Eureka L-band

[A#1]

With so many problems associated with HD Radio, how about something that was talked about years ago, the L-band. I'm not an engineer, so perhaps Chief Engineer or Bob On The Job can shed some light on this technology. Did larger broadcasters lobby against it because it gave the rest of the terrestialites parity signal-wise or what?

 

[Kent]

As I recall, broadcasters can't use the L-Band in the USA because it's reserved for military use. Broadcasters were dead set against migrating out of band for several reasons. One of the biggest was that they were afraid of getting caught up in a spectrum auction. That almost happened to TV with the digital transition, and it scared broadcasters.

The L-Band really hasn't worked in the two countries that have tried it, France and Canada. Canada has scrapped its plans to use the L-Band, and France was rumored to be considering the same. Using the L-Band wasn't feasible in Canada for several reasons. Two reasons were simply that people neither were willing to change their listening habits from the familiar nor would they buy new, overpriced, equipment, which is one of the same problems HD Radio has. The government tried to get around that by making the transition period 40 years, but the technology went nowhere after 10 years. The technical reason the L-Band didn't work in Canada was the vast geography. A single station needed FIVE transmitters to cover Toronto and still had several dead spots in the city. There was really no way to cover the entire country from coast-to-coast. We'd have the same problem here. As things stand now, I can travel I-70 from Indy to Denver and get something on the radio the entire way. With the L-band, there would be extremely large dead spots in areas of Kansas and, possibly, Illinois. The areas of Kansas are an especially big concern given the extreme weather that happens during all times of the year and the need to warn travelers. Yes, most of the stations in western Kansas run heavily automated, but most of them still provide valuable weather information.

Also, if you noticed, only two countries tried the L-Band for digital radio. I believe most countries used Band III, which is a little better but still probably not feasible for the US simply due to the large geography of the country. Eureka is a technology that will work fine above 30 mHz. We can't use it here because of the analog stations already in the FM band. The analog signal is a spectrum hog, and Eureka takes up too much space to piggyback onto existing analog channels. If we had a set transition plan, we could have FM Eureka. It wouldn't be easy, but it would be doable.

 

[w9wi]

As I recall, broadcasters can't use the L-Band in the USA because it's reserved for military use.

That's certainly the argument that was made but it looked rather fishy to me.

As things stand now, I can travel I-70 from Indy to Denver and get something on the radio the entire way. With the L-band, there would be extremely large dead spots in areas of Kansas and, possibly, Illinois. The areas of Kansas are an especially big concern given the extreme weather that happens during all times of the year and the need to warn travelers. Yes, most of the stations in western Kansas run heavily automated, but most of them still provide valuable weather information.

though you won't get anything in HD for most of that route. Eureka L-band receivers are equally capable of reverting to analog when no digital signal is available.

Also, if you noticed, only two countries tried the L-Band for digital radio. I believe most countries used Band III, which is a little better but still probably not feasible for the US simply due to the large geography of the country.

The big problem with Band III is that it's high-band VHF television territory. TV isn't willing to surrender that spectrum. It was available in the UK because they'd closed VHF TV when they went color about 30 years ago.

Personally I think Eureka could have been stuffed in the "white space" between occupied DTV channels. It would have been a much more acceptable alternative (as far as the TV stations are concerned) as the transmitters would be at fixed sites and their interference potential could be easily and accurately evaluated.

 

[Kent]

though you won't get anything in HD for most of that route. Eureka L-band receivers are equally capable of reverting to analog when no digital signal is available.

You're definitely correct that you won't get much in HD between Indy and Denver. My point was more along the lines of, if/when we go to pure digital broadcasting, there doesn't seem to be a technical way to get even similar, let alone the same, coverage of AM and FM on the L-Band, or at least there's not one that I would think would be acceptable to broadcasters. Whether we use HD, Eureka, or something else, we should be able to adjust power to replicate existing FM analog coverage fairly easily. I seem to remember Sean Ross advocating moving to an out-of-band system in '96. I remember someone wrote an article on it about how the same coverage problems that killed AM could kill FM, too, as people continued to distance themselves from the central city and commute further and further to work. While I certainly agree that FM has potential problems with suburb/exurb-anites, I can't see moving to higher frequencies as being a workable solution. The skip on some of the lower bands would be a real problem. So, I don't know if that's workable either.

 

[BobOnTheJob]

I think the proposed refarming of TV channels 5 and 6 into a digital radio band that replicates coverage of each existing AM and FM station has a lot of long term potential. It would take a long time to implement, but it opens the door to keeping or possibly improving the coverage we have now.

My short term fave is FMExtra which causes zero interference to adjacent channels and with FCC rule modifications, allows for a graceful implementation. Simply increasing the FMExtra modulation while simultaneously reducing analog modulation would allow each station to increase digital coverage as local adoption rates proceed. Dirt cheap compared to IBOC too.

The point about sprawling population centers outgrowing existing coverage areas is not made vocally enough or often enough. Equally lacking is that a lot of listening happens outside of the "protected contour" of virtually all stations. Any future path should protect all zip codes where measurable listening exists on a given station--and ideally it should improve reception in those areas. IBOC flunks that test at 1% injection. If all stations were to adopt 10% IBOC, virtually all listening outside of the protected contour would cease...and some listening inside the protected contour would be degraded. Any process that alienates even 1 listener should be dismissed. We are looking to improve our lot in life...not shoot ourselves in the foot. There are better ways...hopefully the bright side of this economic downturn will be bankruptcy and no bail out of iBiquity & IBOC.

 

[Flying-Dutchman]

The FCC is considering expanding the FM band to include frequencies used by TV channels 5 and 6. These new
FM stations need to go to new owners. We need new voices and fresh ideas in this business. The current owners
are killing radio!

