Tecnically....you're right! ;-) LOL BigA!
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- Thread starter Savage
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Tecnically....you're right! ;-) LOL BigA!
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rbrucecarter5
Guest
I needed a good laugh - same amount of real estate? They are slopping the sidebands all over the first adjacent frequencies. Maybe that's not an issue in downtown areas or near the transmitters where the set of receivable stations is well defined, but you go out to suburbs and the situation can change dramatically - one where multiple stations start appearing on first adjacents - stations that may not show in ratings, but stations that have a following. It gets worse the farther out you go, and it also means those first adjacents will start jamming HD anyway. It isn't so much of an issue here where we have full class C stations and long distances between stations, but the allotments get really bad in the densely populated East. You go 30 miles, and you can get a totally different market with a whole new set of stations in the ratings.
They could have solved all - as in ALL of the problems with HD if they had just put the sidebands inside the present +/- 75 kHz deviation. All they had to do is give up on RDS, SCA, blind reading, and other services - things that can be done better by HD sidebands anyway. There would have been plenty of room in the channel. DX'ers would still be screwed because there would be so much energy out there in the edges of the deviation - but think of all the other benefits! HD signals would go much farther, because you are not trying to amplify so much spectrum. That would decrease the drop out problems that I can observe from LO jamming from stations 10.4 and 11.0 MHz below the HD station. Consumers would be happier, because HD signals would be more robust. You wouldn't need outdoor antennas to get the stations from the suburbs, it would hang in better in cars. Broadcasters would love it because those crucial secondary services would be a lot more reliable. There are so many wins - I don't know why iBiquity wouldn't have just done it to begin with. Best of all - it is not too late! I've hacked the code of my HD radios. The code doesn't care where the sidebands are - so broadcasters could move the sidebands in and no firmware change would be needed in the radios. HD radio would get much more reliable and the only firmware changes would be at the stations.
I should stop dreaming - nobody cares about making the system more reliable, and the technical musings of an old hardware / firmware engineer with 35 years of experience in this sort of thing mean nothing to the "geniuses" that designed this white elephant.
I have not seen it mentioned anywhere, but WLW-700 in Cincinnati has not had their noise grinder on for several weeks now. I hope they have noticed how much cleaner sounding their analog signal is .... Not to mention the lack of pollution on 680, 690, 710, and 720. I am about 90 miles south of the WLW transmitter and the change is truly amazing!
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rbrucecarter5
Guest
Great news! I will see if I can get them again at night by nulling KSEV. At one time, they were a late afternoon regular here in Houston during the winter months before KSEV came on the air.
Bruce, Bruce, Bruce.. There you go again trying to spread disinformation. FM-HD (IBOC) doesn't have "sloping sidebands". Here is the required RF mask for FM HD, including a simple summary on how it works for AM and FM:
http://www.google.com/url?sa=i&rct=...1XinqmecClbKcIo3PgA9_roA&ust=1433783218098044
Also contrary you your incorrect claims, standard SCA's, including RDS all will fit inside the mask. Finally, (again) the HD-IBOC carriers are typically created through a separate amplifier, which doesn't take away from the analog station's licensed TPO or ERP. Rather than continuing your technically incorrect statements, I'd encourage you to do some research or ask some of the professionals on this board. A little knowledge goes a long way towards a discussion.
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rbrucecarter5
Guest
I don't want to prolong a dispute with you, Kelly. But sure enough, WLW was back the other night with a strength I haven't heard in years. Of course I haven't tried in months, either, because there is little on WLW of any interest to me. WLW being strong prior to HD is an observation. Its relative lack of strength during HD broadcasts is an observation. The strength I heard last night is an observation. The conclusion that HD had something to do with diminished signal strength is reasonable given the observations.
I never said SCA and RDS wouldn't fit inside the mask. Of course they do. I was saying it would make sense to move the IBOC sidebands inside the mask and sacrifice SCA and RDS because they are outdated and redundant given the capabilities of HD.
Regardless of the transmitting method, asking a radio to receive a wider bandwidth reduces its sensitivity. Google "gain bandwidth product" and you should be able to find some tutorials on the subject.
Bottom line - the narrower you make the channel (by moving HD sidebands in), the greater the sensitivity of the radio. That is why FM DX'ers have been replacing 280 kHz ceramic filters with matched 150 kHz for years with amazing results.
