INTERFERENCE AND PERSPECTIVE

[TheBigA]

Like someone said, above, the FCC has got to show that we're moving toward something "Digital", if only to look like broadcasters are keeping up with the times.

I think the FCC is about to show its cards in that regard, and it won't be about traditional broadcast radio. There already IS a digital system out there, and it's about to get a boost from the government:

http://www.nytimes.com/2010/03/13/business/media/13fcc.html?hp

What this means is that the focus from now on will be on the internet, and not on traditional broadcasting. There won't be re-allocation of spectrum for AM & FM.

 

[Len14043]

Kenglish, my job travel takes me to Utah often. When I take my rental car to the Ogden area, I notice that many of the FM stations suffer from severe multipath distortion despite the strength of the signals, especially in the Riverdale and South Ogden areas. I am curious as to how well HD radio performs in those areas. Also, many of the FM stations are 2 channels apart and many of them run IBOC. Does this short spacing of stations cause problems with the decoding of digital signals. I know the digital signals are interleaved, and in theory, there shouldn't be any problems with IBOC stations decoding that are 2 channels apart, but I wonder how well that works in practice. Thank you.

 

[DaveBayArea]

But in terms of FM, tolerated interference outside the protected contour is a lot older than IBOC. My old campus station, WRSU, could be heard clearly in my hometown, until another 88.7 opened up. WFMU lost central Jersey to a new station at 91.1. A discussion of IBOC interference can't be had without also dinging the short spacing that has caused stations to lose lots of coverage, too.

The examples you cite are co-channel interference, where the interference is caused by a station on the same channel. In those cases the Desired-to-Interference ratios have to be equal or negative, and the receiver has to be about 15 db more sensitive to observe interference. Most of the IBOC interference cases I've heard about and experienced are first-adjacent channel spacing issues. A modern digital radio will succumb to that easily.

So we think it's a mess. Does the FCC? No? They're the authority - change their attitude and you might get somewhere.

No doubt. Discussions on a message board have zero effect. But I have gained some significant knowledge here. I think most people have.

Dave B.

 

[audioguy]

I think the FCC is about to show its cards in that regard, and it won't be about traditional broadcast radio. There already IS a digital system out there, and it's about to get a boost from the government:

http://www.nytimes.com/2010/03/13/business/media/13fcc.html?hp

What this means is that the focus from now on will be on the internet, and not on traditional broadcasting. There won't be re-allocation of spectrum for AM & FM.

I don't necessarily agree. The FM radio spectrum is too low in frequency to be of interest for wireless broadband. The same can be said for the VHF television bands. And the AM radio band spectrum has no other identifiable use, except possibly for ham radio communications.

We should be working on getting an additional piece of VHF spectrum before it goes away forever. Let's stop playing games and quit fooling around with IBOC. We need a dedicated digital radio band if we want digital radio to be successful!

I thought one of the comments posted to the NY Times article was pretty insightful:

"As one who lived in a rural area for a long time, I can testify that the claim that the broadcast industry is needed for emergency situations is bogus. I watched as all the local stations that I could receive went from live broadcasters to canned programming piped in from national center. When we had weather or safety emergencies no information was available over the local radio stations. They perform no public service at all."

 

[TheBigA]

The FM radio spectrum is too low in frequency to be of interest for wireless broadband.

I understand that, and that's not what I'm saying.

What I'm saying is that the FCC will be focusing it's time, personnel, and energy on the internet, not AM & FM.

The FCC won't be giving AM & FM broadcasters anything, especially VHF spectrum. And they won't be spending time dealing with IBOC interference complaints.

I watched as all the local stations that I could receive went from live broadcasters to canned programming piped in from national center. When we had weather or safety emergencies no information was available over the local radio stations.

For over 40 years, the government has provided emergency weather information via their own radio service. They see their service to be the primary one with regards to weather, not one run by private radio companies. The days of local radio stations being the primary provider of emergency information ended back in 1964. Another reason why the government sees no need to devote valuable spectrum space to privately owned radio companies.

 

[BRNout]

Kenglish, my job travel takes me to Utah often. When I take my rental car to the Ogden area, I notice that many of the FM stations suffer from severe multipath distortion despite the strength of the signals, especially in the Riverdale and South Ogden areas. I am curious as to how well HD radio performs in those areas. Also, many of the FM stations are 2 channels apart and many of them run IBOC. Does this short spacing of stations cause problems with the decoding of digital signals. I know the digital signals are interleaved, and in theory, there shouldn't be any problems with IBOC stations decoding that are 2 channels apart, but I wonder how well that works in practice. Thank you.

