FM HD Interference

[Chuck]

Here's one for you. We have a station in East Texas (KXAL) that broadcasts on 100.3 in analog. In the Dallas area, there is also a station (KJKK) that is co-channeled with it, but it is running HD. If you listen on an HD radio, in the early morning when the skip comes rolling in - it does that a lot here in East Texas - the Dallas HD signal sometimes over-rides the analog signal, even though the local analog signal still comes in fine on an analog only radio.

This observation was pointed out to me by a local listener, using a Sony HD tuner. When you first tune in the station, the radio immediately locks onto the local analog signal, which seems to come in fine. After a few seconds the tuner automatically switches to the Dallas station's HD stream. This is not good. The local transmitter is about 8 miles from the listener's home, which is well within the stations protected contour. It seems to happen with quite a bit of regularity, so I don't think it is an isolated instance.

If this isn't "interference," I'm not sure what is. If and when the FCC approves a 10 db power increase for HD, this phenomenon will become much more prevalent. The only good news I see is there aren't many HD radios in the area to be bothered.

 

[BRNout]

Just imagine how bad it would be in a more congested area like the northeast. Yet the lemmings insist on running headlong for that cliff.

FWIW, we've had a discussion about just this issue over on the Boston board: http://boards.radio-info.com/smf/index.php?topic=151980.30

 

[rbrucecarter5]

Here's one for you. We have a station in East Texas (KXAL) that broadcasts on 100.3 in analog. In the Dallas area, there is also a station (KJKK) that is co-channeled with it, but it is running HD. If you listen on an HD radio, in the early morning when the skip comes rolling in - it does that a lot here in East Texas - the Dallas HD signal sometimes over-rides the analog signal, even though the local analog signal still comes in fine on an analog only radio.

This observation was pointed out to me by a local listener, using a Sony HD tuner. When you first tune in the station, the radio immediately locks onto the local analog signal, which seems to come in fine. After a few seconds the tuner automatically switches to the Dallas station's HD stream. This is not good. The local transmitter is about 8 miles from the listener's home, which is well within the stations protected contour. It seems to happen with quite a bit of regularity, so I don't think it is an isolated instance.

If this isn't "interference," I'm not sure what is. If and when the FCC approves a 10 db power increase for HD, this phenomenon will become much more prevalent. The only good news I see is there aren't many HD radios in the area to be bothered.

If I were you, I would file a complaint with the FCC. You have a bonafide gripe against the Dallas station, and unless broadcasters speak up, there is no hope of derailing this train wreck of a power increase. The situation is bad enough as it is, and I have pointed out many times that we are presently at a solar minimum, and have been the whole duration of this HD radio experiment. The solar minimum will not last, it is cyclical - and even the present HD sideband power levels are going to wreak havoc when skip again becomes prevalent.

There is a fix for the Sony that forces it into analog mode only, if your listener is technically minded. He can find it at:
http://www.ham-radio.com/k6sti/xdr-f1hd.htm - the force analog modification is near the bottom of the review. It is a really simple modification, well within the capabilities of most hobbyists.

 

[Play Freebird]

I have a pretty good hunch that KXAL could foil this "hijacking" by feeding bandpass-filtered white noise into the composite input of the exciter. Make sure the filter is tight enough to cut off sharply below 100 kHz and above 200 kHz. This would generate a pair of FM noise sidebands that occupy the same spectrum as the distant digital carriers; you would simply increase the injection enough to spoil the digital decoding while staying within the mask, using the same spectrum analyzer settings as called for by NRSC. A sideband amplitude of -30 dBc might be enough to do the trick, and this low level shouldn't cause much harm to your first-adjacent neighbors.

 

[Savage]

And thus: the HD "interference wars" are joined. But suppose tropo skip delivers the white noise to the HD station's digital sidebands or to other broadcasters? Will the HD station feel compelled to crank up digital injection as retaliation?

Suddenly it's 1923 again, pre-NRC, where the Commerce Department has been told to butt out of regulation. The spectrum is the wild, wild west, with stations changing power and frequency at will to blast out competitors or just to one-up in the marketplace.

