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An FM Broadcast Transmitter For Your Home
Bruce Perens writes "I wanted to be able to listen to net audio and my ham station around the house and yard. Those iPod FM transmitters don't have enough range. So, I bought a digital controlled, 100 miliwatt transmitter that covered my whole block the first time I plugged it into what was, until then, a recieving antenna."
Now every kid on the block will have their own radio station!! won't that be fun for like.... a week?
Just look in the DIY kit section of any electronics store, there's always a number of small FM transmitters, some of which get 2km range.
They usually have an electret microphone, but it wouldn't be very hard to modify one to take a line-level source.
I can listen to what I want anywhere.
Dancin_Santa > Bruce Perens
Ham radio users are quite a bit less technically savvy than they used to be.
Old school Ham Dancin_Santa > Bruce Perens
Doesn't mean anything, but these are all just bits on the Internet.
Cause that's what the FCC will slap on ya.
Just saying, you don't want to be fined or anything while conducting your perfectly legal broadcasting...
should read..
...that covered my whole block the first time I plugged this product on Slashdot."
"
All the images on the linked page are exactly the same as the site selling them.
... has similar stuff - like this. And that's not the only one. they do various versions for, say, in-car use.
interesting way of sharing music - your own mini radio station
Screw you all! I'm off to the pub
if lots of people in the same block start using this?
.at least in europe it is almost completely filled up in the range that all commercial receivers use.
Is there some sort of auto free-carrier slot detection? because if there isn't, it will be nigh-on impossible to listen to the radio without interference.
The fm-band is pretty full already
I'd be pretty miffed if i could not receive my favorite radio stations anymore because some people near me like to listen to deutche schlager zangers or techno.
Didn't we all learn our lesson from "Pump up the Volume"?
you could just turn your speakers all the way up.
Don't violate any FCC regulations, and keep this to yourself so the RIAA won't come after you.
Use ISO 8601 dates [YYYY-MM-DD]
If you play music, can the RIAA sue the air for abetting the distribution of copyrighted material?
UTF-8: There and Back Again
So what kinda receiver do you carry around that's more convenient than an ipod?
----
Some people are good with words, others,
The VHF broadcast band is a regulated resource. What you have created is, in effect, a pirate radio station with all the regulatory and copyright issues that that entails. If the FCC/Ofcom or whatever regulatory authority covers your area doesn't take an interest in your "personal radio station" in fairly short order, I'll be very surprised. The performing rights organisations may take an interest, too.
In short, you will be very lucky if you get away with this for long.
Resistance is futile. Reactance buggers it up.
Be careful
Here in Israel there are a number of pirate radio stations. This is not itself a problem but they are using poor equipment and blasting harmonics onto aviation frequencies. That is bad. It has gotten to the point where the ATC folks have threatened to strike if something is not done about it because it can threaten aircraft communications.
Erlang Developer and podcaster
It used to be. As a ham you SHOULD know this. The rules regarding unlicensed broadcast transmission in the FM band changed. You can, in fact, use any amount of power you want. That is, as long as you don't excced 250uv/meter measured at a range of three meters.
For most of the unlicensed stuff that translates to roughly 10 to 20 mw. This is governed by part 15 of the FCC code and you can read even more about it at http://www.fcc.gov/mb/audio/lowpwr.html#PART.
That would have been great for around the farm when I was a kid.
While driving the tractor about 60 hours a week throughout the summer, I had my choice of precisely two stations. One was country and western and the other covered things like little league baseball games and the farm reports.
There still would have been a problem -- I didn't have anything at home that would have been worth broadcasting. After all, attaching a microphone and listening to the dogs barking occasionally would have gotten old real quick.
We got a great big convoy...
--
"Insert witty quote here."
If I was to buy the 2 Watt model and the antenna...
1. What kind of range could I expect from this combination? I have 15 acres and would love to have my entire MP3 playlist running rather than just my favorite 512MB from my flash-based player while I mow the lawn.
2. With it cranked up to maximum power, would I be likely to recieve a visit from the FCC? I'm about 25 miles from the nearest city and there are very few radio stations that come in out here, so I'm not likely to step on someone else's frequency.
3. If I did end up with the FCC on my doorstep, what's it gonna cost me?
I used to get high on life, but I developed a tolerance. Now I need something stronger.
Going to the store page reveals that a 0.3W transmitter costs a wild $140. Yes, there's an LCD and menus, but no self-respecting budget-minded geek would lay down that much money to broadcast music over a short distance.
