The problem is that the frequencies above 1600 behave nearly like short wave, and 1 kw can regularly be heard for thousands of miles at night
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Is it time to end AM night skywave protection?
- Thread starter davideduardo
- Start date
The problem is that the frequencies above 1600 behave nearly like short wave, and 1 kw can regularly be heard for thousands of miles at night
I remember you telling us about this three-tower directional on (I think it is) 710, but are any US markets as huge as Ciudad Mexico?
Actually, it was Buenos Aires. One 5/8 wave main tower on 710 and one passive reflector, quarter wave, to nudge the signal.
Buenos Aires is geographically smaller than US markets like LA, NY, Chicago, Denver, Seattle, San Francsico and many more. It has more population, but much higher density.
Mexico City metro is under 1,000 square miles, while LA is 4,800. Greater Buenos Aires is 1,400 square miles. New York City's radio metro is over 8,000 square miles.
Interesting table that shows metro areas by square milage: http://www.city-data.com/forum/gene...quare-miles-all-metropolitan-statistical.html
Keep in mind that radio MSA's are not always the same as Federal Government defined MSAs. One is Metro Survey Area, the other is Metropolitan Statistical Area.
I remember reading this article about 8 years ago, and after some searching, found it again!
The author is suggesting that we let AM's increase their power to overcome noise from other devices that have degraded the AM listening experience. At first I thought this was nuts. But it is good fodder for radio folks discussion over a beer. ;-)
There are stations that I used to be able to pick up, and now I have trouble listening to. Because of other stations interferencing? No, because of all the noise and static generated by life in 2019.
https://arstechnica.com/tech-policy/2010/06/should-am-radio-stations-get-a-10x-power-boost/
The biggest problem for AM stations is no longer interference from other stations, Arsenault contended, but from other devices. The service contours and protection ratios that the FCC set up for AM stations in 1991 haven't been updated for almost 20 years. "At that time, the protected contours and the interference ratios made sense," he adds. "Unfortunately, they were calculated without available foresight of the future digital technological revolution."
Bottom line—letting AM stations boost their wattage by a factor of ten wouldn't boost the risk of their interfering with each other, Arsenault says, but it would allow them to override the gauntlet of new platforms that get in their way. "I believe that the AM band as a whole would deliver more usable stations to every AM radio dial across the United States under this proposal."
The author is suggesting that we let AM's increase their power to overcome noise from other devices that have degraded the AM listening experience. At first I thought this was nuts. But it is good fodder for radio folks discussion over a beer. ;-)
There are stations that I used to be able to pick up, and now I have trouble listening to. Because of other stations interferencing? No, because of all the noise and static generated by life in 2019.
https://arstechnica.com/tech-policy/2010/06/should-am-radio-stations-get-a-10x-power-boost/
The biggest problem for AM stations is no longer interference from other stations, Arsenault contended, but from other devices. The service contours and protection ratios that the FCC set up for AM stations in 1991 haven't been updated for almost 20 years. "At that time, the protected contours and the interference ratios made sense," he adds. "Unfortunately, they were calculated without available foresight of the future digital technological revolution."
Bottom line—letting AM stations boost their wattage by a factor of ten wouldn't boost the risk of their interfering with each other, Arsenault says, but it would allow them to override the gauntlet of new platforms that get in their way. "I believe that the AM band as a whole would deliver more usable stations to every AM radio dial across the United States under this proposal."
It would cost more to run and where would they make it up?
That's the thing, especially with AM/MW stations, one has to consider so many other factors besides power: Ground conductivity, antenna system gain, antenna wavelength. To assume stations across the board could raise their "power" by a factor of X, there could be significant interference from one station to another, depending on the other criteria I already mentioned.
Ummm..increased listenership? ;-) Right now I have a hard time getting WBZ (the most powerful station in Boston) on my clock radio.
Also, in slowing the decline of AM into relevancy.
It's an interesting read but there are still class B stations running at 5000 watts that could apply for 50,000 but don't bother.