I never said SCA and RDS wouldn't fit inside the mask. Of course they do. I was saying it would make sense to move the IBOC sidebands inside the mask and sacrifice SCA and RDS because they are outdated and redundant given the capabilities of HD.
Regardless of the transmitting method, asking a radio to receive a wider bandwidth reduces its sensitivity. Google "gain bandwidth product" and you should be able to find some tutorials on the subject.
Bottom line - the narrower you make the channel (by moving HD sidebands in), the greater the sensitivity of the radio. That is why FM DX'ers have been replacing 280 kHz ceramic filters with matched 150 kHz for years with amazing results.
bruce5...
I can affirm what you say above. I live 90 miles south of the WLW transmitter and have found that they are usually UNLISTENABLE here at night (with severe fading and IBOC hash present...even directly on 700 kHz) when their IBOC noise is on. Now that it is OFF, they have a clear signal with excellent fidelity (for AM) at night. I use top end receivers for all my AM DXing: Icom IC-746 [ham transceiver]. Tecsun PL-606 and Bose (high end) audio system in my Silverado. WLW was almost unlistenable - DAY AND NIGHT - while in the pickup with the WLW IBOC on. Now, I can hear it clearly again.
I can affirm what you say above. I live 90 miles south of the WLW transmitter and have found that they are usually UNLISTENABLE here at night (with severe fading and IBOC hash present...even directly on 700 kHz) when their IBOC noise is on. Now that it is OFF, they have a clear signal with excellent fidelity (for AM) at night. I use top end receivers for all my AM DXing: Icom IC-746 [ham transceiver]. Tecsun PL-606 and Bose (high end) audio system in my Silverado. WLW was almost unlistenable - DAY AND NIGHT - while in the pickup with the WLW IBOC on. Now, I can hear it clearly again.
WLW is an AM (MW) station. HD transmission methods for FM vs. AM are completely different. You seem to be confused at that fact by talking about FM, then using an AM station as an example. Not the first time and I doubt it will be the last.
You can't just brush off the differences between broadcasting HD in FM vs. AM. They are two completely different animals. Most HD-FM stations use a completely separate transmitter and some a separate antenna to transmit just the HD carriers on the same allocated channel. There is no loss of field strength when the occupied bandwidth is spread between two completely different transmission systems.
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rbrucecarter5
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Or - you just scan my post quickly and don't realize when I shift from talking about FM to talking about AM.
You keep talking about the transmission side of FM, where you are correct. I am talking about the receiver side, where the larger bandwidth of HD FM matters to the receiver.
I assume you must be talking about the AM CBS stations. The question is: do you really think the new President of CBS Radio, given all the P&L, sales and operational challenges of running a radio group, is going to give a molecular-sized thought to what a handful of DX'ers would prefer? Seriously?
There's the electricity to run it. CBS radio owns several 50kW stations. Let's say the HD power level is 1%.That's 500 watts each and every hour on each station. There's a savings right there. Then, there is the reality that nearly nobody has an AM HD receiver and fewer are using it. I, for example, have one, but not even 50kW WBZ decodes from maybe 30 miles away, but I certainly hear its hash. What kund of listening experience is that? A horrible one. My radio TRIES to get WBZ's HD signal, but all that's there is watery audio with on & off noise while the radio tries to get the HD signal. So, to summarize- saving $ by saving electricity, better sound for the majority of listeners because of less interference. By the way, I know.that 500 watts is just the output, never mind the incoming power to run the hashb
Running a 50kW AM station at 50kW costs the same with our without the HD carriers up. Any ancillary gear (importers/exporters) probably draws less than a 20W light bulb. You're kidding yourself if you think the President of CBS cares about technical things like whether the quality of the HD decoding is great 30 miles away. Someone in that position care about two things..Ratings and Revenue. Topics like HD radio on their stations is unimportant techno-babble.
I think you might be confusing HD FM with HD AM. HD FM is generally generated by a second (HD) transmitter. The digital RF is then combined with the analog RF. With AM, it's generally done within the analog/digital transmitter.
AM HD will slowly disappear as the HD equipment breaks down and the companies take it offline rather than repair or replace it.
Just like the whole AM band! Slowly dissolving and disappearing into irelevancy!
CBS Radio was one of the co-founders of USA Digital, which became iBiquity. They have a bigger stake in it than most radio companies.
And THERE is the only reason that the ones that still run it are doing so.
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