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."

Comments

and for more power and cleaner audio..

[TheGratefulNet]

try:

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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Re:and for more power and cleaner audio..

[GigsVT]

But be prepared to spend at least 2 hrs per kit to build it...

And be prepared to have the FCC knocking on your door if you trasmit at 1-10watts or more on the FM broadcast band, clean signal or not. They don't monitor generally, but if you are in the 1st or 2nd adjecent channel to a real station that is within 50 miles or so, the broadcast engineer of the FM station will sic the FCC on you. Even if you find a clear channel, you might be blasting one of the new LPFM10 or 100 watt stations out of the water with your signal, and they will get pissed and call the FCC.

Don't even think about running illegal power on the FM broadcast band, unless you are ready to be constantly in a cat and mouse game with the FCC. Stay in the 900Mhz or 2.4Ghz public bands, you can run a few watts there legally. (but not from a kit, because the device must be type accepted as far as I know.)

KG4JHX
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Re:and for more power and cleaner audio..

[TheGratefulNet]

I know the BA chip well; have built MANY fm xmitters before. you get what you pay for.

you have way less than 100mw output with the ramsey style single-chip solution. the audio qualtiy is so-so. there's NO limiter on it and its too easy to overdrive and over-deviate (fm modulation concept). and if you're at all tempted to add rf gain to it, better put in a very steep LP filter too else planes might start crashing into your house ;-)

yes, the B-W unit is crazy expensive. but quality analog design's aren't free. the one-chip-wonder based on the BA chip was really meant to inject audio from a car changer directly into the FM antenna input of a car stereo. it was NEVER meant to actually broadcast signals thru the air.

I did drop a lot of change on the UK kit but I wanted true CD quality (as best as you can get within the 15khz limit of US fm band) and this kit can't be beat. in fact, if you price PRO units (like what commecial stations use) you'll find that their specs compare but pre-built pro exciters and audio coders cost many times more..

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Re:and for more power and cleaner audio..

[TheGratefulNet]

oh, and with the B-W kit, you get a real measured 1 WATT output. that's good for, oh, say, 5 miles with a reasonable antenna...

;-)

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Re:and for more power and cleaner audio..

[TheGratefulNet]

I did say to run into a dummy load. that will cut down the power and keep you legal since the radiated amount of power is what's at issue and NOT the rf input into an antenna.

you can legally run 1kw in the 88-108 band; just not into the air, that's all ;-)

I get full house coverage (at home) running into a dummy load. and its keeps the finals happy and cool, too.

1watt into a dummy load is so much better than 10mw into a reactive high-swr antenna..

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Re:and for more power and cleaner audio..

[SubtleNuance]

Yeah - REAL is right, real damned expensive: try this currency converter at yahoo to tell you how much broadcast-warehouse's least expensive unit (1W) costs: $329UK vs $40CDN.
Hint: Its over $700CDN

Exchange Rate

[gtx]

Let's see... $20 canadian, in the US, that'd be worth approximately...

5 "Alpha-Bits" Box tops plus 3 dollars postage and handling, right?

Duo-MP3, make use of your old cassette player!

[edgrale]

Check this one out. Cool or what? Too bad it's way too expencive, I wonder who will buy one for $250?
The idea is great though, use your old cassette players. Second bad thing is that it can only hold 30min of music.
They don't say how much the flash addon costs, but I bet it will be expencive also.

Oh well, bed time, night folks!

Receiver limitations

[Matt_Bennett]

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)

Mr. Microphone

[booch]

Isn't this the same thing as a Mr. Microphone? They used to advertise them on TV for kids. It was a microphone attached to a small transmitter that you could pick up on a regular FM radio between normal stations.

"Hey good lookin! Be back to pick you up later."

Re:Mr. Microphone

[jfunk]

I prefer "Mr. Boom Mike."

For the Canadian humour impaired, there was a parody of the "Mr. Microphone" commercial in an episode of SCTV. It was similar, but involved a very large professional boom mike requiring a boom operator.

Oh man, I love that show.

Re:This is...

[Grape Shasta]

If you talk to your landlord, he might not only allow you to run cables, he might do what mine did and pay for the supplies. My landlord is paying for cabling and a $200 router, and we're doing the work ourselves. We get networking, he gets his property upgraded for no labor cost. It's worth a shot!

Maybe it's just me...

[kmcardle]

...but if I can't hear my mp3s in the other room, I just turn up the volume on my stereo. It works wonders.

(OT) Re:900Mhz Wireless Headphones

[Chris Pimlott]

Offtopic, but which ones? How do you like them? How is the range? I've been considering wireless phones...

Please don't use these near my house...

[isaac]

These cheap 900mhz analog transmitter/reciever pairs just blanket the band with crap, squashing my ricochet service (which uses the 900mhz band for the mobile radios) and rendering 900mhz cordless phones useless. I don't know how the FCC allows them.

-Isaac

Sound quality

[Pacer]

Great! Now I can listen to music filtered through the MP3 codec AND through a $40 low-power transmitter/receiver set!

Pacer

Automated radio station?

[squiggleslash]

Ok, build one, but with components that allow it to transmit with a much higher amount of power. Now add a Linux box with thousands of MP3's (together with song titles), and a speech synthesis program. Put in a simple script to generate phrases like "That was Metalhead's 'Bite My Taco' followed by Deathgurgler's 'Wouldn't it be cool to beowulf cluster these things', now let's hear some Barfbreath...", and choose songs at random (or with some minor logic, you know, rate each piece as slow/fast/loud/quiet and put opposites together in the usual way)

You could then hide the "station" somewhere where it can't be linked to you, and see how many people start to listen to it before the FCC finds the box and shuts it down.

