The power of AM radio

[whitetho]

@Musicat

Are you sure about the 500K power? I don’t recall the FCC allowing anything greater than 50K watts for AM at least since the 1930’s.

WLW in Cincinnati, Ohio, using the slogan “The Nation’s Station”, did indeed operate with 500,000 watts, from 1934 to 1941. (It had a directional antenna that limited its signal toward Canada to the equivalence of 50 kilowatts). This is the only AM U.S. station that ever operated with more than 50 kilowatts. A few other stations applied for more than 50 kilowatts, but eventually Congress stepped in to specify a national 50 kw cap. Some extracts from Gene Martin’s “The Early Days of DX’ing”, from the September 23, 1972 “DX Monitor”

As the 50-kilowatters spread across the country during the mid-1930’s, WLW could see its own position of eminence threatened, and reacted in characteristic fashion. In the summer of 1934, W8XO began test broadcasts from Mason, Ohio, 500,000 watts on 700. [kilohertz]. By the following winter, this had become the regular WLW transmitter, and that stentorian voice was heard over much of the world.

WLW with half-a-million watts remained the giant of American radio for seven years. Its coverage was so great and its commercial rates so high that only national sponsors could afford it; thus it competed with the networks rather than other stations in its immediate area. As a point of interest to DXers, the WLW engineering staff numbered about 60, and the total payroll on the station numbered as high as 600. It was the third highest payroll in the nation, exceeded only by NBC and CBS.

Over the years, many stations in the eastern half of the nation found that they were losing sizable portions of what they thought was their audience to the big station in Cincinnati. It is at least possible that some of those listeners had gravitated over to 700 because they preferred what they heard there.

But then, as now, radio station management had a tendency to take their competitive problems to Washington for a solution. Many other stations wanted WLW muffled, and their combined clamor finally reached Capitol Hill, Senator Burton K. Wheeler, Montana Democrat, introduced a resolution expressing it as the sense of the U.S. Senate that no American station should be permitted to use more than 50,000 watts. The resolution was adopted in 1941, and WLW returned to being a 50-kilowatt station, the giant brought down by pygmies.

[johnpost]

@Magiver

At one time WLW broadcast at 10 times the power rating it has now. In it’s current 50K watt configuration it can be heard in Florida.

@Musicat

Are you sure about the 500K power? I don’t recall the FCC allowing anything greater than 50K watts for AM at least since the 1930’s.

WLW was one of the stations with the 500KW during the 1930s when that power level was experimented with.

i see that not refreshing the page puts me behind another reply to the issue.

[johnpost]

mountains do create radio shadows for skywave. west coast USA would be blocked from stations from the east for example.

reception depends on the radio and antenna. auto radios can tend to be fairly good though have poor antennas.

with a good radio in the USA you can get Canadian and Mexican stations regularly. with the right conditions Mexican stations will block the Canadian stations i regularly listen to.

[guizot]

@Kyla

Thanks for the explanation! I totally learned something new today. Awesome!

I just learned that the amount of reflection under the ionospheric layers is cyclical. Living South America I heard Ohio and New Jersey in 1995 and 1995. According to the cite above, that would have been a time of high radio skip.

[user_hostile]

I note that sometimes you get a waveguide effect with an inversion layer. Since a television signal is a mixture of AM, SSB, and FM, you can get some interesting reception if the weather is just right.

I lived for a while in the hills south of Hemet, California. In the evening, if the weather was clear and there was an inversion layer above the home I could get KEYT-TV from Santa Barbara, CA. The distance between the broadcast antenna and my antenna was 180+ miles. If the marine layer intervened (i. e., aka fog) forgataboutit.

[Bosda_Di_Chi_of_Tricor]

1920s-30s.

Mexico.

Crazy Doc Brinkley, & his goat gland radio station, could be heard across the US, & even further.

