What is the Largest area that a Radio station listening area can be, excluding S!
Question: could you share it in mileage and not square foot I would have no conception of that range.
Answers: could you share it in mileage and not square foot I would have no conception of that range.
There is no clear cut answer to your question.
The area covered by a broadcast radio station is a variable
that depends on several things.
The first is method of broadcasting. AM (for Amplitude Modulation), carries further than FM, Frequency Modulation.
That is because the frequencies of the AM stations are lower
than those of FM stations and lower radio waves follow the
curvature of the earth while higher frequencies tend to go
straight up.
You drive a few miles away from an FM station
and you can't get it because the radio waves have gone up
into the air. But drive a few miles from a powerful AM station
and you can still get it. Those waves hug the ground.
Then it depends on the strength of the transmitter. In the
USA, the most powerful A.M stations are 50,000 watts.
In FM, stations can have ERP (Effective Radiate Power) wattage much higher, but they don't go as far.
Then the coverage would also depend on the number of
other stations on that same frequency. Some of the early
station are what is known as "Clear Channel" stations.
That means that they are the only one, or one of the few,
that broadcast on that frequency.
Mountains, hills and valleys also play a part. If a station
has it's broadcasting antenna on top of a mountain, it
will get out further. Or if the antenna is on the other side
of a mountain, the mountain will stop the waves from
being received.
Finally, the area would depend on the frequency itself.
The stations in the lower frequencies follow the curvature
of the earth. Because there are no mountains to
obstruct the transmission and they are broadcasing
over the Atlantic Ocean, it is possible to hear WABC,
from New York, in Miami.
I remember years ago when I was driving from Dallas, Texas to Chicago, Illinois and I could hear WLS in Chicago all the way just fine. It's 803 miles from Dallas to Chicago.
AM radio signal reception depends on a lot of factors including weather, so it's possible that is not typical.
I once lived in a town 180 miles from Chicago and WLS came in so strong there that it often "washed out" a local channel that was close to the same frequency.
Seryan gives a great answer and should probably take the prize (at least so far). Any additions of mine are for "color," a couple of details and reminiscences; but he really nailed the core of your question.
WLW in Cincinatti has the biggest transmitter in the US (maybe the world) at 250,000 watts. But they can only crank it up once in a while for testing. The transmitter is so big and gets so hot at full power, they have a lake around the building to cool it. It's used in case of national emergency. Boy can that thing honk at night!
Many AM Radio stations in the US are required to reduce power at sunset. This means that your local station that broadcasts at 500-1,000 watts during the day will probably drop to 250 watts at night (or, if it's what we call "a daytimer," will sign off all together). Likewise a 5,000 watt station may drop to 1,000 watts.
This has been so from the early days of radio. AM radio waves travel farther at night, so the smaller stations have to make way for big "clear channel" stations Seryan mentions that broadcast at 50,000 watts (or more). If they did not, there would be interference between the stations.
But the night time is the right time. You can tune all over the dial and get some really interesting radio stations. When I worked at a powerhouse flame-thrower station in Little Rock in the '70s, we once got a "DX" (postcard reporting reception) from the Arctic Circle. That was really cool.
I have an interesting device that I bought years ago that really boosts the antenna power of your AM radio. It's a big, round plastic device called a "Select-A-Tenna." You put it next to your radio and - wow! What a difference. this would also be a good device for those kids who have written in about bad reception on Radio Disney. You can reach them at www.selectatenna.com/
I've also listed a couple of websites that give lists of big "clear channel" stations you can get at night. (NOTE: I've used the lower case "c" with clear channel, so you don't confuse it with the huge radio conglomerate of the same name, but with capital Cs.)
Back in the sixties and seventies there were some great Rock 'n' Roll DJs on big 50,000 watt stations: Wolfman Jack, Jackson Armstrong, Dan Ingram, Cousin Brucie, Brother Dave, John "Records" Landecker, Jay Thomas, Beaker Street (with Clyde Clifford and later, Stuart McRae), Frank "Shoutin" Holler, Gary Gears, Doctari Brock, Rick Shaw, Robt. W. Morgan and so many others. Those were the best days of AM radio and that little spot you see on your computer is a tear that just fell in rememberance of what was, but never again will be.
There are web sites that will let you listen to some of these great old jocks, just use your search engine for "radio air check" withut the quotes).
Good luck & Good listening
-a guy named duh