Adventures in Retail

[semoochie]

Is it the total amount of power that's important or the percentage of the signal? If it's the former, it won't help enough: Where I live, there's a station with 63 watts of HD that runs into trouble only in the same areas as the 1kwers. Otherwise, the higher power stations outlast it in flat terrain. While I'm here, I'd like to mention that I discovered today that first adjacent FM IBOC interference is apparently the figment of someone's imagination. In an area where I was still able to decode HD, there was clear to normal reception on first adjacents. I would describe reception as light fringe in all cases but how could there be a significantly stronger signal on one frequency or the other without pre-existing analog interference?

 

[geostudent]

...While I'm here, I'd like to mention that I discovered today that first adjacent FM IBOC interference is apparently the figment of someone's imagination....

That statement is bound to get responses to the contrary.. I guess mine is the first. First adjacent FM IBOC interference, at least when referring to analog signals, is *very* real. I suspect that the first adjacents you were hearing (in analog, yes?) were strong enough wherever you were at that time to overcome the digital sidebands of the station you say you can get in digital at that same location.

Case in point: I used to occasionally listen a Class B station, 45 miles distant on 93.7, until a first adjacent Class A, 18 miles away on 93.5 in the opposite direction, fired up IBOC last year. Now, mostly all I hear on 93.7 in my area is loud, roaring hiss (and on 93.3 as well). Ok, granted, I don't live within that Class B's protected contour, but, hey, it's one less choice than I used to have..

 

[semoochie]

I'll give a specific example: I was in Salem OR, which is 45 miles south of Portland and about 60 north of Eugene. I was able to get a lock on a Class C2 in Portland on 94.7 while still pulling in a C1 in Eugene on 94.5. If the Eugene station were much weaker than that, most people wouldn't bother listening to it. If this is a problem at all, it doesn't appear to affect very many people.

 

[Chuck]

If this is a problem at all, it doesn't appear to affect very many people.

That may be true. I do remember a couple of years ago, the CE of WEOS, which is an NCE station in Geneva, New York, was upset due to first adjacent HD interference they were receiving from a neighbor. As you know, the Reserved Band is a pretty crowded place, especially in the Northeast. It seems that they were no longer receivable in a neighboring city. Yes, that city was outside of the protected contour of WEOS, but they had a long track record of people from that city contributing during Pledge Drives. I guess somebody was listening, or maybe the folks there were just being altruistic. You be the judge. In any case, they seemed to think that their neighbors HD upgrade was going to take cash out of their pocket.

Since I am nowhere near upstate New York, I have no way of confirming or denying this, however the Engineer in question has a reputation for being straight-forward, honest and sincere. I have no reason to think he was imagining things.

 

[MasterTheseus]

Well, what I hope is that the power can be increased, but would like to see that happen only after the stations get their content right...

With all due respect MasterTheseus... [1] “Content” is a non-issue and is irrelevant to the technical reality. [2] It does not strike me as “unusual” that the representative of an enterprise that markets radio receivers [“HD”-capable radios specifically – given their clearly-established “reception disappointment”] would be hoping for nearly-any regulatory position that would advantage the potential reception ability of their product. The operative word here is “advantage” – and here’s the problem... Increased power [and the resulting ease of reception on “garden variety” radios] brings that unfortunate bedfellow known as “interference” along with it. You need-only look to the AM band with issues regarding “nighttime service” as sterling proof of this. A “fast ‘n loose” attitude with regards to the allocation table; intermediate and mixed-class power appropriations [“shoe-horned” stations]; and now even IBOC are mounting a similar fate on the FM band.

In technical circles, this is known as a “trade-off”, and those with admirable technical credentials CONSTANTLY remind us that “You CAN’T fool Mother Nature.” There is no better paradigm to illustrate this than basic radio propagation. There are equal-opportunity offenders on BOTH sides of the fence. I’m sure that the likes of Sangean are called upon to build a “better radio”. Is that simply a more sensitive radio with a demure antenna that invites RF overload and unrelated RFI from devices in the home and auto environments? Is that a more selective radio [a very-important spec given the existence of IBOC carriers on FM] that compromises FM capture ratio, stereo separation, and distortion performance? Persons like Tom Wells [and myself] enjoy AM radios with a wide IF bandwidth; but at what expense to the casual listener less-likely to tolerate adjacent-channel interference?

