Beautiful HISS in HD AM on WSCR 670 Chicago

[Tom Wells]

Took my wife and daughter over to the doctor yesterday and spent some time listening to the new Kenwood HD radio.

AM HD worked for WLS (30%), not at all for WBBM, and when WSCR decoded (100%) in HD,
the audio feed had more hiss than a bad cassette tape. It was about like an FM dx signal, except without flutter.

What's the point of creating this super whiz-bang new system, when it's going to be used by the ignorant, careless, or clueless?
This is not about a tiny podunk nowhere signal. If they can't get it right in a major market after all this time,
it's over. There's MORE hiss in the HD decoded audio than in a widband analog radio center-tuned on this signal!

Can anyone else see an incredible waste of effort here?
Shouldn't ibiquity actually CARE enough to "certify" or somehow check that their equipment is being used by someone who
cares enough to provide quality source material?
Or will they sell it to anyone stupid enough to believe them?
I'd be seriously underwhelmed if I had bought an HD radio with high hopes, only to hear this much hiss in glorious digital HD.
Get a Noise GATE, already!

Pure foolishness on the part of ibiquity.
It's partly their reputation, too. If the station sounds BAD, it reflects poorly on ibiquity and the whole HD concept.
Many a GOOD concept has been ruined by sloppy, careless application, a poor concept saddled with careless application is truly doomed.

 

[RadeoEngineer]

Actually Tom, I have a friend saddled with two FM HD's and he hears from the iBiquity goon squad all the time. They're constantly on him about the delay sync being micro seconds off, and I understand they monitor other parameters as well on a more or less regular basis.

 

[Savage]

Just what overworked, underappreciated engineering staffs need: a shadow "boss" haranguing them about a Rube Goldberg digital system, critiquing their work and ratting them out to management that bought into HD.
Hopefully the quality cluster managers don't pay attention to iBiquity's Audio Delay Police and leave their engineers alone.

Small wonder good broadcast engineers are becoming about as scarce as steamboat engineers.

HD Radio: bad news for everyone who touches it. I would add, "bad news for those who listen," except there aren't any. At least, not many.

 

[briankay]

Took my wife and daughter over to the doctor yesterday and spent some time listening to the new Kenwood HD radio.

AM HD worked for WLS (30%), not at all for WBBM, and when WSCR decoded (100%) in HD,
the audio feed had more hiss than a bad cassette tape. It was about like an FM dx signal, except without flutter.

Yes you are right about the hiss on WSCR (shame on them). My toy DJ set from 1984 has less hiss. That is just badly adjusted station equipment. The HD sound quality makes the hiss noticable. WLS does a great job with their audio and is a pleasure to listen to even though it's typically 20 kbps core (mono out to 80 miles) and the 18 kbps enhanced stream in stereo kicks in about 30 miles from the transmitter (which give the full 38 kpbs AAC+ quality). The core stream is over 10 times stronger in signal strength than the enhanced, hence it more typically received when further away from the transmitter.

I live in the Chicago are and I receive all the clear channel HD AMs out to about 80 to 100 miles radius from the transmitter. That said I have a 31 inch whip antenna (which I installed) center mounted on my Scion xB roof unlike so many "cosmetic antennas" on the new cars which give crap reception on either band. Plus my antenna amplifier is very low noise. I even get the HD FMs consistently out to about 30 miles and intermittently out to 50 miles. FWIW, Visteon HD Zoom and Directed DHD-1000 are the receivers I use in me and my wife's car repectively.

 

[BRNout]

I live in the Chicago are and I receive all the clear channel HD AMs out to about 80 to 100 miles radius from the transmitter. That said I have a 31 inch whip antenna (which I installed) center mounted on my Scion xB roof unlike so many "cosmetic antennas" on the new cars which give crap reception on either band. Plus my antenna amplifier is very low noise. I even get the HD FMs consistently out to about 30 miles and intermittently out to 50 miles. FWIW, Visteon HD Zoom and Directed DHD-1000 are the receivers I use in me and my wife's car repectively.

The thing is, Brian, almost no one (aside from partisans like those who frequent this board) would go to all the trouble that you did in order to receive HD AM signals. For the [very] few that find themselves with an HD radio to play with, all they'll do with it is turn it on and see what comes in. In those cases, where you're dealing with standard equipment, HD AM signals rarely decode steadily more than 25 or 30 miles from the tx site.

In summary, it's not worth the effort, cost and headaches for stations to bother installing and operating it. The majority only do so courtesy of corporate edits that are the direct result of sweetheart deals with Ibiquity. Technically, AM HD is a failure.

