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Radiation Storm Lets You Listen Long-Distance
bubblegoose writes: "There is a large radiation storm in progress caused by a solar flare on the backside of the Sun. Here's a story from Spaceweather.
It has a pretty cool effect on radio signals. I was picking up a 6000 Watt North Carolina FM station from near Philly." Bubblegoose also brings you this link to dxing.com, a site all about listening in when freak atmospheric conditions create unusual RF propagation patterns.
If you want to learn more about ionospheric skip, sporadic-E, transmission by meteor scatter (literally bouncing signals off meteors), moonbounce, and other neat ways to communicate long distances by radio, check out Amateur Radio (often called ham radio). One good place to start learning more is at the American Radio Relay League, www.arrl.org. There's a lot of amateur radio stuff on the web.
:)
/. :)
Honestly, you can buy or build an inexpensive radio and antenna for peanuts. Some kit radio projects like the "tuna tin" radio can be built in 15 minutes!
While you do need a license, the technician class exam is so easy most slashdotters should be able to pass with no studying. The FCC mandates a fixed question pool from which the questions will be drawn, and these are available on-line. (So are practice tests.) So if you just like to get perfect scores, read all the questions first!
And the exam fee is also mandated by the FCC, currently $10.00, so basically this is very easy to get into.
I hope that a lot of people here are intrigued by the fascinating world of long-distance radio wave propagation. From simple chatting with people in your local area, to talking to Africa and even Antarctica, radio is the only communication system that covers the globe.
Also there's the exciting world of amateur satellites, satellite designed, built, and launched by amateur volunteers and funds. These are another great way for a low-power station to communicate DX (long distance) without much special equipment.
I guess I don't need to add how pleased I am to see radio wave propagation stories on
See you on the air!
"I was picking up a 6000 Watt North Carolina FM station from near Philly"
For those of us in Atlanta, I know I picked up a Cuban station earlier. I don't know how far away this can be heard, because I haven't traveled around checking it out. I'm a little rusty on my Spanish, but it seems to be a Communist Propoganda station. It's crazy!
Never give up! Never surrender!
Eh.. i shouldn't do this, but.. What the hell.
While screwing up human-created radio patterns is an interesting effect, if the idea of listening to sound generated entirely by natural phenomena emitting radio waves interests you, there is a pretty good writing --> at this url <--, at the everything2 entry for "natural radio". The important thing about this site is that it contains a URL at the end containing recordings of the noise parsed by humans from natural radio. Turns out Mother Nature can create ambient about as evocative as anything we could ever replicate using our primitive tape recording systems..
If anyone else has some related links, btw, (and if y'all feel like it, we could maybe let this thread spiral way offtopic and maybe throw in a couple links regarding Oval, Pole, Farmers Manual or Disc or japanese noise groups, "Numbers Stations", etc..) could you post them as a reply to this?
In specific: The recent (excellent imho) issue of Wire with the cover story on nondeterministic music (or maybe it was the Urb where they interview richie hawtin.. can't remember. whatever.) They had a URL for some page at NASA in which they have sound files up containing natural radio emissions picked up by satellites *orbiting mars*.. with the source of the emissions being martian atmospheric phenomena. Freaky stuff, but it sounded really cool. unfortunately, i have lost that link. anyone have it?
I was picking up a 6000 Watt North Carolina FM station from near Philly
Today, WRVA, Richmond, Virginia. Crystal clear DX reception in Toronto. On the original made-in-September-1975 Motorola AM radio (with 8-track!) on the dashboard of my 1976 Dodge Ram. Very cool.
Fire and Meat. Yummy.
When I was a kid in the early seventies, I used to build radios - Crystal sets and hacked together tube radios from parts in the family attic. One of my lucky finds was a 1950's bakelite shortwave radio - something with 'wave' in its name, I think can't quite remember it now. Had a funky antenna that fit into the top, I remember...
I got the damn thing working after frequent trips to Radio Shack's free 'Tube Tester' and a lot of experimentation. (Try any tube with the right number of pins... Replace resistors that had gone black - Victory garden walls and all...)
Got the thing working and my brother and I would stay up late listening to Radio Moscow's propoganda. Brilliant, abstract stuff; The boy scouts were a paramilitary training group and the US govt was making sausage out of Native Americans. The woman who read the news sounded a bit like Natasha from the Bullwinkle cartoons.
Of course, we always switched over then to Dr. Demento when that came on...
A couple years ago on an Aeroflot plane to Moscow, I sat next to a former KGB agent and we drank vodka together and talked about how we missed the cold war. I told him about listening to the 'Voice of Moscow' or whatever it was called. We both agreed that international animosity had reached a certain level of respectability and taste with the cold war.
I asked him if they had the good movies that we did - he called them 'Spymaster' movies, but the ones he told me about only had the west Germans as the opponent - never the Americans, (Too bad. Either he was sparing my feelings, or we weren't as significant as we thought we were... I suspect the former.)
That was a time that really turned me on to communication and technology. Hearing a voice from so far away on a hunk of wires that I had badly cobbed together from cast-off parts. Hearing that series of tones that helped you tune in to the station before the broadcast.
I hope right now, some kid is sitting in his room, burning his fingers with a soldering iron over a pile of junk parts, finally hearing a crackle and then a voice.
I can't imagine a better thrill...
Cheers,
Jim (Now far away...)
-- My Weblog.
Long distance vhf reception may be the result of ionospheric conditions (sporadic E skip, e.g.). A more common cause in my experience is tropospheric ducting ("trop"). Trop creates a waveguide in the atmosphere. It is often caused by a temperature inversion.
Although the speed of light is nearly as fast in air as it is in a vacuum, it does differ slightly. And it is lower in dense, cool air than in thin, warm air. In other words, the refractive index of cool air is higher that of warm air. The signals are bent back to earth when they hit a discontinuity in the refractive index caused by a layer of warm air overlaying a region of cool air. Inversion layers commonly form on cool, clear nights. So you will often hear anomalous FM reception in the morning -- distant stations heard between local stations, or even interfering with weak locals.
A Yahoo search on "temerature inversion radio propagation" will enlighten the curious - this is one result. Or run to the library and look in "The Radio Amateur's Handbook".
www.javaradio.com has links to several shortwave receivers around the world connected to the internet. The lag between the audio and the controls is horrible, if you can bare with that it can be quite interesting.
You can go click the link for a summary of the movie. Fairly decent flick, got too wrapped up in funny timetravellish things, and how the radios magically did not need the TX buttons pushed anymore was particually annoying.
"Skip" (explained in other posts) is common in the HP range (3-30MHz), but much less so in the VHF range (30-300MHz). HF's skip characteristics are varied depending on frequency, but fairly predictable. Hams talk of "maximum usable frequency" (MUF), which deals with the less-predictable frequencies in the upper parts of HF and lower parts of VHF. It is significant to hams when the MUF tops 50MHz, because that allows skip traffic over 6 meters (50-54MHz-so THAT's what happened to channel 1!), which most of the time is restricted to line-of-sight.
On rare occasions, such as during this radiation storm, the MUF can go past 150MHz, allowing skip for FM broadcast, 2-meter (144-148MHz) ham, and many of the VHF broadcast TV channels.
It can be loads of fun seeing what all you can pick up on your FM radio which this happens.
I remember at the peak of the last solar cycle, back in the 80's, there was a radiation storm that knocked out a good chunk of the power grid in Quebec. During that storm, I was receiving FM broadcasts from Germany and the UK. It churned up some pretty kickass Aurora Borealis too.