Major negative for HD Radio (limited coverage)

[papaul1967]

Seems as though no one is telling us just how limited the HD coverage is due to the fact it causes adjacent channel interfernce. I have heard the the FCC limits the the HD transmitter output to 1% of a stations analog power this would explain why stable coverage is only available in city grade contours. In B class areas the stable HD signals on FM are limited to about 30 miles and its vastly dependent on terrain. AM stations are somewhat better but still suffer from Electrical noise (overhead power lines) when this happens the HD signal goes bye bye and you are listening crapola analog again. There's a major flaw in this system and programming isn't one of them. They should have chosen the international standard for digtial radio.. oh i forgot those frequencies are already in use here....big surprise as we always move down a different path in communications from the rest of world.

 

[Chuck]

I'm still wondering how HD will work with translators? Our stations uses two of them, so the topic interests me a lot. In analog, these translators give very decent coverage. I can't imagine that happening with an IBOC signal. Hopefully, I'm wrong, but with the HD signal at 1% of the analog power, I don't see how you get enough signal to be really useful. Translators have a maximum ERP of 250 watts analog, so that would be 2.5 watts maximum HD signal. But most translators are considerably lower powered than that. Some translators are as low as 10 watts. A 0.1 watt digital signal sure doesn't sound like much to me. Armstrong and some others showed HD translators at NAB. Does anyone have any real world experiece with these beasts? Spending a lot of money to "upgrade" to give us a one mile digital coverage area, does not seem like money well spent.

 

[autopaint-1]

"In B class areas the stable HD signals on FM are limited to about 30 miles and its vastly dependent on terrain. AM stations are somewhat better but still suffer from Electrical noise (overhead power lines) when this happens the HD signal goes bye bye and you are listening crapola analog again. There's a major flaw in this system and programming isn't one of them."You really can't state milage figures without mentioning hwat typ eof antenna one is using at the receive end and what the geographic conditions are. I live 25 miles from Manhattan and with my Receptor and dipole I receive every NY area IBOC station on both AM & FM. I keep reading from peopole that this system has major flaws but as of yet my real world experiences have now shown that to be the case. I just exchanged my Rabbit Ears for the B.A. dipole and the reception is even better on FM. Now the lock time for HD channels has decreased. I love my B.A. It does exactly what it's advertised to do and the HD 2 & 3 channels in NY are fantastic."hey should have chosen the international standard for digtial radio.. oh i forgot those frequencies are already in use here....big surprise as we always move down a different path in communications from the rest of world."Why is that? To the best of my knowledge Digital Mondial receivers aren't readily available and I've read that the IBOC codec is superior to that of DRM. Also, I am hearing that other countries are now considering IBOC instead of DRM. As to translators, forgive me for being less than sensitive. Translators serve very small pockets (relatively speaking) of population relative to that of the main transmiting station. Here in NYC where we have over 7 million area residents we have only one small religious operation that uses a translator. I know IBOC involves expense for stations but the results of a properly operating facility are gratifying for the listener. What would you have broadcasters do now that we are faced with competition from 2 sat companies as well as I-Pods and the MP3 players? As for me, I wish I had access to more IBOC radios. I think the technology is fantastic.

 

[Chuck]

As to translators, forgive me for being less than sensitive. Translators serve very small pockets (relatively speaking) of population relative to that of the main transmiting station. Here in NYC where we have over 7 million area residents we have only one small religious operation that uses a translator.

From your point of view in New York city, you may be correct. There simply is no room for translators in your area, but in the rest of the country, translators are very common. I'm sure you realize that not all broadcasting is directed at the Big Apple. I'll certainly agree with you that the religious broadcasters seem to own most translators, but not everyone fits that mold. Many NPR, PRI and community stations rely on translators to deliver a significant part of their audience. If we can trust U.S. Census figures, the two translators our station uses cover over 100,000 people. To us, that is not exactly insignificant. It would be nice to know if those people would be able to receive the HD version of our signal. So far, that question remains unanswered.

