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Cheap MP3 Broadcaster
Raffi Spock writes: "OK, this isn't new or anything, but with all that stuff on transmitters for MP3 that transmit through phone lines to an expensive receiver, I just thought I'd point the dial to Cana-kit who manufacture a little kit that transmits any audio source to a distance of about 150M. Cost is about $40 Canadian. I just built one of these, so I now can listen to MP3s without carrying a very heavy PC around. Oh yeah, since it just plugs into any audio output, drivers are unnecessary making it run on any OS."
broadcast-warehouse.com (in the UK) sells REAL fm exciters and amps. yeah, beyond what's legal in the US, but the audio quality is 100% full pro.
and if you're worried about too much power, just transmit into a dummy-load (50ohm resistor with enough wattage to take the output, at least 5 watts non-inductive).
the ramsey kit (fm10a) is very well known and famous, but has spurs that, if amplified, will make you quite illegal. I opted for the synthesized broadcast-warehouse system since its known to be much cleaner (rf wise) and you have more options on the audio front-end.
but be prepared to spend at least 2 hrs per kit to build it...
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"It is now safe to switch off your computer."
Can't get to the website due to errors over there, but if this kit is based on the BA1404 chip like the Ramsey FM10 (which, for this price I think it has to be) you may have serious problems receiving what this thing puts out on many FM receivers. The BA1404 uses a tank circuit (an inductor and a capacitor) as the part that sets the frequency, and this can drift really badly. Many FM recievers today are PLL based (if it has a digital display, it probably is) and can't tune in an analog sense. If the signal drifts off of the FCC "channel" (they go in 200KHz increments, starting at 87.9 up to 107.9), many receivers won't, and if they do at all you get a really noisy signal. An FM discriminator can pull in a signal a few KHz, but they are generally designed to work within the frequency specification that FM broadcasters are mandated to follow by the FCC, which is *much* smaller than the frequency precision an L-C tank will give you.
There are FM transmitters out there that don't suffer from this problem- they use a crystal controlled PLL circuit to set the frequency, Ramsey sells one. But it is much more complex, and more expensive (I think Ramsey's is about $150)
Be careful about putting these small companies on the front page, you might break them!
Google cache of the front page: http://www.cana kit.com
-inq
You can find a excellent comparison of Ramsey's and Cana and other exciters/low power transmitter kits here.
X10 has what they call MP3 Anywhere. It's just an RF audio send/receive pair, but it works well. It's more expensive ($80 US, but includes an excellent remote) and they haven't Slashdotted (yet). I can't get through to canakit.com...
http://www.x10.com/products/offer85.htm
"The cost of freedom is eternal vigilance." -Thomas Jefferson
Don't buy it -- It's an evil canadian trick! Think about it... what does Cana-kit most sound like? That's right: Rootkit! Even worse, what's its main purpose? To transmit.
But wait, you say. It's just transmitting music.
Ah ha! That's what they want you to think. While it may be sending music on one channel, this is only a front. Its _real_ transmission is on a much lower frequency, right above the 20m ham band. This enables it to bounce signals off the atmosphere and RIGHT INTO CANADA! They're secretly sending all our root passwords to canada!
In sum, I encourage everyone to boycott this nefarious scheme. We Americans control the world and it should stay that way. G-d bless apple pie and the American way!
At my work, a bunch of us have 900Mhz wireless headphones that we use to listen to music (clotheslining yourself while rolling around the lab sucks). The cool thing is that we can all tune into eachother's frequencies. So in a way it's kinda like we have our own mini radio staitons :)