The FCC is so typical of what passes for "government" these days: another federal agency which has jettisoned its career professionals in order to populate it with policy wonks and lawyers with no industry experience - and whose sole real function is to cynically crank more fees and taxes into the federal treasury.

Screw the public, align with the broadcasters who can line your pockets the fastest. Great government we've got going on there.

I'm tellin' ya: time for the Second American Revolution.

 

[bigtom101]

Just imagine how bad it would be in a more congested area like the northeast. Yet the lemmings insist on running headlong for that cliff.

FWIW, we've had a discussion about just this issue over on the Boston board: http://boards.radio-info.com/smf/index.php?topic=151980.30

I guess I'm Big "Lemming" Tom then...

Just remember - one persons "interference" is someone elses desired signal. I'm sitting here in Central Jersey, with that sappy pukefest known as "Delilah" on WBEB 101.1 out of Philly (and 5 other stations within earshot). But, ah ha! I have a signal preamp and a antenna aimed at NYC. So WCBS-FM's HD comes in and saves me from slitting my wrists. It's the only way I can hear WCBS-FM here in Central Jersey, since the brain trust at the FCC thought it would be GREAT to have a 101.1 in Philly & a 101.1 in NYC.

Thanks HD Radio!

 

[BRNout]

Just imagine how bad it would be in a more congested area like the northeast. Yet the lemmings insist on running headlong for that cliff.

FWIW, we've had a discussion about just this issue over on the Boston board: http://boards.radio-info.com/smf/index.php?topic=151980.30

I guess I'm Big "Lemming" Tom then...

Just remember - one persons "interference" is someone elses desired signal. I'm sitting here in Central Jersey, with that sappy pukefest known as "Delilah" on WBEB 101.1 out of Philly (and 5 other stations within earshot). But, ah ha! I have a signal preamp and a antenna aimed at NYC. So WCBS-FM's HD comes in and saves me from slitting my wrists. It's the only way I can hear WCBS-FM here in Central Jersey, since the brain trust at the FCC thought it would be GREAT to have a 101.1 in Philly & a 101.1 in NYC.

Thanks HD Radio!

I'm afraid you're coming off as one!

Yes, it's all fun and games until everyone cranks up the digital sidebands. If and when that happens, Jerry Lee may feel compelled to put the IBOC exciter back on and at full power - on B101.1. Then where will you be? Probably not able to listen to either 101.1 reliably. Certainly not in the car anywhere between Elizabeth, NJ and Morrisville, PA. That large area will be a dead zone for analog listeners and a cluster of drop-ins and outs for the few with HD radios in the car. Same will be true of 100.3, though slanted a bit south. And, all of the adjacents will have issues too. Like WOGL? Well, if New Brunswick's 98.3 cranks up the digital, you won't hear it nearly as far north as you now can.

You get the idea. It's mutually assured destruction - FM style. Absolutely foolhardy to support such a scheme unless you live in a metro that's far from any other.

 

[Savage]

Well, THAT shoe fits either foot: one person's "sappy pukefest" is another person's "desirable programming." Last I checked the reason we have an FCC (at least theoretically these days) and receivers with tuning knobs is so listeners can "make choices." You know: without having somebody with a freakin' iBiquity Decepticon making their choices for them. As in: screwing up reception of other licensed facilities and impairing their abilities to serve their coverage area because it's SOOO important to have digital broadcasting which, in many if not most cases, is inferior in practical application to analog.

And: fine, you have a preamp and a rotatable antenna. So you're part of an exclusive club I've got to believe represents about 0.001% of radio listeners. It's hardly a reasonable answer to critics of HD to argue that all radio listeners have to do to get acceptable everyday reception is to merely install hundreds of dollars worth of additional gear and play "radio engineer."

It continues to astound me how some purported industry professionals defend this train-wreck of a concept. You would think that "real radio people" would stand steadfast against unwarranted and unacceptable interference and stand up for protecting broadcasters and their facilities, regardless of their stance on HD.