Utah is one of the few areas where a power boost for digital may actually work well. Almost no first-adjacents to deal with and excellent line of sight reception for most areas. I could get most HD signals okay from North Ogden and all of them were pretty clear from the Salt Lake valley. BUT, I would still lose lock from time to time when walking around with my Insignia portable - even when I could literally see the Oquirrh Mountains!

Riverdale is a funny spot where the "bench" juts westward and is cut by the Weber River so you have a terrain issue in that location. But it's far from typical for the area. In most cases, the line of site to the transmitter sites is excellent from Brigham City down to the Point of the Mountain. Utah County is a different issue, but most stations have addressed that in one way or another.

Second adjacent signals would not suffer from IBOC hash because the mask only extends about 200 kHz on either side. It's the first adjacents that get hammered. Thanks to it's geographic isolation, there are few (if any) receivable first-adjacents in that region.

 

[RadeoEngineer]

Second adjacent signals would not suffer from IBOC hash because the mask only extends about 200 kHz on either side. It's the first adjacents that get hammered. Thanks to it's geographic isolation, there are few (if any) receivable first-adjacents in that region.

Not criticizing you in the least, but this statement speaks volumes about the trash that's being allowed on the FM band. "Only extends" in my days of serving the public meant a fine. What the hell is wrong with the people that are supposed to make the rules and protect the licensees from illegal operations and provide for the public interest? It's OK to now "extend" your bandwidth into a potential interference situation if you've ponied up for the Rube Goldberg almost digital solution to a nonexistent problem? If radio wasn't so irrelevant, thanks to the big boys that have taken it down, there might be a loud public outcry for the loss. OK, so I can't hear my normal station anymore because of some hissy noise on my Hyundai radio, I'll just conveniently plug in my iPod and go on down the road. Wow.

Not like I wasn't already aware of this, but BRNout's comments just set me off about it. Not your fault BRN. It's a great point.

 

[TheBigA]

What the hell is wrong with the people that are supposed to make the rules and protect the licensees from illegal operations and provide for the public interest?

It should be obvious. They don't care about broadcasting.

This is what they care about: http://www.nytimes.com/2010/03/13/business/media/13fcc.html?hp

 

[kenglish]

I just hope that the FCC plans to share that "buyout" money with the (former) employees of the stations, noy just the (former) licensees.

 

[BRNout]

Not criticizing you in the least, but this statement speaks volumes about the trash that's being allowed on the FM band. "Only extends" in my days of serving the public meant a fine. What the hell is wrong with the people that are supposed to make the rules and protect the licensees from illegal operations and provide for the public interest? It's OK to now "extend" your bandwidth into a potential interference situation if you've ponied up for the Rube Goldberg almost digital solution to a nonexistent problem? If radio wasn't so irrelevant, thanks to the big boys that have taken it down, there might be a loud public outcry for the loss. OK, so I can't hear my normal station anymore because of some hissy noise on my Hyundai radio, I'll just conveniently plug in my iPod and go on down the road. Wow.

Not like I wasn't already aware of this, but BRNout's comments just set me off about it. Not your fault BRN. It's a great point.

Dude, you absolutely took me out of context! The "only" was in reply to Len's inquiry about whether second-adjacents will be affected by sidebands (they're not). It was in that context and not in any way meant to minimize the issues that we are all aware of with IBOC.

Please re-read my rather lengthy posts above about the situation with first adjacents, in doing so you'll see that I am one of the louder complainers about this technology. I hate the way that it's been implemented. At my house, for example, I'd have much better reception of Milwaukee FM's if it weren't for the HD sidebands of my local Chicago FMs. So I get a bunch of subchannels that I'd never listen to in exchange for losing an entire second market's FM signals. Hardly a fair trade.

 

[TheBigA]

I just hope that the FCC plans to share that "buyout" money with the (former) employees of the stations, noy just the (former) licensees.

You must be joking. My cousin works for AIG...he didn't get any TARP money. Any money would go to owners, not employees. Unless the employees were also owners.

