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70th Anniversary FM Commemorative Broadcast
Anonym1ty writes "A special commemorative FM broadcast Saturday, June 11, at noon (EDT) will mark the 70th anniversary of Edwin H. Armstrong's first public demonstration of wideband frequency modulation (FM). The transmission, from Experimental Station WA2XMN (reminiscent of Armstrong's W2XMN call sign) will be on Armstrong's original 42.8 MHz frequency and will emanate from his landmark 400-foot Alpine Tower in NJ. The program will tell the tale of FM's difficult birth, as well as its impact on present-day communications and will include excerpts from a recording of a 1941 test broadcast of the New England Yankee Network. For those unable to receive 42.8 MHz FM, the broadcast is being retransmitted by WFDU-FM on 89.1 MHz and via the Web. Rebroadcasts will take place June 14 and 16 at 7 PM (EDT)"
To play it via linux:
mplayer -cache 128 http://64.92.199.76/WFDU-FM
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I hope we can setup some mirrors so during the broadcast they don't get slashdotted. anybody know how to convert asf to mp3? if so someone setup a mother stream. I am writing up a script right now for dynamic redirection on their server.
I dunno about FM's role, however.. not all RF waves are Frequency Modulated.... [like AM, for example]
E = m * c^(Hammer)
Well, -you-, anyway. I'll probably just run down to the clubhouse and listen there on the Icom 738. Amateur radio kicks ass. =)
Sean
KI4IIB
'If you're flammable and have legs, you are never blocking a fire exit.'
I used to love to DX on my Sony ICF-5500W table radio in the 70's. Then moved up to CB, then the linear amp, then amateur radio. Ahhh, the memories......
It is possible to transmit FM signals unlicenced, as you can probably find from your iTrip, etc. You can find the regulation on it here: http://www.fcc.gov/mb/audio/lowpwr.html
Well, FM was and is still important. Popular modulation schemes include both frequency modulation and amplitude modulation, but either is appropriate in different settings.
One advantage to FM is its relative immunity to certain kinds of noise (often noise is additive, and hence the amplitude is affected directly by noise whereas the frequency is less affected).
FM is the precursor to (and was at the time) more noise and jam-resistant schemes. The tradeoff is it requires greater bandwidth than AM to transmit a given signal.
Check out this wikipedia link to find out more about different MODULATION schemes...
The way radio works is that your car radio has to "tune" to the frequencies that you are listening to. Tuning means you have a little pure-tone synthesizer in your car that produces pure tones at different frequencies.
Now the real reason why it doesn't tune that low in frequency is because there is virtually no demand to listen to amateur radio bands. And it costs money to make that synthesizer generate more frequencies than required. So you have to pay more money to tune into those frequencies, in the form of a new purchase, or you have to build your own tuner that will work across all the frequencies you want to listen to.
Two seconds on google... http://earlyradiohistory.us/recap.htm
It was actually an FM radio band back before FM broadcasting got moved up to 88-108 MHz. Now it's part of the public service band, as in police, utility companies, forest rangers, etc.
As was pointed out above, most scanner radios will receive that frequency just fine.
"Do the Right Thing. It will gratify some people and astound the rest." - Mark Twain
Why do people automatically assume that if it is outside the 2 well known broadcast bands that it is amateur radio bands? This is why there has been such a problem with BPL. It seems like most people think that there are the AM broadcast, FM broadcast a handful of TV stations and the rest of the spectrum is in the possesion of the amateurs. Please look at http://www.ntia.doc.gov/osmhome/allochrt.html
and tell me what 42.8 has to do with amateur radio.
*grumble*
You would be correct.. I didn't read the history page that closely.
Therefore: "Here is a possible explanation as to how the USA got W and K, no documentation on this but sounds plausible. The USA had unofficially used N for North America (e.g., NBZ, Boston), also A for America. The letter "N" in morse is dah dit, adding a dah to N gives dah dit dah which is "K'. Letter "A" in morse is dit dah, adding a dah to A gives dit dah dah which is "W"."
source: http://www.ac6v.com/history.htm/
Actually, US radio call signs begin with A, W, K, or N. The FCC has decided which service classes may use which call groups (e.g., broadcast stations are only assigned calls starting with W & N).
The entire alphabet is maintained by the International Telecommunications Union (ITU) and its precursors. The earliest assignment of these call letters to the US dates back to early radio in 1913, and has been maintained ever since.
73 de N4JCK
"Adventure? Excitement? A Jedi craves not these things."
The only way to accomplish this would be to rebuild the entire radio communications system from the ground up, and not allow anyone to use anything else. That is so not going to happen -- the problem is akin to tearing down a city and rebuilding it from the subterranean level up. It's not that it isn't possible -- it's just that it would cost so much money and displace so many people that there's no reason on earth why anyone should think it a good idea. (The few cases where such a thing is possible -- postwar Germany, Kabul, Beirut, Nero's Rome, Banda Aceh -- it's been because of war or natural devastation.)
People who make this assertion don't really understand the nature of radio waves. You can't simply switch everyone over to a 5GHz spread spectrum scheme -- the propagation characteristics are very different at 1100 KHz, 25 MHz, 100 MHz, 460 MHz, 900 MHz, and 2.4 GHz (to take a half dozen frequencies in commonly used areas). The regions above about 6 GHz are pretty much useless for anything but short-range communication, satellite communication, and radar, while the CB bands at 27 MHz are superbly unsuitable for their intended purpose because they're potentially capable of worldwide propagation given proper ionosphere conditions.
If you want an idea of what an unregulated radio world, look at a shortwave guide and see what the US offers. How many of them aren't religious broadcasters? How many of them broadcast far-right tripe? Look at the CB bands and see what kind of crap goes on there, in a 40-channel swatch that the FCC gave up on enforcing years ago. Eventually you'd have nothing but a vast swatch of radio anarchy, with jammers, rednecks, and general troublemakers shouting down anyone they don't like.
Or you could just google the callsign KG6IRO or name Jack Gerritsen and find out why that fellow recently went to jail for what he did with his ham radio equipment. Talk all you want about the nobility of your cause and giving the airwaves back to the people, but if there was such a thing as radio anarchy, there'd be a lot more douchebags like Gerritsen out there.