 

[Tom Wells]

Yes you are right about the hiss on WSCR (shame on them). My toy DJ set from 1984 has less hiss. That is just badly adjusted station equipment. The HD sound quality makes the hiss noticable.

I doubt there is anything badly adjusted. I'll bet the audio feed really has that hiss in it.
There's also a "zizzle"that is heard on audio peaks, sounding just like an overdriven pre-amp stage .
It is audible in both analog and HD, and I'd be embarrassed if I had anything to do with that signal.

 

[KB1OKL]

Yes you are right about the hiss on WSCR (shame on them). My toy DJ set from 1984 has less hiss. That is just badly adjusted station equipment. The HD sound quality makes the hiss noticable.

I doubt there is anything badly adjusted. I'll bet the audio feed really has that hiss in it.
There's also a "zizzle"that is heard on audio peaks, sounding just like an overdriven pre-amp stage .
It is audible in both analog and HD, and I'd be embarrassed if I had anything to do with that signal.

You should hear WBZ in glorious HD, it's so sibilant, it sounds like it's coming from a three way speaker with a blown out midrange speaker and half a woofer. The audio also sounds like it is a bit overmodulated.

 

[briankay]

I doubt there is anything badly adjusted. I'll bet the audio feed really has that hiss in it.
There's also a "zizzle"that is heard on audio peaks, sounding just like an overdriven pre-amp stage .
It is audible in both analog and HD, and I'd be embarrassed if I had anything to do with that signal.

I heard WSCR on 104.3 FM HD-2 and the hiss is absent. I guess they route the AM feed both analog and HD through a link with a low S/N ratio. Pity that one of the most prestigous clear channel AM frequencies in the US has a feed that a 10 watt amateur college station would be ashamed of.

 

[OKCRadioGuy]

The tuning of the phasor, ATU, etc. can be VERY critical in a AM HD station to make it come closer to working right. Excessive hiss is most likely because someone didn't go to the trouble of making the system broadbanded enough and aligned right for HD. There's quite an art to it. My former boss gave a very informative lecture on how to tune one the right way using the right equipement for the job. I'd say if a guy doesn't have something like a PowerAim 120 or a good network analyzer available to him and know what they are doing in tuning it, they'd easily make a mess of their own signal with the hissers going from their own station. Of course, even with proper tuning, the audio bandwidth has to be pulled back some and the IBOC jammers kick out at night tearing up others, but as far as self-jamming, there are ways to minimize the effect.

 

[Ken Tucky]

You wanna hear something even worse? Try WRTO at 1200! I was in Chicago this past weekend & couldn't believe it!!! My little Sony portable is still bleeding!!!

 

[radiotower40]

You wanna hear something even worse? Try WRTO at 1200! I was in Chicago this past weekend & couldn't believe it!!! My little Sony portable is still bleeding!!!

AMEN!!!!! I agree that WSCR sounds horrible with I Block on, but, WRTO is absolutely the WORST sounding station
I have ever heard. I used to listen to the station when they were WLXX and played a tropical Spanish music format, I don't
speak a lot of Spanish, yet I really enjoyed the music they played. It sounded good for music on AM, of course that was in
the analogue days. It was a very well processed, clean sounding station.

At night their I Block is so bad that it interferes with their signal so badly it hurts your ears(I wonder why they are at
the bottom of the ratings pile??????). By day they interfere with stations as far as WYLL AM 1160, WJOB AM 1230 and
AM 1240 WSBC, WYLL is 50kw by the way. They completely Block out AM 1180 WSQR, which is out of the De Kalb area
west of Chicago. WSQR is quite listenable during the day when WRTO's I Block is "broken". I just can't wait until they
move to their new 20kw site, which is even closer to me(sarcasm :.

 

[Tom Wells]

The tuning of the phasor, ATU, etc. can be VERY critical in a AM HD station to make it come closer to working right. Excessive hiss is most likely because someone didn't go to the trouble of making the system broadbanded enough and aligned right for HD. There's quite an art to it. My former boss gave a very informative lecture on how to tune one the right way using the right equipement for the job. I'd say if a guy doesn't have something like a PowerAim 120 or a good network analyzer available to him and know what they are doing in tuning it, they'd easily make a mess of their own signal with the hissers going from their own station. Of course, even with proper tuning, the audio bandwidth has to be pulled back some and the IBOC jammers kick out at night tearing up others, but as far as self-jamming, there are ways to minimize the effect.

In August 2007, WLS, WBBM, and WGN (all 50 kw Chicago) all saw improvements in self-noise of about 3db.
I don't know whether ibiquity sent out a team to clean up and help, or whether they all fixed it about the same time independently.
I am still amazed at what an awful hiss was present in the HD-decoded WSCR 670. I'd rather have telephone-landline response than that hiss.