AM HD TURNOFF PACE ACCELERATES

[radiotower40]

I am in Chicago for the weekend. I still think WBBM sounds awful in HD! It sounded better driving through Ohio in the middle of the night on the skywave. It usually booms in like a local.

I noticed WRDZ still has HD off, they were the worst sounding of all the HD's.

I don't see the point of having HD on WBBM AM, since they are now on WCFS FM.

I listened to the AM and I agree that it bothers my ears, that is the only reason I'm happy it is on FM. That really seems like a waste of a good station.

 

[KB1OKL]

I am in Chicago for the weekend. I still think WBBM sounds awful in HD! It sounded better driving through Ohio in the middle of the night on the skywave. It usually booms in like a local.

I noticed WRDZ still has HD off, they were the worst sounding of all the HD's.

I don't see the point of having HD on WBBM AM, since they are now on WCFS FM.

I listened to the AM and I agree that it bothers my ears, that is the only reason I'm happy it is on FM. That really seems like a waste of a good station.

WBBM's adjacent obliterater is off tonight.

 

[radiotower40]

Right now, as of 12:30 AM central, 780 is completely off both analog and hd. They must have a problem at the site or shut off for some type of maintanence like a lot of stations used to do back in the day. The FM is on and chugging along.

 

[audioguy]

They must be working on the transmitter or the HD exciter, or both. I tuned by the station at various times on Saturday night and last night (it's hard to miss because it takes up 5 channels at my house), and the HD was off; then the next time it was back on, etc.

It's a totally unreliable system and it's beyond me why CBS is so slavishly devoted to such a piece of garbage. Meanwhile, they are driving away listeners by putting out a crappy, hiss-filled telephone quality signal. Even if you LOVE HD-AM, it's hard to imagine how management can expect people to listen when they can never count on it being available. Imagine if the stereo generator was off half the time on any of the major FMs. That would never fly at my station.

I refuse to listen to the AM any more. I don't listen that much but if I have to (for traffic reports) then it's the FM. As soon as the traffic report is over, I'm outta there.

 

[davideduardo]

They must be working on the transmitter or the HD exciter, or both.

The main reason a 24/7 AM would go off the air today is antenna, antenna tuning unit ("ATU" or "doghouse") and the phaser if the station is directional.

Work on the main transmitter or HD unit would simply be done by switching to the auxiliary transmitter; most aux rigs don't have HD and some are lower power than the main.

Meanwhile, they are driving away listeners by putting out a crappy, hiss-filled telephone quality signal.

With WBBM cuming over 2 million persons, I don't think they have much concern about it "sounding crappy" as on the average consumer AM radio it sounds just fine.

I refuse to listen to the AM any more. I don't listen that much but if I have to (for traffic reports) then it's the FM. As soon as the traffic report is over, I'm outta there.

Most people under 50 or so don't use AM anyway, so WBBM's strategy is to shuttle the "useful" listeners in the under 55 demos over to FM over time since there is no positive endgame for AM anyway.

 

[tomservo]

It's a totally unreliable system and it's beyond me why CBS is so slavishly devoted to such a piece of garbage. Meanwhile, they are driving away listeners by putting out a crappy, hiss-filled telephone quality signal. Even if you LOVE HD-AM, it's hard to imagine how management can expect people to listen when they can never count on it being available. Imagine if the stereo generator was off half the time on any of the major FMs. That would never fly at my station.

David beat me to the point about WBBM's listenership, but I'll tackle the stereo generator issue. I know of several stations here in the south that either don't run stereo at all, and one that runs stereo but send 100% mono content to the transmitter — WONA Winona, Mississippi. I can't fathom the logic for that but it doesn't affect their listenership or it wouldn't have been that way for the last 6 years.

Much of the listening is in cars, under wildly changing conditions which practically every modern car radio I've sampled simply blends to mono under all but the strongest of conditions. I bet a good 30% of urban station listening is in total mono. You could turn it off and I doubt anyone would notice unless you run oldies or some other format with wide stereo separation in music.

I've said it before and I'll say it again but FM stereo is a very imperfect system, one which reduces the listenable area of a station compared to the mono signal, one which introduces its own reception issues which anyone who's ever lived in an urban canyon or mountainous area experiences on a regular basis.

But somehow, it's "great" technology that gets a pass from the HD critics. As someone who lived out in the boonies in a small town for years, stereo was my enemy — I never got stereo content on my radio (even from a local 50 kW station sometimes due to terrain shading) and what I got on my home radios was mono-d out because it was too noisy otherwise.

Kudos to you and your station for being technically proficient, but I bet you could shut the stereo off and tons of listeners wouldn't even notice.

 

[Tom Wells]

As a young man, I used to listen to several my favorite FMs in forced mono to get the benefit of less noise.

 

[spunker88]

I've said it before and I'll say it again but FM stereo is a very imperfect system, one which reduces the listenable area of a station compared to the mono signal, one which introduces its own reception issues which anyone who's ever lived in an urban canyon or mountainous area experiences on a regular basis.