There's plenty of circuit designs at ePanorama that are relatively simple and powerful. DIY; save your money and your honor.
Will nock your doors down?
The only person who is capable of killing my karma, is me, do not even try to help me.
... or another good reason to get a good cancer...
I bought the CCrane transmitter http://www.ccrane.com/fm-transmitter.aspx/ and perfomed the easy mod http://www.xmfan.com/viewtopic.php?t=3257&postdays =0&postorder=asc&start=0/ to increase it's output power.
It works great and covers the entire house. It's cheaper than the original post and includes a case and power supply (problems that the original poster had with the ebay one).
link
For number 3.
Just because you can't hear it doesn't mean you aren't interfering with others. The FCC has monitoring stations throughout the U.S.
Using two watts might just net your a visit.
How would they go about finding out if this guy was broadcasting within a 100 foot radius of himself anyways? Do they have people going around hunting down signals or what?
[EOM]
Not so insightful. If you read the article, you'll notice that Bruce set the output to 100 mW. There was a reason for that: unlicensed transmitters at 100 mW or less are legal in the FM broadcast band.
1: You might get surprisingly long range reception. From my experience on the 145 MHz Ham band, I can easily communicate 30 miles with less than 1 watt with a roof-mounted antenna (of course the receiving station also has a good high antenna). There are differences that will reduce your range (particularly the wide bandwidth of the signal), but in general 2 watts can potentially cover a very wide area..
2. Yes, particularly if the antenna is high up and your signal gets into the city, or if your transmission annoys anybody for any reason.
3. $10,000 a day fines and your equipment (and possibly other nasty things I don't know about!)
I didn't read djplurvert's post a few down. Well, at least Bruce was trying to be legal.
Ultra cheap FM transmitters use a tuned tank circuit to control frequency (ie - a variable capacitor). These are very difficult to get to the exact center of the frequency you choose, the result will more than likely be poor audio response.
Furthermore, your receiver is probably digitally controlled to an exact FM frequency and the variable cap system will change frequency slightly with temperature and humidity, so that the transmitter will slowly go in and out of channel. The receiver is phase locked to the correct channel, and the result is that the system will gain and lose quality over time. Digitally controlled frequency is a must for this application.
Kit systems are usually poor at doing audio; making a noise-free circuit is somewhat of a black art and it takes a lot of research and tinkering to get it right. For example, Ramsey Electronics makes an FM transmitter kit with digital frequency control and all that. The problem is that the board layout introduces an unacceptablt amount of hiss into the audio signal. No amount of adjustment will fix this, and the average hobbyist is unprepared to even figure out what the problem is.
Finally, Be very careful of high end ($300) transmitters used for gyms. Some of them are mono only (!) but do not specify this on the advert.
Your best bet is to look on the net for reviews of any transmitter you're thinking of buying. When people have good things to say and don't point out the obvious flaws, then the product might be OK.
I purchased several poor FM transmitters before I got one that worked well, and I use it for transmitting FM throughout the house.
That would be the C.Crane FM transmitter. You can get it for about $80, and Froogle lists several vendors.
On FM frequencies, these devices are limited to an effective service range of approximately 200 feet (61 meters).
/ Documents/bulletins/oet63/oet63rev.pdf
source:
http://www.fcc.gov/mb/audio/lowpwr.html
see also:
http://www.fcc.gov/Bureaus/Engineering_Technology
Bottom line:
The transmitter described is not even close to complying with FCC regs. FCC compliance depends not only on transmitter power, but also on antenna gain and several other factors. You cannot simply say "X milliwatts is safe". Not only that, but 100mW into almost any antenna is going to be a violation. Something in the range of 1mW into an omni antenna would be more like it.
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All of whose base are belong to the what-now?
You can buy LEGAL cordless headphones and such which operate in the 900 MHz band at Radio Shack and other electronic stores. You can buy headphones, speakers, receivers to plug headphones into, etc. These are assigned to their own LEGAL band which won't cause interference to FM broadcast stations. Range is about 150 feet max.
The jews did not do the wtc, the pentagon yes but not the wtc.
The Homos' did the wtc. It's all part of their plan to bring the Nazi party back to power after reducing the US population down to a bunch of subservient rednecks.
"You can see I know very little about pimp policy." George McGovern.
If you just want a radio station in your home it would seem to make more sense to use a Carrier Current transmitter. What this guy is doing is pretty damn illegal and if you do what he did you can be looking at tens of thousands of dollars in fines!
