Bill said:
Stereo? As in C-QUAM stereo. With only 500 watts? Does anybody still do that anymore with any margin of success?
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ABC CITADEL AM STATIONS SUSPEND NIGHTTIME IBOC
- Thread starter Savage
- Start date
Stereo? As in C-QUAM stereo. With only 500 watts? Does anybody still do that anymore with any margin of success?
A
awj223
Guest
I think everyone may have to admit that Leonard Kahn took the right approach. Rather than ignore the laws of physics and the findings of Claude Shannon, he didn't try to cram 3 liters of water into a 1 liter container like iBiquity did (and now iBiquity is wondering why 2 liters spilled on the floor adjacent to the bag). With channel separations less than channel size, there simply isn't room to transmit a full digital signal next to the analog. If the problem you're trying to solve is the fidelity issue, reuse the information you're already sending in analog and just transmit the treble in digital and use a smart receiver to recombine it!dumber than a box of hair said:
Like you say, the average listener won't care about the engineering aspects. All he'll know is that the frequency response of CAM-D sounds a lot better than analog only. At least you'll still be able to hear your skywave in traditional, lower fidelity when you're farther from the transmitter, rather than the iBiquity-developed situation of mutually assured destruction: being able to hear neither signal.
CAM-D as an interim, followed by conversion to DRM.LinoNYC said:
We also need to clean out the band, especially all the stations that should never have been licensed. As I said before in another post (where someone nominated me "FCC Broadcast Plan Czar"), all Class C and D stations should go to FM, as well as most Class B stations operating on what should be clear channels should vacate mediumwave as well. They should end up on the additional channels created by our friends at iBiquity. All that should remain on mediumwave are the Class A stations, and they should be allowed to raise power to at least 500,000 watts when they switch on DRM, with 10 kHz channel size in mode B or C. The band should be cleared out and kept clear to allow for protected contours of all existing Class A stations out to at least 0.1 mV/m operating at 500 kW.
The message from the FCC should be this: when you broadcast in hybrid (CAM-D) mode or pure analog mode, you are limited to 50,000 watts. When you go DRM with a strict 10 kHz channel size, you can blast 500,000 watts from your facility because you aren't stepping on your neighbors' turf. WLW might have been given 500 kW non experimental if it weren't for the adjacent channel interference.
Bill said:
A few of us out here nailed it: IBOC from WLS was the culprit for your station's nighttime noise. Believe me, being only 19 miles from the WLS transmitter, it sure is nice to have WLS "back in its box" where it belongs, staying mostly between 883 and 897 instead of spewing buzz from 865 to 915. At 19 miles & 50,000 watts, I couldn't get reliable nighttime IBOC reception from WLS, anyway.
JIBGUY said:
Sure is a nice self supporter your sportin’ there Bob. It would be nice to be able to hear that 740 C-QUAM down here in Philly. I used to love AM, until I-Buzz took the life out of it.
Speaking of I-Buzz, has anyone else noticed this? I have never heard this before until now. And I still cannot believe that 1210/WPHT Philadelphia drifts. The analogue center tuning on 1210/Philadelphia drifts, particularly now that they are running AMHD. Before this I have only heard FM stations drift, and this was mostly before AFC. When I first experienced drift on a non digital AM tuner, I thought I was imagining this. At first I figured with all the equipment I have running here, (including, off the record, my own transmitters, at times), perhaps I was creating this phenomenon. But how many time do you have to calibrate your own equipment, before you begin to say, that this may be an exercise in futility. Sometimes it would drift in a matter of less than a half hour. Always at different clock speeds, no pattern. And very subtlety. It’s like you realize that after a measured period of time, you're listening to I-Hash. So I decided to ask someone who also is a die hard AM’er. And they confirmed the same thing. I was stunned.
the "drift" you are noticing is probably due to slight frequency drift in your model of receiver over time causing the on-channel "null" of HD hiss and the need to re-tune. This would be sort of normal on many radios. Also, with HD nighttime operation even minor HD fading of station "sides" can seem to reappear on-channel. Very interesting to hear the on-channel "hiss" roll in and out with fading of even local stations.
hipporadio said:[btw]... THANKS CITADEL!!! I can hear WSB again! ...From ONE state over! Sounds like a BIG-TIME DX to me
Count me in as #3 thanking Citadel for being able to listen to WSB again. I'm two states away now and until nighttime IBOC, I used to get WSB better here in Mississippi than I did in Alabama! Not that I listen all that much, but if I'm on AM at night, it is due to WSB (there is no local AM here, day or night.)