K
kenglish
Guest
If everybody in a room is screaming, does it really help to have them all scream louder?
The FCC needs to have the power to reduce the interference. Banning cheap, unfiltered switch mode power supplies (which turn your entire neighborhood power system in to a noise generator), would be a start. They fail eventually, so it may take a few years for the junk ones to die off, and be replaced by something better.
Requiring proper shielding and filtering on computers, led lights, and solar power would make a huge difference.
Just making the end-user aware of the problem, and of their responsibilities would help. Too many people just assume that the stations are at fault, and Just need to add more power to the noise floor. It comes to a point that the receivers can't deal with the increase, and they make their own interference.
The radio astronomy folks are nearly done with trying to find any quiet places on Earth, and are looking to use the Moon for reception. We can't go on ignoring the problems, and using Band Aid fixes.
The FCC needs to have the power to reduce the interference. Banning cheap, unfiltered switch mode power supplies (which turn your entire neighborhood power system in to a noise generator), would be a start. They fail eventually, so it may take a few years for the junk ones to die off, and be replaced by something better.
Requiring proper shielding and filtering on computers, led lights, and solar power would make a huge difference.
Just making the end-user aware of the problem, and of their responsibilities would help. Too many people just assume that the stations are at fault, and Just need to add more power to the noise floor. It comes to a point that the receivers can't deal with the increase, and they make their own interference.
The radio astronomy folks are nearly done with trying to find any quiet places on Earth, and are looking to use the Moon for reception. We can't go on ignoring the problems, and using Band Aid fixes.
Not an area of interest to regulators. They're really not looking at ways to improve AM signals, as demonstrated by their AM revival plan.
K
kenglish
Guest
It's not just AM (medium wave). The noise problems extends high in to the spectrum. RFI is plaguing reception in the FM band, TV, two-way radio, even cell phones. The cell companies find numerous instances of lighting devices that interfere with their sites. They also hate the rising noise floor, because it makes them need more sites, closer to the users, to overcome the noise. Ham radio uses frequencies all over the spectrum, often working with reception of weak signals. Satellite downlink get clobbered by many sources, even security lights. Now, after years without Telco terrestrial interference, C-band is being chopped up local broadband use.
We all share a limited amount of spectrum, and we need to play by the rules and protect it.
We all share a limited amount of spectrum, and we need to play by the rules and protect it.
No, but if the furnace or washbing machine in the basement is making so much noise that one can't converse...then, yes, talking louder would help people to be heard. ;-)
Or anyone other than station owners who can't get strong enough translators.
I agree here. Even experts here mention that part of AM's problem is that even stations in big metros have smaller signal footprints than the metro which outgrew them, and RFI is part of the problem on top of that. Signal strength over your primary area is important.
As for night conditions, whenever I've experience local AMers cutting power at night, the skywave from other areas kicks in more. When they come back to regular night-time power, the distant skywave isn't so much an issue.
But it will be when those distant stations increase their nighttime power as well.
Not necessarily. The local station's power will be received at the receiver at a much higher relative signal strength, because the local station is physically closer.
If your theory worked, one would be able to hear a distant station even if you have your portable radio within 500 feet of the local station's antenna.
But AM interference is additive. If the signal of a more distant station is increased, it will reduce the interference free contour of the closer one. That's why, when in a location not near any station on the graveyard channels you can sometimes hear a mix of five or six different signals... and the one that id 100 miles away is no stronger than the one 500 miles away.
I don't know, it seems that the closer one (with higher power) would cover up the interference...
True, but that is under the supposition that the local station's power isn't increased as well, isn't it?
At some point, you get to where the interference is audible under the other station, even in its primary service area.
Those of us who are AM DXers know how little power is needed under the right conditions for a very distant station to sound "as good as" a semi-local station.
Back when nearly every station signed off for maintenance on Sunday night, I recall a number of times hearing WSM sign off only to hear, nearly as strong, KORL in Honolulu... and I was in NE Ohio!
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