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Don't forget FM had an uphill battle as well.

kenglish said:
Why do we even care that HD Radio uses more bandwidth. The Regulatory Agencies are going to take it all away, anyway?
Here's the "latest" in the "Spectrum Wars": ::)

http://www.eweekeurope.co.uk/news/ofcom-mulls-fm-frequency-for-rural-broadband-33625
Click to expand...

Well, there's this:
If digital requires MORE bandwidth to get the same amount of information through, AND it's not as robust as analog,
then it's a sort of engineering failure, and not really worth the bother.

By mathematics, bandwidth is bandwidth regardless of mode, and if we're really considering best use of rf for broadcast,
the necessary redudundancy in digital can only be considered as net lost efficiency, and still not enough to
maintain a "stream" under many of the conditions we expect "radio" to work in.

That's why I care. I expect "advances" in technology to somehow work BETTER than what the advancement proposes to
replace. When it doesn't, it doesn't matter how much I or anyone else would LIKE it to replace the existing.
This is where marketing, planned obsolescence and outright interference a la ibiquity come into play.
I tried to listen to some FM analog on the way to work tonight, on a local big signal FM.
Awful lot of multipathing due to atmospheric effects. The HD sidebands chattering in continuously made a lot
more noise than I hear listening to AM "dx" on the way to work.

Really, many nights there's a much cleaner signal from WSM 650 here in Chicago than there is from local FMs.

At least it doesn't spit and flutter continuously as I drive along. FM is fine if I sit still, but I need to get to work. ::)
 
TheBigA said:
Tom Wells said:
If digital requires MORE bandwidth to get the same amount of information through,
Click to expand...

I don't believe that's true.
Click to expand...

In AM modulation, the bandwidth varies according to the information present.
Zero modulation is "zero" bandwidth, that is, all the energy is in the carrier, no sidebands, bandwidth is at a minimum.
In digital HD mode on MW, even with no modulation, all the sidebands are present ALL the time, using up 30-40 khz for NO
information. That's certainly using more bandwidth as I measure it.
 
Please pass the Dramamine platter to L. DeForest. Doctor, once again you've nailed it: the comparison of HD to FM's rollout, yet another tired HD Radio talking point, is ridiculous.

It's like laboring to predict the success of (pick your favorite failed or failing technology, including HD Radio if you prefer) by pointing out how it took 25 years for automobiles to replace horses in most families.

You don't have to go any farther than pointing out that FM did not destructively interfere with existing service such as AM or TV. It gets brushed aside, but the stark truth is - even if everything positive that's claimed for HD were true (it isn't) this fault alone would doom this system. The interference - to originating and neighboring signals - is simply unacceptable.

It's interesting that IBOC's few remaining proponents have stopped insisting that the interference doesn't really exist. Guess stubborn and repeated lying really DOESN'T work, just like our Moms warned us.... ::)
 
It speaks volumes about the merits of HD - or, more precisely, HD's failures - that people buy an expensive high-end consumer product like a BMW which coincidentally happens to include HD Radio - whereupon they promptly pedal back to the dealer to have the HD disabled.

It is likewise revealing that BMW dealers have a protocol in place to deal with HD Radio complaints, and their "SOP" is to just turn the damn thing off for customers. If HD was anything like what's claimed for it, this simply wouldn't happen. Dealers would be perplexed by a complaint about performance instead of summarily dealing with it pursuant to a familiar pattern.

When this kind of thing is happening, HD is Dead Tech Walking. (Actually, it's a corpse being dragged around by its tiny band of remaining supporters.)
 
Tom Wells said:
In AM modulation, the bandwidth varies according to the information present.
Zero modulation is "zero" bandwidth, that is, all the energy is in the carrier, no sidebands, bandwidth is at a minimum.
In digital HD mode on MW, even with no modulation, all the sidebands are present ALL the time, using up 30-40 khz for NO
information. That's certainly using more bandwidth as I measure it.
Click to expand...

Zero modulation is not a fair comparison.
 
Okay, how about 100% modulation? If you push AM to the point of carrier cutoff, there still isn't incursion into neighboring channels. That only happens when the carrier gets clipped by overmodulation and/or power supply tilt and the RF becomes uncontrolled. It winds up splattering. So in analog AM you don't get pollution of adjacents until you're illegally pushing your signal to no good purpose. In HD, pollution of adjacents with digital noise (as detected by an analog receiver) is standard practice, and is unavoidable to make the system work (25 OFDM carriers in each adjacent passband.) It's just that a lie was concocted about how far the digital carriers are suppressed in order to blow this scam past clueless FCC non-engineer policymakers.

In fact, analog overmodulation isn't anywhere near as destructive as HD Radio, because overmod splatter is highly intermittent. COFDM noise is steady-state and very high amplitude. It never stops.

The point is, invading adjacent channels via HD is just as destructive as improperly operating an analog plant. There's an allocation system for a reason. It should be observed industrywide, as it has been for 80 years, instead of finessing it for a bunch of self-styled "innovators" with a personal and/or professional agenda, at the expense of other broadcasters (and listeners.)
 