 

[gr8oldies]

The employees didn't take any risk to build or buy the station so no they would get no buyout. The FCC's doctrine at least since the 80s has been that you have no right or reason to listen to out of town signals.

 

[RadeoEngineer]

Not criticizing you in the least, but this statement speaks volumes about the trash that's being allowed on the FM band. "Only extends" in my days of serving the public meant a fine. What the hell is wrong with the people that are supposed to make the rules and protect the licensees from illegal operations and provide for the public interest? It's OK to now "extend" your bandwidth into a potential interference situation if you've ponied up for the Rube Goldberg almost digital solution to a nonexistent problem? If radio wasn't so irrelevant, thanks to the big boys that have taken it down, there might be a loud public outcry for the loss. OK, so I can't hear my normal station anymore because of some hissy noise on my Hyundai radio, I'll just conveniently plug in my iPod and go on down the road. Wow.

Not like I wasn't already aware of this, but BRNout's comments just set me off about it. Not your fault BRN. It's a great point.

Dude, you absolutely took me out of context! The "only" was in reply to Len's inquiry about whether second-adjacents will be affected by sidebands (they're not). It was in that context and not in any way meant to minimize the issues that we are all aware of with IBOC.

Please re-read my rather lengthy posts above about the situation with first adjacents, in doing so you'll see that I am one of the louder complainers about this technology. I hate the way that it's been implemented. At my house, for example, I'd have much better reception of Milwaukee FM's if it weren't for the HD sidebands of my local Chicago FMs. So I get a bunch of subchannels that I'd never listen to in exchange for losing an entire second market's FM signals. Hardly a fair trade.

BRN I'm in total agreement with you and wasn't intending to suggest you were supporting HD. Sorry if it looks like I took your comments out of context. It wasn't intended.

 

[BRNout]

BRN I'm in total agreement with you and wasn't intending to suggest you were supporting HD. Sorry if it looks like I took your comments out of context. It wasn't intended.

Good deal! Just wanted to make sure that there were no misunderstandings...

 

[kenglish]

The employees didn't take any risk to build or buy the station so no they would get no buyout.

A lot of hard working broadcast employees, many of whom gave up a lot of their own lives (as well as family time) to work years of holidays, weekends and overnights, might feel a bit differently. How about the family of the morning crew member, who has to go to bed right after dinner every night? I hope his kids give him a nice video scrapbook one day, so he can watch them growing up.

Why would their jobs be considered so easily lost? And, since the stations' owners have never owned any license, but merely "occupied" the frequency for decades, or years, or months (with an FCC License), why should they be reimbursed either? All parties have an interest, and all parties have worked to make broadcasting a business. Now, Congress wants to shut an industry down, so people can play on Facebook (even though the Commish did use all the right feel-good words, like "children" and "safety" and "empower").

 

[TheBigA]

A lot of hard working broadcast employees, many of whom gave up a lot of their own lives (as well as family time) to work years of holidays, weekends and overnights, might feel a bit differently. How about the family of the morning crew member, who has to go to bed right after dinner every night? I hope his kids give him a nice video scrapbook one day, so he can watch them growing up.

No one working in any industry should ever forfeit their personal life for work. To hold that over the head of an employer is simply unfair. If you choose to do mornings (and I always avoided it) that's the price you pay. But you knew it when you accepted the job. Unless you have a "sweat equity" program in your job (and some do), just saying you gave up personal time for your job means nothing to the government or a court of law. I doubt that you could write the time off for a tax refund either. So don't do it. If work doesn't get done because the employee was on scheduled personal time, that is the employer's problem.

 

[Tom Wells]

A lot of hard working broadcast employees, many of whom gave up a lot of their own lives (as well as family time) to work years of holidays, weekends and overnights, might feel a bit differently. How about the family of the morning crew member, who has to go to bed right after dinner every night? I hope his kids give him a nice video scrapbook one day, so he can watch them growing up.

No one working in any industry should ever forfeit their personal life for work. To hold that over the head of an employer is simply unfair. If you choose to do mornings (and I always avoided it) that's the price you pay. But you knew it when you accepted the job. Unless you have a "sweat equity" program in your job (and some do), just saying you gave up personal time for your job means nothing to the government or a court of law. I doubt that you could write the time off for a tax refund either. So don't do it. If work doesn't get done because the employee was on scheduled personal time, that is the employer's problem.

