Finally tried HD radio for the very first time. Here’s what I liked and didn’t like

[fordranger797]

Hey everyone,

I recently had the opportunity to borrow a car with an HD radio receiver. Obviously I’m extremely late to the party on this one, but I thought I’d share a few thoughts that I had.

Positives:

1. The addition of HD sub-channels was an interesting experience. I didn’t find myself listening to these channels often, but the fact that they’re there at all is a nice feature. It seems like these sub channels are a great place to migrate the programming that may be too niche for regular broadcast radio. With that being said, it looks like broadcasters have already been treating those sub channels as a place for niche programming.

2. The information displayed about the song, artist, and station is nice touch. Obviously a lot of this can be accomplished with RDS, but it’s not a bad thing to have.

3. When HD is locked in, the audio quality does sound very good.

Negatives:

1. Signal strength is a problem. Much like DTV, it’s an all or nothing situation. I found that most of the HD signals didn’t lock in (and stay locked in) unless the conditions were favourable (good LOS to the tower, nothing in the way). I’m not really sure that I see someone using an HD-2 or HD-3 for casual listening all that much if the signal constantly drops out.

2. Sticking with signal strength, I noticed that the radio switched from HD to analog pretty frequently. If the HD and analog signal are synched up well, it shouldn’t be all that notable, however, I definitely noticed it. If I had HD radio in my personal vehicle, I’d probably turn it off just to prevent the constant switching back and fourth from happening.

3. Audio quality. I mentioned earlier that HD radio sounds good, but it’s definitely not significantly better than what you get with regular FM. I think analog FM would need to sound a bit like AM for me to prefer HD (where you’d have to deal with dropouts, but would get significantly better audio quality).

Overall, I’m glad I finally got to try it. However, I agree with some of the broadcast engineers I’d talked to over the years (who have told me that HD radio is more of a fun experiment as opposed to the future of radio).

Feel free to discuss.

 

[RadioGuy1864]

Hey everyone,

I recently had the opportunity to borrow a car with an HD radio receiver. Obviously I’m extremely late to the party on this one, but I thought I’d share a few thoughts that I had.

Positives:

1. The addition of HD sub-channels was an interesting experience. I didn’t find myself listening to these channels often, but the fact that they’re there at all is a nice feature. It seems like these sub channels are a great place to migrate the programming that may be too niche for regular broadcast radio. With that being said, it looks like broadcasters have already been treating those sub channels as a place for niche programming.

2. The information displayed about the song, artist, and station is nice touch. Obviously a lot of this can be accomplished with RDS, but it’s not a bad thing to have.

3. When HD is locked in, the audio quality does sound very good.

Negatives:

1. Signal strength is a problem. Much like DTV, it’s an all or nothing situation. I found that most of the HD signals didn’t lock in (and stay locked in) unless the conditions were favourable (good LOS to the tower, nothing in the way). I’m not really sure that I see someone using an HD-2 or HD-3 for casual listening all that much if the signal constantly drops out.

2. Sticking with signal strength, I noticed that the radio switched from HD to analog pretty frequently. If the HD and analog signal are synched up well, it shouldn’t be all that notable, however, I definitely noticed it. If I had HD radio in my personal vehicle, I’d probably turn it off just to prevent the constant switching back and fourth from happening.

3. Audio quality. I mentioned earlier that HD radio sounds good, but it’s definitely not significantly better than what you get with regular FM. I think analog FM would need to sound a bit like AM for me to prefer HD (where you’d have to deal with dropouts, but would get significantly better audio quality).

Overall, I’m glad I finally got to try it. However, I agree with some of the broadcast engineers I’d talked to over the years (who have told me that HD radio is more of a fun experiment as opposed to the future of radio).

Feel free to discuss.

The best use of HD is to legally feed a translator. Many stations however directly feed the translator and do not take the OTA signal and re-transmit it.

 

[Kelly A]

One must understand the intended purpose of HD when it debuted some twenty five years ago:
1. Satellite radio was new to the scene and terrestrial radio felt it needed a response.
2. Additional programming without having to purchase or operate additional analog stations was appealing.
3. HD was going to showcase how digital quality, including superior frequency response, stereo separation, and lower noise could be attained on the existing FM band. No additional government licensing needed. Also, assuming a wide receiver distribution occurred, the option was there to eventually go full digital, even on an existing FM channel.

