Second Adjacent Chaos for HD Radio

[Shiny Knob]

There seems to be almost no talk about this major technical problem for HD Radio. It's real and it's going to get nasty.

A lot of markets have multiple move-in stations on channels that are second adjacents to local stations. Many of these second adjacent stations have fairly substantial signals, even if they're rim-shots.

For example, in Seattle, KFMY has recently relocated to the mountains west of Seattle. At 97.7, it's second adjacent to both 97.3 KIRO and 98.1 KING, both of which are on a mountain east of town. All three are Class C stations and all three have 80dbu or better signals over downtown Seattle. The Longley-Rice study shows the KFMY signal in Seattle is well above the FCC predicted level because of the high transmitter site and a favorable lay of the land. In fact, because of unfavorable terrain between downtown and the east side, the KFMY drop-in signal may be stronger than KIRO and KING in much of downtown Seattle.

The HD radio signal is found in the spectrum that is the first adjacent channel above and below the analog channel, 97.3 KIRO has its upper HD signal at 97.5. 97.7 KFMY's lower HD signal would also be at 97.5. KFMY will have to duke it out with KIRO for the HD radio to lock on at 97.5.

Similarly, 98.1 KING's lower HD signal is at 97.9, same spot as KFMY's upper HD signal. The result will not be pretty for KFMY, since both of its HD carriers will be clobbered by a neighboring HD signal.

KFMY has not yet started HD broadcasting. With luck, KIRO and KING will be able to limp along with the HD signal on the non-adjacent channel. But with the loss of one of their two HD streams, they would both lose the bandwidth redundancy that supposedly helps reduce HD fade caused by multipath.

This scenario is far from an isolated case. It will be repeated in markets across the country, wherever an FM drop-in has a good signal on a second adjacent and the band is already spaced with locals every fourth channel, as most urban areas are. The more evenly matched the drop-ins are to the local station, the worse the HD interference will be.

This will be an issue whether the FCC approves a 10 dB increase in HD levels or not. The rim-shots will get the same HD power increase as the local station.

This particularly large free-range chicken will come home to roost as more FM stations add HD signals.


-The Knob

 

[Savage]

Prescisely, shiny, and exactly what I have been saying in this forum ever since the 10db digital increase was proposed for HD-FM.

Now, we're not talking about skywave injury to given-up-for-dead or ignored AM properties. We're talking about FM move-ins which currently are worth millions, and once they can't be heard any more reliably thanks for adjacent-channel HD noise, will be worth precisely nothing.

That's why I've been saying: unleash the noise. If 10db doesn't improve signal penetration (and it won't) let 'em crank it up to 20db. Watch the lawsuits fly. THAT'S what will end the nasty, brutish and brief experiment known as HD Radio.

 

[Chuck]

Several months ago in Radio World, there was an illustration of this problem using the DFW market, as an example. It was on the front page of the magazine, which is a little hard to miss. Didn’t anyone in radio read it? As I recall the example of two close spaced competing signals wiped out something like 1.5 million potential listeners. That can hardly be called an insignificant problem. I'm amazed that the article did not cause more of an uproar.

Keep in mind that this was just a single example involving just two stations in the DFW market. I think there are in the vicinity of 60 receivable FM signals in the area; many of them rim shots that have moved in from afar. If they all lit up with increased power HD, I think you'd really see the fur fly.

Predicting this interference problem should no longer be rocket science. My own personal observation is that Longley-Rice Predictions are remarkably accurate. It seems to me like it would be a good idea to calculate this on paper (or computer) rather than actually fire up a 10 db power increase and "see what happens."

 

[ajc_trw]

There seems to be almost no talk about this major technical problem for HD Radio. It's real and it's going to get nasty.

A lot of markets have multiple move-in stations on channels that are second adjacents to local stations. Many of these second adjacent stations have fairly substantial signals, even if they're rim-shots.

Philadelphia has exactly this with 93.3 (WMMR) and 94.1 (WYSP) surrounding Wilmington, DE 93.7 (The River). All three are HD and I'm sure share the same coverage area (Philly Metro). All 3 are receivable no problem down to Dover.