Usually they are pretty decent around here, but lately there'd be periods where the signal meter was nearly maxed out in the car, yet it would be completely inaudible audio beneath hash. Ugh.
You know it's time to move on when the thread's discourse deteriorates to this level:
Q: In light of Citadel's yanking HD-AM off their big AMs due to adjacent-channel interference, what SPECIFICALLY do you propose to fix IBOC-AM since you so passionately believe it is the only hope to save the band? (After all, the Citadel decision is the thread's subject matter.)
A. (i) Why did you spend $400,000 upgrading your AM and why didn't you get an FM instead? (As if the poster had never heard of a little thing called "the filing auction.")
(ii) Your station is one of a group "which never should have been licensed."
(iii) You don't have enough audience, and your station will soon be sold to a religious broadcaster.
(iv) I've talked to BE/Harris/iBiquity engineers. They know what they're doing.
Best wishes to all - I'm wanted back on Planet Earth.
Q: In light of Citadel's yanking HD-AM off their big AMs due to adjacent-channel interference, what SPECIFICALLY do you propose to fix IBOC-AM since you so passionately believe it is the only hope to save the band? (After all, the Citadel decision is the thread's subject matter.)
A. (i) Why did you spend $400,000 upgrading your AM and why didn't you get an FM instead? (As if the poster had never heard of a little thing called "the filing auction.")
(ii) Your station is one of a group "which never should have been licensed."
(iii) You don't have enough audience, and your station will soon be sold to a religious broadcaster.
(iv) I've talked to BE/Harris/iBiquity engineers. They know what they're doing.
Best wishes to all - I'm wanted back on Planet Earth.
R
rbrucecarter5
Guest
Sam Lit said:
C-Quam is robust as the main signal. I have heard C-Quam stations in almost perfect stereo for hundreds of miles in stereo daytime, and over a thousand at night. It is IBOC that has coverage problems, not C-quam.
JIBGUY said:
Also, C-QUAM never deteriorated the sound quality of the mono AM signal that most of us listen to. IBOC adds hiss to the audio, especially if you're using a wide-band tuner, which is what most cheap Chinese junk radios are these days, not to mention hi-fi sets like the Tivoli #1 series of radios.
Even if you tune in very carefully, the hiss is still there.
Savage said:
Bob... EXACTLY the PROBLEM HERE! I often hear the question: “WHERE are the technically-competent engineers who just happen to ride-herd over stations transmitting in HD?” I would suggest that while they may prowl – they choose not to post. Would YOU want “the affiliation” with SOME of the “HD ilk” that make this site an outlet for their fantasy? I wouldn’t! Fortunately, the CRITICS of “HD” on this board DO NOT [generally] embarrass me; many are insightful and apt with regard to technical issues; and some like Chuck and Tom Wells are predominantly-guided by courtesy—but even they are not immune to the all-to-typical “resume comparison”. Remember, Chuck is “just some low-power broadcaster” and Tom “doesn’t have a real job in radio” [sic.: He is incapable of such :
] GEEEZE!Just a few days ago, I spent an entire evening composing a post that specifically addressed such [the “Band-Plan” thread]. It is far from perfect, and is merely a “first swing” [I DO get two more strikes don’t I]. Within a few days—a FEW responded... Their observations are fair and the augmentative ideas are good; BUT... 'Guess who are conspicuously-missing from that exchange? ...[Save just one], the usual suspects known for their “HD Radio” enthusiasm here. :-\
...And as if a paltry $400,000 would buy you a mere TEN-WATTer licensed to a metro-Rochester high school! We can thank corporate radio and its gluttonous late-90s buying spree for this greed-driven commoditization of available frequencies.
...And as if corporate radio has missed ANY opportunity to enjoy the SAME fruits of past “AM initiatives” to enhance one of THEIR almighty clusters!
Just this past weekend, the pro-IBOC-on-AM camaraderie had settled-in on teenage fodder to make their case :
...Now I see yet another seminar-style justification taking shape: “If IBOC on AM fails, those religious zealots will confiscate the AM band!” PATHETIC!I really liked my Harris rep back in the day, but nearly-every time I talked to a compadre’ – that “sales-type” wanted to sell [or lease] me something. UNDERSTANDABLE!