Long ago, the practical interference limit on both AM and FM was exceeded... A further increase WILL only drive the broader public to less-challenged mediums. Crudely put: “IBOC is a HOG rolling in mud” – the key is to carefully-limit the amount of mud it is permitted to displace.

Ok, to point 1. I was not saying that content had anything to do with technical, I was simply stating that I think content is FAR more important to signal strength.

Point 2. I am advocating signal strength only to improve reception a little. I myself get all stations in my are in HD if broadcast and have not had a station drop yet, but I am fortunate and close to the transmission signals, but I know that for example, in retail stores and in some homes they are only 2 or 3db's away from getting an HD lock. If it even ends up being 2 or 3 watts, that can be a huge difference as far as reception. I am not so much advocating anything more than that and agree that there should not be a trade off.

To be a devils advocate here though, if instead we lobied the FCC to mandate transfer to HD Radio would that really make people happier? I myself wouldn't care, I have HD Radio, but I don't think it any better to mandate people to switch and throw out their beloved analog radios.

 

[Play Freebird]

That may be true. I do remember a couple of years ago, the CE of WEOS, which is an NCE station in Geneva, New York, was upset due to first adjacent HD interference they were receiving from a neighbor. As you know, the Reserved Band is a pretty crowded place, especially in the Northeast. It seems that they were no longer receivable in a neighboring city.

I'm quite familiar with the Geneva area, in the Finger Lakes region of upstate New York. Considering the local topography, I agree that it would be very easy to receive a useable signal from WEOS well outside their FCC protected contour. In fact, I used to live near Syracuse University and received WEOS fine, long before they raised power to the current level.

Keep in mind that the FCC contour prediction method was developed over sixty years ago and is based on several usually-false assumptions:

1) FM signals always decrease in strength with distance, it doesn't matter which side of a hill you're on

2) Only terrain between 3 and 16 kilometers from a station's transmitter has an impact on coverage

3) Receive antennas are mounted a full 9 meters above ground level

4) "Non-directional" transmit antennas are perfectly omnidirectional, even when side mounted on a tower or even a large smokestack (see the database record for WEBE)

5+) There are also many statistical assumptions factored into the prediction curves, which I won't even get into, other than to say they don't always apply.

Therefore, the 60 dBu "primary" contour is more a legal definition that a reflection of reality.

The adjacent-channel station (probably WRVO 89.9) may not have bothered WEOS before going digital, because public broadcasters tend not to process aggressively. If the peak modulation isn't constantly at 100 percent (or over), a decent receiver can provide good selectivity. However, as we've discussed many times, digital sidebands are constant and fall directly on top of the desired signal.

 

[Chuck]

I know that for example, in retail stores and in some homes they are only 2 or 3db's away from getting an HD lock. If it even ends up being 2 or 3 watts, that can be a huge difference as far as reception. I am not so much advocating anything more than that and agree that there should not be a trade off.

To be a devils advocate here though, if instead we lobied the FCC to mandate transfer to HD Radio would that really make people happier? I myself wouldn't care, I have HD Radio, but I don't think it any better to mandate people to switch and throw out their beloved analog radios.

One major problem is the decibel is a logarithmic unit of measurement. A 3 db increase in power is approximately doubling your power. It's not just two or three watts we are dealing with here. A 1000 watt digital station would need to be 2000 watts to have a 3db increase in signal strength.

As for doing a “hard cut” to digital, that isn’t going to happen any time soon. There is simply too much investment in current equipment and infrastructure. Wait until you hear the howling when (and if) analog TV is shut off in February 2009. A lot of politicians have recently woken up to the reality that a lot of their constituents are going to be royally PO’d when they discover that their analog TV’s no longer work without a converter box. I think you can watch this upcoming event and learn a lot about HD radio’s chances of ever being a digital only system.