But somehow, it's "great" technology that gets a pass from the HD critics. As someone who lived out in the boonies in a small town for years, stereo was my enemy — I never got stereo content on my radio (even from a local 50 kW station sometimes due to terrain shading) and what I got on my home radios was mono-d out because it was too noisy otherwise.

Maybe on older radios where it was harder to lock a stereo signal and a weak stereo signal added quite a bit of static, you'd have a point. But on something newer like the XDR-F1HD a stereo signal can be picked out of a very weak signal and their isn't added static when a mono signal transitions to stereo.

I can easily pick up WYYY and WWHT both from Syracuse which is around 60 to 70 miles from me. The stereo signal is easy to receive on my XDR-F1HD. The HD signal on the other hand is non existent, and yes both of these do run HD. In a moving car the stereo will go in and out, but its a lot less noticeable than HD going in and out.

I do notice stations which run mono only get out a bit further than similarly powered stereo stations, but most stations aren't trying to get this extra fringe coverage unless they are rimshot station. For example WYUL 94.7 tries to target Monteal listeners around 50 miles away with a CHR format. Last time I was in the area they were running mono.

 

[satech]

With analog FM you can at least get a noisy signal in weak reception and/or high multipath areas. With HD, you can't get any signal in those areas!

And with analog FM (or AM), there are many methods receivers can use to help clean up noisy signals, especially nowadays that many receivers are DSP-based. But with a digital signal, there's nothing you can do if the IBOC chip isn't decoding the signal -- you can't make something out of nothing!

 

[tomservo]

Maybe on older radios where it was harder to lock a stereo signal and a weak stereo signal added quite a bit of static, you'd have a point. But on something newer like the XDR-F1HD a stereo signal can be picked out of a very weak signal and their isn't added static when a mono signal transitions to stereo.

I can attest that this must be magic, because none of my (relatively) modern radios have this ability.

The Insignia portable is perhaps my keenest FM DX machine as far as stereo FM radios go, and it's blending everything to mono except the local 100 kW stations whose towers are just 12 miles away. Anything less is full blend mono.

The other radios? They can get relatively quiet stereo from distant stations, but the difference between stereo and mono is still like the noise floor of a K-Tel record and a quality mastered CD. In other words, no comparison!

I have an added aggravation of owning a beloved ViewSonic tube CRT computer monitor, which I will love and cherish until the day it dies, technology be damned…

BUT… it is a booger on FM. It completely wipes out the more rimshotty stations and even the big 100 kW monsters get a lot of noise. Until I flip the radio to mono, then it clears up.

Now, to be fair, where the stereo carrier suffers, so does HD. Those same 100 kW stations running HD tend to drop out if the radio is less than a few feet from the monitor when it's on.

Maybe FM's stereo system sounds good to people who've grown up listening to radio and only radio, but after experiencing the crystal clear reproduction of my favorite music on CD or FLAC files, or even the low noise floor of satellite or streaming, there's just no going back for me. Static and mono music is only acceptable now to me if I'm DXing.

 

[davideduardo]

Much of the listening is in cars, under wildly changing conditions which practically every modern car radio I've sampled simply blends to mono under all but the strongest of conditions. I bet a good 30% of urban station listening is in total mono. You could turn it off and I doubt anyone would notice unless you run oldies or some other format with wide stereo separation in music.

Actually, about a third of radio listening is in the car. But your point is very valid: road noise, foldback to mono in receivers, etc., mean that a large percentage of in-car listening is in mono.

At home and at work, very little listening is in real stereo... clock radios, kitchen radios, radios that are used at work. Most are not stereo, and those that are have speakers a few inches apart, so at any distance from the radio there is in reality no stereo.

Kudos to you and your station for being technically proficient, but I bet you could shut the stereo off and tons of listeners wouldn't even notice.

When I put stereo on my first FM in 1967, we immediately found a large increase in multipath. Our final solution was to use only vertical polarization, but in the US that is not possible. We found, though, that being a "stereo" station and lighting the little light was an important image issue, so we kept the stereo on despite the issues. But the fact is, now and then, that most listening is not in stereo.

 

[KB1OKL]

Much of the listening is in cars, under wildly changing conditions which practically every modern car radio I've sampled simply blends to mono under all but the strongest of conditions. I bet a good 30% of urban station listening is in total mono. You could turn it off and I doubt anyone would notice unless you run oldies or some other format with wide stereo separation in music.

I've said it before and I'll say it again but FM stereo is a very imperfect system, one which reduces the listenable area of a station compared to the mono signal, one which introduces its own reception issues which anyone who's ever lived in an urban canyon or mountainous area experiences on a regular basis.

But somehow, it's "great" technology that gets a pass from the HD critics. As someone who lived out in the boonies in a small town for years, stereo was my enemy — I never got stereo content on my radio (even from a local 50 kW station sometimes due to terrain shading) and what I got on my home radios was mono-d out because it was too noisy otherwise.

