Why digital is necessary

[radiopilot]

Why bother? Well for one thing "noise free" on analog fm means a noise level of maybe -55 to -60db. With HD it means -96db. With analog FM it means distortion of perhaps a percent or two (actually often MUCH more the way fm is over-processed). With HD, potentially it's .05 percent or lower. With analog FM you can either be loud, or you can be bright and clean, but you can NEVER be both because of pre-emphasis, which doesn't exist with HD...so HD will ALWAYS (when engineered well!) sound cleaner and more open. Stereo separation is DRAMATICALLY better with HD (the least of the benefits mentioned, imho...after all separation on analog fm can be pretty damn good). Those are the SOUND QUALITY differences. And I haven't even mentioned MORE CHOICE! EVERY station can offer more than one program at a time...giving listeners MANY new choices!

Uh...that's why. I could come up with more, I'm sure. But that'll do.

Somebody's lying here to think that HD potential to lower THD down to 0.05% is surely wrong...

Here is a caption of the performance of the Sangean HDT-1

"For the measurements below I used IEEE 185-1975 where applicable, except for the following: I used 98.5 MHz instead of 98.0 MHz to avoid local interference; I measured distortion and separation only at 1 kHz; I did not use a 1-kHz BPF for the selectivity measurement. I used the test equipment listed here.

Mono 50-dB quieting sensitivity 17.2 dBf (estimate)
Stereo 50-dB quieting sensitivity 39 dBf (estimate)
1-kHz mono THD 0.08%
1-kHz stereo THD, L or R 0.3%
1-kHz stereo THD, L+R or L-R 0.1%
1-kHz separation 45 dB
65-dBf mono S/N 76 dB
65-dBf stereo S/N 71 dB
Capture ratio 1.4 dB
Capture ratio, stereo 30 dB 12.6 dB
Capture ratio, stereo 50 dB 32.6 dB
Adjacent-channel selectivity 63.5 dB (noise limited)
RF IMD for 50-dB quieting 78.5 dBf (99.3 + 100.1 -> 98.5)
Minimum stereo pilot 0.75%
Deemphasis error L +2.0/-0.8 dB, R +1.9/-0.9 dB
40-Hz response -0.7 dB
20-Hz response -1.1 dB
Audio level referred to 600 mV +8 dB (1.5 V)
Latency 118 mS

http://users.tns.net/~bb/hdt-1.htm

Now you can clearly see that the distortion is 0.1-0.3%... the best analog recievers I've seen are .005% or better... so these HD units are no better than the 100.00 cheap units at Walmart.

I'd believe the above test by a competent engineer over someone not qualified to give lab results.

Radiopilot

 

[Mike Walker]

Those are ANALOG measurements on the Sangean, not digital. And I've NEVER seen an analog fm tuner measure .005 percent distortion! That's an AMPLIFIER spec, not an analog tuner spec.

Even if analog tuners can measure very low in distortion under laboratory conditions, in real-world situations with multipath, etc...ACTUAL distortion is almost always several percent more than a few miles from the tower. And the processing used at most stations these days guarantees actual distortion closer to ten percent than one percent! HAVE YOU FREAKIN' LISTENED TO WHAT FM RADIO SOUNDS LIKE THESE DAYS? Anyone who says it isn't "distortion-city" is obviously hard-of-hearing. There was a time when FM was a clean, high-fidelity source. Those days died with the mis-use, and over-use of the digital processing boxes in the 90s and 00s. Yes, FM stereo always had the problems it has today...multipath distortion, hiss, etc. But at least once upon a time it left the tower nice and clean. No more!

FM tuners are far worse than a generation ago, and the broadcasts themselves infinitely worse. HD offers a chance (which I hope broadcasters will seize) to get back to "clean livin'. i.e. audio you wouldn't be ashamed for a friend to hear! At least the public stations in my area (most of what I listen to) are living up to the potential quality of HD. Some of the commercial outlets, sadly, are "cranked up to blast-off" on HD, just as on analog. Sad!

 

[PhilJSmith67]

Now you can clearly see that the distortion is 0.1-0.3%... the best analog recievers I've seen are .005% or better... so these HD units are no better than the 100.00 cheap units at Walmart.