The right thing to do is to establish a new band for digital radio. Although it is unlikely that it will happen, there is some international movement towards that direction as the reality of HD is begins to sink in. Should it happen, I’m sure Sangean will make some excellent radios that work well in that service.

 

[geostudent]

I'll give a specific example: I was in Salem OR, which is 45 miles south of Portland and about 60 north of Eugene. I was able to get a lock on a Class C2 in Portland on 94.7 while still pulling in a C1 in Eugene on 94.5. If the Eugene station were much weaker than that, most people wouldn't bother listening to it. If this is a problem at all, it doesn't appear to affect very many people.

It depends on location.. I agree that it's less likely to affect people *in FCC Zone II,* which includes OR, than where I live. The stations in the example you gave are over 100 miles apart, and the radio markets there cover much larger geographic areas than here.

I'm in southeastern PA, in Zone I, and the FM band is crowded with more Class A and B stations than anywhere else in the country. It's no surprise to me that FM IBOC adjacent channel interference would be more likely to occur here, and affect more people, than in OR (or practically anywhere else in Zone II).

 

[semoochie]

I'll try going the other direction and see if it makes a difference with a Class A in Longview WA but 94.7 protects them.

 

[MasterTheseus]

I know that for example, in retail stores and in some homes they are only 2 or 3db's away from getting an HD lock. If it even ends up being 2 or 3 watts, that can be a huge difference as far as reception. I am not so much advocating anything more than that and agree that there should not be a trade off.

To be a devils advocate here though, if instead we lobied the FCC to mandate transfer to HD Radio would that really make people happier? I myself wouldn't care, I have HD Radio, but I don't think it any better to mandate people to switch and throw out their beloved analog radios.

One major problem is the decibel is a logarithmic unit of measurement. A 3 db increase in power is approximately doubling your power. It's not just two or three watts we are dealing with here. A 1000 watt digital station would need to be 2000 watts to have a 3db increase in signal strength.

As for doing a “hard cut” to digital, that isn’t going to happen any time soon. There is simply too much investment in current equipment and infrastructure. Wait until you hear the howling when (and if) analog TV is shut off in February 2009. A lot of politicians have recently woken up to the reality that a lot of their constituents are going to be royally PO’d when they discover that their analog TV’s no longer work without a converter box. I think you can watch this upcoming event and learn a lot about HD radio’s chances of ever being a digital only system.

The right thing to do is to establish a new band for digital radio. Although it is unlikely that it will happen, there is some international movement towards that direction as the reality of HD is begins to sink in. Should it happen, I’m sure Sangean will make some excellent radios that work well in that service.

We already make several DAB digital only radios, but DAB is only really taking off in the UK. Most the rest of EU is not having such a good time from the reports of our EU offices, and reports are that more nations are seriously considering HD Radio as a more viable option.

But here is another consideration, eventually as more stations go HD Radio, for the short haul there would be more interfearance, but if we were able to then convert to the full digital side of HD Radio we could expect an improvement, right?

 

[SUPERCASTER]

I know that for example, in retail stores and in some homes they are only 2 or 3db's away from getting an HD lock. If it even ends up being 2 or 3 watts, that can be a huge difference as far as reception. I am not so much advocating anything more than that and agree that there should not be a trade off.

To be a devils advocate here though, if instead we lobied the FCC to mandate transfer to HD Radio would that really make people happier? I myself wouldn't care, I have HD Radio, but I don't think it any better to mandate people to switch and throw out their beloved analog radios.

One major problem is the decibel is a logarithmic unit of measurement. A 3 db increase in power is approximately doubling your power. It's not just two or three watts we are dealing with here. A 1000 watt digital station would need to be 2000 watts to have a 3db increase in signal strength.

As for doing a “hard cut” to digital, that isn’t going to happen any time soon. There is simply too much investment in current equipment and infrastructure. Wait until you hear the howling when (and if) analog TV is shut off in February 2009. A lot of politicians have recently woken up to the reality that a lot of their constituents are going to be royally PO’d when they discover that their analog TV’s no longer work without a converter box. I think you can watch this upcoming event and learn a lot about HD radio’s chances of ever being a digital only system.

