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How many AM stations still actively use HD Radio (AM-HD)? Are there any in your area?

In the KC area, I don’t think there have ever been any AM HD stations. A lot of the AM stations just have a translator and sometimes two translators, like KXCL in Liberty. Or they’ve got a full FM signal like 98.1 or 96.5.
 
In the Saint Petersburg/Sarasota/Tampa area there is only one HD AM station left; WTMP-11050HD; they turn off the HD at sunset; but their two translators (both 250 watts) employ HD; I wasn’t sure a translator could employ HD, but apparently they can. The HD on the FM translators allow some album art and other features on their RDs that analogue FM doesn’t…The big problem with the 1150HD AM1150 is they are directional to the north and n.n.e. which means as little as 3 miles to the north , nullifies the HD; whereas to the south the HD AM 1150 is strong as far south as Tierra Verde, Palmetto, Bradenton, Bayshore Gardens and downtown Sarasota.
 
Ironically I think 810 WGY stopped transmitting an HD signal because skywave interference from 820 WSHE (ex-WWFD)'s all-digital signal wiped out their nighttime HD coverage. It often gets bad enough to obliterate WNYC(AM) here in central NJ.

Also what didn't help HD AM is that the first-gen exciters were really just an embedded PC running Linux, and thus they ended up with the same capacitor plague that caused early deaths of many mid-2000s PCs. And when their HD exciter crapped out, most stations didn't bother to replace it.
 
Just Frederick's 820 WSHE in Maryland now. Baltimore's 600 WCAO seems to have dropped it 6 months ago, was sounding very rough at the end.
 
In the KC area, I don’t think there have ever been any AM HD stations. A lot of the AM stations just have a translator and sometimes two translators, like KXCL in Liberty. Or they’ve got a full FM signal like 98.1 or 96.5.
The only ones I knew of in Missouri were KMOX and KFUO. I haven't been to St. Louis in several years so I don't know if KFUO is still doing that, but they're about to move transmitter site anyway.

Columbia/Jefferson City has only one HD FM station (KBIA), last time I checked.
 
According to their website, KMOX has an HD2 station:
KMOX has been on, I think KEZK-HD2, for years. Plenty of HD FM in St. Louis, but you can't get most St. Louis FMs in Columbia any more (something I was routinely able to do 30 years ago) due to the proliferation of translators as well as a few move-ins.
 
I wondered in 2021 if my then-new car's radio had AM HD as well as FM HD. It took until a couple of weeks ago to find out it did. I was leaving Denver, listening to KOA, and decided to scan the dial when I got out of downtown. Voila, up popped 670 KLTT with the HD logo popping up. I couldn't tell if it was better than analog since it was just talk, but at least I know what the radio can do. Then it was back to KOA and eventually mostly XM for the long trip home.
 
I wondered in 2021 if my then-new car's radio had AM HD as well as FM HD. It took until a couple of weeks ago to find out it did. I was leaving Denver, listening to KOA, and decided to scan the dial when I got out of downtown. Voila, up popped 670 KLTT with the HD logo popping up. I couldn't tell if it was better than analog since it was just talk, but at least I know what the radio can do. Then it was back to KOA and eventually mostly XM for the long trip home.
Too bad you didn't land on KLVZ (810) to hear what music sounds like in AM HD. I have a hard time deciding which is worse, the digital artifacts on AM HD or the noise and picket-fencing on its FM translator, but maybe it's OK for that station's target audience, which seems to be in its 70s. KPOF (910), also in HD, has some music as well.
 
1080 KRLD’s HD has been off for several months now. This has happened in the past and it’s came back, so not sure if it’s permanent this time or not. KRLD is on 98.7 HD2, 100.3 HD2 and 105.3 HD2. When the HD was on, it was 24/7.

The only other AM station in DFW that runs HD is 1270 KFLC, but they only run it during the day.

Also, there are no longer any AM stations in St. Louis that run HD and I think Mark is right about 91.3 KBIA being the only station in Columbia that runs HD.
 
