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D
Darth_vader
Guest
Quoth rbrucecarter5,
"They could have cleaned out all the RDS and other stuff above the stereo subcarrier, and forced those services onto HD-2, etc. and the text capabilities of the system. But wait - a few hundred people might have been forced to buy HD radios instead of clinging to their old SCA, reading for the blind, and other specialty radios. But FM HD could have fit nicely in the existing allocations, not bothering adjacent channels, and the narrower IF bandwidth would probably give much better coverage - negating the need for a power increase, etc."
They did that already--
http://en.wikipedia.org/wiki/FMeXtra
http://www.dreinc.com/
"They could have cleaned out all the RDS and other stuff above the stereo subcarrier, and forced those services onto HD-2, etc. and the text capabilities of the system. But wait - a few hundred people might have been forced to buy HD radios instead of clinging to their old SCA, reading for the blind, and other specialty radios. But FM HD could have fit nicely in the existing allocations, not bothering adjacent channels, and the narrower IF bandwidth would probably give much better coverage - negating the need for a power increase, etc."
They did that already--
http://en.wikipedia.org/wiki/FMeXtra
http://www.dreinc.com/
Savage declared:
I have been alluding to this for an awfully long time on this here message board. You almost have it right, Bob and we have to keep following the money.
What actually happened is that somebody AGREED to pay SOMEbody a lot to stay OUT of the digital BROADCASTING business. And guess what? That SOMEbody actually deserves to get paid because their algorithms and design are superior to what we have.
But the payout hasn't happened yet and it won't happen until HD actually "takes off". It will all be determined by the success or failure of the product that is out there and being rammed down our throats.
Knowing this, do you find it to be a dilemma? I know I surely do! What a wonderfully complicated and complex scenario we have here!
I have been alluding to this for an awfully long time on this here message board. You almost have it right, Bob and we have to keep following the money.
What actually happened is that somebody AGREED to pay SOMEbody a lot to stay OUT of the digital BROADCASTING business. And guess what? That SOMEbody actually deserves to get paid because their algorithms and design are superior to what we have.
But the payout hasn't happened yet and it won't happen until HD actually "takes off". It will all be determined by the success or failure of the product that is out there and being rammed down our throats.
Knowing this, do you find it to be a dilemma? I know I surely do! What a wonderfully complicated and complex scenario we have here!
One scenario:
HD radio gets bailout, pays huge bonuses, stiffs shareholders, stations, creditors, employees, the public and the government, then goes bankrupt.
HD listeners will be the smallest group to get stiffed.
HD radio gets bailout, pays huge bonuses, stiffs shareholders, stations, creditors, employees, the public and the government, then goes bankrupt.
HD listeners will be the smallest group to get stiffed.
I got the last laugh! A visitor came to our station today from New York. He's a radio announcer in the Big Apple and he said he dropped by see us in North Myrtle Beach because he wanted to see a "stand alone" AM Station and just couldn't understand how we could "make it" in an area served by about two dozen FM stations. The conversation, at his direction, went to AM quality. He saw a couple of HD radios sitting on one of our display cases and said "Are you broadcasting in HD?" No, I replied. We are very happy with our AM Stereo system (cquam) and he said "isnt' that just more of the same static on AM, except in stereo, where no-one can hear it?" I asked him to hear it for himself, so we went into our control room where the AIR monitor is a simple Sony SRF-A100 receiver. His eyes lit up at the sound of the clean and bright stereo separation coming out of the speakers. Next, we went outside and took a drive in our Ford Explorer. "Unbelievable" he said as we switched between WNMB's AM Stereo and the local FM Stations. He was amazed at the fidelity, and again, the AM stereo separation was better than the FM's. Next, he listened to a new Sony portable with AM Stereo. Same reaction. The point is that AM already has the answer to its need for fidelity, and the answer is not the limited scope of HD Radio. There is nothing failed about AM Stereo technology. The failure has been the timing of the marketplace, broadcasters, and receiver makers to come together at the same time. The failure is the FCC not adapting a receiver "standard" while so many radio makers today put ultra cheap chips in their receivers. For example, the Chevy Corvette for all of its cost, has a chip that passes not more than 5 khz frequency response.
A lot of broadcasters have no idea how many AM radios there are in cars still on the road today which receive AM Stereo.
Will AM stereo come back and have a chance at success? Doubtful, but it is still the best answer for our medium. Will the government adopt a receiver standard? It should, but it probably won't because the focus of the Fed's today is social engineering.