From what I can tell anyone can setup a Carrier Current station(check for yourself), you can find some pretty cheap kits.
This guy doesn't seem to be all there, he says he has a HAM licence, but is stupidly violating FCC laws. He also says the thing has a BNC type connector but the picture looks like a type RG6 connector.
Ramsey has what looks to be a gret new kit - see here:
. exe?preadd=action&key=FM30
. exe?preadd=action&key=FM100B
http://www.ramseyelectronics.com/cgi-bin/commerce
I have this one already and, though large, it is excellent.
http://www.ramseyelectronics.com/cgi-bin/commerce
As mentioned here, the unit is not FCC approved. Once this guy comes onto the radar (by a slashdotting, for example) he might well get a call from the FCC.
In Europe it is not permitted to use any transmitter on broadcast frequencies, unless you are a licensed broadcaster. And it doesn't matter how low the output power is, so those Ipod thingies are not allowed either.
I got all excited there for a second with visions of covering downtown with some good, commercial free music. 100mw and a short feed to a good antenna on the roof of my building would have done the trick for many blocks around me.
I looked into a 'real' low power FM setup and it seems you have to be a 501C3 religious or educational organization, can't use directional antennas, can't look funny at people on the street, can't name your cat Morris, have to blow the FCC OO, and that was just the rules for the first page - quite a lot of work for the privilege of spending $6,000, eh?
Maybe I'll just hook the 300mw unit to my attic 2m and run it when the mood takes me
I am very easy to get along with, but I don't have time to waste being nice to people who are being stupid. -Theo
Think about it, grab a embedded linux system with onboard sound and network (wifi or ethernet), have a central server broadcast non-RIAA regulated tunes, then find people willing to stick one of these up where they live. Have enough people do this around the area, and boom, you have a radio station which the RIAA can't touch (because they don't regulate the music on it), the FCC can't exactly complain about (broadcast power on each node doesn't warrant a license right?), and annoying the hell out of the local commercial radio stations.
The only problem I could see is keeping each broadcast node in sync, especially if you're all broadcasting on the same frequency.
Thats people power for you.
a two watt transmitter and a proper antenna would give you at least a 5 mile range.
From the photo, the circuit board looks to be no better than prototype quality. It doesn't even have a soldermask, let alone silkscreening. The layout seems rather inelegant, as well. For $140, one has the right to expect a well-designed, commercial-quality PCB. This one clearly is not.
What other stategy is there?
ATC "Hey, boss, those pesky radios are causing a danger to air traffic. If a plane crashes I will be blamed for not getting something done about it!"
Boss "STFU and get back to work. Don't worry, in the event of a crash I will protect my own ass."
They whose government reduces their essential liberties for temporary security, receive neither liberty nor security.
Does hating liberals make you feel better about yours?
It seems like a better tool for the job might be GNU Radio...
From a pure legal point of view (regulation concerning the FM band, the privacy of short waves transmissions a.s.o), it could be more interesting to use another dispatching technique. Why don't you choose a simple bluetooth piconet (quite efficient in voice transmission applications) or a 802.11 network and a VoIP protocol ? The WiFi receving part could be very expensive... and you have to hack a WiFi based phone gear to receive your audio. But Ethernet is powerfull enough to offer you the "way back" that FM transmitters cannot afford. Data stream tho change the frequency or the band, for exemple. :- )
Using Bluetooth is cheaper... wireless headphones are sold in every cellular shop, and the hack of the transmitting part could'nt be a big problem (a used PDA sold on e-bay, a bluetooth pcmcia card...)
A third and simpler solution is to use a Dect or any UHF 900 MHz hand free phone system, directly plugged in the audio output of your rig (your even can use the mic input...). Most of those phone systems have intercom capabilities. You even can, depending on you installed base, use the DTMF signals to remotely control your ham equipement. Could be fun
Yes, in fact, "low power FM" is NOT really available to individuals. Look for information on micropower FM. Micropower is the term typically used for part 15 unlicensed transmission. You can cover a few blocks LEGALLY without a lot of cost in some circumstances.
You can own up to six part fifteen transmitters by fcc rules. What some people are doing is using multiple transmitters fed with the same audio signal.
I'm surprised that slashdotters aren't very aware of the issues of micropower broadcasting as it is about "your rights online", in a matter of speaking.
Google for "micropower FM" and you will have enough to read for a few days.
that you have an Ipod
Well, that kit can be run from 10 to 300mW in 10mW steps. So, it can be dialed low enough to be legal.