 

[autopaint-1]

"I'll certainly agree with you that the religious broadcasters seem to own most translators, but not everyone fits that mold. Many NPR, PRI and community stations rely on translators to deliver a significant part of their audience. If we can trust U.S. Census figures, the two translators our station uses cover over 100,000 people. To us, that is not exactly insignificant. It would be nice to know if those people would be able to receive the HD version of our signal. So far, that question remains unanswered"As you can only speak from your perspective so can I. As to translators, let's give HD time. The power figures concerning digital vs analogue are calculated differently and digital translators are becoming available, but as secondary markets are starting to roll out HD 2 channels, they've been available in the major cities for quite some time. This will take a few years to get everything in place. My response was due to your obviously taking a negative view without having actual experience with this technology. The HD element can use a seperate antenna so maybe if they find an issue with the HD part of the low power signal they can license the HD element for a higher antenna placement. That woul have the effect of improving coverage with less power.

 

[wgliradio]

Are you out over LI with your radio, in NJ, Westchester or CT? I'm curious because the BA I have, some 35 miles east from NYC, won't lock on any HD signals even with an outdoor Yagi pointed in Empire's direction. AM, forget about it... even with an outdoor loop. I get text from WOR, but not HD audio.

 

[Chuck]

My response was due to your obviously taking a negative view without having actual experience with this technology. The HD element can use a seperate antenna so maybe if they find an issue with the HD part of the low power signal they can license the HD element for a higher antenna placement. That woul have the effect of improving coverage with less power.

That's odd I thought I merely asked a question. It seems that neither of us has any real world experience with HD translators. I was hoping someone on this board did.I suspect that a higher antenna position won't compensate for ultra low power, at least for people who want to listen inside buildings. As far as I know different modulation schemes (analog or digital) don't have a lot to do with penetration through buildings. RF power is responsible for that. Further, under current rules, translators max out, power wise, about 200 feet. Above that elevation, they must lower their power.Maybe I'm being too general, but my experience with RF is you need antenna height to get distance, and power to get penetration. Naturally, there is some interaction, but there is a reason why people build 100,000-watt stations on an 1800-foot tower. While it is true that you can get very acceptable results using much lower power and digital modulation, I suspect there is a diminishing return when you get into extremely low power levels. That's what my question is about.Perhaps the FCC will need to establish some kind of minimum power for HD. Ten watts might be appropriate. It would be a large improvement over a few milliwatts.

 

[autopaint-1]

Are you out over LI with your radio, in NJ, Westchester or CT? I'm curious because the BA I have, some 35 miles east from NYC, won't lock on any HD signals even with an outdoor Yagi pointed in Empire's direction. AM, forget about it... even with an outdoor loop. I get text from WOR, but not HD audio.

I'm in a nortern Suburb of NYC, 25 miles north of midtown Manhatten. If you are having trouble on the island using a yagi, then my suggestion would be to return the radio because there is obviously something wrong with it. The first Receptor I purchased had sensitivity issues, being unable to receive any of the area HD signals and when I returned the radio to the store, we did an A/B and there was no comparison, the replacement was able to receive HD where the original couldn't. The replacement radio I have works fine and with the dipole which I just received from B.A. I am able to listen to every NY area HD station, both AM & FM. On AM I am using a passive indoor Radio Shack loop and can hear HD on WOR, WNYC and WADO. If you purchased on from a store I'd take it back and make sure the replacement radio works properly. If you did mail order you might want to contact B.A. and tell them of your problems so that they can make the needed repair.

 

[autopaint-1]

"That's odd I thought I merely asked a question. It seems that neither of us has any real world experience with HD translators. I was hoping someone on this board did."I responded to the wording in your title. You say major negative and that can't be proven based on one radio. As I've stated elsewhere, my reception of all HD signals in the NYC market has been fine and with solid signals. While 100,000 people is a large group, it's dwarfed by the 15 million plus in the NY market. Translators are just now being developed. Give it a few years for the kinks to be worked out. "I suspect that a higher antenna position won't compensate for ultra low power, at least for people who want to listen inside buildings. As far as I know different modulation schemes (analog or digital) don't have a lot to do with penetration through buildings. RF power is responsible for that. Further, under current rules, translators max out, power wise, about 200 feet. Above that elevation, they must lower their power."Changes will be made as needed. Don't use anaolgue dogma to draw conclusions for digital transmissions. I'm sure any issues will be resolved over time. "Maybe I'm being too general, but my experience with RF is you need antenna height to get distance, and power to get penetration. Naturally, there is some interaction, but there is a reason why people build 100,000-watt stations on an 1800-foot tower. While it is true that you can get very acceptable results using much lower power and digital modulation, I suspect there is a diminishing return when you get into extremely low power levels. That's what my question is about.Perhaps the FCC will need to establish some kind of minimum power for HD. Ten watts might be appropriate. It would be a large improvement over a few milliwatts."Again, after the research has concluded I'm sure the needed changes to the law will be made.