Come now Bob... PLEASE tell us you’ve caught just a bit of “drama” [as one would the common cold] and will return after a reasonable period of recuperation. I’m sure as the owner of a financially and ratings-challenged “AM interference machine” on the verge of a TBN-style take-over – your time and attentions are well-demanded; but I [for one] enjoy your cogent and creative contributions here... FACE IT, Bob—this is too much fun at times to cast-off merely for the misadventure and substandard debate etiquette of “The HD Radio Gang”
Yes, WNMB broadcasts in C-Quam AM Stereo and we are very blessed to be doing well. Maybe we are like the old story of the hot dog vendor and no one has yet told us we can't succeed. We do "Local" radio about our community of license, North Myrtle Beach. We, along with our local news, community involvement and so on, play oldies and classic hit songs. Business is good. We sell ideas to advertisers. Listening is good and we have a constant stream of people whom we know can hear the AM Stereo because we are running constant education campaigns about it in our local market. Listeners let us know they can hear it. We don't have a magic formula for success. We make many mistakes. But, folks, local radio done well still works. Even on AM. Now as to the AM Stereo, and excuse the arrogance, it is not a failed technology. Instead, we (broadcasters and the FCC) failed it to date. I am really proud of my fidelity and on a decent receiver I am not afraid to compare it to anyone's FM.....or, for heaven's sake, AM IBOC transmission. If AM Broadcasters in this country would go to AM stereo and promote it, it can still work. HD, however, with it's inherent inequities for AM, is not going to be an AM solution. It is a problem instead because it introduces a new set of problems. For example, if I put IBOC on my 500 watt station, what kind of HD coverage would I get? Not a lot. The AM Stereo, however, gives me most all my existing coverage area and it does not degrade the mono.
hipporadio said:
And HD Radio sure has been the golden opportunity to sell boxes. "Exporters", "Importers", E-PALs, Dexstars, Flexstars, Neural Neustars, HD monitors, A to D converters, sample rate converters, test equipment and a bunch of digital studio gear and digital STLs. (Because, if your "pristine" digital audio touches an analog device anywhere in the chain, you're a sinner!)
I predicted that we would see some of this stuff in the Dayton flea market in less than five years, but the AM HD exciters may be showing up on eBay as soon as next week. Ten bucks would be a fair offer -- you might be able to re-use the power supply for a ham radio project.
And to think that many of those great airchecks on ReelRadio required only a talented individual working with two turntables, a few Tapecasters, a Gates Yard, Audimax/Volumax, a 1 kW AM rig in the back room and a 300 foot stick in the field.
L
LinoNYC
Guest
You left out; Listeners.
Lino
Oh they had listeners. Lots and lots of them.
somebody wrote: "...but the AM HD exciters may be showing up on eBay as soon as next week..."
Curiousity has the best of me on this one:
Since the 0-5KHz part of IBOC signal is phase-modulated (as is the L-R CQuam), I'm wondering if one could rewrite the code in the HD exciter with the CQuam algorthym and use it for C-Quam at night? Or even Uncle Leonard's CAM-D? Enhancing the analog is the key, and making a really decent AM tuner as part of an FM-HD tuner package.
I'm curious on how strong the CAM-D sidebands are too?
Can somebody loan me a Dexstar (DeathStar) so I can try it out with different software?
Curiousity has the best of me on this one:
Since the 0-5KHz part of IBOC signal is phase-modulated (as is the L-R CQuam), I'm wondering if one could rewrite the code in the HD exciter with the CQuam algorthym and use it for C-Quam at night? Or even Uncle Leonard's CAM-D? Enhancing the analog is the key, and making a really decent AM tuner as part of an FM-HD tuner package.
I'm curious on how strong the CAM-D sidebands are too?
Can somebody loan me a Dexstar (DeathStar) so I can try it out with different software?
LinoNYC said:
...And he also left out the DIGITAL DELAY—necessary to keep “those dumb listeners” fooled and in-synch with the real-time ANALOG world... MANDITORY equipment given the poor HD signal coverage, poor structure penetration, and downright UNRELIABLE HD-AM service... Flip-Flop... ‘Now when’s the “flop” going to “flip”?
Savage said:
I knew you couldn’t resist us, Bob...Plus the sun set just an hour ago – much of the AM band is under assault from IBOC and unworthy of any TSL
LinoNYC said:
Ladies and gentlemen, we've just entered the Twilight Zone. A solution for a badly engineered digital-radio system, which pours interference onto adjacent channels, hundreds of miles from the transmitting antenna, causing decreases in NIF contours, is to cripple it even further???????? How do these engineers propose to kill skywave propagation and interference altogether, when no one has been able to do so for the almost 100 years the AM service has existed? How do they propose to change the laws of physics?
Oops, almost forgot...the FCC and Congress do it all the time... ;D
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