So what's my point? We have a technology that works with our AM Stereo. HD AM radio is inferior to the FM version and it won't work or change band perceptions among listeners. So, if someone laughs at AM Stereo, just remember to laugh louder and longer at HD, whether it's AM or FM.
A lot of broadcasters have no idea how many AM radios there are in cars still on the road today which receive AM Stereo.
Will AM stereo come back and have a chance at success? Doubtful, but it is still the best answer for our medium. Will the government adopt a receiver standard? It should, but it probably won't because the focus of the Fed's today is social engineering.
So what's my point? We have a technology that works with our AM Stereo. HD AM radio is inferior to the FM version and it won't work or change band perceptions among listeners. So, if someone laughs at AM Stereo, just remember to laugh louder and longer at HD, whether it's AM or FM.
What a great story! I believe it; I know how good CQUAM can sound! I agree with you that the failure of AM stereo was not due to technical deficiencies. There were some gripes with "platform motion" due to co-channel interference in the outer fringes of a station's coverage area, but at least it did not create interference to other stations and it did not degrade the station's mono signal!
I would love to see AM stereo come back, but I don't know that talk radio programmers really care about audio quality, and AM is predominantly talk. The way things are going, FM may be mostly talk in a few years as well, unless the industry can find a way to resolve the music royalty dispute.
Wish I lived close enough to hear your station!
I would love to see AM stereo come back, but I don't know that talk radio programmers really care about audio quality, and AM is predominantly talk. The way things are going, FM may be mostly talk in a few years as well, unless the industry can find a way to resolve the music royalty dispute.
Wish I lived close enough to hear your station!
R
rbrucecarter5
Guest
audioguy said:
I never experienced any problems with platform motion. When DE started posting on here the iBiquity party line about C-Quam limiting coverage and there were problems with platform motion in the LA basin with all the mountains around, on weak signals - I found the worst possible listening scenario that would duplicate the LA basin / weak C-Quam signal scenario. I went 290 miles - yes 290 miles - from the DFW area - and did a test in the canyon near Crosbyton. I was prepared with a loop antenna - but to my surprise I didn't need it. DFW stations on 620, 770, and 820 that ran C-Quam were not only receivable, but actually still pleasant to listen to, with a modest walkman AM stereo model - the SRF-A1. I cleaned up reception to static free with a small loop, and experienced no platform motion at all. Not even on 770, which was starting to experience interference from co-channel KKOB.
The Crosbyton canyon is a serious canyon with walls hundreds of feet high, a lot of odd angles and side canyons - if anything was going to cause problems that place would. It certainly does cause problems with FM, even semi-local Lubbock FMs. But AM stereo? Solid as a rock on an inexpensive receiver. What station manager could possibly gripe about 290 mile daytime stereo reception on a walkman??? What more do they want - its not like the rattlesnakes in the canyon care about Dallas Ft. Worth reception 290 miles away, let alone the few ranchers in the canyon.
Contrast those fantastic results, demonstrating once and for all, the abysmal coverage of the same stations post the IBOC conversion. WBAP has trashed the system because it really WAS hurting their range, unlike the fictional range decrease associated with C-Quam. The decrease in range is real and dramatic on AM - there was a small but loyal standards audience in NW Houston for KAAM when Houston lost its standards station. No more - KAAM's daytime coverage now sucks, and is almost obliterated by sidebands from local 790.
Same canyon, a few years later, post IBOC. Both stations running IBOC were seriously weaker post the conversion, almost unlistenable. KKOB owned the frequency on 770. 620 lost probably 100 miles of their range post conversion, although they are receivable if you are away from power lines in Lubbock. Nothing like the semi - strong signal they used to have. 660, by comparison, is the same now as it was before. And it is very strong in NW Houston. I wouldn't be surprised if they had a few listeners. Same with WBAP. I heard it severely degraded in Houston post conversion in NW Houston, now the IBOC, they are strong again. KLIF - same thing. Once almost a match for KTSA and even KLVI in parts of NW Houston, now it is severely degraded and weak. Why should they care? Because most people don't own a decent radio, and their signals are probably trashed over suburban areas of DFW, where they really WOULD care one way or the other. So the signal degradation with C-Quam wasn't real, but degradation with IBOC is definitely real.