Find me a $100 receiver at Wal-Mart that has a THD for analog FM-Stereo below 0.1%. I had a $450 Onkyo tuner with a THD of "approximately 0.1%" for FM-Stereo. My Blaupunkt RDM-168 lists a THD of 0.3% right here in the owner's manual, and it is the cleanest FM receiver I've owned since the Onkyo.

Make sure you're looking at the FM receiver specs for the THD, not the amplifier itself. Many receivers don't even bother to publish detailed specs for AM or FM reception anymore, they just focus on the amplifier specs. My Pioneer SX-2300 receiver's only published specs for the entire FM section is sensitivity in dBf, the I.F. of 10.7 MHz, and nothing else.

 

[PhilJSmith67]

Oops... The Pioneer manual also listed one more spec.

Tuning range: 87.5 - 108.0 MHz

;D

 

[wgliradio]

Why bother? Well for one thing "noise free" on analog fm means a noise level of maybe -55 to -60db. With HD it means -96db. With analog FM it means distortion of perhaps a percent or two (actually often MUCH more the way fm is over-processed). With HD, potentially it's .05 percent or lower. With analog FM you can either be loud, or you can be bright and clean, but you can NEVER be both because of pre-emphasis, which doesn't exist with HD...so HD will ALWAYS (when engineered well!) sound cleaner and more open. Stereo separation is DRAMATICALLY better with HD (the least of the benefits mentioned, imho...after all separation on analog fm can be pretty damn good). Those are the SOUND QUALITY differences. And I haven't even mentioned MORE CHOICE! EVERY station can offer more than one program at a time...giving listeners MANY new choices!

Uh...that's why. I could come up with more, I'm sure. But that'll do.

Actually the sound and quality differences go right out the window when you factor in the codec. Now, you need to be fair. If you are bothered by a noisefloor of -55, that's fine. The audio codec bothers me more. Once the multipath starts in... or the reception becomes unstable, the analog stays usable, the HD goes away.

As for the processing.. many HD casts are using the same amount of audio manipulation on their HD as their FM. As for FM pre-emphasis, when engineered correctly, can sound just fine. I've never heard an average end user complain about pre-emphasis.

As for the more choice, beforewe begin about the reduced range of those broadcast and the reduced range of ideas by programmers and the reduced audio quality of each additional HD stream... well, you get the picture.

HD does not work out of the box for the average person. Sattelite does, the MP3 player does. HD requires extra antennas, wires strung all over. Reception changing on a daily basis during different seasons affects HD reception. I have 50kw AM's 40 miles west that are clean as hell on my Accurian, but HD is only possible for about an hour or so a day if the conditions are just right. This is with the supplied loop and as far as I will justify the demo, since this is how far I think the average person will go before he/she will no longer tolerate it. I have a 6kw FM 10 miles west in HD that will only lock on a roof antenna... yes, let's go back to that! I can't see this being 1955 all over again with roof antennas to recieve HD broadcasts... let's get real, but this is what is needed to secure a stable signal on all but the most local HD signals in suburban areas.

If it is not going to work with what is supplied, it will not be worth it to them. The Accurian is a fairly (by today's standards) sensitive radio, which has to make the HD supporter worry. If this doesn't work, what will?

 

[Mike Walker]

Actually HD is FAR MORE RESISTANT to multipath interference than analog fm stereo. Anyone who actually has a radio will tell you the same.

"Doesn't work out of the box for the average person". MOST PEOPLE LIVE IN URBAN AND SUBURBAN AREAS WHERE A FREAKIN' COATHANGER WILL WORK JUST FINE FOR AN ANTENNA! It's only fringe people who have to worry with "tweaking" antennas, and that's always been true with fm stereo.

I GUARANTEE those who complain about tweaking antennas at their locale haven't actually been receiving analog fm stereo.

The codec is proven transparent in double-blind testing...at least at high bitrates (64kbps and higher) People who complain about the "codec" think that 96kbps is equivalent to a 96kbps mp3 stream. HARDLY! The coded used in HD is FAR NEWER, and FAR MORE EFFICIENT! Unlike many here, I actually get a chance to compare work that I produce with what it sounds like ON THE AIR. On the HD stations where my work has run, it sounds amazingly like what I heard on my studio speakers, and through my favorite headphones. THAT'S a test many here can't perform...actually hearing their own voices, and their own work, on HD. I can. And it passes with flying colors!

