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Article on AM radio

johnnm

johnnm

Audio Enthusiast
I found this article on AM radio. I don't know if the proposed 10x increase in wattage would help the situation, but I'd like AM to stay around for a while longer. And admittedly, I don't listen to it too much precisely because of the static issues. Browsing through the first page of comments makes it seem I am the sole minority.

Should we kick AM to the curbside?
 
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I actually listen to more AM than FM these days. Funny but I rather like the soft static of AM. Even the commercials are more tolerable.

We have a little AM station at the top of the band, WMLB, or the "Voice of the Arts". It replaces our old AM classical station that changed formats many moons ago.
 
Once they take it out of cars, it will be the beginning of the end, I think, which will be sad. Though it will be interesting to see whether or not news/talk will enable it to survive, because I can't see where else you'd get programming like that (especially local content) without the MW band.

I've been spending a lot of evenings lately listening to old standards on WNIO 1390 in Youngstown, OH, which comes in pretty good, especially on the RF-2200 -- I found it one night while I was recapping the receiver. I've got that and Zoomer 740 in Toronto for now, for as long as they're around anyway.

And there's always microbroadcasting after that, if nothing else. Some kinds of music just sounds better on AM.
 
A 10X power increase would result in a doubling of signal strength...a BIG help in areas of poor ground conductivity...but a skywave nightmare. To work, there'd have to be quite the thinning of the herd in the AM ranks. It was felt that with the increase in FM penetration that eventually a lot of AM daytimers would go dark...but most seem to be hanging on in some way or another. The existing 50kW clears have been petitioning the FCC since the 40s for a 500kW limit but to no avail. It wouldn't be much help to all the 1kW stations out there...just increased interference. A good example would be the blanket nighttime increase from 250W to 1kW for class IV AMs...just made the nighttime jumble even more jumbly. And...have you priced a 10kW AM rig lately? Beyond the means of a LOT of existing stations.
 
I use WMLB 1690 as a DX daytime bandmarker for re-alignment of pre 'X' band analogue AM recievers as well as a listener station on occasion.
Interference issues are best addressed by meaningful enforcement of gutted and unenforced FCC Part 15 rules. Digital AM was an apparently commercially failed effort to address these issues at the cost of greater cross-channel interference and reduced effective broadcast range distance. Most digital-equipped (at great expense) AM stations no longer bother to turn on the digital exciters as almost nobody owns or uses digital AM recievers. AM DXers are relieved to see them shut down.
Higher AM power was experimentally tested in the 1930s on the most impressive installation ever put on MW and the interference issues extended from Mexico to Canada across the Midwest into the plains and to the East Coast. 50kw has proved to be the ideal practical limit in the U.S. and is unlikely ever to be increased.
See here for a virtual tour of that facility, along with a pair of the largest Hi-Fi audio output transformers ever produced at ca 1 megawatt capacity each;
http://www.hawkins.pair.com/wlw2/wlw500kw.jpg
The schematic, note this is a classic pre-high efficiency modulation "brute-force" plate modulation scheme requiring audio drive at least equal and preferably greater than the maximum peak power of the transmitter's RF section;
wlw500kw.jpg

http://www.hawkins.pair.com/wlw500schematic.shtml
 
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Ah, yes..."Serial #1" @ WLW. Quite the rig. The driver was their Western Electric 50kW unit, which I believe was the first 50kW transmitter licensed in the US. WLW had their own power substation just to power that beast. Figuring 30% efficiency or so...that meant 1.5 MEGAWATTS input to put 500 kW into the antenna!
 
At home, AM is useless because of the power line noise... there are 25kV lines 30 feet from my house. In the car it's great; I rely on distant stations (New York, Boston) even in daytime for news because my local choices are limited to Fox News, NPR, or Spanish. :(

Tom
 
I listen to AM radio. Mostly WGN radio 720 in Chicago and WBBM 780 for news, traffic and sports. AM sounds nice on my vintage equipment.

I used to DX, listening to far away radio stations. I don't do that anymore since I work nights.
 
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