The right thing to do is to establish a new band for digital radio. Although it is unlikely that it will happen, there is some international movement towards that direction as the reality of HD is begins to sink in. Should it happen, I’m sure Sangean will make some excellent radios that work well in that service.

We already make several DAB digital only radios, but DAB is only really taking off in the UK. Most the rest of EU is not having such a good time from the reports of our EU offices, and reports are that more nations are seriously considering HD Radio as a more viable option.

But here is another consideration, eventually as more stations go HD Radio, for the short haul there would be more interfearance, but if we were able to then convert to the full digital side of HD Radio we could expect an improvement, right?[/b]

Wrong.
With more HD stations, more power and more interference, reception will only get progressively worse. HD radio is not the "magic bullet" that supporters have been deceived into believing.

 

[Tom Wells]

No.
We could expect an improvement in sales figures for HD "radios", but not in coverage or listener satisfaction.
Less than sufficient bit recovery will still mean fallback to analog (except there won't be any) so of course reception will always be perfect.
Listeners who were accustomed to hearing radio with some noise will eventually die off and be replaced by people who never knew any better, so there won't be any problems.
Once all stations are modulating AM with square waves, the noise floor will rise to the level of a geomagnetic storm.
Remember a spark (like a square wave generator) put its energy out evenly on all frequencies from DC to light.
ibquity seemed surprised by the spectral regrowth issue. Ha ha, welcome to the world of RF modulation.

Trying to "align" such signals to fall into a "passband" is much like herding cats; they aren't really interested in being "tuned".
This will very effectively eliminate the radio-ness of radio.
We would then have streaming audio on an RF modem.
RF modems are useful for data links and other point-to-point uses, but omnidirectional broadcast is an unwise application.

Sine waves are very easy to control, tune and harness. They also allow the energy to be decoded asynchronously.
There need be no timing circuits or active reconstructing of a wave-form.
Analog radios have all the intelligence in the design so there needn't be so much complication in reception.
Let me know when they get that HD crystal-radio reference design completed.
Once HD can be demodulated by passive circuits, I'll be ready to call it radio.

 

[Black_Shire]

An HD AM crystal radio is theoretically possible. The processor chips could be powered by the RF, as is done with some crystal radios that use an RF-powered 1-transistor amplifier.

Such an HD AM receiver might work very well--within 100 yards of the transmitting tower.


-- Black Shire

 

[Chuck]

But here is another consideration, eventually as more stations go HD Radio, for the short haul there would be more interfearance, but if we were able to then convert to the full digital side of HD Radio we could expect an improvement, right?

I'd have to say, "The jury is still out on that one." My gut feeling is it won't help that much even if stations do go all digital. As others have pointed out, it may get much worse. That pessimistic outlook seems more likely if the current IBOC standard is used. That's because HD actually takes up the space formerly occupied by three analog channels. Of course, if those stations ever do go all digital, it would be entirely possible to do so within one 10 kHz analog channel allotment. That's not how HD works, but it is exactly how it should be done.

Unless the current HD radios are easily upgraded via software to work under a digital only broadcast standard, they will all become obsolete. Perhaps they already have that capability built in, but I doubt it. Because Ibiquity won't share the "secrets" about how they do this, it is hard to tell. Most likely it would simply relegate the existing HD radios you are selling right now, to the land fill. They will be there right along with your old analog radios.

It might not be too late to fix this. There are two ideas that would work. One is to take over the 26 MHz band and migrate most AM stations to it for an all-new digital only service. The other (and I think better) idea is to annex TV channel 6 (and maybe channel 5 too) for digital radio under a similar migrating plan. At the February 2009 shut down of analog TV only a hand full of stations will revert to channel 5 or 6 for digital TV. It would be cheaper to pay them to stay on their current DTV channel, and use that channel 5 & 6 spectrum for radio.

Under such a plan, existing AM stations would have 7-10 years to make the switch from analog to digital. If you aren't a super powered AM station you would be required to make the switch, but be allowed to simulcast on the new frequency as well as your old frequency until the mandated cut off date.