I have a hard time deciding which is worse, the digital artifacts on AM HD or the noise and picket-fencing on its FM translator, but maybe it's OK for that station's target audience, which seems to be in its 70s.
It may just be. I developed the habit decades ago (when extremely low bitrate streaming with early primitive codecs was rife) of using Winamp plug-ins to lowpass away everything above 4-5 kHz. I still do this today for the occasional 32 kbit/s MP3 streaming clunker I come across. The complete loss of highs is preferable to hearing 100% synthetic, high frequency slush. Since many 70+ year olds have natural lowpass filters built into their hearing, they're probably hearing the same audio I do in those cases and are left with nothing to complain about.
 
Crawford’s KCBC in Manteca (770) is still broadcasting in HD as far as I know. That could be considered fringe Bay Area, or the gateway to Stockton; your call.

At one time, KCBS, KGO, whatever 960 is called now, and KTCT all broadcast in HD. For various reasons, those stations dropped the system. KNBR could not use HD because its antenna system couldn’t pass the necessary bandwidth.

You were right! Wow! That almost sounds like FM, what a tenfold increase. Too bad I’m not religious! It came in incredibly well and held HD signal. Brilliant sound:

Doing this makes no sense. The main problem with AM is noise, not bandwidth.
In an amplitude modulation scheme, there is a trade off between noise and bandwidth. Simply increasing the bandwidth would mean more noise at the receiver, not less, which listeners would probably find more objectionable than the present system.

I’m not sure I agree with this, your statement rings true to an extent but it also can not be ruled out that AM’s bandwidth limits how much sound quality can be pushed out.

A wider bandwidth would allow more of the audio spectrum to be transmitted on AM radio thus increasing the overall fidelity of the sound. Basically, it would enhance the clarity and richness of the audio and improve the treble and bass response.

Digital AM, like Kelly A said, probably was the move to make, if HD Radio adoption wasn’t so mediocre. I would have said increasing bandwidth with that would solve most issues. Digital signal improves the issue of noise. There isn’t much more to say, it just does.

The thing is, implementing this fix and reallocating stations would be a hard sell that will require the band to literally “die” to happen, by then, radio is a technology of the past I’d argue.
 
No AM even close to the Charleston area has HD. The AM band here is pretty much a waste. We just had a AM sign off at 1450 (oldies) as almost no one was listening. Plus they get the feed off of a HD FM signal.

I’d get WGY’s HD carrier tripping on at night when they used it even though I was close to 1000 miles away. WPHT also tries to come in the same way.

WFXJ 930 in Jacksonville is the closest AM running HD. Charleston has 7 FMs running HD but none of them make any real effort on their subs. A couple of them are leased out to religious outfits that already have FM translators in the market.

Savannah only has 3 and 2 are non-commercial.
 
No AM even close to the Charleston area has HD. The AM band here is pretty much a waste. We just had a AM sign off at 1450 (oldies) as almost no one was listening. Plus they get the feed off of a HD FM signal.

I’d get WGY’s HD carrier tripping on at night when they used it even though I was close to 1000 miles away. WPHT also tries to come in the same way.

WFXJ 930 in Jacksonville is the closest AM running HD. Charleston has 7 FMs running HD but none of them make any real effort on their subs. A couple of them are leased out to religious outfits that already have FM translators in the market.

Savannah only has 3 and 2 are non-commercial.

Those HD subs are to feed the translators
 
It may just be. I developed the habit decades ago (when extremely low bitrate streaming with early primitive codecs was rife) of using Winamp plug-ins to lowpass away everything above 4-5 kHz. I still do this today for the occasional 32 kbit/s MP3 streaming clunker I come across. The complete loss of highs is preferable to hearing 100% synthetic, high frequency slush.
I tried that on a file I recorded of KLVZ AM HD, with low-pass frequencies of 3, 4, and 5 kHz. (KLVZ is the one Denver Crawford station that plays music.) Of course, I lost the highs. But the phasing effects remained. I would say it was slightly more listenable but there were still substantial digital artifacts.
 
Hanover/Lebanon/White River Jct. NH/VT:

No AM HD now or ever, AFAIK. A handful of FM HD2s, none ever promoted on-air on the main signal, most just feeding a translator. The local NPR affiliates (one all-news/talk, the other all-classical music) just use their HD2s to carry the other station's programming, a complete waste. HD is dead as the proverbial door nail up here, no public awareness at all.
 
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