If this problem is going to rear it's ugly head in a big way it will be in Los Angeles. I'd lived there my entire adult life (now in Dover, DE) and I'm very sure virtually every even channel from 222 thru 300 is occupied and receivable in the LA/OC area.

HD: Huge Disaster. When will we discover (Eureka) this mistake?

 

[clouseau]

There seems to be almost no talk about this major technical problem for HD Radio. It's real and it's going to get nasty.

Philadelphia has exactly this with 93.3 (WMMR) and 94.1 (WYSP) surrounding Wilmington, DE 93.7 (The River). All three are HD and I'm sure share the same coverage area (Philly Metro). All 3 are receivable no problem down to Dover.

A good question. This scenario is as described. Now I"M inclined to put on my Clarabelle hat and ask... WHERE'S THE BEEF? This situation exists today at the current HD level. WSTW reaches all the way into Philly. Wysp is running KYW on their HD-2 which I see posts indicating they have a few listeners. I'd like to quote the posts from the Philly board of where this causes a problem... except I don't see any. I am inclined to think this could be an issue...

But WHERE'S THE BEEF?

Philly, Dallas, Houston, do we have a problem? Has anyone actually seen this issue? Anyone... Bueller?

Clouseau

 

[Savage]

Ahem. Mr. Stein? I'm not Bueller, but I can answer! Call on ME!

In an irony-rich situation IBOC drum-beaters Crawford used to have really good penetration of the western suburbs of Rochester with their 80-90 Class A on 102.7. As the original Clouseau said, "not-enny-meure" since grandfathered Class C 102.5 from Buffalo started walloping them with USB HD. If 10db digital is added Crawford can kiss much of their metro coverage - which they are suddenly having a considerable amount of success with an oldies format, BTW - buh-bye.

As much as I don't want to see an AM-HD style mess afflicting the FM band, I confess it would be fun to reciprocally pontificate to Cris Alexander and his furry friends about how their suddenly-worthless Rochester FM "really isn't entitled to coverage" outside their COL of Webster, NY, on the northeastern fringe of the metro. Allow me to quote Tom Ray, who piously lectured us "a lot of stations think their coverage areas are a lot bigger than they actually are."

I got a big hearty belly-laugh at Tom's piteous bleating on this board about how big mean old nasty Cuban stations are obliterating WOR's nighttime coverage and the FCC....well, dang it, they and the State Department JUST WON'T DO ANYTHING ABOUT IT! Wah, wah, wahhh.....Mr. Ray is already reaping a little of what he's sown.

 

[Play Freebird]

In an irony-rich situation IBOC drum-beaters Crawford used to have really good penetration of the western suburbs of Rochester with their 80-90 Class A on 102.7. As the original Clouseau said, "not-enny-meure" since grandfathered Class C 102.5 from Buffalo started walloping them with USB HD. If 10db digital is added Crawford can kiss much of their metro coverage - which they are suddenly having a considerable amount of success with an oldies format, BTW - buh-bye.

As much as I don't want to see an AM-HD style mess afflicting the FM band, I confess it would be fun to reciprocally pontificate to Cris Alexander and his furry friends about how their suddenly-worthless Rochester FM "really isn't entitled to coverage" outside their COL of Webster, NY, on the northeastern fringe of the metro.

It seems the Crawford guys might be getting tired of beating the IBOC drum. Take a look at their latest newsletter -- most of the market engineers don't even mention it, and of the two who do, they aren't really happy.

Even Cris says the company has to start watching capital expenditures. Makes perfect sense to eliminate those with zero ROI:

http://www.crawfordbroadcasting.com/~cbc/Local_Oscillator/December 2008 Local Oscillator.pdf

 

[audioguy]

I got a big lecture in the pages of Radio World a couple of years ago from the great Chris Alexander about how I wasn't entitled to be able to listen to my 400W local AM station at a distance of 10 miles from the transmitter. They are being interfered with in the morning and late afternoon hours by the 50kW adjacent channel station on 1530 running IBOC. Cris used a fancy legal term for coverage that a station isn't legally entitled to that I can't remember. Perhaps someone on here does.