Store with salt
... a few weeks ago, my nephew showed his Ipod FM transmitter he got with him from the States. It's quite neat, and the power is low enough not to disturb your neighbours' radio. But, in The Netherlands it's not allowed (though I don't see how the 'radio controle dienst' (dutch FCC) will find out about it, as people mostly use it in cars.
In other news, frequencies for radio-transmitters in the FM-range where auctioned last year for a few billion euro's. In the end, it's all a money thing.
Slashdot: stuff for news, nerds that matter, matter for news, stuff that nerd
Although I don't expect a person who lives on a 15 acre lot 25 miles from the nearest city to act logically.
Well yes, but to be clear, that's NOT what makes it legal, what makes it legal is that it is NOT radiating more than 250uv/meter at a distance of three meters from the antenna. That might be lower than 10mw in some cases.
Now, frankly, I don't think the fcc is going to get TOO uptight if you are using it in a responsible fashion and are reasonably close to the legal limit.
However, the larger point here is that people buying transmitters from ebay OUGHT to be doing some research before putting them on the air. They should certainly look things up before presenting their half baked ideas to salivating slashdotters.
One of my hobby projects is searching the shed and attic for the $5 FM sender (100mW) that I once bought and soldered together to experiment with digital transmission (wanted to hook it up to the serial port) through the radio (cheap...). It would kill any other radio station using the same frequency in my block, and it could be received throughout the street (we did not live in a very long one though). I used half a meter of copper wire as antenna.
I wonder why (1) they are no longer for sale at all in the Netherlands (Velleman kit), and (2) why the alternatives cost over ten times that much, and provide less than a fraction of the output.
Musicians don't die. They just decompose.
The FCC has monitoring stations throughout the U.S.
And for many areas without stations they are quite infamous for little black vans with lots of antennas on top and very small white letters that say "FCC"
The FCC are not idle people, and they not only track you down (if you are radiating RF it's emberassingly easy in case you didn't already know), but they confiscate your equipment also, and you will not see it again. Also, you might have to come up with serious cash for the fines.
Contrary to what you might think, they still chase after CBers with illegal amps too.
I'm someone with a ham license, and am somewhat disappointed with Bruce for advertising something like this, as it goes against the ham ethos of responsible use of technology (esp. radio). If not for his own sake, but for others that will ignorantly decide not to go with the seemingly innocent 100mw version, but those who decide bigger is better and move up to 3 watts, which blows the doors off part 15.
I say seemingly innocent, because if you pump this out your standard home fm antenna as suggested by some, these are almost always a yagi that has gain and will certainly exceed the 250uW at 3 meters.
If enough of these pop up, you can count on NAB to become the next dirty acronym on slashdot, as they become more proactive in squelching (pun convenient) the competition. Except that these guys have a vast amount of caselaw/FCC resources to help back themselves up with.
I truly believe that there is a need for Low Power FM broadcasting, contary to what NAB and NPR propaganda tells you. But breaking the law rather than working to change it is not the way here.
I can't help but wonder if Bruce didn't confuse AM Band with FM band concerning power levels. Without pulling out my calculator, I don't see how 100mW can be legal for FM unless you are using an extremely long length of coax. I believe that the max you can have going to the antenna is around 1 mW.
I hate to take of the rose colored glasses on this one, but it's a bad idea all the way around.
That was retarded...yet funny.
To comply with the unlicensed rules, you need to turn that thing down by a couple orders of magnitude. The lower limit isn't actually in watts, it's actually something like 85uv @ 3 meters. I don't recall exactly, but it's not my ass on the line here... go read the rules before yous gets busted. :-)
To comply with the licensed rules (you said you don't wanna lose your ham license), you need to start broadcasting your call sign periodically. Worse, you need to stop broadcasting music - mostly because the FCC will kick your ass for abusing your amateur license (again, go read the rules), but partly because the artists' organizations may kick your ass for not paying royalties. Yeah it's only your neighbors you're entertaining, but they can be every bit as abusive as the FCC.
Wait... did Bruce P write that article, or does the story just link to some random guy who bought one of these things?
For (1), check out this very recent /. article. 40.6uW gets you 546.8 miles. Admittedly that's only a beacon station and not going for anything complicated like FM, but even so your signal could be going a lot further than you expect.
