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#21
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"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 |
#22
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"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 .. |
#23
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"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 |
#24
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= = = "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' ) 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 ! .. |
#25
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"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' ) 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 |
#26
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"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 |
#27
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"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 |
#28
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In article
, "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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