Anyway, I still think it's a crock that high powered AM stations that don't even care about skywave coverage (by their own admission) are allowed to knock out local radio for hundreds or even thousands of miles on AM. Why should we allow the FM band to be degraded in a similar manner? The big Class C's will run roughshod over suburban and rural Class A's. I've already lost reception of several stations in the car at the 1% level.

 

[clouseau]

Ahem. Mr. Stein? I'm not Bueller, but I can answer! Call on ME!

In an irony-rich situation IBOC drum-beaters Crawford used to have really good penetration of the western suburbs of Rochester with their 80-90 Class A on 102.7. As the original Clouseau said, "not-enny-meure" since grandfathered Class C 102.5 from Buffalo started walloping them with USB HD. If 10db digital is added Crawford can kiss much of their metro coverage - which they are suddenly having a considerable amount of success with an oldies format, BTW - buh-bye.

I hate to even say this, but 102.7 should never have been allowed under the circumstances. 102.5 is more than double standard power and more than double the height. I can see 102.7 deosn't need top protect them (Although Not really), but 102.5 has unallowable overlapfrom their 54 to 102.7's 60. And obviously 102.7's site on the other side of town shooting back to Webster is an attempt to not have the null pooint over Rochester. This is one of the worst examples of how these grandfathered stations are a problem. To license it correctly, it would be a C-0 and even then it's 10KW over power. Not to mention protected out to 54db. Only not so because it grandfathered. I suspect 102.7 has issues with 102.5 before HD.

Oh Well.

 

[Savage]

Suspect what you will down there on the Gulf, Inspector. Up here in the real world of snow-and-vacant houses, 102.7 didn't have a problem with 102.5 pre-HD. Now it does. And my point is, a profitable and successful station's gonna get checked into the boards by a 10db digital increase.

Whether 102.5 should have been grandfathered at 100kw or not, or whether 102.7 should have been authorized, are beside the point. They're licensed stations which should get protection according to their licenses.

"HD Radio" is not an excuse for the Table Of Allocations and useful service contours to go out the window on an ad-hoc basis. Either the FCC's allocation scheme works, or it does not.

Once again, an HD proponent proposes that there be a "special" set of rules for HD. And once again, when I successfully respond to a challenge to provide a real-world example of harmful adjacent-channel interference, the challenger changes the subject.

 

[fybush]

I hate to even say this, but 102.7 should never have been allowed under the circumstances. 102.5 is more than double standard power and more than double the height. I can see 102.7 deosn't need top protect them (Although Not really), but 102.5 has unallowable overlapfrom their 54 to 102.7's 60. And obviously 102.7's site on the other side of town shooting back to Webster is an attempt to not have the null pooint over Rochester. This is one of the worst examples of how these grandfathered stations are a problem. To license it correctly, it would be a C-0 and even then it's 10KW over power. Not to mention protected out to 54db. Only not so because it grandfathered. I suspect 102.7 has issues with 102.5 before HD.

That it did, Inspector. When Crawford put then-WDCZ on the air (I want to say it was 1993-ish), it was from the WBEE site in Penfield, which makes sense for a Webster-licensed station. But the sheer distance from Five Mile Line Road across to the west side of town led to problems with first-adjacent interference from Buffalo (which used to put a killer signal over Brighton when I was growing up - I listened to BEN-FM as much as, if not more than, PXY and MJQ.)

So Crawford moved 102.7 across town to the WRMM tower on Colfax Street around 1996. From there. it's a directional signal with a fairly mild null (32% of 6 kW, or 1920 watts) in the direction of Buffalo. In practice, my experience has been the combination of the west-side site and the fairly mild null gives 102.7 decent coverage of almost all of Monroe County, with some weaknesses out Churchville way. (It falls apart completely in Genesee County, as would be expected.)

And 102.7's IBOC is loud enough that it wipes 102.5's analog completely here in Brighton. (The IBOC from 102.3 in Cdga doesn't help matters any.)