Kudos to you and your station for being technically proficient, but I bet you could shut the stereo off and tons of listeners wouldn't even notice.

I've been saying that for years, most people don't know the difference between good hifi mono and stereo by listening unless it's an old Beatle record where half the vocals drop out or something. High Fidelity is much more important to most people than stereo and most don't even know it.

 

[Savage]

And I've been saying for years: the key to winning the marketing war over stereo radio, AM or FM, isn't actually getting a stereo signal to the listener. The key is getting a little red "stereo" LED to light.

In the midst of an AM vs. FM top 40 war in Pittsburgh, I wandered into a convenience store where the clerk was listening to our FM competitor - on a plastic Radio Shack "stereo" radio with its 3-inch speakers physically separated maybe 5 inches and two audio amps which probably fed the 1-ounce magnet PM speakers with all of 200 mw of audio power mashed through about 20% THD. I aksed her why she listened to FM instead of AM.

She shrugged. "Sounds better," she said.

I've seen this countless other times. The consumer is listening to a mono blended signal. But the "stereo" light is on. Voila: "it's stereo!!"

 

[tomservo]

Do most radios even have a stereo indicator anymore? Only about 25% of the stereo-capable radios in my steed have an indicator of any type. The ones that do are mostly pre-2000 models.

 

[Carmine5]

Some time ago there was talk of a new HD Radio configuration for AM that Ibiquity was working on known as MA-1. This configuration reduces the digital bandwidth while increasing the analog bandwidth of the AM IBOC signal. The idea was to reduce host interference and lower the cost of implementing HD-AM as it relaxes more stringent antenna bandwidth symmetry requirements.

Does anyone know if this configuration is in use today and has it delivered on its promises?

 

[satech]

Some time ago there was talk of a new HD Radio configuration for AM that Ibiquity was working on known as MA-1. This configuration reduces the digital bandwidth while increasing the analog bandwidth of the AM IBOC signal. The idea was to reduce host interference and lower the cost of implementing HD-AM as it relaxes more stringent antenna bandwidth symmetry requirements.

Does anyone know if this configuration is in use today and has it delivered on its promises?

MA1 is the name for the current hybrid AM IBOC system, which allows either 5 or 8 kHz analog audio bandwidth. (MA3 is full-digital AM IBOC with no analog audio.)

I think what you're referring to is the plan to use just the AM IBOC PAD data stream to transmit station identification (like RDS), but without the actual digital audio carriers in use, which would allow full 10 kHz analog audio bandwidth. I heard about this about a year ago, but I don't know if it ever went anywhere.

 

[pianoplayer88key]

Any reason why AMs couldn't use some type of QRS(S?) CW subcarrier within, say, 6 Hz of the main carrier (or maybe a 2-6 Hz range FSK), to provide station ID and possibly other limited text data? I've never noticed any problems when receiving an AM Stereo station (with its 25 Hz pilot tone) on ordinary mono AM radios, and I think the low cw "piggyback" frequency would reduce/eliminate the conflict when stations want to air music featuring organs or other wide-range instruments. (There's a couple organs - in Atlantic City, NJ, and Sidney, AU - that have pipes sounding as low as 8 Hz naturally. Also back when KDIS was running C-Quam, I never noticed issues listening to Eiffel 65's "Blue" (in which I hear a 19 Hz note) or Raven Symone's "Supernatural" (with its 27.5 Hz note) on my then-functional SRF-42..)

 

[satech]

Broadcast audio processors filter out audio below 50 Hz, so subaudible frequencies don't get through to the transmitter. C-Quam uses a 25 Hz pilot tone in the phase-modulated stereo difference channel, so it is invisible to mono receivers.

 

[JohnnyElectron]

I think the Magnavox AM Stereo system had the option for a low speed data for station ID by modulating a subaudible out of phase pilot tone?

I don't know why you couldn't just transmit the (3) 4 call letters with something like that as an AM RDS ID. It would take a few seconds to send it ASCII, but it would work easily enough. Again, nice and easy.

I'd still like to take an iBiquity AM noise generator, ramp down the bandwidth to +/- 10.2KHz, and use the phase modulation feature with the CQUAM math formula to transmit analog AM stereo, and use 8 bits below the 25Hz pilot tone to transmit the station ID. It would be a way for stations that invested in HD to actually use their hardware for something that works without disturbing their neighbors on the dial. Probably against the iBiquity 'law' though.

 

[satech]

IBOC exciters are really just computers running Linux. They certainly could be reprogrammed to transmit C-Quam AM Stereo, if iBiquity would allow it. Motorola's 25-year patent on C-Quam has expired, so it is free for anyone to use. And considering that many HD Radio receivers decode C-Quam, it would certainly make sense for stations with disused AM IBOC equipment to take advantage of that capability.