 

[PocketRadio]

Actually HD is FAR MORE RESISTANT to multipath interference than analog fm stereo. Anyone who actually has a radio will tell you the same. "Doesn't work out of the box for the average person". MOST PEOPLE LIVE IN URBAN AND SUBURBAN AREAS WHERE A FREAKIN' COATHANGER WILL WORK JUST FINE FOR AN ANTENNA! It's only fringe people who have to worry with "tweaking" antennas, and that's always been true with fm stereo.

"U.S. Population Living in Urban vs. Rural Areas"

Population living in Urban Areas 225,956,060 79.219%
Population living in Rural Areas 59,274,456 20.781%

http://199.79.179.101/planning/census/cps2k.htm

Most people live in urban areas - I am in an urban area, and never have problems with multipath, hissing, crackling, and pops on FM.

 

[Mike Walker]

More meaningless statistics, because it leaves out SUBURBAN AREAS...usually within 20-30 miles of a city, where signals are usually as strong as in the city. MOST PEOPLE GET GREAT RECEPTION WITHOUT DOING ANYTHING SPECIAL! The antenna debate is a distinction without a difference.

 

[PocketRadio]

More meaningless statistics, because it leaves out SUBURBAN AREAS...usually within 20-30 miles of a city, where signals are usually as strong as in the city. MOST PEOPLE GET GREAT RECEPTION WITHOUT DOING ANYTHING SPECIAL! The antenna debate is a distinction without a difference.

Suburban is now Urban - these people, with analog AM/FM radios, do not need AM-loop and external FM-dipole antennas, as with HD Radio.

 

[PocketRadio]

More meaningless statistics, because it leaves out SUBURBAN AREAS...usually within 20-30 miles of a city, where signals are usually as strong as in the city. MOST PEOPLE GET GREAT RECEPTION WITHOUT DOING ANYTHING SPECIAL! The antenna debate is a distinction without a difference.

"Urban sprawl"

"Urban sprawl (also: suburban sprawl) is the spreading out of a city and its suburbs over rural land at the fringe of an urban area."

http://en.wikipedia.org/wiki/Urban_sprawl

Suburban is now considered urban.

 

[Mike Walker]

Your statistics DO NOT INDICATE THAT SUBURBAN AND URBAN NUMBERS ARE COMBINED! In lieu of facts, you simply made that up (again). And suburban and urban ARE NOT THE SAME!

Suburban areas have grown tremendously in the last four decades, but THIS decade people (for a variety of reasons) are reversing the trend and moving back into cities. I know this, because I actually read books, not relying on Google for all the world's knowledge.

 

[wgliradio]

Actually HD is FAR MORE RESISTANT to multipath interference than analog fm stereo. Anyone who actually has a radio will tell you the same.

I owe three... all three have issues.. I have a JVC HDR-1, the Accurian and the BA. All three have issues with Multipath where the signal will fall back to analog.

"Doesn't work out of the box for the average person". MOST PEOPLE LIVE IN URBAN AND SUBURBAN AREAS WHERE A FREAKIN' COATHANGER WILL WORK JUST FINE FOR AN ANTENNA! It's only fringe people who have to worry with "tweaking" antennas, and that's always been true with fm stereo.

I don't know where you live, but in metro NYC, people I know in Nassau County and Stamford CT, not that far outside NYC (Nassau County has a population of 1,333,137... 4,650 per square mile... not exactly rural) have difficulty recovering HD 2 signals and maintaining reliable coverage of main channels.

I GUARANTEE those who complain about tweaking antennas at their locale haven't actually been receiving analog fm stereo.

No, it's probably been blended to mono and they probably don't care. But at least its usable. In HD, it's not there. Remember, these are the same people who have no problem with 128 kbps audio files and all of the sudden they care that the noise floor is -95dB?

The codec is proven transparent in double-blind testing...at least at high bitrates (64kbps and higher) People who complain about the "codec" think that 96kbps is equivalent to a 96kbps mp3 stream. HARDLY! The coded used in HD is FAR NEWER, and FAR MORE EFFICIENT!

No dount, but if we are talking about which artifacts in audio that bother ME on a personal level more, it's codec artifacts over noise floor TO A POINT. I can tolerate a noise floor of -55 on a well processed and clean analog FM signal with an analog tuner of my choice over an HD radio codec where I can hear the artifacts.