I agree with Clouseau in principle that 102.7 should probably never have been allocated here in the first place - that channel probably should have gone to WMHR in Syracuse, with Rochester on 102.9 as a B or B1 - but in practice, it actually doesn't work out all that badly. Crawford gets its Monroe County coverage (and would do so even in the unlikely event Buffalo got a 10 dB increase), and I've seen no evidence that the former WBEN-FM has lost any of its in-market coverage, nor that it cares much (at all?) about losing its coverage over here in Rochester.

 

[fybush]

Whether 102.5 should have been grandfathered at 100kw or not, or whether 102.7 should have been authorized, are beside the point. They're licensed stations which should get protection according to their licenses.

Which they do. Buffalo is licensed as a class B facility and protected accordingly, and I've heard no complaints from the west about incursions into WTSS' coverage from 102.7's IBOC. It probably helps that Genesee County, where the real interplay between the two stations exists, is in Arbitron's Rochester market, not Buffalo. (At least I think it is this week.)

102.7 has never had meaningful coverage to the southwest of Rochester. It wasn't usable in Batavia when it was a nondirectional A from Penfield (1993-1996), it wasn't usable in Batavia when it was a directional A from Colfax Street in the all-analog era (1996-2005ish), and it's not usable now.

And look, Crawford knew what it was getting into when it put 102.7 on the air. An A that's shoehorned in first-adjacent to a grandfathered superpower B is never going to enjoy the full-market coverage of an A on a better channel. If Crawford really wanted the full-market coverage that only a B will provide, it's had opportunities to acquire several of them (or, for that matter, additional As to supplement the 102.7 coverage) and has chosen to hold steady with what it already has.

"HD Radio" is not an excuse for the Table Of Allocations and useful service contours to go out the window on an ad-hoc basis. Either the FCC's allocation scheme works, or it does not.

Once again, an HD proponent proposes that there be a "special" set of rules for HD. And once again, when I successfully respond to a challenge to provide a real-world example of harmful adjacent-channel interference, the challenger changes the subject.

I guess I'm less convinced than Bob that WLGZ is really suffering all that much - but then I live in a much more favorable location for WLGZ reception than he does, and I suspect neither of us spends that much time in Churchville or Brockport to be able to say authoritatively that the 102.7 signal is worse now than it was a couple of years ago.

If anything, given the crowded nature of the FM dial up here, I think I'd still pick the 102.7 signal over many of the other class As in the market, given the choice - Fickle suffers tremendous on-channel interference from the 93.3 over in Cobourg, Zone is often unlistenable in Brockport because of co-channel CBL-FM, Sunny 102.3 gets taken out by the 102.1 in Albion and the 102.3 in Cobourg, and on and on.

Particularly given the slim odds that Entercom, if given the chance, would want to make the significant financial investment that would be required to upgrade 102.5's plant to put out 10.5 kW of IBOC, rather than the present 1050 watts, I'm not sure I'd rank "high-powered IBOC adjacent-channel interference" at the top of a hypothetical list of things I'd be worried about if I were WLGZ.

(One more note here on that topic - even if the FCC is happy to authorize 10.5 kW of white noise from a tall tower in Colden on 102.3 and 102.7, might Canada have something to say about it? The Canadians - no slouches themselves when it comes to jam-packing an FM dial to make out-of-market listening but a fond memory - have 102.3s on the air in London and Cobourg, not to mention a fairly powerful 102.9 just 35 miles or so away in Hamilton.)

 

[clouseau]

"HD Radio" is not an excuse for the Table Of Allocations and useful service contours to go out the window on an ad-hoc basis. Either the FCC's allocation scheme works, or it does not.

I would agree with you, Bob. However we now have an issue PRECISELY because of the bastardizing of the already too tight spacing rules in the northeast several years ago. RIGHT NOW, actual Violations of spacing rules exist in the example you cited. I guess they don't count since their not HD, right?

You are actually proposing rewriting the rules. 102.5's HD Carrier is fully spaced NOW. At 1.1KW. Well under the 40 DBU limit. Should the entire 10 DB be allowed it could cause an isolated probblem in this situation. They could almost double the HD power and be legal with todays analog rules. You do know the stations are not legal NOW with today's analog rules, right? Where's the outrage there? The proposed rules supported by the NAB (or at least their comments) call for special treatment in the isolated situation where this can happen.

