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The atrocity known as AM HD radio

Discussion pertaining to Detroit, Ann Arbor, Port Huron, and SW Ontario
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MWmetalhead
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The atrocity known as AM HD radio

Post by MWmetalhead » Sat Jul 06, 2019 5:14 pm

My new car has HD radio. For those of you who've read my commentary on the Buzzboard for a couple years or more, you won't at all be surprised by what I have to say next - consider me underwhelmed.

Decently engineered FM stations seem to have better stereo channel separation in HD and better sound stage. But all too common - I'm hearing garbled highs that sound very hissy in HD mode. This is especially evident on HD2 & HD3 channels, which in many cases have worse overall audio quality than the typical Sirius XM music channel.

HD mode on the AM band doesn't even sound as good as properly processed 10 kHz analog audio and sounds nowhere remotely as good as analog FM. Anyone suggesting music in hybrid digital mode on the AM dial sounds "almost as good" as FM is an absolute liar.

Not only that - I've found that getting an HD signal on the AM band to decode reliably while driving around Metro Detroit is damn near impossible.

950 WWJ is the only station whose HD signal remains locked in at least 80 percent of the time for me.

I live less than eight miles from the 1340 WCHB tower site and have never been able to decode their AM HD signal, not even near Catalpa & Woodward in Royal Oak!!!

1200 WMUZ is a 50,000 watt monster during the daytime, yet I can only decode their HD signal maybe 40 percent of the time during daytime hours in my area.

910 WFDF is the big winner (or loser) when it comes to Hybrid Digital ineffectiveness. I've tuned into the station along M-10 from downtown Detroit to Southfield on a half dozen different locations, and three of the six times, my receiver didn''t even know the HD signal was there. Two other times, the HD icon lit up intermittently, but never got a good enough "lock" to actually decode the signal. One time & one time only on M-10 - I was able to pick up the actual HD audio, and that lasted no more than 30 seconds before the station reverted to analog.

I've also tried getting WFDF's HD signal to decode on another handful of occasions in the Royal Oak, northern Southfield and Beverly Hills areas,and only had success on one occasion. This is a 50,000 watt station whose city grade contour extends a good thirty to forty miles north of my listening location, yet deep inside what should be city grade reception territory, getting an HD lock is almost impossible!

Finally, there's 1270 WXYT. I can get their HD signal to decode maybe 60 percent of the time during daylight hours. I tuned in the station during PM drive on July 3. Guess what? Whenever my receive decoded the HD signal, the audio was so horrendously distorted that the station was absolutely unlistenable!!! (Meanwhile, the exact same broadcast on WXYT-FM HD 3 sounded fine.)

I would LOVE to know how much money the radio industry as whole has thrown into the toilet with regard to investing in Hybrid Digital audio.



Deleted User 14990

Re: The atrocity known as AM HD radio

Post by Deleted User 14990 » Sat Jul 06, 2019 5:24 pm

I didn't know cars even came with HD radios.



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Re: The atrocity known as AM HD radio

Post by Arthur Mometer » Sat Jul 06, 2019 7:16 pm

When WFDF runs the full 50000 watts, I have heard them neck and neck with WWJ in HD, all the way to Sterling, MI on I-75. I’ve heard it goes even further on US-23 on Lake Huron. I get the impression that the newer 50000 watt transmitters have a lot of issues. WWJ has two, so it’s not as much of a problem to switch back and forth. But when WFDF runs on their auxiliary 10000 watt transmitter, I’m not sure they can run HD. I’ve heard both WFDF and WWJ at Night in HD Intermittently near the Straits. Seems like the only other ones I’ve heard in HD there are the Directional Class As like WBZ, which beams right at us. Seems like KYW and WRVA are/were others. WMVP stopped years ago, and we all know the atrocity that happened to WOWO.


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Re: The atrocity known as AM HD radio

Post by MWmetalhead » Sat Jul 06, 2019 7:53 pm

WFDF is still running HD; it just has miserable range. I can hear the IBOC-induced splatter on the sidebands.

Speaking of WWJ, their HD was turned off completely when I listened both yesterday & today.



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Re: The atrocity known as AM HD radio

Post by Arthur Mometer » Sat Jul 06, 2019 8:18 pm

When the signal has to cut across the Northwestern part of Detroit, it affects the WFDF signal. WWJ cuts through the river bed delta areas more, next to the Detroit River. I suspect that besides the pattern and the different locations, that explains it. Because if you go straight North, the signals are equal.


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Re: The atrocity known as AM HD radio

Post by innate-in-you » Sun Jul 07, 2019 6:34 pm

Arthur Mometer wrote:
Sat Jul 06, 2019 8:18 pm
When the signal has to cut across the Northwestern part of Detroit, it affects the WFDF signal. WWJ cuts through the river bed delta areas more, next to the Detroit River. I suspect that besides the pattern and the different locations, that explains it. Because if you go straight North, the signals are equal.
Interesting.
Is the northwestern part of Detroit Proper known to have poor conductivity?

I lived near Joy/West Parkway many years ago, AM reception was good (CFCO with oldies on a crystal set).

I've said it before and I'll say it again: AM HD radio was never intended to provide a useful service. It was an attempt to placate AM owners who asked "What About Us?".

HD AM radio imparted a strong hiss on any AM radio that gave good audio on AM. It generated severe adjacent-channel interference, rendering clear-channel nighttime service obsolete when it was being used. AM HD broadcasts dropped out with lightning at great distances that would barely would have been noticeable on analog AM.