John R. Brinkley

Within weeks, construction resumed and soon two 300-foot (91 m) towers reached up into the sky.[24] XER, at 840 kilohertz on the AM dial, radiated by a sky wave antenna, made its first broadcast in October 1931. Brinkley called it the “Sunshine Station Between the Nations”.

---

Though Brinkley’s American radio license had been revoked, XER’s signal was so strong that it could still be heard in Kansas.[25] In 1932, the Mexican government allowed Brinkley to up his allowed wattage to 150,000 watts. Several months later, Brinkley was allowed to up his wattage to one million watts, “making XER far and away the most powerful radio station on the planet” that, on a clear night, could be heard as far away as Canada. According to accounts of the time, the signal was so strong that it turned on car headlights, made bedsprings hum, and caused broadcasts to bleed into telephone conversations.[26] Local residents didn’t even need a radio to hear Brinkley’s station; ranchers reported that they received it through their metal fences and in their dental appliances.

Only thing neater than a 1920s Style Death Ray would be to own his tricked-out station.

I’m on-a Mexican ray-di-ooooo…

[tetranz]

As others have said “DXers” make a hobby of this. Last month my ham radio club had a tour of a local radio station here in New Hampshire where one of our members is head of engineering. They have four stations in one building. I think he said he had just received a report of their AM station from someone in Norway. Of course the reports come by email these days and usually have a mp3 file attached.

Back in New Zealand long ago I was somewhat into this myself before I got into ham radio. I remember listening to KFI and KNX from Los Angeles. Back in those days, most NZ stations went off the air after midnight which made it easy.

The main challenge is interference from local stations. Those who are really into it have elaborate loop antennas etc which can be quite directional. Also, multiple antennas which can be tuned in such a way as to null out local stations.

[wd8cyv]

in the early 50’s …we moved out side a small town .
Parkersberg wv
i got intrested in radio when a friend of my fathers gave me an earphone out of
an airpane with a diode across it and a bunch of wire and the hunt for radio
stations was on i have heard every state and several forgeian stations
the most distant was PERTH AU on the west side
later got into swl with a rtty machine in 1975 got a ham license
first contact was on 2 way rtty
and have been active on ssb on the ham bands
160 meters is just above the standard broadcast band in the usa
i have worked at least 25 countries on that band at 1885khz to 1965khz
with 100 watts pep good reciever and antenna required

i also worked over 130 countries one weekend on rtty on 10 meters
28.070 and have also been on PSK 31 a digital mode
had a bunch of fun and it all started as a 6 year old kid with an earphone a 1n34 diode and a hand full of wire
so have fun
dave
the reason am radio is dieing is the power lines are in bad repair the noise
is so bad at the house where i started that to hear AM radio i have to drive about 15 miles to a friend farm even the short wave radios
the noise is nasty any more…
hope i did ok spelling i did this from the browser in
REAL PAYER with no spell checker

[Musicat]

@wd8cyv

hope i did ok spelling i did this from the browser in
REAL PAYER with no spell checker

And if anyone really needed one, you do. Consider investing in Chrome (it’s free).

And the extra-large font size isn’t a good thing. It tends to make your bad spelling much more glaring.

Nevertheless, from one OM to another, welcome to the SDMB. Ham radio sure has changed, eh?

[guizot]

Hmmm… Interesting that this thread should come up now. We’re in Barranquilla (Colombia) on vacation this week, and I’ve been spinning the AM dial. (Literally, because the radio is that old–the only AM radio left in the inlaws’ house.) So far, the farthest broadcast I can find at the moment is Florida.

[Kobalt]

One of my favorite winter-time activities is to scan across the AM dial when driving at night. Living just east of St. Louis, I’ve picked up a station in New York City once and can get a station in San Antonia, TX fairly regularly.

[Saint_Cad]

@Spectre_of_Pithecanthropus

Driving from Santa Clarita back to L.A., late at night, I once got a station in Denver, but I don’t remember which one.

Probably KOA 850AM. It’s our local high-powered station