The whole thing kind of depends on which set of violations you don't like, doesn't it?

I think I'll just let the next paragraph I wrote not see the light of the board. But, frankly, we all don't have a problem bending those rules at the time when it benefits us.

I plead guilty. Ever happen to you?

Once again, an HD proponent proposes that there be a "special" set of rules for HD. And once again, when I successfully respond to a challenge to provide a real-world example of harmful adjacent-channel interference, the challenger changes the subject.

Well congrats. I'm sure you've illustrated your point to your satisfaction. I'm not changing the topic. This interference situation is not HD based. IT IS THERE NOW. Now you can claim it's not, but according to you, I'm the one looking for "Special" treatment. How about when they built the station. Their "Special treatment" doesn't count?

102.5 can almost double their HD power and meet todays co channel spacing. Something that their first adjacent analog does not do NOW.

I guess interference you don't like only happens when it's caused by HD.

Clouseau

 

[Savage]

With respect, Clouseau and Scott, the issue I was debating was not the validity of the current FCC allocations table, nor was it whether WLGZ 102.7 has now or has had in the past, coverage problems because of 102.5 in Buffalo. Or vice versa.

I was positing what would be likely to happen to this station if the tenfold increase in digital power were implemented by 102.5.

I'm sure Crawford has known "what it was getting into" when it built both the original NDA and more recent DA facilities for 102.7. My point is: if 10db FM digital is okayed Crawford will be unfairly hurt by a unilateral move to "benefit" 102.5 (debatable) at their expense, with no compensation. They sure didn't "know" THAT was going to happen. This is the HD scenario, all to often. Innocents get screwed for the sake of a highly dubious "improvement."

As far as "whether 102.7 should have been allocated in the first place," that's a subject for another board and another time. It's also irrelevant to the issue of HD Radio.

 

[fybush]

I'm sure Crawford has known "what it was getting into" when it built both the original NDA and more recent DA facilities for 102.7. My point is: if 10db FM digital is okayed Crawford will be unfairly hurt by a unilateral move to "benefit" 102.5 (debatable) at their expense, with no compensation. They sure didn't "know" THAT was going to happen. This is the HD scenario, all to often. Innocents get screwed for the sake of a highly dubious "improvement."

Seems to me it's actually something of a mutually assured destruction scenario - while Entercom might or might not want to bother with the expense of bumping Star's HD up to 10.5 kW, Crawford may well think it's worth the expense of upping the HD signal on Legends from 60 to 600 watts - and 600 watts, right on Star's 102.5 channel, may well wreak havoc with the Buffalo signal in places like northeastern Erie County if conditions are right.

As far as "whether 102.7 should have been allocated in the first place," that's a subject for another board and another time. It's also irrelevant to the issue of HD Radio.

Disagree, strongly - as do many (if not most) of the commenters in the rulemaking proceeding. The adoption of HD has to be seen in the context of the existing allocations scheme, as does the viability of the power increase.

The issue of grandfathered superpower stations and HD is nothing new. Ask the nice folks at WHMI in Howell, Michigan, who have suffered for years because they're on 93.5, first-adjacent to mega-superpower WBCT (320 kW ERP) in Grand Rapids. Early on, they asked the FCC for a ruling that would have limited grandfathered stations to running their HD carriers at - but not above - the class maximum. They're already getting hammered by 3.2 kW of IBOC noise on their channel from Grand Rapids, and if the 10 dB increase is approved and implemented, they'd have a whopping 32 kW on their channel.

I don't think you can separate the HD issue from the overall allocations picture. If we were having this discussion in 1983 instead of 2008, there would be no 102.7A in Webster, and no interference issue with added sideband power at 102.5B in Buffalo. (But there also wouldn't have been the possibility of putting 93.3A in Avon, which might have changed Bob's life along the way...)

The problem is, FM HD got shoehorned in there without explicit discussion of signal protection or allocations standards, so there was never any real decisionmaking about what to do in a situation like our 102.5/102.7 (or 102.7 vs. WMHR on 102.9, or...)

 

[clouseau]

Man, where to start with this one.

