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FM IBOC Power Increase Sought

K

KB1OKL

http://www.rwonline.com/dailynews/index.cgi


A group of broadcasters and equipment manufacturers now has formally asked the Federal Communications Commission to approve increasing the allowable FM IBOC digital operating power by up to 10 dB, from the current –20 dB to –10 dB.

[EDIT]

Now the excrement hits the fan.

[EDIT-post truncated because originating material is copyrighted. Unauthorized use of copyrighted content is in violation of Radio-Info's TOS.]
 
KB1OKL said:
http://www.rwonline.com/dailynews/index.cgi


A group of broadcasters and equipment manufacturers now has formally asked the Federal Communications Commission to approve increasing the allowable FM IBOC digital operating power by up to 10 dB, from the current –20 dB to –10 dB.

[EDIT]

Now the excrement hits the fan.

[EDIT-post truncated because originating material is copyrighted. Unauthorized use of copyrighted content is in violation of Radio-Info's TOS.]
Click to expand...

I would have liked to have seen the rest of your post unedited. Could KB1OKL please provide us with links to the unauthorized copyrighted content?
 
SUPERCASTER said:
I would have liked to have seen the rest of your post unedited. Could KB1OKL please provide us with links to the unauthorized copyrighted content?
Click to expand...

This is the link (posted in his original message):
http://www.rwonline.com/dailynews/index.cgi

On the same page, I note with interest (under the headline Newberry Takes NAB Radio Board Top Slot) that both the radio and TV boards of NAB decided to adopt a resolution opposing the use of Channels 5 and/or 6 for radio broadcasting.

Here we have 12 MHz of prime VHF spectrum that will become largely vacant next February, a band where existing AM stations could simulcast their digital signals and avoid the nightly IBOC skywave disaster. VHF would also be easier to incorporate into mobile phones (as discussed in the preceding article), but NAB doesn't have the foresight or common sense to investigate the Channel 5/6 proposal further.

Instead, the TV Board apparently would rather invite new applicants to file to build new stations on those channels and allow these operators to take a slice of local TV revenue.

Who can explain the logic here?
 
Play Freebird said:
Who can explain the logic here?
Click to expand...

It is just a guess, but they probably see more money in TV than they do in radio. Historically, NAB hasn't been all that helpful to radio since they produced the famous Stan Freeburg - Sarah Vaughn "Who Listens to Radio?" spots back in the 1960's.

If you ever want to understand the motivations of NAB, I suggest following the money.
 
Play Freebird said:
On the same page, I note with interest (under the headline Newberry Takes NAB Radio Board Top Slot) that both the radio and TV boards of NAB decided to adopt a resolution opposing the use of Channels 5 and/or 6 for radio broadcasting.

Here we have 12 MHz of prime VHF spectrum that will become largely vacant next February, a band where existing AM stations could simulcast their digital signals and avoid the nightly IBOC skywave disaster. VHF would also be easier to incorporate into mobile phones (as discussed in the preceding article), but NAB doesn't have the foresight or common sense to investigate the Channel 5/6 proposal further.
Click to expand...

I think a plan to add only channels 5 and 6 as radio spectrum would have some serious holes in it. In many markets it wouldn't add any available room at all. (Nashville, Memphis, Philadelphia, Albany just to name a few) While a lot of TV stations are indeed leaving these channels, some are staying.

And it's way too late to tell them to go somewhere else. At least one has already completed its channel 5 DTV facility & tested it on the air. Moving these stations would have a "domino effect", forcing other stations to move as well. It would postpone the DTV transition for at least a year and cost millions of dollars. It won't happen.

What *could* be done is to allot the entire 2-6 band for radio *on a secondary basis to DTV*. Some of this spectrum should be available pretty much everywhere.
 
I think the FCC will eventually eliminate channels 2-6 anyway. Reserving a whole band for less than 50 full-service stations is stupid. The ones that are there will quickly figure out that they made a horrible mistake when viewers start calling in with complaints because they can't see anything, or what they see is riddled with pixels and dropouts. I have first-hand experience with low-VHF digital, it's no fun. My father has almost given up on PBS, we've done pretty much everything we can and it still is useless most of the time while the UHF digitals from the same location max out the signal meter.

What happens to channels 2-6 is another story. I, too, would like an expanded FM, with daytimers and Class C AM stations being allowed to relocate to the spectrum currently used by channels 2-4, but I'm not sure it would ever actually happen.

Either way, I don't expect to see channels 2-6 sticking around.

- Trip
 
w9wi said:
What *could* be done is to allot the entire 2-6 band for radio *on a secondary basis to DTV*. Some of this spectrum should be available pretty much everywhere.
Click to expand...