The possibilities are endless. You could set up "phone in" competitions using GOP telemarketer numbers. You could spread news and rumours (ie "And I've just been told that KFCs all around the city are going to give out free chicken to anyone who comes in within the next 30 minutes and says the words 'I'm a chicken, cluck cluck cluck' to the cashier".

I mean, wouldn't that be cool?
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The CanaKit Product

[SubtleNuance]

You can find the reference to CanaKit's FM Transmitter (thas has been /. ed) via Google's Cache here . Thanks to our friends at Google!

Note to submitters/slashdot editorial staff - why not provide a link to the google cache when linking to tiny sites like CanaKit in future.

Re:DVD/MP3 Anywhere

[Overt Coward]

The remote's a pain to set up, but mainly because it's designed to be extremely flexible. Once it's set up, it's easy.

Sounds like something else I've read about on /. -- frequently, in fact -- now what was it again... hmmm.. pain to set up... designed to be extremely flexible... darn! If I could just remember...

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wow, that was fast (Google cache link)

[inquis]

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

Re:wow, that was fast (Google cache link)

[slashdoter]

Thx for the link, I had forgot about Google's cache. Haaaa caching lets us have some much fun. Check out CNN from a month ago, or how about Yahoo. and yes we have to look at slashdot from the 26th. Kids can you say "time travel". Lets look at some more wired,Linux, and MSNBC. you to can have fun, just change the web address at the end of the URL and WOW! http://www.google.com/search?q=cache:www.msnbc.com

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Re:My GOD, the Canadians have invented. . .

[jfunk]

Actually, it was a Canadian (Fessenden) who invented radio as we now know it. He was the first to transmit an audio signal through the air. Before then, it was all morse code.

I definitely have to agree with you on the Mims books, though. I learned sooo much from them when I was a kid. I even remember going to Buffalo, NY to get the 3 mini-notebooks that weren't available in Canada at the time. For some reason, back then, there were three exclusive to the US, three exclusive to Canada, and three you could get in both countries. Now they're all available anywhere and there are new ones. I also highly recommend his "Getting Started in Electronics" book and the new flashy ones, "Basic Electronics," and "Basic Digital Electronics," written by other people, as well.

In fact, buy every book in that store. Nowhere else can you easily get excellent beginners electronics books for so cheap, especially since McGraw-Hill stopped the book clubs. :-(*

an fm broadcaster does the job too

[capefearsenior]

I built one of these using an cheap fm broadcaster from ramsey electronics. http://www.ramseyelectronics.com It works very well and did not costs 40 bucks.

Compare Kits

[SubtleNuance]

You can find a excellent comparison of Ramsey's and Cana and other exciters/low power transmitter kits here.

My GOD, the Canadians have invented. . .

[kfg]

RADIO!

I hope they don't patent it.

Seriously, go to the library, get out a book about hobbiest electronics, then go to Radio Shack and buy the bits for five bucks or so. Hell, buy the book at Radio Shack for a $1.99, Engineer's Mini-Notebook-Communications Projects, by Forrest M. Mims III.

You might even, God forbid, learn something in the process.

So..

[mindstrm]

What does this have to do with mp3, exactly? It's an audio -> FM transmitter. very common, you can buy kits all over the place, and have been able to for years. Same stuff old (and new) CD changers work off of.... very simple circuit to build yourself.

How is this news?

Re:900Mhz Wireless Headphones

[Nerds]

clotheslining yourself while rolling around the lab sucks

Yeah, but getting co-workers is kinda fun...

Also from x10.com

[bluestar]

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

Don't do it!

[Evil_Way]

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!

Re:Don't do it!

[WillSeattle]

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.

Funny. Actually, though, most "US" satellites and telecom devices are Canadian, except for the other ones made in other countries, so it's too late.

They want "one million dollars!" for the data. To you, that's not much, but it's like a billion Canadian dollars, with the current exchange rate. In fact, the entire Canadian banking industry almost collapsed when Bill Gates accidentally wrote a check in US dollars to buy out a Canadian firm instead of the quoted Canadian dollar amount.

Why just MP3?

[Cavio]

I prefer to use an array of them as a repeater net for my home surveilence system. So far, my efforts have been concentrated around the area of my female roommates bedroom... ;)

900Mhz Wireless Headphones

[Dice]

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 :)

Haha.. also

[mindstrm]

Someone mentioned the 'Win 95 compatable' power strip. Also known as the 'plug & play' power strip.
Also, I've seen plug&play UPS units (though they arent' actually manageable, so they act like a power strip).

Then there's the 'soundblaster live mp3+' which is really the exact same hardware as the 'soundblaster live x-gamer', and the 'soundblaster live value OEM (though the oem one is missing 1 smd resistor pack and the digital CD in, but you can add them yourself).

Then there's 'digital ready' headphones.... that's funny. let's see.. what else....

or like 'Cholesterol free' or 'Fat free' bran flakes during the cholesterol retail wars.... yeah. They were ALWAYS fat free. Funny.

There are a plethora of 'plug&play' and 'windows XXX' compatable serial/keyboard extender cables (just cables.. not active components).

I know there was an even dumber one I saw.. I can't recall what it was, it was so dumb. Something like a keyboard dust cover or something that was 'win98 compatable'.

Of course, there's the new buzzwords too, right?
'p2p' for napster/gnutella stuff. How is that new?

There's the SAN (storage area network).. which really isn't something new.. though it's certainly come of age.
When I think 'storage area network' I think of ip over scsi! not some kind of fc-al disk array...

Ha.

Stereo Xmitter

[inKubus]

Why not just buy a nice STEREO FM transmitter from http://www.ramseykits.com/ ? 34.95, transmits up to 1/4 mile to any FM radio in the house. I got one and they rule. Seriously.