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Can The AM Band Be Saved?
- Thread starter DToTheJ
- Start date
NightAire said:
Maybe this is my misinterpretation, but I thought that the NRSC-3 standard added recommendations for receivers that included the HF boost, while the NRSC-1 followed more thoroughly by NRSC-2 determined the cut-off at 10 kHz, and the attenuation from 10 to 20 kHz and above 20 kHz, among other things (like the low frequency rolloff, also). I did not understand that there was a 10 db boost in transmission... and have never observed it in receivers made pre-NRSC that have greater bandwidth than the 10 kHz NRSC mask.
TheBigA said:
It wouldn't surprise me, although I haven't heard anything, that the other Big Ten schools with AMs (Illinois, Iowa, Michigan State, Minnesota, Purdue, Wisconsin) dump them in the next few years. I think they're the last major universities that still operate AM stations, along with a few small colleges.
The most important point is that The Ohio State University SOLD their AM station. In other words, somebody wanted it. Now if they couldn't find a buyer and just shut it down, that would be more compelling proof of the demise of AM radio.
Sort of. WOSU AM was purchased by a Catholic non-profit for a modest $2 million and is running religion. Ohio State paid $6.5 million for the class B1 FM signal that succeeds WOSU AM.
KeithE4 said:
Wisconsin's station in Madison is the justification for a translator, so I think it will probably stick around for awhile. (it's also a point of pride, claiming to be the first broadcast station in the U.S. and having a pretty decent claim as #2.) I'm a bit surprised they haven't shut down the other station, but I haven't run the FM coverage up there, it's possible there are still significant gaps.
Minnesota's station is also the justification for some translators. I suppose they might think about closing it if they can get reliable access to someone's HD2.
I would see MIchigan State as the one most likely to go away.
David,
Unless this is just a suggested specification, check out page 10 of this pdf file for the pre-emphasis, and page 12 for the de-emphasis:
http://www.nrscstandards.org/SG/NRSC-1-A.pdf
I remember an engineering friend who told me after NRSC came in, he could no longer stand to listen to the AM radio in his ('55? '65?) pickup... everything was too bright. ;D
(I'd gotten the impression some stations had been boosting their highs a LOT more than 10db, so this was a bit of a compromise at the time!)
I find most AM stations sound a little better in wideband on the Superradio III with the treble dialed back a little, but it's not horrible.
EDIT: re-reading your response, I think we may be talking about nearly the same thing. The cutoff is basically 10 Khz (9.6, close enough) and drops like a rock below that.
A little more research has shown, though, that the NRSC mask IS a requirement for all U.S.A. AM radio stations:
from http://part15.us/node/703
Unless this is just a suggested specification, check out page 10 of this pdf file for the pre-emphasis, and page 12 for the de-emphasis:
http://www.nrscstandards.org/SG/NRSC-1-A.pdf
I remember an engineering friend who told me after NRSC came in, he could no longer stand to listen to the AM radio in his ('55? '65?) pickup... everything was too bright. ;D
(I'd gotten the impression some stations had been boosting their highs a LOT more than 10db, so this was a bit of a compromise at the time!)
I find most AM stations sound a little better in wideband on the Superradio III with the treble dialed back a little, but it's not horrible.
EDIT: re-reading your response, I think we may be talking about nearly the same thing. The cutoff is basically 10 Khz (9.6, close enough) and drops like a rock below that.
A little more research has shown, though, that the NRSC mask IS a requirement for all U.S.A. AM radio stations:
from http://part15.us/node/703
K
kenglish
Guest
MickeyD said:
Lotta good that'll do us, with all the noise on it :
/The HF ham bands are as noise plagued as the AM broadcast band
K
kenglish
Guest
Yeah. My "Faraday Cage" (stucco-construction,,,that cement over wire-mesh stuff) apartment has noise all the way up in to the mid VHF band.
A tunable loop near the door can null out the worst MF and HF noise source (cud riding on the Cable TV lines in the wall), but there is still a lot of other noise, including the electrical wiring, and even some things like metal door frames. Ferrites on most things-digital, like VCR, DVD Recorder, ATSC tuner, etc help a good bit, but the noise is even there with the main circuit breaker turned off.
I can even triangulate on some buzz coming thru the floor.
A tunable loop near the door can null out the worst MF and HF noise source (cud riding on the Cable TV lines in the wall), but there is still a lot of other noise, including the electrical wiring, and even some things like metal door frames. Ferrites on most things-digital, like VCR, DVD Recorder, ATSC tuner, etc help a good bit, but the noise is even there with the main circuit breaker turned off.
I can even triangulate on some buzz coming thru the floor.
With the flat land and great soil surrounding Champaign, Lafayette, Madison, Lansing, Iowa City and the Twin Cities, AM radio stations still do very well, and though it's been a couple years since I personally saw any Aribitron info for the non-comms in these markets, IIRC the NPR News-based AMs like WILL, WBAA, WHA & WKAR had strong audiences. Illinois split the Classical FM and the News-Talk AM many years ago, and the last time I looked, 580 was #3 or #4 in C-U. (And commercial newser 1400/WDWS was also in the top tier).