Savage said:
Okay, how about 100% modulation? If you push AM to the point of carrier cutoff, there still isn't incursion into neighboring channels.
Click to expand...

The statement was digital requires more bandwidth than analog for the same information. My understanding about digital is that it requires the same amount of bandwidth regardless of the amount of information. Is that wrong?
 
Yes. HD Radio requires approximately 25 kHz to accomodate the system's simultaneous analog and digital information. Analog-only, particularly post-NRSC (1990) occupies 10 kHz.

That's the crux of the problem. FM HD has a similar and parallel issue. There isn't enough bandwidth, either mode. It's like trying to put a gallon of water into a quart container. (Maybe if I push really hard? Do it really fast? Distract everyone so nobody notices how much gets spilled??)

The immutable laws of physics get in the way. No matter how much you wish it were otherwise.
 
Still seems like the various governments are doing everything they can to get rid of over-the-air broadcasting, in any of it's forms.
(Kinda feels like a knife in the back, with all we've done for the public over the years.)
 
Absolutely, k. Government is all about consolidation of power in big federal authorities. They don't want a multiplicity of pesky dissenting voices. That's why they're trashing broadcast TV and radio using the most convenient means available - in this case, corporate clods greedily eyeing "HD Radio" as some kind of annuity.

They want us all dependent on the Internet. Which they will swoop in and start regulating at the most opportune time. After everyone's given up on TV and Radio because "it doesn't work as well as it used to."
 
The internet is great, but just too unreliable. It requires bandwidth for each user, compared to broadcast radio, TV, etc which can support an infinite amount of users on the same signal. Even though the internet has come a long way, I can remember it being dragged to a halt on 9/11. During disaster the internet, cell sites will become overloaded. Even if its only in a local area, its pretty easy to overload cell sites and your local ISP. There isn't much spare capacity on these systems and when everybody starts calling, texting, going to websites, etc its the equivalent of everybody turning on all the lights and appliances in their homes and expecting the power grid to stay up.

If everybody instead turned on their radios they would all get information and there would be no overload. Analog radios are dependable also. They are cheap so you can afford to store them like flashlights.

I love technology, don't get me wrong. Computers, internet and smartphones are great devices to have. But during a disaster I'll be grabbing my radio.
 
Savage said:
It is likewise revealing that BMW dealers have a protocol in place to deal with HD Radio complaints, and their "SOP" is to just turn the damn thing off for customers. If HD was anything like what's claimed for it, this simply wouldn't happen. Dealers would be perplexed by a complaint about performance instead of summarily dealing with it pursuant to a familiar pattern.
Click to expand...

I realize this is getting off topic a bit, but this says more about the ignorance of the general public than it does about the HD technology. If someone can't figure out how to disable the HD part of their new high end radio, they need to reevaluate their understanding of the car's entire electronics system for their own safety. So much of BMW's control system is integrated into the iDrive system, I would hope the people buying those cars would familiarize themselves with every aspect of it before setting off in a 2 tonne metal rocket.

It's like renting a car. Before I pull out of the rental parking lot, I go through all the gubbins and electronics and HVAC and yes, even the radio, so I don't get surprised while doing 70 on the interstate.

Sorry, now back to whatever topic this was supposed to be.
 
RadeoEngineer said:
Zach, you're kidding right? Someone that can afford a BMW is going to search the manual for how to turn off the HD on their radio?
Click to expand...

They shouldn't have to unless they can't figure it out by fiddling with it. So if taking the car back to the dealer is the story, it's as much about poor software as it is poor HD radio, but in the end if they didn't read the manual it's about a poor user.

And yes, I expect people with any amount of wealth to "RTFM" before calling anyone for help. That is what it's there for, whether it's a $60,000 car, a $600 home theater system or a $60 microwave. It'd be different if we were talking about repairing a radio station's transmitter or exciter, or changing the timing belt on that Beemer. But this is simple stuff the consumer should figure out themselves. I can't believe someone could be smart enough to earn enough money to buy a nice car like that but too dumb to figure a god forsaken RADIO.

I'm sorry to get this so off topic, but it really makes me mad when I have to go fix something simple on a relative or friend's computer because they're too stupid to read the manual and figure out themselves. On the other hand, it's made my friends in IT a good chunk of money over the years so I probably shouldn't complain. ;)
 
And yes, I expect people with any amount of wealth to "RTFM" before calling anyone for help.
Click to expand...

When was the last time (pre-IBOC) anyone had to read a manual before operating their car radio?

As all know, iBiquity's system is a hybrid one. Existing, more or less, along with the analog signal. Common sense would suggest that the receiver manufacturers would make the digital signals as easy to receive as the analog. That means no menus you have to drill through to get to want you want. Digital on or off? Should be just as simple as the old front panel stereo On/off button.

HD radio's supporters appear to be their own worst enemy.
 
The Big A said
And yet...it really doesn't matter. Because the FCC isn't going to shut it down.
Click to expand...

Your right. The FCC doesn't seem to work that way. They will let the market decide. Sound familiar?
 
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