I think in hindsight, where the broadcast industry really missed the boat was AM-HD. Running full digital is a game changer, putting AM on-par from a quality standpoint with FM. The many problems were:
1. Technical quality of AM transmission plants wildly varied. Many directionals wouldn't support digital operation, and owners weren't interested in gambling on spending hundreds of thousands to improve their plants on the chance of AM-HD catching on.
2 By the time HD came along, consumer interest in buying radios was on the downhill slide. Plus, auto manufacturers were starting to integrate tuners into the vehicle entertainment system. Buying an aftermarket car stereo and swapping the factory one out was becoming a hassle, if not impossible.
3. In spite of being inside the NTSC IBOC mask, some ajacent stations were irritated that AM HD station stidenands could be heard, especially in fringe areas.
My attitude was 'too bad'. If those complaining stations added HD, then they would have no reason to complain. Sometimes you need to break a few eggs to make the perfect omlet.
4. And finally, broadcasters did a horrible job of promoting HD. That was the case for AM and FM. AM-HD stations never if ever promoted what they were doing, or what it meant to listeners. How does one expect to gain listener interest, if you don't promote what it is, and what the benefits of seeking HD out are? Stations running AM HD should have shown examples of the quality difference at every remote broadcast. Until you hear the difference between analog and hybrid HD, it's hard to comprehend the potential impact.

 

[K6JHU]

I almost entirely agree with Kelly A. FM HD sound quality mostly depends on the material and the audio chain. Using an FM adjusted audio chain means that you will mostly get FM quality out of the HD. It also depends as well on the source. If the engineers pay attention to the HD audio chain, the results are stunning. I am thinking particularly of KUSC and KBAQ.

I also agree that AM missed the boat completely on AM HD. If adopted, it could have made a difference in stopping the decline of AM. I have posted earlier about listening to an AM HD. Stereo, no powerline noise, and FM quality sound. To quote. "It could have been a contender"

 

[The New Chico]

Ford, where were you driving that you had HD drop in and out so much? We are in the same general area and I rarely run into this issue.

 

[fordranger797]

Ford, where were you driving that you had HD drop in and out so much? We are in the same general area and I rarely run into this issue.

I live in Richmond BC and normally listen to KISM 92.9. KISM is strong in this area, but I couldn’t get HD to lock in very often (and it definitely wouldn’t stay locked in as I was traveling around town).

HD seemed to work better on the Mount Seymour FMs, since they have a pretty clear shot of the entire region.

All in all, I couldn’t imagine this system working that well back at home in Seattle (where our terrain already makes FM problematic).

 

[fordranger797]

One must understand the intended purpose of HD when it debuted some twenty five years ago:
1. Satellite radio was new to the scene and terrestrial radio felt it needed a response.
2. Additional programming without having to purchase or operate additional analog stations was appealing.
3. HD was going to showcase how digital quality, including superior frequency response, stereo separation, and lower noise could be attained on the existing FM band. No additional government licensing needed. Also, assuming a wide receiver distribution occurred, the option was there to eventually go full digital, even on an existing FM channel.

I think in hindsight, where the broadcast industry really missed the boat was AM-HD. Running full digital is a game changer, putting AM on-par from a quality standpoint with FM. The many problems were:
1. Technical quality of AM transmission plants wildly varied. Many directionals wouldn't support digital operation, and owners weren't interested in gambling on spending hundreds of thousands to improve their plants on the chance of AM-HD catching on.
2 By the time HD came along, consumer interest in buying radios was on the downhill slide. Plus, auto manufacturers were starting to integrate tuners into the vehicle entertainment system. Buying an aftermarket car stereo and swapping the factory one out was becoming a hassle, if not impossible.
3. In spite of being inside the NTSC IBOC mask, some ajacent stations were irritated that AM HD station stidenands could be heard, especially in fringe areas.
My attitude was 'too bad'. If those complaining stations added HD, then they would have no reason to complain. Sometimes you need to break a few eggs to make the perfect omlet.
4. And finally, broadcasters did a horrible job of promoting HD. That was the case for AM and FM. AM-HD stations never if ever promoted what they were doing, or what it meant to listeners. How does one expect to gain listener interest, if you don't promote what it is, and what the benefits of seeking HD out are? Stations running AM HD should have shown examples of the quality difference at every remote broadcast. Until you hear the difference between analog and hybrid HD, it's hard to comprehend the potential impact.

It’s too bad, since HD on AM could have opened up some very new possibilities for the AM band. If everybody had an HD capable receiver, I could potentially see there being a ton of useful frequencies on the AM dial that could be on par with FM. It’s a shame it didn’t happen.