 

[rbrucecarter5]

Careful - any suggestion of HD coverage problems brands you a heretic in the eyes of the professionals. You better be ready for an inquisition!

 

[Chuck]

I responded to the wording in your title. You say major negative and that can't be proven based on one radio.

Please note that I did not start the title of this thread. I merely responded with a question to the part about "Limited Coverage." "Limited coverage" is a huge concern to me as the operator of a couple of translators. If you are unhappy with the title, you should address the original poster, rather than me.

Changes will be made as needed. Don't use anaolgue dogma to draw conclusions for digital transmissions. I'm sure any issues will be resolved over time.

Well, RF is RF. Its behavior is not "analog dogma." It still behaves in a similar fashion, no matter what the modulation scheme. Some modulation methods are more effective than others, and digital can be a better way to get a signal from point "a" to point "b" under the right circumstances. That does not mean that "digital" is always better. Your cell phone is "digital" but I'll bet you'd hate to listen to live music on it. The good news is the HD broadcasts that I've heard actually sounded quite decent, although they do so at some expense, which has been discussed ad nauseum elsewhere on these boards.

Again, after the research has concluded I'm sure the needed changes to the law will be made.

That's pretty optimistic. Meanwhile, right now, people are trying to sell me HD equipment and HD translators. I think it would be very irresponsible on my part to invest in something that might work "after the research has been concluded." If anyone has any real world experience with HD at very low power levels, I'd love to hear from them.

 

[Chuck]

I responded to the wording in your title. You say major negative and that can't be proven based on one radio.

Actually, the title was not mine. You should check those things before you throw stones. I merely responded to an existing post. If you have a gripe with the title, you should address the original poster.

Changes will be made as needed. Don't use anaolgue dogma to draw conclusions for digital transmissions. I'm sure any issues will be resolved over time.

That's nice, but as a General Manager whose station relies on translators, it seems irresponsible of me to invest in technology whose "Issues will be resolved over time." I need more concrete information before I can invest in new technology.

Again, after the research has concluded I'm sure the needed changes to the law will be made.

That is assuming a lot. It's hard to write a check based on "after the research has been concluded." Right now, people are trying to sell me on HD radio translators. That's why asked if it will actually work. Nobody has answered that question.If anyone on this forum has any REAL EXPERIENCE with HD radio at very low power, I'd be interested in hearing from you. [/quote]

 

[autopaint-1]

"Actually, the title was not mine. You should check those things before you throw stones. I merely responded to an existing post. If you have a gripe with the title, you should address the original poster."I am sorry if I mistakenly confused your initial response to a post of mine with the originating post. This should be the biggest mistake any of us make. "That's nice, but as a General Manager whose station relies on translators, it seems irresponsible of me to invest in technology whose "Issues will be resolved over time." I need more concrete information before I can invest in new technology."I've worked as an engineer at one of the major broadcast networks for over 28 years. I was initially responding to the fact that the heading of the initial post stated that HD radio has limited coverage. I said nothing about translators or whether anyone should consider investing in HD radio. We're getting far afield from anything I originally talked about in my post."That is assuming a lot. It's hard to write a check based on "after the research has been concluded." Right now, people are trying to sell me on HD radio translators. That's why asked if it will actually work. Nobody has answered that question."If I were in your position, working at a station which requires a number of low power translators as part of my transmission facilities, I'd wait and see. HD Radio is relatively new technology and I'd venture to guess that the large majority of your audience doesn't have an HD capable radio. No need to transmit in a mode which most people can't receive. HD translators are just starting to appear and much work needs to be done before any conclusions can be reached."If anyone on this forum has any REAL EXPERIENCE with HD radio at very low power, I'd be interested in hearing from you."Lots of luck but as I mentioned in my last paragraph I don't believe anyone really has MUCH experience with very low power HD transmission yet. Now if you were running a 50 K AM facility I'd suggest you contact Tom Ray at WOR. He's been working with IBOC at his station for a few years. Tom is a great guy and he's very knowledgeable when it comes to IBOC. In NYC we have approx 17 IBOC stations at this time. They are still in an experimental stage however. Some stations turn their IBOC exciters on and off while they make equipment adjustments. By next year, hopefully there will be more stabilty but we're at the birth of a new technology and these things take time to perfect.