Oh, wait. I have an update on that: it turns out most industry professionals DO agree with me. As in, the 83% of FMs and 98% of AMs who have NOT installed HD. And the car manufacturers who won't make HD available in their products. And the receiver manufacturers and electronic retailers who, once burned, are gone forever.

Just heard one of those absurd on-air promos inviting people to "pre-order" MS Zune HD portables through amazon.com. Right. Like anybody is actually going to do that. I can walk into the Apple store in the mall and update my iPod nano this afternoon if I want....no waiting.

 

[bigtom101]

I'm afraid you're coming off as one!

Yes, it's all fun and games until everyone cranks up the digital sidebands. If and when that happens, Jerry Lee may feel compelled to put the IBOC exciter back on and at full power - on B101.1. Then where will you be? Probably not able to listen to either 101.1 reliably. Certainly not in the car anywhere between Elizabeth, NJ and Morrisville, PA. That large area will be a dead zone for analog listeners and a cluster of drop-ins and outs for the few with HD radios in the car. Same will be true of 100.3, though slanted a bit south. And, all of the adjacents will have issues too. Like WOGL? Well, if New Brunswick's 98.3 cranks up the digital, you won't hear it nearly as far north as you now can.

You get the idea. It's mutually assured destruction - FM style. Absolutely foolhardy to support such a scheme unless you live in a metro that's far from any other.

It's already mutually assured destruction - analog 101.1 is a mess, no matter who has the digital sidebands on, and at any power level. WPHI 100.3 is directional, so the 100.3 frequency isn't as much of a mess in Central Jersey, same with WXTU vs WXRK. And with my nifty Visteon HD Jump in the car, I can hear WOGL within eyesight of the WMGQ tower. Adjacent interference can't really get much worse here in Central Jersey - the shore class A's come in, Atlantic City 50kw powerhouses boom in, Allentown/Easton signals, and of course there's the NYC & Philly FM's. My FM reception hasn't gotten any worse since HD has come along in my area, and quite frankly I haven't had any of these interference problems people are mentioning.

I doubt either of us will see eye to eye on this - I like HD because of the lack of preemphasis/dempahasis, the low noise floor, PAD, multichannels, and better stereo separation. Is it better than sliced bread? No - the system has its drawbacks, and the costs are outrageous for smaller broadcasters, but it's better than nothing. Off topic: AM is dying as a medium - nobody under 35 will listen to it, no matter what programming is on it. Bringing back C-QUAM or wideband AM won't do a damn thing - it's still noisy as hell and going near powerlines and under tunnels renders it uselsess or not. And I say this as someone who does a show ON a AM station every Friday night, and faithfully tuned into KB 1520 and 1530 WSAI via skywave when they tried oldies in the early 00's. I'm not saying throw in the towel on the whole band, but that's where we're heading.

 

[Savage]

Even if somebody were to agree with your "it's lights out for AM Radio" premise - I don't, FWIW - how does HD Radio help AM?

 

[BRNout]

The thing is, big Tom, you may not have an issue with interference now - but you will have one if the IBOC sidebands are increased 10 fold. You are happy with reception as it stands now on FM and that's fine. My initial comment was "ok, that just goes to show that no power increase is necessary" and I stand by that. The average listener is very passive. They are not running to stores to buy HD radios, nor has there been any 'oh wow' interest in it. You see some folks here with HD radios (I actually have 2), but we are not a representative group by any means when it comes to radio.

Yeah, when I lived back there, I used to get WOGL as far north as Piscataway and beyond - despite the signal from New Brunswick. I didn't need an HD radio to pull that off. However, IF we ever get to the point when everyone is banging away with increased sidebands, things will be far worse on the FM dial.

As it stands now, it's tolerable and this is why there have been virtually no complaints. Crank it up and there will be. And the WRNI example is only debated by the folks at Greater Media who just don't want to hear it. They're interfering within the protected contour of a neighboring market's signal. If everyone does it, there will be a lot more of that.