 

[davideduardo]

I almost entirely agree with Kelly A. FM HD sound quality mostly depends on the material and the audio chain. Using an FM adjusted audio chain means that you will mostly get FM quality out of the HD. It also depends as well on the source. If the engineers pay attention to the HD audio chain, the results are stunning. I am thinking particularly of KUSC and KBAQ.

I also agree that AM missed the boat completely on AM HD. If adopted, it could have made a difference in stopping the decline of AM. I have posted earlier about listening to an AM HD. Stereo, no powerline noise, and FM quality sound. To quote. "It could have been a contender"

The problem was and is that cars in the last 20 years have been lasting longer and longer... the average age of vehicles on the road today is around 12 years, meaning that half are over 12 years old (if those data tidbits really mean "mean" and not a true average).

With over half of all radio listening in cars, even today if an AM station went all HD Digital with no analog, nearly no home and work radios and probably more than 75% of vehicle radios could not hear the station.

Unlike India, where digital "AM" radio is well developed using DRM through simply adding separate DRM transmitters on separate frequencies while keeping the old analog ones, the US has such a crowed Medium Wave band that such a solution would be impossible.

With the overall decline of radio's revenue base, nobody has the money to wait a decade or more for there to be "enough" radios to even hear those stations.

 

[landtuna]

Hey everyone,

I recently had the opportunity to borrow a car with an HD radio receiver. Obviously I’m extremely late to the party on this one, but I thought I’d share a few thoughts that I had.

Negatives:

1. Signal strength is a problem. Much like DTV, it’s an all or nothing situation. I found that most of the HD signals didn’t lock in (and stay locked in) unless the conditions were favourable (good LOS to the tower, nothing in the way). I’m not really sure that I see someone using an HD-2 or HD-3 for casual listening all that much if the signal constantly drops out.

2. Sticking with signal strength, I noticed that the radio switched from HD to analog pretty frequently. If the HD and analog signal are synched up well, it shouldn’t be all that notable, however, I definitely noticed it. If I had HD radio in my personal vehicle, I’d probably turn it off just to prevent the constant switching back and fourth from happening.

3. Audio quality. I mentioned earlier that HD radio sounds good, but it’s definitely not significantly better than what you get with regular FM. I think analog FM would need to sound a bit like AM for me to prefer HD (where you’d have to deal with dropouts, but would get significantly better audio quality).

Overall, I’m glad I finally got to try it. However, I agree with some of the broadcast engineers I’d talked to over the years (who have told me that HD radio is more of a fun experiment as opposed to the future of radio).

Feel free to discuss.

I've had HD radio in several vehicles since 2012 and basically agree with your assessments.

I live in the relatively flat desert and do not spend time driving in the downtown (think "high rise") areas. I've found only one single spot (near Scottsdale airport) that suffers an HD drop out. Other than that (and on I-10 from Phoenix almost all the way to Tucson, about 100 miles) the signal is rock solid. It doesn't even drop out inside my garage or the Deck Park Tunnel.

I listen to oldies so the audio quality doesn't seem to be noticeably better on HD than analog FM. In a less noisy environment (or a quieter music source) that might be different. And, I'm listening with 79 year old ears.

I'm happy my vehicles came with HD but would not have paid extra for the feature.

 

[fybush]

You're in an unusual location for HD reception that may explain some of the issues you were having.

Even though you get a strong analog KISM signal on 92.9, there's no protection for US signals from interference on the Canadian side of the border, and Red 93.1 in Vancouver thus exists far closer to KISM than it would otherwise be allowed to be located. It might not be enough to wipe out KISM's analog for you, but it's plenty to cause dropouts or worse on the HD carriers that sit above and below the main FM channel.

The same happens as you get closer to the border for the Mt. Seymour signals - any slight increase in propagation from the US side can bring in short-spaced signals that can interfere with the Canadian HD signals. I hear this all the time in the similar short-spaced situation between Buffalo, Niagara and Toronto.

I also don't know whether the Bellingham or Vancouver stations are running full HD power or are on older transmission systems that are less robust. This was a huge issue for the Toronto CN Tower stations until just this past summer and the installation of a new combiner and antenna system.

What I am getting at is - don't automatically assume you can translate your experience in this unusual location to Seattle or elsewhere. In some terrain-challenged markets like San Francisco, I and others have found HD to be a game changer, taming multipath that destroys listenable analog and delivering a much more consistently usable stereo HD signal.