As far as stereo range with IBOC - don't make me laugh. KAAM with C-Quam: 290 miles. KAAM with IBOC: not even 9.6 miles. Nine point six, not 96. What sort of DFW audience does less than 10 mile radius reach? The area is 120 miles EW and 70 or 80 NS in places. You won't reach but a tiny fraction with a stereo system that has less range than a LP FM or translator.
Bottom line: IBOC sucks compared to C-Quam. iBiquity needs to throw in the towel but quick and market C-Quam as "IBOC". At least it works and won't hurt sales of radios that won't work.
I experienced the platform motion on an early AM stereor tuner that radio shack sold. It was only a problem on some of the early receivers, and really it was kind of interesting. The affected stations would bounce from speaker to speaker. These signals were very weak anyway when this happened and the average person would have not even bothered listening anyway to such a weak station. Even a weak station with platform motion was still a fairly pleasant experience compared to what a lot of signals sound like now. I had an SRF 42 which never had the platform motion and I noticed on that radio that IF a station was receivable at all, it would be in stereo. A fun thing to do was switch the radio to mono, and the signal was completely gone. Switch to stereo and it would pop out of nowhere with a signal that was listenable. C-QUAM absolutely worked. It sounds BETTER than FM and it should have been standard in all radios by the mid 80's. You'd still see music on AM today if that had been the case. Here in Canada where it was the standard, you'd still see full AM dials playing the hits like they did in the 80's and early 90s. Teens didn't tune out of AM radio here until it stopped offering them what they wanted to hear.
There was one pronounced case in this region of platform motion with C-QUAM, but it was limited to a unique and well-known phenomenon involving a certain station.
WKBW, 50kw 1520 DA-1 Buffalo employs a 3-tower in-line array which shares ne tower in a common site with WGR 550 (there is a total of seven towers there.) The "common" tower is approximately a half-wave for 1520 and quarter-wave for 550. But KB moved from 1480 to 1520 as part of the massive NARBA reshuffle in 1941, so its towers were never precisely quarter-waves...IIRC they're something like 122 degrees at 1520, not 90.
The high frequency and odd array height have produced a listening phenomenon very famliar to those who have listened to KB throughout its decades of dominance in Western New York: from about 40 miles out to about 90 miles out, the arriving night skywave interacts with the still-robust groundwave to produce a "phasing" effect familiar to shortwave listeners. In SW it's apparently the product of various components of skywave arriving via different routes; but with 1520 it's the local versus the reflected power.
Of course this played havoc with the C-QUAM. Back when I was working there in 1986 my C-QUAM equipped Chevy had 6 speakers and the stereo image would not only shift from side to side, it would actually rotate in circular fashion around in interior of the car. The stereo would slowly spin clockwise, then the rotation would speed up and slow down again, finally stopping, then reversing and going counterclockwise!
It was actually slightly nausea-producing. On a couple of occasions I had to poke the MONO button to stop the sound from spinning around the interior of the car. But at least you could go to mono unlike IBOC where there's no way to stop the mode-hunting.
But again: this was the only serious C-QUAM platform-motion case I encountered. Like rbruce I thought the system's typical performance was excellent.
WKBW, 50kw 1520 DA-1 Buffalo employs a 3-tower in-line array which shares ne tower in a common site with WGR 550 (there is a total of seven towers there.) The "common" tower is approximately a half-wave for 1520 and quarter-wave for 550. But KB moved from 1480 to 1520 as part of the massive NARBA reshuffle in 1941, so its towers were never precisely quarter-waves...IIRC they're something like 122 degrees at 1520, not 90.
The high frequency and odd array height have produced a listening phenomenon very famliar to those who have listened to KB throughout its decades of dominance in Western New York: from about 40 miles out to about 90 miles out, the arriving night skywave interacts with the still-robust groundwave to produce a "phasing" effect familiar to shortwave listeners. In SW it's apparently the product of various components of skywave arriving via different routes; but with 1520 it's the local versus the reflected power.
Of course this played havoc with the C-QUAM. Back when I was working there in 1986 my C-QUAM equipped Chevy had 6 speakers and the stereo image would not only shift from side to side, it would actually rotate in circular fashion around in interior of the car. The stereo would slowly spin clockwise, then the rotation would speed up and slow down again, finally stopping, then reversing and going counterclockwise!
It was actually slightly nausea-producing. On a couple of occasions I had to poke the MONO button to stop the sound from spinning around the interior of the car. But at least you could go to mono unlike IBOC where there's no way to stop the mode-hunting.