If you were a 50 KW powerhouse you could elect to stay on your existing AM frequency and run analog, HD or a combination of both. You wouldn’t be forced to, move, but at the changeover date, you would have to surrender one frequency or the other. This would effectively remove the graveyard stations on AM and put them on the new digital band after the mandatory shut down date. It would accomplish several things. First, it would give small broadcasters a chance to preserve whatever it is that they have, and for many, actually improve their situation at reasonable cost. Thes new digital only stations would not have to be excetionally powerful. Day timers would be allowed to run the digital channel 24 hours, so for many small stations, they could probably finance the growth through broadcasting local sports. It's easy to get sponsors for that kind of programming, and people would purchase the radios because it was something they wanted to hear. Most small station operators I’ve talked to would jump at the chance to do this.

It would also have the happy effect of cleaning up the existing AM band, making it useful again. Although I'm not a fan of "thinning the herd" since that takes someone's livelihood away, I believe that the AM band is simply too crowded for HD to work well there. Analog AM has enough trouble under the current conditions and right now, it looks like it will only get worse.

I'm sure there are several problems with these scenarios, but they seem to be a great deal less than what we are currently facing. At least, the problems are not insurmountable, if Congress and the FCC got onboard. If such a plan came to pass, IBOC could flourish on AM with the stations that are left. There would be enough space to do that. Small and medium size broadcasters and their communities would benefit from increased operating hours, better audio quality, and perhaps the ability to multi-cast. Large AM broadcasters would have greatly improved signals, because at the AM abandonment date they could increase their power levels to those necessary for the existing HD system to work well, or they could just stay analog and remove the NRSC roll off curve. They would once again sound good.

Radio manufacturers should love it, because it gives them new products to sell. The public would have the possibility of gaining more and better service for their community. Just about everyone wins. That's most likely why we aren't doing this. It would do too much to level the playing field. Business interests prefer that there are big winners and big losers. That's how the game is played.

 

[MasterTheseus]

OTA Upgrades

From what I am told the full digital transmision mode is being built into the HD Radio module and that our products from day one have supported all but I think 2 of those modes. Those last two modes are even still not official from IBiquity according to the documents filed with FCC and I know only that they are theoretical to exist and have not found any proof of such yet.

I also believe that IBiquity is expecting to use some of their data streams to provide firmware upgrades OTA. This means that as a listener listens to an HD Radio station, the station will broadcast the HD Radio firmware upgrades to the radio. This makes upgrade on the side of HD Radio easy and almost invisible to the customer.

That does not include brand specific software, but only the HD Radio software.

 

[PhilJSmith67]

I've posted several times in the past that the HD Radio specs for AM and FM are available from the FCC, but I keep seeing repetitious spew about "waaah waaah iBiquity keeps everything 'secret' about HD Radio." Apparently going to fcc.gov and typing a few keywords into a search is too challenging.

Well, now there is no excuse. Here are URLs to the specs, which have been online for five years in the same location, unencrypted, in multiple formats of your preference (text, PDF, etc.).

The "parent" Daily Digest page from 10/15/2002:
http://www.fcc.gov/Daily_Releases/Daily_Digest/2002/dd021015.html
-- Search for the only occurrence of "iBiquity" on this page

iBiquity's IBOC AM Transmission Specification (PDF):
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-286A3.pdf

iBiquity's IBOC FM Transmission Specification (PDF):
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-286A2.pdf


If you know of an updated copy of the spec, please post its location.

 

[SUPERCASTER]

I've posted several times in the past that the HD Radio specs for AM and FM are available from the FCC, but I keep seeing repetitious spew about "waaah waaah iBiquity keeps everything 'secret' about HD Radio." Apparently going to fcc.gov and typing a few keywords into a search is too challenging.

Well, now there is no excuse. Here are URLs to the specs, which have been online for five years in the same location, unencrypted, in multiple formats of your preference (text, PDF, etc.).

The "parent" Daily Digest page from 10/15/2002:
http://www.fcc.gov/Daily_Releases/Daily_Digest/2002/dd021015.html
-- Search for the only occurrence of "iBiquity" on this page

iBiquity's IBOC AM Transmission Specification (PDF):
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-286A3.pdf

iBiquity's IBOC FM Transmission Specification (PDF):
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-286A2.pdf


If you know of an updated copy of the spec, please post its location.

