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DRM field tests

DRM is impressive, but as I understand it, it's incapable of "IBOC" (in band, on channel). In other words, you can't broadcast analog and digital simultaneously on the same frequency.
 
DRM is impressive, but I did not come equipped with an internal modem.
It seems well suited as a radio service for computers.
I will always prefer "self decoding" signals, where the intelligence went into the design, avoiding such extreme complexity in operation.
If used in a new chunk of spectrum, I will still wecome DRM as a useful mode, but just like TV, fax, texting, cable, wi-fi, satellite, etc....
it's not >radio<.
 
At least the developers of DRM (a non-profit consortium) have invited outside participation, experimentation and testing, and there are open-source versions of the decoder available for free download: http://drm.sourceforge.net/

Along with a healthy respect for the laws of physics, those are some reasons DRM is likely to succeed.

On the other hand, I'm sure that anyone who attempts to distribute iBiquity's "intellectual property" as freeware to hobbyists would soon be stung by a swarm of their lawyers.
 
Mike Walker said:
DRM is impressive, but as I understand it, it's incapable of "IBOC" (in band, on channel). In other words, you can't broadcast analog and digital simultaneously on the same frequency.
Click to expand...

HD radio
can't broadcast analog and digital simultaneously on the same frequency.
Click to expand...
HD radio is not "In Band On Channel". HD radio is adjacent channel, incompatible with existing analog channel assignments, provides negligible benefits or improvements for the typical listener and is highly destructive.

FMeXtra is the only totally compatible "In Band On Channel" digital broadcast system available.
 
SUPERCASTERS MOTTO: "HD RADIO- MAKES FM SOUND LIKE AM, AND AM SOUND LIKE CRAP!"

Most of us here are trying to discuss HD radio in an intelligent and honest manner. We (myself included) acknowledge the current system has problems, especially for AM, but are aware of the benefits of the FM system. I own 2 HD radio and can state with certainity that the sound quality of FM is greatly improved and multipath is eliminated. Your statement "MAKES FM SOUND LIKE AM......" is silly, false and adds nothing of value to the discussion.
 
HD radio seriously degrades analog AM and FM fidelity, signal to noise ratios, and reception across the broadcast bands, as well as to the analog fidelity of the "carrier" station. This has been proven hundreds of times right here on this HD Radio board and elsewhere. Just read it right here!
How is that "silly, false and adds nothing of value to the discussion."
Therefore I stand by my truthful statement:
"HD RADIO- MAKES FM SOUND LIKE AM, AND AM SOUND LIKE CRAP!"
 
Still at it, huh?

HD radio seriously degrades analog AM and FM fidelity
Click to expand...

The AM side is linited to either 5khz or, optionally 6khz

This 2006 cut from WABC during iboc operation gives lie to claim the analog AM must be severely degraded.

http://www.sendspace.com/file/9h9cq7 8mb

FM iboc has no effect on the analog audio quality it's pointless to comment further on this one.

Instead of degrading this discussion with lies ol' Sup stick to the facts.

Lino
 
LinoNYC said:
FM iboc has no effect on the analog audio quality it's pointless to comment further on this one.

Lino
Click to expand...

If you are close enough to the HD transmitter site (within their protected contours) the sideband hiss is audible. A non-techno friend of mine even noticed it about a regional HD station, and just today asked me why there was a loud hissing sound on either side of this particular station on his car radio. Funny that you should bring it up today. Even casual listeners notice the noise, but usually they just blow it off as “It must be the weather.” The bottom line is they stop listening to some stations they previously enjoyed.

In most metro areas, the sidebands are not much of a problem, since people are not used to listening to stations outside of their protected contours. In rural areas, there are very few HD stations. So far, it is a non-issue.

Just listening to the radio in your car in Rural America is almost a DX experience. It always has been. It is not at all uncommon to listen to stations way past their protected contours. Millions of Americans do it every day, although Arbitron may not record them. If everyone lights up HD on FM, many people will not be able to receive stations that they previously enjoyed.