Point is, while AM is toast in most of the U.S., it is still competitive in the Midwest.
And as well as WTVN continues to do in Columbus, 820 could have still been a viable service for OSU. Somehow they managed to observe all the success down the dial at 610 and determine that it didn't apply to them...
Point is, while AM is toast in most of the U.S., it is still competitive in the Midwest.
And as well as WTVN continues to do in Columbus, 820 could have still been a viable service for OSU. Somehow they managed to observe all the success down the dial at 610 and determine that it didn't apply to them...
K
kenglish
Guest
I was thinking earlier this morning, what if the FCC tried something similar to what Canada is doing, and cull-out the smaller AM channels in the congested areas, allowing for AM's in the more widely-spaced areas to increase power on both daytime and nighttime service?
FM works fine when you are near a tower, but there are plenty of places "out in the country" where AM service improvements would be preferable.
FM works fine when you are near a tower, but there are plenty of places "out in the country" where AM service improvements would be preferable.
Our form of governance (and political climate) requires that government do things in an objective, measurable, calculated way. I like the idea of change comparable to your description of the Canadian efforts, but you have to give the bureaucracy a lot of freedom to be subjective and do what looks like "the right thing".... which will probably NOT be the right thing in the eyes of the licensee that is told to shut down.
kenglish said:
But that is not, in broad terms, what Canada has done. Canada has allowed the migration of many AMs to FM, in an "exchange" of the AM for the FM. In most cases, the AM signal has disappeared.
The exception is in larger metros with special interests, such as Asian communities in Vancouver, and the miltiethnic communities in Toronto: AM channels vacated by a a move to FM have sometimes been replaced with specialized services that serve these interests.
Several provinces, like Nova Scotia, PEI and New Brunswick are being left with no AMs at all.
Canada is not improving rural AM coverage or, in general, promoting the improvement of facilities by the remaining AMs. They are, simply, recognizing that AM reception in urban areas is plagued by interference and in rural areas the audience is better served by more FM relays and repeaters.
But that is not what Canada has done. Among the first proponents of the move to FM was the CBC, which gave up its two clear channels in Toronto and the two in Montreal to move to FM due to the noise and coverage holes of AM.
Nearly any broadcaster who can has moved or is trying to move to FM under this policy.
In Mexico, of 759 AMs, 599 can tecnically move to FM and 506 have already received grants to move, and another 50 or so are still in the legal process of being licensed. That means that about 75% of all Mexican AMs will disappear, and not be replaced by any class of service.
Re: Canada. I guess those out on the highways with hundreds of miles to cover will just have to sing for music
and wonder what's going on for news. Or spend 15 minutes out of every 60 looking for the next FM out of
Moose Factory or whatever the next burg is up the road.
How convenient!
and wonder what's going on for news. Or spend 15 minutes out of every 60 looking for the next FM out of
Moose Factory or whatever the next burg is up the road.
How convenient!
A very large percentage of Canada's population lives within a couple of hundred miles of the US boarder. So I guess the US AM's will cover a lot of the Canadian rural population who live "outside" Canadian FM coverage.
Tom Wells said:
Canada has always made extensive use of repeaters. Commercial stations may have a bunch of FMs in much smaller population centers. These have sometimes been synchronous relays, or separate facilities. Some may originate an hour or so locally, then join the master station for the rest of the day. Canada understands economics, and does not license stations if there is a doubt that they can be self supporting and that they will not cause other stations to cut back services.
The CBC has a long tradition of LPRTs (low power relay transmitters) at CN stations, and many of these became FMs. Using RDS, it is possible to drive great distances without losing a particular program.
Of course, Internet streams are available anywhere that a cellular phone works, and Canada is pretty good at getting service to remote areas.
If you are referring to the quasi-suburb of Regina, it's "Moose Jaw" where CJAB used to run on 800 AM.
If you want CBC english, they still have the venerable CBK in Watrous, which with 50 kw on 540 is arguably the biggest coverage AM in North America. But there are FM signals nearly everywhere... remember, Canada looks to Europe as much as to the US for radio technology and has long understood the European model of hundreds of lower powered repeaters for major stations all across a nation.
Canada is very sensitive to its special issues, which is why they started moving away from AM long before the priest was called to administer the last rites to AM in the US.
secondchoice said:
The Canadian licensing authorities are quite famous for their attitude that the "only" stations are those in Canada.
Canada even had /has a law making advertising on US radio stations non-tax deductable.
For reliable daytime service, there are not that many US stations that get good signals into of Canada. The parts of Canada that adjoin Maine, VT, NY and upstate NY either are Francophone or not near any major, listenable US stations. Except for the Windsor, Vancouver and Niagara Falls, not much of interest hits Canada with a good, good signal... and the US signals that do get there (like KFYR, etc.,) are either so centered on the US or are so small they are on satellite or have little news and information. Yes, a few exceptions, but you won't find that much listening to US AM radio going on in Canada partly because Canada has made AM quite obsolete.
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