Unlike many here, I actually get a chance to compare work that I produce with what it sounds like ON THE AIR. On the HD stations where my work has run, it sounds amazingly like what I heard on my studio speakers, and through my favorite headphones. THAT'S a test many here can't perform...actually hearing their own voices, and their own work, on HD. I can. And it passes with flying colors!

I work as a broadcast engineer with HD everyday on a 50kw AM station in market #1 and am well aware of what the codec does to the audio and can speak from experience as well. I have also assisted and sampled in the fruits of many FM HD setups. HD has done one thing, it has improved receiver design. But even with that improved design, it has not helped HD signals get where they need to go with the supplied equipment. It is a problem that does not have an easy solution.

HD is a solution to a problem that doesn't exist. Broadcasters have two issues right now. Content and rights fees for internet streaming. That is where the rubber will meet the road and where broadcasters should be raising hell. That is where the bread and butter will be. Yet broadcasters have been quiet. I have said it before and will say it again, as someone who sees what internet streaming can do. If your station is NOT on the web streaming, forget it. Forget HD radio, you need to be ON THE WEB. That is where ther future is in content delivery. Maybe not today or tomorrow, but all this waste of money on HD... it's not even a band-aid, I can't tell you what it is... it's a tech from a time when the internet was a pipe dream and radio needed the D word back at project acorn (1990). It is obsolete before it was born.

The idea is convienance... not quality. Consumers want it quick and now and wherever they go. HD radio does not offer that. The internet and wi-fi does. And when you have people with a cell phone.wi-fi,radio package in the future where all this content will be in the palm of their hand, and this plugs into their dash... and it plays WHATEVER they want, be it reelradio.com or WIL.com or WINS.com or whatever... that will replace 88-108 and broadcast over the air radio will be quaint. What will be even more interesting will be seeing NYC with not 70 over the air stations, but 70 million... that Z-100 could have to compete with some grassroots CHR in the basement of some house in Hillsdale NY. Content and ideas can be exchanged freely and it won't be controlled by a few. Everyone will finally be on equal ground. No more AM, FM, daytimers, directionals, sharetimes. If you think it's not coming, think again. Think where we were in 1997 with computers and cell phones and think where we are now. Now, think how that will explode in 10 years.

 

[R.F. Burns]

Actually HD is FAR MORE RESISTANT to multipath interference than analog fm stereo. Anyone who actually has a radio will tell you the same.

I owe three... all three have issues.. I have a JVC HDR-1, the Accurian and the BA. All three have issues with Multipath where the signal will fall back to analog.

"Doesn't work out of the box for the average person". MOST PEOPLE LIVE IN URBAN AND SUBURBAN AREAS WHERE A FREAKIN' COATHANGER WILL WORK JUST FINE FOR AN ANTENNA! It's only fringe people who have to worry with "tweaking" antennas, and that's always been true with fm stereo.

I don't know where you live, but in metro NYC, people I know in Nassau County and Stamford CT, not that far outside NYC (Nassau County has a population of 1,333,137... 4,650 per square mile... not exactly rural) have difficulty recovering HD 2 signals and maintaining reliable coverage of main channels.

I GUARANTEE those who complain about tweaking antennas at their locale haven't actually been receiving analog fm stereo.

No, it's probably been blended to mono and they probably don't care. But at least its usable. In HD, it's not there. Remember, these are the same people who have no problem with 128 kbps audio files and all of the sudden they care that the noise floor is -95dB?

The codec is proven transparent in double-blind testing...at least at high bitrates (64kbps and higher) People who complain about the "codec" think that 96kbps is equivalent to a 96kbps mp3 stream. HARDLY! The coded used in HD is FAR NEWER, and FAR MORE EFFICIENT!

No dount, but if we are talking about which artifacts in audio that bother ME on a personal level more, it's codec artifacts over noise floor TO A POINT. I can tolerate a noise floor of -55 on a well processed and clean analog FM signal with an analog tuner of my choice over an HD radio codec where I can hear the artifacts.

Unlike many here, I actually get a chance to compare work that I produce with what it sounds like ON THE AIR. On the HD stations where my work has run, it sounds amazingly like what I heard on my studio speakers, and through my favorite headphones. THAT'S a test many here can't perform...actually hearing their own voices, and their own work, on HD. I can. And it passes with flying colors!