:-/
Which kind of ties in to point (2). "If you build it, they will come." The point isn't that no-one else happens to be using the frequencies, the point is that you're using a regulated resource (EM bandwidth) and if one person gets away with it then everyone will have a go. I know that's all screwed up, but I'm not the one running the country.
But for point (3), the fact that there's no-one else on that frequency will likely mitigate the penalty (which will probably just be a letter saying "don't do it again"). Especially if you're not trying to do a "real" pirate radio station. Claiming ignorance will probably get you out of the worst of it if you haven't done any damage.
Grab.
Well.
1) As I have ALREADY stated, it's 250uv/meter at three meters.
2) Licensed hams, like everybody else, can use part 15 rules to transmit if desired. Further, since there is no such thing as part 97 (ham radio) transmission in the FM broadcast band there is NO need to transmit one's license or restrict themselves from playing music.
Since we are all talking about getting busted and such I thought I might mention Free Radio Santa Cruz which has been around for over 10 years. They were just recently busted and the FCC just shut them down. You are not gonna get busted by the FCC if you do this. If the FCC wants to bust you they must come to the place first and notify you to stop. If you do not stop they can come in and take your equipment . I have never heard of anyone going to court ever. We need more community radio stations with more diverse points of view. So I encourage you to break the law and be a Dj. If you want to learn more about pirate radio go here http://www.frolympia.org/website/index.php?module= pagemaster&PAGE_user_op=view_page&PAGE_id=6&MMN_po sition=6:6
Listen to Free Radio Santa Cruz and Free Radio Olympia.
We've had a similar transmitter in our house for a few years now, and I do recommend it for parties. Basically, the setup is:
1. Switch on machine with mp3 store
2. Create vast randomised playlist
3. Switch on the transmitter
4. Switch on every radio in the house
5. Open case of beer / chosen drink
6. Party party party!
And voila, synchronised music in every room that wants it.
One issue though is that we have to drop the output power of the transmitter to avoid interfering with anyone else's radio - here in the UK they don't take too kindly to that.
- this is the same bonehead that advocates 'dumbing' down of amateur radio by elimination of the FCC Element 1 code exam for HF frequency privileges for U.S. amateur radio operators
- he's also the person pushing for dilution of the definition of free software by obfuscating what 'free' really means in the minds of the public... no wonder he's been ostracized by the free software community...
- i'm sick of listening to his whining, self-serving diatribes...
- at least i can have a little self-respect and look myself in the mirror in the morning - i didn't make a career out of promoting myself
Especially when you can go with one of these for a fraction of the cost. True, a little modification may be necessary, but hey, we live for that sort of thing, don't we?
End of Line.
You can, in fact, use any amount of power you want. That is, as long as you don't excced [blah blah blah...] that translates to roughly 10 to 20 mw.
Hey Dad, is that you?
One lucky farmer who was a HAM radio operator, actually made a conntact with the Space Shuttle while out plowing the back 40 about 10 years ago.
He didn't have a notebook, so he scratched the shuttles call sign onto his tool box.
Waaaay GEEKY!
sexually...
- I'd prefer not to.
$75,000.00 fine...
PENALTIES FOR OPERATION WITHOUT A PERMIT OR LICENSE
The Commission considers unauthorized broadcast operation to be a serious matter. Presently, the maximum penalty for operating an unlicensed or "pirate" broadcast station (one which is not permitted under Part 15 or is not a Carrier Current Station) is set at $10,000 for a single violation or a single day of operation, up to a total maximum amount of $75,000. Adjustments may be made upwards or downwards depending on the circumstances involved. Equipment used for an unauthorized operation may also be confiscated. There are also criminal penalties (fine and/or imprisonment) for "willfully and knowingly" operating a radio station without a license. DON'T DO IT!
fools do this kind of stuff. and yes, they will find you. and probably label you as a terrorist.
I can rebroadcast the Stern show from Serius in 2006 for all my neighbors or his former FM frequency... lovely.
Sorry, I'm not sure if I read that right? There's a political party in the Knesset that operates pirate radio stations?
;)
Out of curiousity, is pirate radio used to promote the party, or is the party used to promote pirate radio? Or did I just completely misunderstand you
(Just curious - I have little knowledge of Israeli domestic politics)
This is where the serious fun begins.
Pssshhh...I've been doing this since the 70s when I was telling that good looking girl I'd be back to pick her up later...
Bruce
Bruce Perens.
Whats wrong with the perfectly good geek solution of WIFI and a PDA? PDAs can play media streams these days and you could even change station, surf the net and post to /.