Just think how many new stations could go in Indianapolis!!!!!!!!!!! I am ready to help new people get on the air!!!

 

[w9wi]

I think the proposed refarming of TV channels 5 and 6 into a digital radio band that replicates coverage of each existing AM and FM station has a lot of long term potential. It would take a long time to implement, but it opens the door to keeping or possibly improving the coverage we have now.

I think this is unlikely to happen as-is. There are a number of digital TV stations assigned to these channels, and it's too late to reassign them. I know of three whose interim DTV channels are outside core and whose permanent channels are 5 or 6. (I strongly suspect there are more) If channels 5 and 6 are withdrawn from DTV service, these stations will have to go off the air altogether in February until new channels can be found and new permanent DTV facilities built -- at considerable expense -- for which these stations haven't budgeted. You can rest assured they will fight any such move.

I do think it would be worthwhile to look at allocating the entire 54-88MHz (channels 2-6) spectrum for digital radio on a secondary basis to digital TV. At least two of these channels should be available everywhere, just not the same two everywhere.

The point about sprawling population centers outgrowing existing coverage areas is not made vocally enough or often enough. Equally lacking is that a lot of listening happens outside of the "protected contour" of virtually all stations. Any future path should protect all zip codes where measurable listening exists on a given station--and ideally it should improve reception in those areas. IBOC flunks that test at 1% injection. If all stations were to adopt 10% IBOC, virtually all listening outside of the protected contour would cease...and some listening inside the protected contour would be degraded. Any process that alienates even 1 listener should be dismissed. We are looking to improve our lot in life...not shoot ourselves in the foot.

You will hear that audience outside the protected contour cannot be sold. I'm in TV engineering so I won't claim to know one way or the other. There definitely is audience outside the protected contour. Me, if nobody else. People listening to stations outside their protected contour are doing so because no station that does deliver a protected-contour signal airs a format they want to listen to. Take away their access to out-of-contour stations and they are not going to switch to protected-contour stations. They're going to turn their radios off.

There are better ways...hopefully the bright side of this economic downturn will be bankruptcy and no bail out of iBiquity & IBOC.

I don't know if bankruptcy is in iBiquity's future but I do think the economic downturn is not going to help the rate of deployment of IBOC. (and I think it will really stall the deployment of the 10dB power increase for FM-IBOC)

 

[BobOnTheJob]

You will hear that audience outside the protected contour cannot be sold. I'm in TV engineering so I won't claim to know one way or the other. There definitely is audience outside the protected contour. Me, if nobody else. People listening to stations outside their protected contour are doing so because no station that does deliver a protected-contour signal airs a format they want to listen to. Take away their access to out-of-contour stations and they are not going to switch to protected-contour stations. They're going to turn their radios off.

While I'm far removed from the sales aspect of radio, I do know of two examples where the non-protected contour produces/produced significant revenue. The former WJCP 92.7 Austin,IN had studios in North Vernon,IN which, at the time, was outside of the protected 60db circle (they have since doubled power & North Vernon is now just inside the 60db contour). The lion's share of that station's billing came from North Vernon. The other example is a non-com, WIKL 90.5 Greencastle,IN. Their 60db contour just scrapes the I-465 circle around Indy, yet when K-LOVE has their pledge drives, this station is consistently among the first to reach the local goal. This station is directional and doesn't reach any other significant population.

While these two examples don't provide rock solid proof that areas outside the protected contour can be sold, it seems likely that money does change hands outside of the protected areas.

Unrelated, but since you (w9wi) are in TV engineering, I went past the WSM tower on I-65 Thursday & was again reminded that there is a TV antenna at the top. Is that still in use? If not, what's the history behind it?

 

[fybush]

Unrelated, but since you (w9wi) are in TV engineering, I went past the WSM tower on I-65 Thursday & was again reminded that there is a TV antenna at the top. Is that still in use? If not, what's the history behind it?

Not a TV antenna...that was W47NV, the original FM outlet for WSM. Someone sent me video a few years ago from a tower crew that was working up on the tower, showing the base of the FM antenna slowly creaking in the wind up there. Better them than me.

The current WSM-FM is on the WSMV-TV 4 tower across town.

 

[BobOnTheJob]

Unrelated, but since you (w9wi) are in TV engineering, I went past the WSM tower on I-65 Thursday & was again reminded that there is a TV antenna at the top. Is that still in use? If not, what's the history behind it?

Not a TV antenna...that was W47NV, the original FM outlet for WSM. Someone sent me video a few years ago from a tower crew that was working up on the tower, showing the base of the FM antenna slowly creaking in the wind up there. Better them than me.

The current WSM-FM is on the WSMV-TV 4 tower across town.

Fascinating...there can't be many of the old pre 88-108 FM antennas still in the air. From the Interstate, it looks like a channel 2-6 bat-wing TV antenna. Thanks for the scoop...my inquiring mind is at peace...

 

[PTBoardOp94]

I imagine climbing a Blaw-Knox is not the easiest task anyone ever attempted. Never seen it myself. Plus, WSM probably wouldn't want to shut down long enough to dismantle it.

Come to think of it, the 40 MHz band might have some free space these days.

 

[bigtime]

The odds of anything new exploding on any band are slim. What great new formats exist that aren't being done?

 

[fybush]

I imagine climbing a Blaw-Knox is not the easiest task anyone ever attempted. Never seen it myself. Plus, WSM probably wouldn't want to shut down long enough to dismantle it.

There's a ladder that runs right up the middle of the thing, actually, so it's probably relatively easily climbed. But because the 40 MHz antenna is part of the AM radiator, removing it would require an engineering application to be filed and might even trigger the dreaded ratchet rule - so better to leave it alone.