It's important to note that while this might be your first experience, we've been doing HD on FM on the US side for over 20 years now. A lot of the problems that emerged early on, including insufficient digital power levels, bad sync between digital and analog audio and inconsistencies in pattern between separate HD and analog antennas, have long since been solved, IF stations have invested in upgraded transmission systems. (Not all of them have, especially in small markets like Bellingham, and that's why some of those problems from 20 years ago still linger. That same company owns stations in a small market near me and it's HD implementation there has always been pretty awful.)

But: Modern HD systems from GatesAir or Nautel don't use separate transmitters or antennas for digital and analog. I just put in a GatesAir system here - it's all one transmitter that does both, and it is constantly checking and correcting the delay so it is always perfectly synced.

As for processing, I agree that you can't just feed the analog processor output into the HD and have it sound good. Again, modern processors like the Orban 8700i I'm using here are designed with this in mind. It has both analog and HD outputs that run through separate chains. At the same time, I don't want to make the ultimate sound too different because I don't want it to be super obvious in fringe areas where my listeners might be going back and forth from analog to digital. I'm still tweaking this for best results.

Does that all make some sense?

 

[kfbkfb]

IIRC, some HD "carriers" are at 1%, some 10% power (I don't know the precise way the power comparison of FM and OFDM is made).

Is there a list of HD stations that are using 10%?


Kirk Bayne

 

[fordranger797]

You're in an unusual location for HD reception that may explain some of the issues you were having.

Even though you get a strong analog KISM signal on 92.9, there's no protection for US signals from interference on the Canadian side of the border, and Red 93.1 in Vancouver thus exists far closer to KISM than it would otherwise be allowed to be located. It might not be enough to wipe out KISM's analog for you, but it's plenty to cause dropouts or worse on the HD carriers that sit above and below the main FM channel.

The same happens as you get closer to the border for the Mt. Seymour signals - any slight increase in propagation from the US side can bring in short-spaced signals that can interfere with the Canadian HD signals. I hear this all the time in the similar short-spaced situation between Buffalo, Niagara and Toronto.

I also don't know whether the Bellingham or Vancouver stations are running full HD power or are on older transmission systems that are less robust. This was a huge issue for the Toronto CN Tower stations until just this past summer and the installation of a new combiner and antenna system.

What I am getting at is - don't automatically assume you can translate your experience in this unusual location to Seattle or elsewhere. In some terrain-challenged markets like San Francisco, I and others have found HD to be a game changer, taming multipath that destroys listenable analog and delivering a much more consistently usable stereo HD signal.

It's important to note that while this might be your first experience, we've been doing HD on FM on the US side for over 20 years now. A lot of the problems that emerged early on, including insufficient digital power levels, bad sync between digital and analog audio and inconsistencies in pattern between separate HD and analog antennas, have long since been solved, IF stations have invested in upgraded transmission systems. (Not all of them have, especially in small markets like Bellingham, and that's why some of those problems from 20 years ago still linger. That same company owns stations in a small market near me and it's HD implementation there has always been pretty awful.)

But: Modern HD systems from GatesAir or Nautel don't use separate transmitters or antennas for digital and analog. I just put in a GatesAir system here - it's all one transmitter that does both, and it is constantly checking and correcting the delay so it is always perfectly synced.

As for processing, I agree that you can't just feed the analog processor output into the HD and have it sound good. Again, modern processors like the Orban 8700i I'm using here are designed with this in mind. It has both analog and HD outputs that run through separate chains. At the same time, I don't want to make the ultimate sound too different because I don't want it to be super obvious in fringe areas where my listeners might be going back and forth from analog to digital. I'm still tweaking this for best results.

Does that all make some sense?

You brought up some really good points here. I didn't put enough thought into the HD signal being different from the analog signal. If we're only talking about analog radio, KISM easily wipes out Red FM in many parts of the metro. But HD is a completely different story. As I recall, there was actually quite a few complaints on the Canadian side about how 93.1 sounded after KISM activated HD for the first time (greatly reducing the reception of Red in some of the most critical parts of the market).

I would love to take the car I borrowed back home to Seattle and see how HD performs in some of the areas that are tricky for analog (parts of I-405 come to mind, obviously downtown, and other areas that are hilly). If the receiver didn't continuously switch from HD to analog over and over again, I'd probably leave it alone and never deactivate it. Also, I do see the value of exploring what unique offerings are on some of the HD sub channels. There's not much to see in Canada since the HD sub channels are only used to relay stations on the AM dial, but I might be more enticed to try an HD-2 or HD-3 if the programming I wanted was located there.

 

[bossbill]

Hey everyone,

I recently had the opportunity to borrow a car with an HD radio receiver. Obviously I’m extremely late to the party on this one, but I thought I’d share a few thoughts that I had.