I would suspect that grandfathered analog stations do not get coomparable grandfathered DIGITAL facilities. Frankly, I've never seen it addressed, but I'd suspect 102.5 would be limited to digital based on it's PROTECTED analog which would be 5KW at 150. Not 11KW at 355. BIG DIFFERENCE. In fact, it makes the interference predicted to basically be at allowable levels. aka 40dbu. The area of overlap is a couple of km at the most. No problem.

The more I look at this 102.7 scenario in analog, the less sense it makes. 102.7 has moved west to become MORE short spaced to 102.5 than it is allocated. (The Allocation actually works, the license does not.) 102.7 has moved 19KM WEST of it's original tower which was just west of Webster. With a 16 KM City grade contour, it does NOT have city grade coverage of it's COL. So it's short spaced to Buffalo, Doesn't cover it's COL with city grade and had to go directional to boot.

As I see the increase, we gotta have rules based on the allowable distances. In theory, FM radio is calculatable with distance alone. Bob, you should see this as clearly as anyone. If they hadn't revised spacing, your 24 hour AM would never have seen the light of day. And that would be too bad.

Scott pointed out how he believes overall allocation and HD are really intertwined. I agree "I Think". From an FCC standpoint, FM licensing isn't AM licensing. If you're not dealing with 73.215, FM is straight milage. Quick. Dirty. Easy. Anyone on the internet can file an acceptable application using nothing more than FCC.gov. That's the methodology in proctice for FM today. LPTV as well. What they are chasing at the portals is how to overlay HD on the existing structure. And if you were to sit down and actually work with the database, the existing HD levels are easily accomadated on FM. Ands the more I work with it, the more it looks like the 10db works as well. At least most of the time.

Like AM, they will need to look at specific exceptions on FM (Like this one) to see if they need modification. I can certainly see your reluctance to believe that will happen based on your experience with AM, though.

Clouseau

 

[fybush]

I would suspect that grandfathered analog stations do not get coomparable grandfathered DIGITAL facilities. Frankly, I've never seen it addressed, but I'd suspect 102.5 would be limited to digital based on it's PROTECTED analog which would be 5KW at 150. Not 11KW at 355. BIG DIFFERENCE. In fact, it makes the interference predicted to basically be at allowable levels. aka 40dbu. The area of overlap is a couple of km at the most. No problem.

Yes, problem...because as I noted earlier in my discussion of WHMI and WBCT in Michigan, the FCC explicitly rejected a request that it limit digital powers based on class maxima. As a 320 kW grandfathered super-B, WBCT can - and does, AFAIK - run 3.2 kW of digital, not the 500 watts it would otherwise get. And I'm pretty sure, based on how well it covers WLGZ in Genesee County, that WTSS is running 1.1 kW of digital, not 500 watts (which, adjusted for HAAT, would be even lower.)

The more I look at this 102.7 scenario in analog, the less sense it makes. 102.7 has moved west to become MORE short spaced to 102.5 than it is allocated. (The Allocation actually works, the license does not.) 102.7 has moved 19KM WEST of it's original tower which was just west of Webster. With a 16 KM City grade contour, it does NOT have city grade coverage of it's COL. So it's short spaced to Buffalo, Doesn't cover it's COL with city grade and had to go directional to boot.

It actually did make a bit of sense at the time, and still does. Think D/U ratios - with the tower in Penfield, the 102.7 signal was centered over eastern Monroe County, where the 102.5 signal was already much weaker than out west. By moving 102.7 to Colfax Street, the 60 dBu contour was centered right over the heart of the market's population.

In Brockport, WLGZ is now predicted to deliver 59.3 dBu, against 58.6 dBu for WTSS. A decent radio ought to have a fighting shot at a clean 102.7 in that scenario. But WFKL, another A at the exact same location as the "original" 102.7, delivers only 55.2 dBu.

Not dramatic enough? Let's plug in zip 14624 (Gates) - v-soft.com tells me WLGZ delivers 72.8 dBu, against 55.2 dBu from Buffalo. WFKL clocks in with 64.8 dBu, still respectable, but I'll take a 17 dB D/U ratio over 10 dB any day of the week.