Isn't rebroadcasting amature radio broadcasts over FM radio against amature radio regulations?
Allegedly Illegally broadcasting allegedly illegally downloaded mp3s.
Join the Slashcott! Feb 10 thru Feb 17!
Bruce
Bruce Perens.
http://www.ramseyelectronics.com/cgi-bin/commerce. exe?preadd=action&key=FM10C
Join the Slashcott! Feb 10 thru Feb 17!
Wouldn't it be safer and more secure to use WiFi to transmit and use some sort of PDA/Hacked portable WiFi radio to listen? It would have the added bonus of being two-way allowing you to transmit back to your ham radio and also to change song tracks? And obviously the most important advantage - mobile porn..
This comment does not represent the views or opinions of the user.
From radio-info.com (emphasis mine):
The guy reviewing the unit seems to think some company produced this unit. Its pretty obvious to me (maybe because I do the same kind of thing) that its built in someone's garage. Its a generic PCB with components that were obviously hand-soldered.
Mind you, I'm not complaining. I'm just saying that the reviewer doesn't seem to get it.
is a good thing, if you limit it to the "not trampling on people's rights, and sticking to the business of keeping others from doing the same". When the government gets into the "everyone must be equal at all times" game, thats when things start to get ugly.
I want to delete my account but Slashdot doesn't allow it.
I'm interested in this type of setup to rebroadcast a station that I can only receive w/ a roof mounted antenna, so that I can get it on my clock radio and other radios throughout the house. Is it possible to broadcast at a power that is legal, yet still have decent coverage in a single family home? Also, would rebroadcasting a station be illegal?
It is absolutely untrue that unlicensed transmitters at 100mW or less are legal in the FM broadcast band in the U.S.
Well, actually, it is true that some unlicensed transmitters at 100mW or less are legal in the FM broadcast band. But only those that operate at far, far less than 100mW.
I'm really surprised that the person who wrote the original article (i.e., the one who posted on technocrat.net) admits to being a ham operator, but then seems to know nothing about part 15 of the FCC regulations. If you want to know all about the limitations on unlicensed operation, you need to know part 15 -- no excuses. And the 100mW limitation applies ONLY to unlicensed transmissions in the AM broadcast band, and NOWHERE ELSE. Instead, each band in which any kind of unlicensed transmission is permitted is subject to its OWN RULES.
See: FCC rule regarding unlicensed operation in the band 88-108 MHz (Note that although this document is served by akamaitech.net, the source of the document is the U.S. Government printing office)
FCC PDF document with all you ever wanted to know about unlicensed operations under Part 15
Ramsey Electronics kit page with FCC information regarding lawful use of low power transmitter kits
American Radio Relay League (ARRL) information on part 15 of the FCC rules (The ARRL is the largest national organization for ham radio operators)
Note that the actual permitted field strength for unlicensed operation translates into the a signal of only a few nanowatts -- around the single digit range -- certainly not anything even remotely resembling 100 milliwatts!
Thus, the immediate parent of this comment should be modded WAY down -- it certainly isn't "informative." If anything, it is perpetuating misinformation that could get someone into serious trouble.
Irrespective of any other rule, for almost all frequency bands, you can't have more than 1 watt ERP. Neglecting cable loss for a moment (yes, I know), if Barry feeds 100mW into an antenna with more than 3 dB of gain, the ERP will be more than a watt, and most definately illegal here in the U.S. Most 'omni' antennas actually have a donut shaped pattern, and can easily give 3 dB of gain. A one watt signal is easily visible from a mile with good line of sight, way more if you know what you are looking for. Food for thought.
Ramsey Electronics Has tons of DIY FM kits, and even some very high end professional equipment.
They also have tons of other hobby kits for electronics.
Apple free since 1990!
what about the people who dont give a damn (like me) who just like to bop out radio waves. this is a neat looking device with +/-1khz PLL thats not that bad looking. the shit i use now is far more inaccurate that that. - actually just emailed the guy to buy one since its cooler then the one i currently have. and if i can shoot 1.8w into space all the better.
THAT'S why when Israeli "Defense" Force rockets a "terrorist" palestine leader, it also kills 15 more people living in the same neighbourhood, right?
Man, i owe an apology to Sharon...
I don't have a sig.
Than when the topic is P2P everyone either says it's "fair use" or even if it is illegal, you're chances of getting caught are so small it's never going to stop it anyway.
But when the topic is FM transmitter, suddenly everyone comes out of the wood work and posts about the illegality of the situation.