What? Since 1988, My employment has been in way or another totally dependent on my willingness to forfeit personal time.
For 20 years that meant being on the road, at which point family is a distant concept, while I pretend to enjoy being stuck
in Sleepy Eye Minnesota or suburban Cleaveland.
In order to earn the 55 hours of pay I had to invest about 100 hours, door-to-door, away from the family.
That's a pretty good deal to get your employee's time at a 50% rate, don't you think?

Now the last 10 months, I'm on a continuous 7-day a week schedule on midnights, because that's what was available.
If I'm alive, I'm expected to be at work. Never mind any labor laws, I'm considered a "key employee" necessary for the
safety and operation of the business, and exempt from getting scheduled time off.
I must pray for business slowdowns to get a day off, or get 2 others also working 7s to work 12 hour days in my absence.
Industry is not willing to pay a good wage unless it is in some sort of creatively opressive position where the efficiency approches
that of a machine.

How exactly do you think corporations would work if they did not find efficiencies such as these to exploit?
I cannot imagine meaningfully gainful employment that does not require some equal level of time "donation", because
that is all I've ever known.

Please, tell us how industry and corporations would be profitable enough if they did not enjoy the advantage of employees'
willingness to forfeit personal time?
That's the ONLY way to earn a higher wage than a regular punch-the-clock job, for most people in my position.

"Scheduled Personal Time?"
Even speaking that phrase out loud at my employer would get me branded as some kind of union-organizer fringe loony.
Such a concept does not exist, even discussing it would be like declaring yourself a troublemaker.

 

[TheBigA]

Please, tell us how industry and corporations would be profitable enough if they did not enjoy the advantage of employees' willingness to forfeit personal time?
That's the ONLY way to earn a higher wage than a regular punch-the-clock job, for most people in my position.

If you feel you're getting something out of it, that's fine. But if the company you work for ends up in bankruptcy, all the time you put in won't matter to the judge. You need to know and understand that.

And it's not to their advantage to allow you to kill yourself by over-work. Because if you turn up dead, they'll be forced to replace you, and that will be harder for them than simply giving you the time off. I had that discussion with my employer once, and they agreed.

 

[jhardis]

the criteria for spurious radiation (part 73.317) was based on the capabilities of early FM transmitters.

The state-of-the-art in 1959, to be precise.

Now comes IBOC. At first the -20 dbc injection level was purported to meet this mask. In most cases it did. Just barely.

In most cases it didn't. Just barely.

No one has ever been able to explain to me how -20 dBc is less than -25 dBc. The fact is, it's 5 dBc greater, and always will be.

If you go back and look at iBiquity's (then, USADR's) Petition for Rulemaking in 1998 they got the matter right. What they asked for then was to apply § 73.317 only for transmitters in an analog-only mode. For digital broadcasting, they proposed adoption of a new mask, specified as -40 dBc/kHz -- which is almost the same thing as -20 dBc.

§ 73.317 does not bind the Commission in how much digital power they might allow. That's the concern of § 73.404. The thing that makes me cry is when both the petitioners and the Commission (Media Bureau) say that § 73.317 is satisfied too. No -- it isn't.

Ibiquity's argument to the FCC now is that the spurious emission should be measured with a spectrum analyzer set to a 1 kHz bandwidth. Of course, this is voodoo science because there isn't an FM IF anywhere that is 1 kHz wide.

What's actually going on is that they are claiming that they are meeting the § 73.317 mask because each individual 1 kHz slice of spectrum has a power of -40 dBc, which is below -25 dBc. Okay. My fantasy is that some brave analog broadcaster is going to turn up his power knob to maximum, and when the inspector comes around he'll demonstrate that he's within his authorized power in each 1 kHz slice of his authorized spectrum separately. Let's see how far this argument really goes!

- Jonathan

 

[DaveBayArea]

No one has ever been able to explain to me how -20 dBc is less than -25 dBc. The fact is, it's 5 dBc greater, and always will be.

Agreed on all points, Jonathan. Except don't forget that the -20 is 1/2 above the FM carrier and 1/2 below. So that makes it -23 for purposes of this measurement. In addition some of the digital carriers are less than 120 KHz away from the assigned frequency. So if the transmitter is VERY free from intermod the original HD spec appears to be legal. It's just that radio receivers and transmitters have long since surpassed the capabilities of that old rule, so listeners got used to better performance.

Dave B.