The situation on AM is a lot worse so currently it is getting all the attention, but it exists on FM as well. That may be hard to understand if you live in a market that is well served by full power stations, but that is not the case in lots of places in the country
 
Supercaster, a convincing case can be made that HD radio "seriously degrades signal to noise ratios) of AM HD. NOT SO with FM, on anything but the very cheapest FM stereo radios. I have actually never heard the reduced s/n ratio on cheap "Walkman-type" headphone radios caused by the presence of digital subcarriers on the FM band (and I've tried), but trust others who say it's there. It only makes sense that it's there. It also makes sence that, due to the capture effect, with a well designed analog fm radio, it makes little or no difference. But Supercaster makes a good point about HD not being "in band, ON channel". At least on AM, it's "in band, on your neighbor's channel!" But then so are the sidebands of a hotly modulated, wideband AM signal. I KNOW, HD is continuously at the maximum level allowed by the RF mask, while analog signals, even very broadband ones, are trasient in nature...sometimes you're putting out lots of info in the sidebands, sometimes not much at all.
 
HD radio reduces the stereo signal to noise ratio substantially with most radio stereo decoders.
Most radios sold are "cheap radios" and are the ones typically used by the overwhelming majority of radio listeners, for most of their time spent listening.
"Cheap radios" are generally wideband radios subject to HD hash because additional sophisticated selectivity circuitry is sacrificed for price.
HD radio degrades analog listening near and far and creates listening problems and interference almost everywhere, for almost everyone (not just DXers).
http://www.radio-info.com/smf/index.php/topic,82174.msg609676.html#msg609676
 
I'm sorry, but tests have shown significant (more than a few db) s/n degradation on only a couple of the cheapest of radios (next you're going to ask where I read it, and I'll be damned if I remember. I think it was research done by NPR). I have MANY fm radios, expensive and in(expensive), and can't hear any degradation on any of them, including my 25 dollar Sony SRF-42 (GREAT AM/FM Walkman!)

Want to argue about AM, you have a point. Arguing about degradation of FM, and you're just being silly. Know how I know it's not an issue? Not a single engineer I've talked to has received a single complaint from a listener! 'Nuff said!
 
Mike Walker said:
I'm sorry, but tests have shown significant (more than a few db) s/n degradation on only a couple of the cheapest of radios (next you're going to ask where I read it, and I'll be damned if I remember. I think it was research done by NPR). I have MANY fm radios, expensive and in(expensive), and can't hear any degradation on any of them, including my 25 dollar Sony SRF-42 (GREAT AM/FM Walkman!)

Want to argue about AM, you have a point. Arguing about degradation of FM, and you're just being silly. Know how I know it's not an issue? Not a single engineer I've talked to has received a single complaint from a listener! 'Nuff said!
Click to expand...

Amen!
 
Mike Walker said:
Want to argue about AM, you have a point. Arguing about degradation of FM, and you're just being silly. Know how I know it's not an issue? Not a single engineer I've talked to has received a single complaint from a listener! 'Nuff said!
Click to expand...

Many HD promoters and supporters claim interference, analog degradation, poor coverage and complaints about HD radio both AM and FM don't exist. Yet they continue to pour in daily.

"'Nuff said!".
Click to expand...
 
SUPERCASTER said:
Mike Walker said:
Want to argue about AM, you have a point. Arguing about degradation of FM, and you're just being silly. Know how I know it's not an issue? Not a single engineer I've talked to has received a single complaint from a listener! 'Nuff said!
Click to expand...

Many HD promoters and supporters claim interference, analog degradation, poor coverage and complaints about HD radio both AM and FM don't exist. Yet they continue to pour in daily
Click to expand...

From those such as yourself who have dedicated an unusually large chunk of their waking hours to filling message boards with mostly false claims.

-Such as your current one about FM iboc.

Lino
 
The funniest thing about your post is that the only ones that make up "false claims" are the tiny HD cult who try to sell their HD radio disaster and are the HD promoters and supporters who (truly?) believe HD is radio's salvation.

Try:
CD quality sound. :D
Get hundreds of new "stations between the stations". :eek:
Immune from interference, and interruptions. ::)
etc., etc. etc. ;D
 
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