Let's set the record straight. The FCC will shut down your station, if and only if, a broadcaster complains. And because anyone smart enough to set up their own FM transmitter is smart enough to choose a frequency not already occupied by a local station, the FCC will never shut them down. Never.
I know a group of people who run a pirate station which transmits over 20 miles and have run it since the early 90s. At one time the FCC got a complaint from a local station, the FCC investigated, found it didn't really interfere, and so it did nothing.
If someone says he and his monkey have nothing to hide, they almost certainly do.
Ok, so you willfully violated FCC regulations by transmitting with an unlicensed transmitter in the FM broadcast band in excess of the allowable ERP for unlicensed transmitters.
You also put you amateur radio license in jeopardy.
Any person off the street might violate the unlicensed transmitter ERP and plead ignorance. Anateur radio operators are supposed to know better.
I was really suprised to look at the poster and see it was Bruce.
. there used to be a sig here.....
I have a Belkin Tunecast II and it's nice to be able to select the frequency but the receiver or antenna has to be practically right beside the thing to get a clear signal.
As a Ham radio operator, using it once as a test device might be OK, but no more.
These devices are ILLegal no matter how you slice the dice.
Are the transmitters attached to the same antenna, other wise there would be a phase shift problem with mulitple antennas
You know, it's interesting that I don't see such a flood of "that is illegal" comments for stories regarding filesharing, wardriving, etc. It's actually a decent idea - an FM system capable of covering a single home. Much like the range of WiFi without directional antennas.
I think the two things that caused a backlash with this story were covered my whole block and ham station. Hams can be pretty rough on one other regarding regulations.
Dan East
Better known as 318230.
Everyone is sick of political parties everywhere since a long time. If a used car salesmen lies enough in many countries you can charge them in court with false advertisement. If a politican lies, he does a good job and will climb up the hierarchy of politics! What a sick world where used car salesmen are held to higher standards than statesmen who marshall millions of mankind.
This has to be a cheaper solution than the digital media receivers that I've been looking at -- not to mention more versatile.
One man's Funny is another man's Offtopic.
next week on a new series on slashdot entitled how to get arrested, modifying laser pointers for optimal aircraft interference.
This isn't some clever new idea, there is a reason things like this aren't sold.
ôó
It's hard to broadcast over a "real" commercial crap station. These things are pretty clean and people set them to empty space. Most people won't have the ability to build an antenna that gets out of their house, even in empty space, so you don't have much to worry about.
Where I live, there's no problem at all. There are ten houses on my block and many more free spots on the dial than that. I doubt more than one of those houses will ever want one of these devices.
My wife mentioned apartments as a likely radio congestion zone, but I don't think so. Most apartments only have one stereo, which eliminates half the need for the device in the first place. I want one in my house so that the boom box in the kitchen and the stereo in the living room play the same thing at a low volume. In most apartments, the boom box in the kitchen fills every nook and cranny of about four living spaces, producing a more realistic problem than your tuning worry.
Friends don't help friends install M$ junk.
But they'd have to get in line.
After the FCC, ASCAP & BMI get through with you, there will be nothing left for the RIAA.
If all you want is a signal in your house just wrap your house in foil and increase the signal untill you start getting tumors.
So, instead of paying $140, plus shipping, plus mods, and transmiting at above the FCC's legal limit, why not pay half the price, make no mods and be legal?
Oh! I get it. You make some money on the sale of these on eBay. Maybe even indirectly? That's cool.
(Thanks, Salshdot for the nice ad.)
Prior experience says that 1) if you were not really interfering with local licensed broadcasters 2) you were not collection fees of any kind (advertising is a very big no-no) 3) you were not broadcasting 24 by 7 and 4) you did not broadcast obscene material:
You get a letter (a big letter). You get a good talking to (take it politely, say you are sorry). You may or may not lose your equipment, but you need to sell it because they will return in short order to be sure that it has been disposed of in a responsible manner. Keep a record of who bought it because they will go to see them next.
This was several years ago. Post Sept 11 and post DCMA you may have a different experience, but somehow I don't think so. Real pirate radio is a different thing than clueless geek having fun. Just do not be stupid about it.
I would bet that if you were half-way careful and you live in a rural area with wide open FM slots that you could run a station long term with very little chance of repercussions. I was operating from central NJ (not rural) and it worked for several years, running at 4 watts, to a high gain omni on a 50 ft mast, six hours (8PM to 2AM) every weeknight.
It just can't be easy, can it?
