of the main channel at 830 and the IBOC sideband centered at 843. You can minimize the interference from the IBOC sideband if you listen to the station at 840 in LSB mode. http://earthsignals.com/add_CGC/KMXE.PDF Of course, normally it's preferable to listen to that station at 840 kHz in USB mode, but the IBOC sideband interferes heavily with that sideband. Frank Dresser |
= = = "Frank Dresser"
= = = wrote in message ... "RHF" wrote in message om... . FD, If the IBOC Signal is a 'broadcast' as "Digital Encoded Algorithm". Either as Dual IBOC Signals (Stereo) or as 'separate' Voice and Data/Information Channels. Then, how do you 'decode' it and Listen to it simply using standard "Analog" SSB ? ~ RHF . I didn't take it as a method of decoding the IBOC signal. I took to mean a way to minimize the interference from a IBOC station on a close adjacent channel signal. Let's say a station at 830 kHz is using IBOC and you want to hear a station on 840 kHz. There's interference to the station at 840 from the splatter of the main channel at 830 and the IBOC sideband centered at 843. You can minimize the interference from the IBOC sideband if you listen to the station at 840 in LSB mode. http://earthsignals.com/add_CGC/KMXE.PDF Of course, normally it's preferable to listen to that station at 840 kHz in USB mode, but the IBOC sideband interferes heavily with that sideband. Frank Dresser .. FD, I can understand what you are saying, IF (Big 'if') I was trying to get away from one interfering IBOC Side-Channel. BUTT (Big 'butt' :o) What happens when there is 50% implementation of IBOC and on average every other Channel is an IBOC Broadcaster with an IBOC Side-Channel at both +15kHz and -15kHz. So now your Old Fashion AM Station at 840kHz has a 860kHz Lower IBOC Side-Channel and also a 820kHz Upper IBOC Side-Channel; both sitting within -&+ 5kHz of 840kHz. As, I read and interpret the Spectrogram the IBOC Signals are about 12 dB above the band scan base noise level. The Main AM Signal is another 18 dB above the IBOC Side-Channels. While IBOC may be 'claimed' to be backwardly compatible with the current AM Broadcast media. It is apparent to me that with may be 33% IBOC adoption the AM Band as we know it will cease to be; and all remaining AM Band Broadcasters will be FORCE by the 'new' IBOC Noise Levels to transition to IBOC or NOT Be Heard. IBOC to IBOC will not be a problem because of the specific IBOC Side-Channel Off-Set and the Encoding and Decoding of the IBOC "Digital Algorithm". BUTT - To the old fashion AM Analog Radio Station the IBOC "Digital Algorithms" from the upper and lower adjacent IBOC Side-Channels will simply sound like NOISE "BIG TIME" ! Oh Well - I have rambled on long enough. iboc ~ RHF = = = I Be Overly Concerned ! .. |
"RHF" wrote in message om... FD, I can understand what you are saying, IF (Big 'if') I was trying to get away from one interfering IBOC Side-Channel. BUTT (Big 'butt' :o) What happens when there is 50% implementation of IBOC and on average every other Channel is an IBOC Broadcaster with an IBOC Side-Channel at both +15kHz and -15kHz. So now your Old Fashion AM Station at 840kHz has a 860kHz Lower IBOC Side-Channel and also a 820kHz Upper IBOC Side-Channel; both sitting within -&+ 5kHz of 840kHz. This will have to make reception tough in the station's fringe areas. I don't know what area the FCC protects, but the figure of 700 miles for the "clear channels" comes to mind. It's unclear if there will be any problem in each of the station's home cities. But the NRSC (not the FCC as I posted earlier) has stopped nighttime IBOC tests As, I read and interpret the Spectrogram the IBOC Signals are about 12 dB above the band scan base noise level. The Main AM Signal is another 18 dB above the IBOC Side-Channels. While IBOC may be 'claimed' to be backwardly compatible with the current AM Broadcast media. It is apparent to me that with may be 33% IBOC adoption the AM Band as we know it will cease to be; and all remaining AM Band Broadcasters will be FORCE by the 'new' IBOC Noise Levels to transition to IBOC or NOT Be Heard. Only if the interference effects radio stations in their home market. IBOC to IBOC will not be a problem because of the specific IBOC Side-Channel Off-Set and the Encoding and Decoding of the IBOC "Digital Algorithm". I don't know how well this system will perform, but I suspect the digital sidebands will be interfering in areas where the received signal isn't much stronger than the interfering signal. That is, I don't think digital will save digital from digital. BUTT - To the old fashion AM Analog Radio Station the IBOC "Digital Algorithms" from the upper and lower adjacent IBOC Side-Channels will simply sound like NOISE "BIG TIME" ! And 95% of the listeners will never notice the interference. But there's no guarantee they will want the extra "features" digital radio promises, especially if they have to pay extra for digital radios. Oh Well - I have rambled on long enough. iboc ~ RHF = = = I Be Overly Concerned ! . http://www.rwonline.com/reference-ro..._rw_iboc.shtml Frank Dresser |
"Brenda Ann" wrote in message ... The thing is, as has been brought forward before, that the FM and VHF low bands are not amenable to use by the people who are looking for those high-bucks bands.. the necessary antennas are simply too large to use for portable devices such as cellular or wireless internet services (yes, there are indeed small FM radios with little or no antenna, but these are grossly inefficient and require a very high signal level to work.. nor do they have to transmit, which would require a minimum 1/4 wave antenna (~30" @ 90MHz)) Yeah, let's wait 'till the VHF low band gets filled up before we conclude there's a shortage of VHF bandwidth. Frank Dresser |
"Chuck Reti" wrote in message ... IBOC in the end has nothing to do with audio quality. If that really was the point we might have had a chunk of spectrum for Digital Radio like the DTV transition for video. IBOC is about Digital Rights Management, enabling others to decide what you may or may not hear or, God Forbid, record. -- chuck reti detroit mi Others already decide what is broadcast, and I don't see how digital modulation can keep anyone from recording audio. Just what does IBOC have to do with Digital Rights Management? Frank Dresser |
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, "Frank Dresser" wrote: "Chuck Reti" wrote in message ... IBOC in the end has nothing to do with audio quality. If that really was the point we might have had a chunk of spectrum for Digital Radio like the DTV transition for video. IBOC is about Digital Rights Management, enabling others to decide what you may or may not hear or, God Forbid, record. -- chuck reti detroit mi Others already decide what is broadcast, and I don't see how digital modulation can keep anyone from recording audio. Just what does IBOC have to do with Digital Rights Management? Frank Dresser I'm just pessimistic and cynical about the Brave New future of digital broadcasting. IBOC as a "digital modulation" technique is not in itself the evil (well, OK, it spews hash across the AM dial), but as a transport for DRM-encoded digital content it may likely disable the listener from doing what is considered fair use recording. I could see the instance where one might not be able to "time shift" a program without a subscription or use fee. For sure not in the immediate future, but possible eventually. chuck reti detroit mi |
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