My thoughts exactly. I realize it would be difficult to completely clear 5 and 6 of full service TV stations, but in almost every market where one of those channels will remain in use, the other is vacant, leaving 6 Mhz of spectrum between 76 and 88 MHz available for other uses. As I've mentioned before, there is already a precedent for shared use of Channel 6 by radio stations: FM Channel 200.

LPTVs and translators should be put on 2, 3, or 4 rather than 5 and 6. Unless the FCC steps in to prohibit abuse, many LPTV licensees will ask to move to Channel 6 so they can program their aural transmitters as "FM 87.7" and waste the remaining 5.8 MHz.
 
Regarding 54/76 through 88 MHz for radio, vis a vis HD Radio: Wouldn't these lower freqs, be undesirable for digital radio for the same reasons as they are for digital TV broadcasts, what with the skip and all?

Don't get me wrong, I'd LOVE to see them added to the FM band, though I only propose 76 MHz as the bottom as Japan-spec radios, most of which tune 76-108, could be imported immediately. Even if some markets could only use a portion of the new spectrum, it could conceivably relieve HUNDREDS of AM daytimers.
 
Skip would still be a problem, but from what I've read, FM isn't affected by impulse noise in the same way that the AM video and digital signals are. That's the biggest problem with using those for any kind of video.

- Trip
 
Chad-Stevens said:
Regarding 54/76 through 88 MHz for radio, vis a vis HD Radio: Wouldn't these lower freqs, be undesirable for digital radio for the same reasons as they are for digital TV broadcasts, what with the skip and all?

Don't get me wrong, I'd LOVE to see them added to the FM band, though I only propose 76 MHz as the bottom as Japan-spec radios, most of which tune 76-108, could be imported immediately. Even if some markets could only use a portion of the new spectrum, it could conceivably relieve HUNDREDS of AM daytimers.
Click to expand...

The way I look at it: Yes, there's skip in the VHF low-band a few days out of each year -- but in the medium wave band, skip happens every night!

As part-owner of an AM daytimer (which isn't allowed ANY night power) I would clearly prefer the VHF option over AM IBOC. Not to mention the channel width in the VHF band would be much greater, allowing for better audio quality.
 
audiophile. said:
OK THE GAME IS ON.

13 broadcasters have filed to turn the FM band into a vast wastland:

http://www.rbr.com/radio/filing_hd_radio_power_increase_broadcasters.html

http://www.rbr.com/files.php?file=Request_for_Increased_Digital_FM_Power_484952980.pdf
Click to expand...

As I suspected, this request is "piggybacked" on Docket 99-325, it is not a new Petition for Rulemaking. You see, they want to eliminate the opportunity for public comment and just push it through.

Note that this request includes Appendix A (the long list of owned FM radio stations, demonstrating how high and mighty these companies are) but where are all of the referenced test reports that were supposed to be included in Appendix B and C? I would kinda like to read them.

A- Ha! Footnote 5 explains that the test reports are being submitted directly to the FCC by iBiquity and CBS, Inc.

Sneaky!
 
 
audiophile. said:
part2: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014138

Techies: Read part 2! Barry what's your take?
Click to expand...

Thanks for the links -- you saved me a trip to search ECFS, which would have been the next step in my mission to reveal the Truth.

Part 2 kicks right off with pictures of The Mask showing apparent compliance with 73.317. But I find this statement interesting: "The IBOC analog to digital carrier ratio is shown in a resolution bandwidth of 1 kHz, far less than the total integrated power bandwidth of 140 kHz for the digital carriers." This is very important to keep in mind: it means that the digital sidebands shown in these plots were passed through a narrow (1 kHz) filter, which causes their amplitude to appear much lower relative to the FM signal than a broadcast receiver (with 150 kHz or wider IF filter) would detect when tuned to a first-adjacent channel. Therefore, you can disregard any claims of compliance with the 73.317 FM emission standards.

To paraphrase Gerald R. Ford, if Major Armstrong were alive today, he'd be turning over in his grave.
 
Chad-Stevens said:
Regarding 54/76 through 88 MHz for radio, vis a vis HD Radio: Wouldn't these lower freqs, be undesirable for digital radio for the same reasons as they are for digital TV broadcasts, what with the skip and all?
Click to expand...

Certainly 200-something MHz would probably be a better place.

But as Trip says, the noise issues that make it a bad place for DTV aren't a problem for a FM service. Skip is less of a problem for FM for two reasons:

- Because of the capture ratio effect, the skip interference has to be a LOT stronger before it bothers a radio listener, when compared to how strong it must be to generate visible interference to an analog TV signal or make digital TV reception impossible.

- FM channels are narrower, so there are more of them, so the chances that there will be a distant station on the same channel you're trying to listen to are lower.