Note the lack of codec and receiver specifications. This is not the complete disclosure or open system promised the FCC when IBOC was proposed.

Thanks for posting another HD radio promoter "red herring". Keep it up, if you think HD radio still has any credibility left to destroy.

 

[PhilJSmith67]

I've posted several times in the past that the HD Radio specs for AM and FM are available from the FCC, but I keep seeing repetitious spew about "waaah waaah iBiquity keeps everything 'secret' about HD Radio." Apparently going to fcc.gov and typing a few keywords into a search is too challenging.

Well, now there is no excuse. Here are URLs to the specs, which have been online for five years in the same location, unencrypted, in multiple formats of your preference (text, PDF, etc.).

The "parent" Daily Digest page from 10/15/2002:
http://www.fcc.gov/Daily_Releases/Daily_Digest/2002/dd021015.html
-- Search for the only occurrence of "iBiquity" on this page

iBiquity's IBOC AM Transmission Specification (PDF):
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-286A3.pdf

iBiquity's IBOC FM Transmission Specification (PDF):
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-286A2.pdf


If you know of an updated copy of the spec, please post its location.

Note the lack of codec and receiver specifications. This is not the complete disclosure or open system promised the FCC when IBOC was proposed.

Thanks for posting another HD radio promoter "red herring". Keep it up, if you think HD radio still has any credibility left to destroy.

So, you actually look at the spec which gives full disclosure about the RF effect (actually quite damning to themselves), and call it a red herring? The discussion was about RF interference. These specs nail it. The codec and matrices used to transform the bits over the existing COFDM carriers is completely irrelevant to the discussion. If you have anything to do with RF engineering at all and don't understand this, your days in radio are numbered... Possibly in one or two digits.

I didn't post this as a promoter of HD Radio. I've even said things that have pissed off "promoters" on this site, and the funny thing was, it was a result of me reiterating the spec. I posted this as a promoter of truth -- Truth that the hollow whining about iBiquity "keeping secrets" about the impact of their system on the AM and FM bands is sadly unfounded. It's always been there, in plain view, and the FCC adopted it anyway.

I'm done. This is just too mind-numbing for even a caveman.

 

[Tom Wells]

Well, yes, this info has been out a long time, and yes, it fully described a long time ago how bad the AM would sound.

It is not my idea of full disclosure. I see no "sequencer listing" (the program), no encryption (codec) info, no schematics,
and very few block diagrams.

Block diagrams are a bad sign that something is being fudged or kept secret.
Not disclosing the program should make the deal completely unpatentable, making this aspect a trade secret.
Is the FCC permitted to authorize trade secret designs? I think not. I could be wrong here...

If there is not enough info shared for radio engineers to "roll their own", it is incomplete disclosure.
I say this from a patentability perspective....I don't know what the FCC requires for type acceptance these days, maybe just
a nice fat wad of cash.

The US Pat and Trademark Office requires a full disclosure such that "one skilled in the art" would be able to construct
a working model from the info disclosed in the patent Specification and Drawings.

Go ahead ibiquity, show us a schematic. Show us the "sequencer listing". Double dare ya.
I made a full disclosure of my invention, you probably made some phone calls.

 

[SUPERCASTER]

Tom Wells said:

It is not my idea of full disclosure. I see no "sequencer listing" (the program), no encryption (codec) info, no schematics,
and very few block diagrams.

My point exactly. Much HD radio information and specs. are still kept secret.

To Phillip J Smith:
It's clear you have misunderstood my post completely, and are off on some strange technical tangent you seem obsessed with forcing on others as what you believe to be "complete disclosure" implying HD radio is some kind of an open system, when it is not.

I still have not seen any comprehensive, independent engineering analysis of iBiquity's HD radio system except the one serialized in 5 parts by Barry McLarnon in 2005 issues of "Radio Guide".
Where can I find another?
FCC? -Nope.
Publications? -Nope.
Broadcasters? -Nope.
Manufacturers? -Nope again.

No complete disclosure of HD radio anywhere, just a few incomplete, biased, misleading, and totally self serving information releases.