I work as a broadcast engineer with HD everyday on a 50kw AM station in market #1 and am well aware of what the codec does to the audio and can speak from experience as well. I have also assisted and sampled in the fruits of many FM HD setups. HD has done one thing, it has improved receiver design. But even with that improved design, it has not helped HD signals get where they need to go with the supplied equipment. It is a problem that does not have an easy solution.

HD is a solution to a problem that doesn't exist. Broadcasters have two issues right now. Content and rights fees for internet streaming. That is where the rubber will meet the road and where broadcasters should be raising hell. That is where the bread and butter will be. Yet broadcasters have been quiet. I have said it before and will say it again, as someone who sees what internet streaming can do. If your station is NOT on the web streaming, forget it. Forget HD radio, you need to be ON THE WEB. That is where ther future is in content delivery. Maybe not today or tomorrow, but all this waste of money on HD... it's not even a band-aid, I can't tell you what it is... it's a tech from a time when the internet was a pipe dream and radio needed the D word back at project acorn (1990). It is obsolete before it was born.

The idea is convienance... not quality. Consumers want it quick and now and wherever they go. HD radio does not offer that. The internet and wi-fi does. And when you have people with a cell phone.wi-fi,radio package in the future where all this content will be in the palm of their hand, and this plugs into their dash... and it plays WHATEVER they want, be it reelradio.com or WIL.com or WINS.com or whatever... that will replace 88-108 and broadcast over the air radio will be quaint. What will be even more interesting will be seeing NYC with not 70 over the air stations, but 70 million... that Z-100 could have to compete with some grassroots CHR in the basement of some house in Hillsdale NY. Content and ideas can be exchanged freely and it won't be controlled by a few. Everyone will finally be on equal ground. No more AM, FM, daytimers, directionals, sharetimes. If you think it's not coming, think again. Think where we were in 1997 with computers and cell phones and think where we are now. Now, think how that will explode in 10 years.

So where's the infrastucture and who's going to pay for it? I've worked as an engineer in NYC for 30 years and I've heard all sorts of doom and gloom about the future of radio since I was a child. Lets use cable tv as a reference as to what might happen to terrestrial radio (who already have a pressence on the internet but the audience numbers are nowhere near the numbers over the air broadcasting achieves daily). Sure cable has cut into the BIG 3's overall numbers but the key is that far and away they have many more viewers than even the best cable broadcaster and they have been competing for more than 10 years already. The novelty of internet radio will wear thin and the vast majority of people will want to hear their hometown voice. I know that in Florida my father listens to WFAN via computer and if he could get it in the car he'd never tune to a Florida station. I'd also like to know how the internet operator intends to provide hundreds of thousands of simultanious feeds on a single station. At this time it can't be done for a reasonable price. In NY that's what is needed if internet were to replace over the air broadcasting. It's not going to happen any time soon. Imagine another 9-11 and everyone has internet radio except that the internet fails as it did in much of NY on 9-11. Yep, who needs terrestrial broadcasting.

 

[wgliradio]

How are people watching the Big 3 over the air vs cable and satellite? I'm not saying people won't listen to content delivered by broadcasters, I'm just saying the method of delivery will be quite different.

As for the foresight to prevent a failure during a national disaster, when did I ever say that those who will design the system would have the brains to see the forest thru the trees, but those who think they can make a buck off this will try and build it and probably not prevent failure in a disaster. Don't forget, this will be funded at the corporate level, not exactly the home of logical thinking. 8)

 

[tomservo]

Once again I am a day late and dollar short, so here are some intemperate thoughts on some things brought up in this thread...

• I'm going to have to side with Mike on a few issues, most notably the codec and multipath points he made. I've only had limited experience with FM HD but what I have heard does sound noticeably better in digital mode, with the picket fencing and choppy analog replaced by a solid signal. The codec - well it's good but it ain't perfect... But then what is? Lossy compression is, sadly, a way of life these days. I gave up arguing on the XM boards with the people who thought that sounded "CD quality". If people can't tell the difference between awful low bitrate XM and a pristine CD, then the codec on FM (or AM even) is completely irrelevant to society at large.
  
  
  
• The points made about people not wanting to fiddle with antennas is spot on. The magic of pulling signals from the air is lost on most folks -- these days it's not a novelty anymore, it just needs to work. Again using satellite radio as a comparison, there are those who get rid of their satellite setup because they gave up fiddling with the antenna to get a signal. (I'm lucky, this is a wood frame house and the antenna works if it's even remotely pointed in the right direction. No repeaters for 100 miles, either.)
  