No, perhaps we won't see eye to eye on this. I do not consider digital to be an improved transmitting platform over analog. The nasty side effects are more than enough to outweigh the perceived advantages. And, I am not referring to the sidebands as much as I am the finicky signals that cut out for any little spot of what would be static on analog. Also, some of the digital audio sounds overly processed and 'fake' - but that depends on who's engineering the stream.

As for AM, yes it's been skewing older without question. Up to now, you have had some people migrating to AM for certain content as they get into their mid 30s to early 40s for talk radio. Rush, in particular, is a big draw. It's not as black and white as "all the listeners are old and getting older" because there is some replacement going on. However, the current trend of talkers heading to FM is a bad omen for the business side of AM. On the technical side, the FCC has been negligent in allowing the band to become too crowded by shoehorning any Tom, Dick and/or Harry's signal into a band that's already quite full. Permitting the damn IBOC hash on AM was another boner on their part. Those things have collectively raised the noise floor, which is the last thing it needed as increased electrical interference has been doing that as well (something the FCC can't really control).

It's as simple as this: the stations with compelling content can still make it - those that don't are in trouble.

 

[bigtom101]

Even if somebody were to agree with your "it's lights out for AM Radio" premise - I don't, FWIW - how does HD Radio help AM?

When the signal locks, AM doesn't sound like ass & it provides PAD for title/artist and other nice information (added value for spots - have the website, phone #, etc scrolling on the display). I used to listen to WPHT in C-QUAM for their Sinatra programming, and I now listen to it over IBOC. The lack of noise is a big plus, at least while sitting in my room where I usually am on Saturday & Sunday mornings. In my Cadillac that had a noise free electrical system, I had no problem locking onto AM HD on the local 50kw ND blowtorches during the day while driving around.

In any case, AM isn't going to die overnight. You will see more and more heiratage AM brands move over to FM where possible (KCBS in San Francisco as an example), and more emphasis on listening thru mobile devices like iPhones & Blackberries to get younger demos to listen to the "brand". I spend allot of time around young'ns (college kids since I am one), and I know only a handful that listen to AM - and it's only for sports (WFAN & WIP). Hell, most of my friends don't even listen to the radio period. Blackberries running Pandora along with iPods & iPhones, and CD's, take care of mobile listening.

One more example: my buddy & I went out to the movies and we took his car, I noticed that the whip antenna was gone, and the threads had rust on them. I asked him if he wanted an antenna since I had a spare whip, and he said that since he never listened to the radio it didn't matter. In fact, he liked that the antenna was gone since it meant less interference for his iPhone FM modulator. If he wants to listen to anything, he punches it up on the iPhone. I don't forsee AM being a moneymaker

To BRNout: I agree with you on stations providing compelling content are the ones that will make it, and allot of what is on radio these day's isn't as compelling as the Dan Ingram airchecks on my iPod.

About that interference: when WRAT & WJRZ were testing -10 power levles, I had no issues recieving WBEN/WPLJ or WODE/WHTZ. And this was with a dipole, before I got a yagi. Again, I live in radio hell where the only "local" stations are a few 50kw powerhouses from Trenton - I am 45 miles by air from the ESB, and 43 from the main Philly antenna farm.

Digital is the future, and it is here to stay whether anyone likes it or not. HDTV makes NTSC look like crap, and FM HD Radio when done right sounds allot better than analog FM. The younger generations think turntables are cool for nostalgia (and hip hop mixing), but everything else is digital all the way. To paraphrase "Publish or perish"...digital or death!

 

[Savage]

Oh, please. I've heard this over and over: "digital is the future, digital or death," etc. Says who? Other than HD fanatics?

Point us to one credible study - that would be, for emphasis, a "credible" one, meaning one unconnected with the HD Alliance, Big Group Radio which is heavily invested in HD as a power grab for hegemony, or iBiquity - which conclusively proves that radio audiences would return and grow "if radio broadcasting were only in digital." I've thrown down this challenge dozens of times publicly - and have never gotten a response.

The truth is: the audience just doesn't care. And they have NO inclination to go out and buy new radios just to get signals in digital. None. Irrespective of price points.