They would have been better off if AM stations imparted a sub-audible signal that would have referred AM-FM HD receivers to an FM HD stream with the same.content.



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Re: The atrocity known as AM HD radio

Post by CK-722 » Sun Jul 07, 2019 7:58 pm

I've tried to make sense of the difference between the WFDF and WWJ signals for the last 14 years almost. On the one hand, the locations of each TL make a big difference in the radiation roughly in the direction of the Oakland Macomb border and Eastward. Woof Doof (an insider semi official moniker along with Wood and Woof Boom (WFBM), when they were all coowned) is significantly further West than WWJ (don't have a pronunciation), and the IDF in that direction is substantially less because of the TL. The path in that direction is also more sandy and gravelly, the path from WWJ is more clay and silty along that path.

Zoom in on this map and draw some lines in your mind.

https://ngmdb.usgs.gov/Prodesc/proddesc_71889.htm

Anyway, the path is better straight North from WFDF than through the West side of Detroit. So they equal out further West. By the time you get over to A^2 and Livingston, the Woof Doof signal is BETTER than WWJ, even with 25 kW Night, because of the TL and the pattern.

You can also see some of this on the WDEO proofs in the WMVP application online.

Long ago, WFDF should have seen some of the transmitter problems, and put in a second 50 kW transmitter. I think the 10 kW auxiliary has caused some perception problems about the relative signals. If they didn't have the IBOC maintenance, they might have avoided some of this also. Though WFDF at full power and also WWJ are probably some of they longest range HD AM groundwaves they have, at least to the North. The WFDF 50 kW Day isn't that bad in Macomb County, but it is demonstrably easier to listen to WFDF at Night at the Straits than in Macomb County.


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Re: The atrocity known as AM HD radio

Post by Myron Falwell » Sun Jul 07, 2019 10:31 pm

WZRC 1067 wrote:
Sat Jul 06, 2019 5:24 pm
I didn't know cars even came with HD radios.
That goes back to the overall failure of whatever PR campaigns have been used for HD Radio. When iBiquity owned the whole setup and had the patent claims to the IBOC standard, they initially had Clear Channel, CBS, Citadel and a few other groups run PSAs for HD Radio as often as possible. That only lasted about a year, and the quality of the PSAs were utterly horrific.

Car manufacturers have been including HD Radio receivers in their new models for the past year or so, but no one really talks about it beyond the industry trades. You know, tree falling in the forest but no one around blah blah blah...


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Re: The atrocity known as AM HD radio

Post by Deleted User 14990 » Sun Jul 07, 2019 10:48 pm

The Last time I bought a new car was 2008, the current car I have I bought used 4 years ago through a private owner. I feel kind of dumb now, I'm a Honda man and I've honestly heard nothing about them having that as an option in any of there vehicles, so that's the main car company I keep up on. I was just at the dealer getting my car serviced, I saw no signs, brochures, or anything talking about HD radio. AM HD sounds honestly futile.



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Re: The atrocity known as AM HD radio

Post by SolarMax » Mon Jul 08, 2019 12:04 am

Myron Falwell wrote:
Sun Jul 07, 2019 10:31 pm
That goes back to the overall failure of whatever PR campaigns have been used for HD Radio. When iBiquity owned the whole setup and had the patent claims to the IBOC standard, they initially had Clear Channel, CBS, Citadel and a few other groups run PSAs for HD Radio as often as possible. That only lasted about a year, and the quality of the PSAs were utterly horrific.
Not unlike the lousy, ineffective campaign in Canada a few years ago for DAB, another lead balloon.



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Re: The atrocity known as AM HD radio

Post by Tman » Mon Jul 08, 2019 12:47 am

Granted . HD radio is not what it was 10 years ago . The bit rate sound wise has dropped a lot through the years .Not as bad a Sirius yet . And it's free .



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Re: The atrocity known as AM HD radio

Post by 48125er » Mon Jul 08, 2019 2:19 am

Sirius is absolutely garbage for sound quality.



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Re: The atrocity known as AM HD radio

Post by MWmetalhead » Mon Jul 08, 2019 6:35 am

Sirius sounds better than almost every HD2 and HD3 station I've heard.



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Re: The atrocity known as AM HD radio

Post by audiophile » Mon Jul 08, 2019 7:31 am

HD radio was designed around 96k for HD1. It was NPR that suggested HD2-4. That was an afterthought.

There is an option extended set of 24k that is available that is only available for HD3-4, but it extends the IBOC closer to stereo subcarriers, which ironically creates white noise in hi-fi receivers with wide I.F. filters.

HD radio is using a bit-tweaked AAC and it is believed Sirius/XM is using some form of AAC.

How its sounds depends how smart you pre-process the audio to compensate for the low bitrate codec, and more importantly the codec configuration itself and the artwork refresh rate, etc.

AM HD doesn't sound very natural on voice, unless you think speaking through a kazoo sounds good. On *some* music it sounds ok. IIRC, Some the HD radio demos for AM were faked, or they used an unfamiliar song did a good job of hiding the effects of the codec were used for demo.

FM HD sounds worse than Analog in most cases with any HD2-4 channels. Anyone running less than 64k on HD1 should be taken out behind the woodshed.


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Re: The atrocity known as AM HD radio

Post by Deleted User 3751 » Mon Jul 08, 2019 12:30 pm

Sirius is absolutely garbage for sound quality.

I agree 100%, that is why I don't subscribe, my ipod is much better at 320k.



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