  Going digital is more about new revenue streams than better sound, better reception and more channels. Those are just selling points - not guarantees.
  
  
  
• iPods are only cool because a) they look good, b) they work with the heavily promoted and successful iTunes and c) people are buying into the Apple cult appeal. The super-intuitive interface deserves an honorable mention, too. Why anyone would want an mp3 player that is so locked down and featureless out of the box is beyond me. I'll take my brick (iRiver 5 GB) with FM, recording and DRM-free playback anyday.
  
  
  
• If you strip out PocketRadio's constant not-so-notable quotable posts, this thread might only be two pages.
  
  
  
• One reason that HDTV ≠ HD radio is that those analog TVs show more than OTA broadcasts. Once the analog sunset occurs (if they don't push it back again) 60+% of people will notice no change, because they are hooked up to cable/satellite. They won't be rendered obsolete because a digital converter can be attached. Sunsetting analog radio would render radios useless because many if not more than half lack inputs for auxiliary purposes. (It may anger you small government types, but they are subsidizing decoders for those who can't afford to buy one on their own, so they will cost little to nothing for qualified applicants.)
  
  
  
• The AMPS phone system, which supposedly is still in use in some places, was propped up by the government for two reasons that should hit close to home with the HD radio crowd: lack of adoption in rural areas and coverage benefits. The last article I read on AMPS from a few years back noted that the phone companies were very reluctant to upgrade very rural locations to digital because the sites covered a broad geographical area with very few people. It wasn't cost effective. If the telco dropped AMPS, people would actually lose their only wireless coverage. Some Verizon phones still offer analog fallback for those areas. My prepaid Kyocera did, and there were many many places in rural Alabama where, with external car antenna, analog was all that worked -- this was in 2006. Sprint also comes to mind - PCS, but with AMPS fallback. My best friend has one and when we're out in the country, where my T-Mobile is dead to the world, he's always "analog roaming". It's worth noting that since Cingular took over the B block of the AMPS system, they converted it to GSM, thereby offering digital to a vast amount of the country in that form.
  
  
  
• HD is neccessary because we won't pay more or upgrade for no reason. HD radios don't sell out here because there are still no stations that have gone digital. If no stations went digital, why would anyone want to buy an HD radio for some supposed future "turn on"? If the radios were digital compatible by government mandate, the cost would go up exponentially and the alternatives (sat/mp3/net) would be the real benefactors.
  
  
  
• Comparing digital TV to digital radio is all well and good, but remember the transmission schemes can be tailored to the environment. 8-VSB is not real robust in a moving environment (I recall that is "quite useless") but the scheme used by iBiquity is much better. If digital was truly useless in a moving environment, why do digital cell phones work so well (usually)?
  
  

Let's face it - hybrid digital mostly works, is somewhat beneficial to end-users and is absolutely not going anywhere. Why can't we agree to band together to fight the real scourge: hybrid digital on AM?

 

[Mike Walker]

Personally I think it's silly to believe that cell phones requiring 20-100 dollar data plans in order to stream a few stations are a threat to anything. Earth to everyone: the public thusfar doesn't give a damn about these multimedia features, but audio HAS been more successful than video on the tiny screens, because...well the screens are tiny, and data rates are lower for audio so it's more practical (just).

 

[wgliradio]

Now, but you have to look at where the tech will be in 5 years.

 

[Mike Walker]

Where was the technology five years ago? They were just beginning to offer music and mp3 capability. And data plans were expensive THEN.

 

[PocketRadio]

the public thusfar doesn't give a damn about these multimedia features...

"In-Sights: Will Multimedia Phones Threaten Portable Music Players?"

"Recent In-Stat surveys of cellular customers reveal that an increasing number will test the music playback capability in their mobile phones. But, is this data enough to conclude that music-playing cell phones will eat away at Apple’s market share and standalone MP3 player sales in general? In May 2006, In-Stat fielded a survey of 1,033 typical cell phone users in order to understand this specific question; and our conclusion is that there may, indeed, be some threat to the music player market from mobile phones."

http://www.instat.com/catalog/Wcatalogue.asp?id=231#IN0602904MCM

Portable HD Radio, anyone ?

 

[PhilJSmith67]

Excellent post, Zach!