 

[autopaint-1]

"I said nothing about translators or whether anyone should consider investing in HD radio. We're getting far afield from anything I originally talked about in my post."Actually rereading my post I did mention translators but it was really and afterthought. At this point IBOC is a new technology and not fully operational on most traditional full power AM & FM facilities. Translators and the like are down the road. "That is assuming a lot. It's hard to write a check based on "after the research has been concluded." Right now, people are trying to sell me on HD radio translators. That's why asked if it will actually work. Nobody has answered that question."If I were in your position, working at a station which requires a number of low power translators as part of my transmission facilities, I'd wait and see. HD Radio is relatively new technology and I'd venture to guess that the large majority of your audience doesn't have an HD capable radio. No need to transmit in a mode which most people can't receive. HD translators are just starting to appear and much work needs to be done before any conclusions can be reached."If anyone on this forum has any REAL EXPERIENCE with HD radio at very low power, I'd be interested in hearing from you."Lots of luck but as I mentioned in my last paragraph I don't believe anyone really has MUCH experience with very low power HD transmission yet. Now if you were running a 50 K AM facility I'd suggest you contact Tom Ray at WOR. He's been working with IBOC at his station for a few years. Tom is a great guy and he's very knowledgeable when it comes to IBOC. In NYC we have approx 17 IBOC stations at this time. They are still in an experimental stage however. Some stations turn their IBOC exciters on and off while they make equipment adjustments. By next year, hopefully there will be more stabilty but we're at the birth of a new technology and these things take time to perfect.[/quote]

 

[Chuck]

Actually rereading my post I did mention translators but it was really and afterthought. At this point IBOC is a new technology and not fully operational on most traditional full power AM & FM facilities. Translators and the like are down the road. <snip>If I were in your position, working at a station which requires a number of low power translators as part of my transmission facilities, I'd wait and see. HD Radio is relatively new technology and I'd venture to guess that the large majority of your audience doesn't have an HD capable radio. No need to transmit in a mode which most people can't receive. HD translators are just starting to appear and much work needs to be done before any conclusions can be reached.

Well, that's the conclusion I've reached. It's just too early to tell if they will work or not and I'm not eager to be the guinea pig. That detail hasn't stopped a few manufacturers from marketing the equipment. It was being shown at NAB. For better or worse, it is a requirement of my job to be able to look to the future and make intelligent decisions about how we are going to spend our money (or maybe not spend our money). Since none of he local stations in our area have switched to HD as yet, I doubt that there are any HD radios in our area. At least, the decision doesn't have to be made very soon. In fact, my opinion is that until these radios become standard equipment in cars, this is much to do about very little. I'm currently shopping for a new car, and none of the cars I've looked at have HD capability. They are all pushing satellite, iPod connections and mp3 players. Even RDS has recently surfaced as a "feature" on modern car radios. That's taken a good ten years. I wonder if HD will take as long?

 

[autopaint-1]

In fact, my opinion is that until these radios become standard equipment in cars, this is much to do about very little. I'm currently shopping for a new car, and none of the cars I've looked at have HD capability. They are all pushing satellite, iPod connections and mp3 players. Even RDS has recently surfaced as a "feature" on modern car radios. That's taken a good ten years. I wonder if HD will take as long?I agree and that is why I said that this is a new technology. However, BMW offers HD radio in their vehicles. Let's wait a few years and see what happens. At this time there are a number of HD capable car radios available as after market devices. In the last year or so I've seen the price of HD capable car radios drop from over 500 dollars to 299 for the JVC. Prices will fall, quality will improve and it won't take 10 years. I will be looking for a new car next year and hope that HD will be available as an option but who know's. I first saw a IBOC demo at an SBE meeting 2 and a half years ago. Since that time radio's have come on the market and the codec used by Ibiquity has vastly improved. Let's see what happens 2 years from now.

 

[rfburns]

In fact, my opinion is that until these radios become standard equipment in cars, this is much to do about very little. I'm currently shopping for a new car, and none of the cars I've looked at have HD capability. They are all pushing satellite, iPod connections and mp3 players. Even RDS has recently surfaced as a "feature" on modern car radios. That's taken a good ten years. I wonder if HD will take as long?