But again: this was the only serious C-QUAM platform-motion case I encountered. Like rbruce I thought the system's typical performance was excellent.
I had a 1989 Dodge Spirit with "AM Stereo" that used the C-Quam system and it worked quite well, even through the Wasatch Mountains of Utah. At the time, we lived in a valley to the northeast of Park City and I often drove through canyons to get into Salt Lake (Parley's) and Ogden (Weber). The FM signals would bounce all over the place and were quickly degraded in the mountains, yet AM Stereo (even from AM signals that weren't that strong) was rock solid throughout those mountainous areas. The only dropouts would be those rare instances where I drove below an underpass.
No way that the same can be, or ever will be, said about this fraud known as IBOC.
Another good laugh was had by me during a trip back to New Hampshire. Saga Communications has figured out that nobody is hearing their WZID-HD2 CHR format from Manchester, so they've taken to airing it on two FM translators that are respectively located in Concord and Manchester. Now they can get some listeners. An obvious admission that there's just no demand for HD Radio.
The whole thing is a joke and someday HD radios will be sold for $8 as novelties on eBay.
No way that the same can be, or ever will be, said about this fraud known as IBOC.
Another good laugh was had by me during a trip back to New Hampshire. Saga Communications has figured out that nobody is hearing their WZID-HD2 CHR format from Manchester, so they've taken to airing it on two FM translators that are respectively located in Concord and Manchester. Now they can get some listeners. An obvious admission that there's just no demand for HD Radio.
The whole thing is a joke and someday HD radios will be sold for $8 as novelties on eBay.
At WNMB we use a new Delta AM Stereo exciter. Compared to the 80s generation of equipment, there have been numerous improvements in the technology. Platform motion is pretty much a thing of the past. On the receiver side, the same is true. For example, the AM Stereo section in my Thunderbirds and Explorer cut away from broadband when signal strength is low. As to AM Stereo coverage relating to our signal, we can drive out about 16 miles from the station and hear the stereo just fine. Then the radio reverts to mono. The signal goes on for another 3 miles or so. I am told this is much better coverage than HD radio on AM.
Savage said:
WKBW's three towers are about 195 degrees, so there is indeed a high angle minor lobe which causes skywave reflections at relatively short distances from the site. Towers of most other Class A AM stations don't exceed 190 degrees for this reason. For example, WLW, which shortened its tower due to bad results with greater height.
I remember listening to KB in the '70s at my home several miles west of Syracuse and the skywave vs. groundwave interference was quite bad even that far out. But here in southeast PA, the station's nighttime service is much better.
Needless to say, if C-QUAM is affected by this type of phase cancellation, IBOC doesn't stand a chance. In fact, it has trouble decoding even if the host analog is clean.
Freebird is correct - please excuse the typo. Of course a 122-degree tower would be closer to a quarter-wave, not a half-wave. I meant 192 degrees for the WKBW array.
It was odd that when they rebuilt the DA-1 in the late 70s or early 80s that they didn't correct the tower height to eliminate the near-in cancellation. Presumably this was because co-located WGR wasn't co-owned at the time. Cap Cities then owned 1520 and Taft owned 550 with both stations sharing the site.
When I listened to WKBW at night in Binghamton and Ithaca there was no phasing since you were far enough away to escape the groundwave.
It was odd that when they rebuilt the DA-1 in the late 70s or early 80s that they didn't correct the tower height to eliminate the near-in cancellation. Presumably this was because co-located WGR wasn't co-owned at the time. Cap Cities then owned 1520 and Taft owned 550 with both stations sharing the site.
When I listened to WKBW at night in Binghamton and Ithaca there was no phasing since you were far enough away to escape the groundwave.
This may be a condition in the higher medium frequencies in conjunction with the electrical length of the antenna and the ground system. Condition has been a constant on several high end of the dial stations I have been involved with over the years. On two occasions, found a higher than expected field at like an angle of almost 90 degrees (theta). That is why WLAC is useless about 38 miles south of their transmitter with IBOC on at night. Before, you could tolerate the selective fades, but not now. There is the expected waterfall but there is also a random component that is a low frequency beat sounds like a rumble amidst the phase cancellation rolloing in and out.
w/
w/
See my post under "Re: Give up the HD Ghost already" about converting IBOC buzzgenerators to C-Quam generators...
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