Besides - without conceding anything, even if "the future is indeed digital," who says HD Radio is the answer? Looks to me like HD's circling the drain. Want to talk about "like it or not??" THAT'S the truth, which you can prove to yourself by visiting any reasonably objective trade publication, reading FCC comments on the pending digital power proposals or reading this or other blogs.

Anyone who concludes that consumers are going to go out and replace serviceable radios variously estimated at between 500 million and a billion devices, just to get digital audio which is incrementally better than existing analog, has a vastly exaggerated sense of the importance of radio and its sound quality to listeners. They're fine with it the way it is.

 

[bigtom101]

Oh, please. I've heard this over and over: "digital is the future, digital or death," etc. Says who? Other than HD fanatics?

Point us to one credible study - that would be, for emphasis, a "credible" one, meaning one unconnected with the HD Alliance, Big Group Radio which is heavily invested in HD as a power grab for hegemony, or iBiquity - which conclusively proves that radio audiences would return and grow "if radio broadcasting were only in digital." I've thrown down this challenge dozens of times publicly - and have never gotten a response.

The truth is: the audience just doesn't care. And they have NO inclination to go out and buy new radios just to get signals in digital. None. Irrespective of price points.

Besides - without conceding anything, even if "the future is indeed digital," who says HD Radio is the answer? Looks to me like HD's circling the drain. Want to talk about "like it or not??" THAT'S the truth, which you can prove to yourself by visiting any reasonably objective trade publication, reading FCC comments on the pending digital power proposals or reading this or other blogs.

Anyone who concludes that consumers are going to go out and replace serviceable radios variously estimated at between 500 million and a billion devices, just to get digital audio which is incrementally better than existing analog, has a vastly exaggerated sense of the importance of radio and its sound quality to listeners. They're fine with it the way it is.

Look, digital radio in any form is not going to "save" radio. Radio getting back to innovative programming distributed on a multuplatform level is going to get audiences growing again, but doing it over digital platforms is the easiest way to get youngsters to listen. Apple just announced that for the 1st time an iPod will come with a FM tuner with RDS. That's a great step...but it's going to take radio that doesn't suck for the people to stick around.

And the general populace doesn't usually demand squat in terms of technical advancements. 40 years ago people were ok with AM fidelity. 15 years ago people were fine with dial up for web browsing. 10 years ago people were kosher with 480i analog TV. Not so today. People not satisfied with "good enough" drive innovation...not just content with "good enough."

It really doesn't matter in the grand scheme of things. The world will still turn, the sun will rise, and we'll just disagree.

I'd quit arguing with me and go develop some cool iPhone & Blackberry apps for WYSL and hop on Facebook & Twitter and promote the station. Our disagreements aside, you are a great owner/broadcaster and from the looks of your website, you really do care about your community and have a staff who truly love broadcasting and doing things right. Best of luck man!

 

[pocket-radio]

Digital radio is the internet and your cell phone! Strubull is a fool, because he believes IP radio won't grow because At&T can't meet the bandwidth demands. Trust me if consumers are willing to pay, At&T will play ball...

Radio would have been better off investing in social media! Something consumers want!
Besides the geeks and radio people, consumers haven't adopted HD.

5 in 10 consumers on both iPhone and iPod touch devices use the mobile Web more frequently than they read printed newspapers.
• More than 40% of users of both devices reported using the Internet on their mobile device more often than using the Web from their computers or listening to the radio.

http://blog.admob.com/2009/06/16/ne...and-ipod-touch-users-from-admob-and-comscore/

 

[BRNout]

Right now, digital radio has a lot of drawbacks. For one thing, it takes a lot more juice to approximate the same service area for the signal. And, it takes more juice on the part of your radio to decode it. A lot of the HD2 and HD3 signals are equal or even inferior in sound quality to what you can recieve via the internet.

I just got done listening to Costa Rica blow a world cup qualifying game this evening, via the internet and a small FM transmitter connected to my computer. The sound quality was almost as good as a local FM and I didn't need to buy a new radio to listen to it. Nor did a 2 hour game blow through a set of batteries. The radio didn't cut out to silence when I moved it. All these things happen with digital - like it or not.