For example, imagine there's a skip opening between Nashville and Minneapolis.

Of the five TV channels between 54-88MHz, three of them - 60% - have stations in both cities.

Of the 100 FM channels between 88-108Mhz, only seven - 7% - have stations in both cities.
 
Play Freebird said:
audiophile. said:
part2: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014138

Techies: Read part 2! Barry what's your take?
Click to expand...

Thanks for the links -- you saved me a trip to search ECFS, which would have been the next step in my mission to reveal the Truth.

Part 2 kicks right off with pictures of The Mask showing apparent compliance with 73.317. But I find this statement interesting: "The IBOC analog to digital carrier ratio is shown in a resolution bandwidth of 1 kHz, far less than the total integrated power bandwidth of 140 kHz for the digital carriers." This is very important to keep in mind: it means that the digital sidebands shown in these plots were passed through a narrow (1 kHz) filter, which causes their amplitude to appear much lower relative to the FM signal than a broadcast receiver (with 150 kHz or wider IF filter) would detect when tuned to a first-adjacent channel. Therefore, you can disregard any claims of compliance with the 73.317 FM emission standards.

To paraphrase Gerald R. Ford, if Major Armstrong were alive today, he'd be turning over in his grave.
Click to expand...

You're welcome!

Also worth noting, it ONLY states the Digital portion of the signal meets the 73.317 mask...but what about the digital + analog?

I hope the engineering community comes unglued over this.
 
audiophile. said:
Techies: Read part 2!
Click to expand...

I have...and unless I missed it completely, I see no mention of any studies done by iBiquity of adjacent-channel situations, which ought to be the undoing of this proposal. Not holding my breath waiting for that, however.
 
I agree - they should use correct filtering in their reporting - 200KHz being most typical, not a 1KHz (cw) filter.
As much as I would love to have digital coverage equal to or greater than analog service, it still might not happen, even with the additional 10dB of signal.
PLUS - assuming all of this does happen, what radio group has the coin these days to ACTUALLY spend the MONEY and dump it into A/C and transmitter accessories for this additional 10dB of FM signal? Not many, if any.
 
audiophile. said:
part1: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014135
part2: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014138
part3: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014136
part4: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014139
part5: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014137
part6: http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520014140

Techies: Read part 2! Barry what's your take?
Click to expand...

No big surprises - just the usual smoke and mirrors, and bad science. Techies should also read part 3, since it deals with (sorta, kinda) the interference issues. Part 2 tells us that a 10 dB power increase provides an improvement in digital coverage. Well, duh. What's more surprising is that there was little or no improvement in some instances. And I didn't see any definition of how they define "coverage". No tests were done using Class C stations.

No surprise too that the NRSC-5 mask would have to be bumped up by 10 dB in the 100-200 kHz region in order to accommodate the higher digital power. Although much is made of the fact that the higher power emission "fits" under the FCC mask, as we all know by now, this is irrelevant. That mask was never intended to serve as a template for a digital emission measured with a 1 kHz resolution bandwidth.

Interference tests apparently were done only using three test stations at the -10 dBc digital power, and only 1st adjacents were examined. I didn't notice any mention of 2nd adjacents, or self-interference to the host stations. Only 6 receivers were used, one of which was an HD model, and none were portables. The 1st adjacent results look odd in some cases. For example, a short-spaced situation showed a significant increase in interference with the 10 dB power increase when the D/U ratio was +6 dB, but not when it was 0 dB. Very fishy.

Lastly, it's worth noting that the tests were conducted entirely by IBOC proponents, with no unbiased observers present. Thus there was a wealth of opportunity to select contrived situations for the tests, and to selectively report the results that suited their conclusions.

I don't see the folks at NPR supporting this nonsense, though stranger things have happened, I suppose.
 
ve3jf said:
I don't see the folks at NPR supporting this nonsense, though stranger things have happened, I suppose.
Click to expand...

Speaking of "stranger things happening", now it seems that NAB is prodding the FCC to adopt the 10 dB digital power increase as a way to help LPFM stations -- which they oppose. What gives? Also, NAB apparently sees no problem with Class A stations increasing digital interference 10 dB across the board, in complete contradiction with their position on the 1980s Class A power increase petition. See the second-to-last paragraph on Page 2:

http://fjallfoss.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6520028611

Also noteworthy: "NAB recognizes that the proposed increase in power for FM IBOC broadcasts may create new instances of interference in certain situations, and notes that the recommendations made for authorization of this service include Commission action to address instances of unexpected levels of interference on a case-by-case basis." This is likely to be as successful at solving problems as the current "case-by-case" approach to AM IBOC interference.
 
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