(For what it's worth, v-soft predicts 70.3 dBu for WLGZ at the "new" site over Webster's 14580 zip code; I suspect they used a Longley-Rice study to make the case for covering all of Webster after the move.)

And yes, things go to seed as soon as you head west on 490 - in Churchville, WTSS delivers just over 60 dBu, while WLGZ offers just 54.8 dBu, deep in its null...but that's not significantly worse than the 56.5 dBu WFKL delivers there.

So in effect, 102.7 traded a little Wayne County coverage for much more "oomph" over the middle of the city and the west side, where it needed the extra juice to overcome a stronger Buffalo signal. I think I'd have done the same, if it were my signal.

(And remember, this is a signal that was never going to be full-market no matter what you do with it. Down Bob's way in northern Livingston County, where WTSS delivers just over 60 dBu, neither the old or the new site put much over 50 dBu of 102.7 into WYSL-land.)

Scott pointed out how he believes overall allocation and HD are really intertwined. I agree "I Think". From an FCC standpoint, FM licensing isn't AM licensing. If you're not dealing with 73.215, FM is straight milage. Quick. Dirty. Easy. Anyone on the internet can file an acceptable application using nothing more than FCC.gov. That's the methodology in proctice for FM today. LPTV as well. What they are chasing at the portals is how to overlay HD on the existing structure. And if you were to sit down and actually work with the database, the existing HD levels are easily accomadated on FM. Ands the more I work with it, the more it looks like the 10db works as well. At least most of the time.

Like AM, they will need to look at specific exceptions on FM (Like this one) to see if they need modification. I can certainly see your reluctance to believe that will happen based on your experience with AM, though.

No argument there!

This is where it will be very interesting to see how the FCC comes down on the 10 dB rulemaking. If you read through the comments (and there weren't that many of them), pretty much NOBODY but the "Joint Parties" was in favor of 10 dB across the board. The near-consensus, aside from the diehard HD haters who argued against any increase, was that the solution falls somewhere in between, using contour protection or mileage tables to determine which stations should be eligible for a digital power increase, and how much.

That makes sense to me, too, but of course the devil is in the details.

At least a set of protected contours or mileage separations would establish a black-and-white definition of what constitutes interference, which is more than they've done for afflicted AM stations. (Not that that helps Bob at this point, alas.)

 

[W2JUV_AL]

This thread has been quite interesting, but so far the discussion has mostly about more HD interference to analog if HD power goes up 10dB. Maybe this is a silly question, but could the power boost also add interference to HD signals as well? Case in point; a 100kW grandfathered B on 94.5 in Syracuse vs. a class B on 94.9 in Utica, 55 miles separation. I live about half way in between and receive city-grade analog on both. If both pump out white noise on 94.7, which HD signal wins that battle? Probably the same scenario with 104.3 (100kW-Utica) and 104.7 (50kW-B) from Syracuse.

 

[clouseau]

It actually did make a bit of sense at the time, and still does. Think D/U ratios - with the tower in Penfield, the 102.7 signal was centered over eastern Monroe County, where the 102.5 signal was already much weaker than out west. By moving 102.7 to Colfax Street, the 60 dBu contour was centered right over the heart of the market's population.

I understand why they wanted to move, I just don't understand why it was allowed. Apparently there is a good deal more consideration given to covering the big city than I have seen elsewhere. We have a guy down here who has been trying to move in to Corous Christi for almost 10 years, now. An easy way out is Longley Rice community coverage to where he's leaving. No go with the Commish. Circustances may be different, I guess. Doesn't look like it.

In Brockport, WLGZ is now predicted to deliver 59.3 dBu, against 58.6 dBu for WTSS. A decent radio ought to have a fighting shot at a clean 102.7 in that scenario.

Uh... I guess. 59.3 is "Non service" and adjacent 58.6 would have to be down at 54 to be within existing rules.

But WFKL, another A at the exact same location as the "original" 102.7, delivers only 55.2 dBu.

Not dramatic enough? Let's plug in zip 14624 (Gates) - v-soft.com tells me WLGZ delivers 72.8 dBu, against 55.2 dBu from Buffalo. WFKL clocks in with 64.8 dBu, still respectable, but I'll take a 17 dB D/U ratio over 10 dB any day of the week.