If digital radio is the future, it's way in the future. So far out that it'll be obsolete before it can be rolled out to a significant number of listeners. In the meantime, analog radio is being battered in this poorly executed attempt to force a new technology on consumers who aren't the least bit interested.

 

[Mike Walker]

Brnout and Pocket Radio are both right. Digital radio does require "more juice" to work properly. And digital radio "is the internet". Just not yet. Read the latest radio world about how the bandwidth simply doesn't exist, especially on mobile devices, to replace terrestrial radio listening. Yet. Acknowledging the problem is the first step toward solving it. I actually have a significant (to me) "dog in this race"...my show ( www.savingthe70s.com ) is on lots of internet radio stations, and available through I-tunes, Shoutcast, Windows Media, Reciva, and Radiotime aggregation sites, among others. I WANT the bandwidth to allow huge expansion of internet radio. I've bought two internet radios in the last year (to only my original Accurian HD Radio). Digital radio is about delivering packets of information from point a to point b. I truly don't give a rat's hiney how it's done, only that it IS done!

 

[Mike Walker]

Digital has the capability (not always realized!) for better sound quality, and greater spectrum efficiency, allowing more program sources in less bandwidth. Digital technology powers all those cute devices people carry with them. And accepting the truth that all future media will be digital doesn't require that you believe it. It will happen anyway. NO new analog services have survived since the dawn of digital audio in the late 70s. Most people blindly accept as fact that "digital is better, and it's the future". That's all that's required to make it so. Having said all that, because digital "IS the future" doesn't eman that analog should go away. Imho, digital and analog should co-exist for a long, long time to come. Even with a power increases, there will likely be places that FM HD just can't penetrate, but analog can (fewer, but still some). And being a radio collector, i have zero interest in turning my great old radios into doorstops and paperweights! Those of us over 40 know that FM stereo can sound much better than it now does, because it once did! Recordings from the 70s and 80s bear out the truth that analog FM stereo was cleaner and more listenable BEFORE heavy-handed digital audio processors went into racks at most stations! Beautiful music from open-reel on 1970s automation, regardless of how you feel about the music, was of EXTREMELY high fidelity. Ditto classical and jazz on public radio from LPs, and eventually CDs. Even pop/rock played from hissy cart machines (or phonograph records) sounded better than most of what we hear today.

 

[scanman1]

I remember FM stations sounding pretty good in the 80s! Digital audio reproduction can sound great, but analog, to me, just sounds better! Analog forever baby!

 

[Play Freebird]

The big issue with HD Radio isn't so much a case of whether digital is "better" or "worse" than analog, but rather a faulty allocation plan.

Remember, the proponents of IBOC originally told us that the digital carriers could occupy the same channel as the analog sidebands. Of course, they could never get that idea to fly (those pesky laws of Physics, again), so they decided to dump the digital signal into adjacent channels, then try to justify the interference through a "creative" (and misleading) legal interpretation of FCC occupied bandwidth standards.

If the NAB would stop opposing efforts to re-use vacant TV channels, a digital radio system could be implemented that resolves practically all of the major problems with AM IBOC:

1) It wouldn't interfere with existing analog signals.

2) Digital transmit power could be run much higher, allowing for improved coverage

3) It would be much more tolerant of lightning and noisy power lines.

4) A shorter wavelength would improve building penetration and allow iPod-type devices and cell phones to receive the signal effectively

5) The analog AM simulcast could still use C-QUAM and would not require a 5 kHz lowpass filter.

6) The wider digital channel would offer a much higher bitrate and enable a more natural-sounding codec.

7) Ample bandwidth would remain for emergency alerting (an enhanced EAS or CAP system) that doesn't require regular audio programming to be interrupted.

8) Daytimers, Class C, and DA-2/DA-N stations would gain consistent day and night coverage.

9) Borrowing a successful concept of cellular technology, on-channel digital boosters could be added on demand to fill in areas shadowed by terrain or tall buildings.


The advantages of this plan are so numerous that it's "unthinkable" -- so maybe we should just give up and forget about it.