I have the same opinion - you'll see a huge increase in HD radio awareness once the major auto manufacturers start offering HD radio as standard equipment.RFB

 

[SUPERCASTER]

I have the same opinion - you'll see a huge increase in HD radio awareness once the major auto manufacturers start offering HD radio as standard equipment.RFB

Just keep holding your breath, and spend your money to buy and install the HD radio transmitting equipment. Standard equipment HD radios in cars will be along any minute now.Three years have passed since that statement was expressed, and there has been little interest or activity from virtually all car manufacturers in having anything to do with HD Radio. Three years from now the situation will be pretty much the same. BMW may be the only one, and they are taking their sweet old time.In case you haven't noticed, car manufacturers are having a hard enough time marketing their main product (cars). With rapidly rising gas prices, I doubt that they are spending any sleepless nights worrying about HD radio, especially with virtually no consumer demand or interest after all these years.The car manufacturers don't need all those HD Radio problems. They have enough headaches already without installing a defective technology that they will then have to support."CD quality sound, get hundreds of new stations". What's the next claim to try to sell the public and car manufacturers on HD Radio, "hundreds of miles to the gallon"?

 

[rfry]

I suspect that a higher antenna position won't compensate for ultra low power, at least for people who want to listen inside buildings. As far as I know different modulation schemes (analog or digital) don't have a lot to do with penetration through buildings. RF power is responsible for that.

Depends on the values of "ultra" and "higher," but in general -- a higher radiation center allows better clearance for the the direct path and its Fresnel zones, and that can reduce path losses by better than 10 dB in some cases ( = >10 dB higher field strength at the receiver location from the same ERP).Anything that increases field strength outside a building improves building penetration. That can be done with higher ERP, a shorter and/or less cluttered propagation path, or some combination of those.The tx system ERP and total path loss (including through the walls of the building where the HD receiver is located) will determine the field strength available for the HD receiver. The path loss will be nearly identical for the analog and HD signals. FM HD radios are designed to work with 20 dB less ERP than the analog host, so that is not an issue inside the building any more than it is outside the building.RFhttp://rfry.org

 

[Chuck]

Depends on the values of "ultra" and "higher," but in general -- a higher radiation center allows better clearance for the the direct path and its Fresnel zones, and that can reduce path losses by better than 10 dB in some cases ( = >10 dB higher field strength at the receiver location from the same ERP).

OK, let’s define it. As I understand it, ERP from a digital translator will be anything from 0.1 watt to a maximum of 2.5 watts, making the assumption that there are few, if any, translators that operate at less than 10 watts ERP analog, and translators have a maximum ERP of 250 watts analog. Right now, I am inside a concrete and steel office building with my cell phone. It works "sort of" but not reliably. I can see the red clearance light at the top of the cell tower from the front door of the building. I'd guess it is less than a mile away in an open area (no large buildings or other obstructions). It may not be a valid comparison, since it operates in a different frequency range, but the 300 mw or so the phone puts out is not enough to reliably penetrate the steel and concrete in the building. Will 100 mw of HD work any better?

Anything that increases field strength outside a building improves building penetration. That can be done with higher ERP, a shorter and/or less cluttered propagation path, or some combination of those.

Agreed

The tx system ERP and total path loss (including through the walls of the building where the HD receiver is located) will determine the field strength available for the HD receiver. The path loss will be nearly identical for the analog and HD signals. FM HD radios are designed to work with 20 dB less ERP than the analog host, so that is not an issue inside the building any more than it is outside the building.RFhttp://rfry.org

At reasonable power levels, I agree with you, but somewhere there is a threshold where reception will not be satisfactory, or will not work at all. Given the very low power levels of translators, at least under the current rules, I suspect the HD threshold will come at a very short distance from the transmission site. It simply may not be worth the trouble to use a translator for HD. In many instances, that is no big deal, but many rural parts of the country get quite a lot of service from translators.Worse yet, if the FCC ever lifts the freeze on the translator applications that are the result of "The Great Translator Invasion," Then there are going to be a lot more of them on the dial. There were some 14,400 or so applications. Love them or hate them, quite a few are likely to become your RF neighbors. I have found the public really isn’t aware if their signal is coming from a translator or a regular radio station. To them, it’s just “radio.” For the most part, they only know they enjoy the programming, or they don’t. If thousands of these little radio stations are unable to work well with HD past a couple of miles, it will make HD’s acceptance by the public all the harder. At least, there is no “drop dead” date for a digital radio conversion, so I think it is safe to say that analog will be with us for a very long time. FYI, most analog translators put out a signal that is receivable in a car for about a 15 mile radius. Obviously, they do not do as well with cheap indoor clock radios from Wal-Mart, but most decent indoor radios can receive them for a 7-10 miles radius.