No argument that it will deliver better signal in carious areas. However I hthought they were to serve Webster first. (Sorry I just spit Diet Pepsi on my screen when I reread that )

(For what it's worth, v-soft predicts 70.3 dBu for WLGZ at the "new" site over Webster's 14580 zip code; I suspect they used a Longley-Rice study to make the case for covering all of Webster after the move.)

And yes, things go to seed as soon as you head west on 490 - in Churchville, WTSS delivers just over 60 dBu, while WLGZ offers just 54.8 dBu, deep in its null...but that's not significantly worse than the 56.5 dBu WFKL delivers there.

So in effect, 102.7 traded a little Wayne County coverage for much more "oomph" over the middle of the city and the west side, where it needed the extra juice to overcome a stronger Buffalo signal. I think I'd have done the same, if it were my signal.

Me too, but I doubt I have the connections to get this particular piece of engineering "Work" through.

(And remember, this is a signal that was never going to be full-market no matter what you do with it. Down Bob's way in northern Livingston County, where WTSS delivers just over 60 dBu, neither the old or the new site put much over 50 dBu of 102.7 into WYSL-land.)

...

This is where it will be very interesting to see how the FCC comes down on the 10 dB rulemaking. If you read through the comments (and there weren't that many of them), pretty much NOBODY but the "Joint Parties" was in favor of 10 dB across the board. The near-consensus, aside from the diehard HD haters who argued against any increase, was that the solution falls somewhere in between, using contour protection or mileage tables to determine which stations should be eligible for a digital power increase, and how much.

That makes sense to me, too, but of course the devil is in the details.

At least a set of protected contours or mileage separations would establish a black-and-white definition of what constitutes interference, which is more than they've done for afflicted AM stations. (Not that that helps Bob at this point, alas.)

To me, there should be a classification of HD as a "Secondary Service". If you treated HD as an FM translator or LPTV, if it caused actual interference, you could just use 74,1203
(Changes to HD from FM Translator/booster in bold
§ 74.1203 Interference.
(a) An authorized HD transmission will not be permitted to continue if it causes any
actual interference to:
(1) The transmission of any authorized broadcast station; or
(2) The reception of the input signal of any TV translator, TV booster, FM translator or FM booster station; or
(3) The direct reception by the public of the off-the-air signals of any authorized
broadcast station including TV Channel 6 stations, Class D (secondary)noncommercial educational FM stations,and <deleted> FM translators and FM booster stations. Interference will be considered to occur whenever reception of a regularly used signal is impaired by the signals radiated by the FM translator or booster station, regardless
of the quality of such reception, the strength of the signal so used, or the channel on which the protected signal is transmitted.
(b) If interference cannot be properly eliminated by the application of suitable techniques, operation of the offending [b}HD transmission[/b] shall be suspended and shall not be
resumed until the interference has been eliminated. Short test transmissions may be made during the period of suspended operation to check the efficacy of remedial measures. If a
complainant refuses to permit the HD licensee to apply remedial techniques which demonstrably will eliminate the interference without impairment to the original reception,
the licensee of the HD station is absolved of further responsibility for that complaint.
(c) An HDstation will be exempted from the provisions of paragraphs (a) and (b) of this section to the extent that it may cause limited interference to its primary station’s signal, provided it does not disrupt the existing service of its primary station or cause such interference within the boundaries of the principal community of its primary station.

I only bring this up because it already exists. I suspect it's WAY too logical to actually be considered.

Now it looks like the subject HAS been changed. Sorry...

Clouseau

 

[rbrucecarter5]

There seems to be almost no talk about this major technical problem for HD Radio. It's real and it's going to get nasty.

It now seems likely that the HD-AM thing will implode - with more and more stations taking HD off the air due to interference issues.

Let the democan appointees load the FM band with a power increase, let the interference implode it like it is imploding the AM band - and maybe we can eventually get this garbage off of BOTH bands.

Nobody has mentioned the FM translators of AM station. We suddenly got two in the DFW area - on second adjacents! How long before they want HD so they can multicast? Let's see how many second adjacent situations we can get before no HD stations can be received at all!