Positives:

1. The addition of HD sub-channels was an interesting experience. I didn’t find myself listening to these channels often, but the fact that they’re there at all is a nice feature. It seems like these sub channels are a great place to migrate the programming that may be too niche for regular broadcast radio. With that being said, it looks like broadcasters have already been treating those sub channels as a place for niche programming.

2. The information displayed about the song, artist, and station is nice touch. Obviously a lot of this can be accomplished with RDS, but it’s not a bad thing to have.

3. When HD is locked in, the audio quality does sound very good.

Negatives:

1. Signal strength is a problem. Much like DTV, it’s an all or nothing situation. I found that most of the HD signals didn’t lock in (and stay locked in) unless the conditions were favourable (good LOS to the tower, nothing in the way). I’m not really sure that I see someone using an HD-2 or HD-3 for casual listening all that much if the signal constantly drops out.

2. Sticking with signal strength, I noticed that the radio switched from HD to analog pretty frequently. If the HD and analog signal are synched up well, it shouldn’t be all that notable, however, I definitely noticed it. If I had HD radio in my personal vehicle, I’d probably turn it off just to prevent the constant switching back and fourth from happening.

3. Audio quality. I mentioned earlier that HD radio sounds good, but it’s definitely not significantly better than what you get with regular FM. I think analog FM would need to sound a bit like AM for me to prefer HD (where you’d have to deal with dropouts, but would get significantly better audio quality).

Overall, I’m glad I finally got to try it. However, I agree with some of the broadcast engineers I’d talked to over the years (who have told me that HD radio is more of a fun experiment as opposed to the future of radio).

Feel free to discuss.

Regarding the sync between HD1 and the analog audio... Inovonics makes an alignment device that locks the analog and the HD1, so that the transfer from HD1 to analog is seamless. I installed our unit after a major advertiser asked me why his audio was "skipping" in his HD car radio.

 

[TheBigA]

Signal strength is a problem.

Regarding signal strength, this was reported last week:

FCC Approves HD Radio Change That Supporters Say Will Improve Signal Coverage.

The FCC approves a proposal to give most FMs greater flexibility in their digital operations. At the urging of broadcasters, the FCC will permit FMs to use asymmetric sideband power

www.insideradio.com

 

[davideduardo]

Regarding the sync between HD1 and the analog audio... Inovonics makes an alignment device that locks the analog and the HD1, so that the transfer from HD1 to analog is seamless. I installed our unit after a major advertiser asked me why his audio was "skipping" in his HD car radio.

Adverti$ers tend to make their way to the front of the line...

 

[Deleted member 76036]

Regarding the sync between HD1 and the analog audio... Inovonics makes an alignment device that locks the analog and the HD1, so that the transfer from HD1 to analog is seamless. I installed our unit after a major advertiser asked me why his audio was "skipping" in his HD car radio.

I wish more stations would invest in stuff like that. Here in DFW, the sync on the Audacy stations seem to be off by as much as a second quite often. 101.1 WRR used to be perfectly synced, but it hasn’t been synced at all for probably a year or so now. The other stations are usually pretty good with their sync.

 

[Deleted member 76036]

At the same time, I don't want to make the ultimate sound too different because I don't want it to be super obvious in fringe areas where my listeners might be going back and forth from analog to digital. I'm still tweaking this for best results.

I wish more car manufacturers would put an HD on/off button on the main screen for this reason, instead of hiding it in the settings. My 2020 Hyundai Elantra has the button on the main screen and it’s super convenient in fringe areas. However, who knows if most average listeners actually understand what’s happening when the radio switches from analog to HD?!

 

[fybush]

The early problems with HD/analog sync have long since been solved IF stations are willing to spend the money to keep things updated.

Current HD transmission systems from GatesAir and Nautel include automatic delay correction as part of their exporter/importer package. Set it and forget it.

Outboard devices like the Inovonics Justin can do the same trick for older transmitters.

It's all software, after all, and the life cycles of these technologies are getting faster. You wouldn't run a computer from 2004 today without a lot of upgrades. Yet I still see broadcasters trying to keep HD equipment of that vintage running as their main transmitters, and that's problematic.

 

[kevtronics]

We're a far cry from the early years of HD Radio when there was often a skip or repeat of several seconds of audio whenever the radio switched from analog to digital or vice-versa. But it's still rarely seamless today; there's often a momentary "tape flanging" effect due to phase cancellation -- and of course, even having the analog and digital perfectly aligned down to the microsecond won't help when your processing has a drastic difference between them in loudness and EQ.