How much longer do we have to put up with legal stupidity based on obsolete technology? The sooner traditional broadcasters and all the other copyright warriors go out of business, the better. Between frequency hopping and the ease of publishing, these people have no further reason to exist. Anyone can make high quality recordings now and everyone should be allowed to self publish. There is no longer a scarcity of broadcast frequencies.
The law should reflect that fact instead of getting tighter and encouraging more people to invest in obsolete equipment. Like dinosaur bones, FM radios belong in museums.
Friends don't help friends install M$ junk.
Do I hafta say it?
You know it....
No wonder America is turning into a police state. Half of the posters on here sound like they're ready to welcome one.
A guy is doing something cool and all anyone writes about is whether or not, and how, it violates some obscure rules. No one is going to be hurt by this. Shut up and learn!
I bought one of those little consumer FM transmitters (this was a Belkin model) that you're supposed to plug into the audio jack of your MP3 player, but it really sucked. The main issue is that reception was so bad it was unacceptble even if I put it on top of my car dashboard.
So, since the thing was so useless I was out thirty five bucks anyway, I took it apart. The antenna turned out to be a length of wire about two inches long stuffed into the same cable used for the audio jack. Obviously, this was nearly worthless. I drilled a small hole in the case and soldered in a piece of wire the right length for a half wavelength antenna -- a little less than 63 inches for the low end of the FM band. As a result, I can now broadcast all over my house.
Now, since I was using it in a car, a five foot piece of wire was a bit unweildy, so I wound it around a pencil to make a loopstick antenna. I don't know anything about designing loopsticks, but it still worked OK for broadcasting around the house. Basically, I'd guess just about any length of wire a few feet long would work way better than the tiny length of wire they were using.
The only remaining issue is that the volume is very low; you have to jack up the volume on your receiver nearly all the way to get acceptable listening levels. If you're planning on driving around town with your windows down so your car's subwoofers won't blow them out, this is not for you. Also, the sound is a bit muddy. I suspect that in order to avoid any FCC issues, they took a number of steps: using a low transmit power, using a worthless antenna, filtering out the high end audio frequencies, and undermodulating the signal. I could probably desolder and replace some resistors and capactitors or something if I were motivated enough to analyze the circuit. Plus, as an old fogie I'd have to learn to deal with surface mounting (I learned to solder on bakelite terminal strips for chrissakes). Altogether this is too much trouble.
I'd recommend that if you bought one of these consumer MP3 transmitters and found it totally worthless, then you should replace the antenna with any old piece of wire and it will gain enough range to be some use to you. If you haven't bought one yet, don't. Getting a device like this guy is using would be a bit more expensive but probably a lot more satisfactory.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Am I right in thinking that these units are also legal in Canada as we tend to "fall in line" with the FCC rules to avoid issues where border communities are very close together?
Or am I out-to-lunch?
-psy
Want a more mature forum than Slashdot? Try Technocrat.net
Does your sig imply that there could be a LESS mature forum than Slashdot?
I've tried the "Bought it in Compaq's" FM Transmitters in the Boston area, and found there were just far too many frequencies in use for such devices to be practical.
What does the slashdot crowd think would be a good way to let me listen to my portably devices in a car whose stereo has no Line In or Cassette adapter?
"Live Free or Die." Don't like it? Then keep out of the USA
The article specifies that the person connected his FM card to an aerial antenna. Could you connect your wireless router to the aerial antenna as well? I have an aerial antenna, but do not have a wireless router. (Yes, I'm a little behind on my technology purchases...)
Why did I lurk so long before registering for a Slashdot account? I could have had a Slashdot ID of less than 100000.
Some buddies and I use to do this same sort of thing by hooking up a 9 volt power supply to a Mr.Microphone. The Mr.Mic was a 1980 something kids toy that was shaped like a microphone that sent a FM signal about 15 foot. We cut the wires to the actual microphone and hooked up an RCA jack and then plug it up to the line out on a mixing board. Since I lived on the highest hill in town we could pretty much saturate my whole town of 1200 people with the signal. We totally thought we were the shit when Pump up the Volume came out. It was such great fun and my old school chum still has all the original broadcasts on reel to reel tape :P
"At first, we thought it was just another snake cult."
Any ideas on a suitable attenuator? I would imagine that you can attenuate the 100mW output down to 20 or 30, and bring it within limits. According to the FCC link in the grandparent, the FCC seems to be concerned more with your transmitter having a range of 200 feet or less, regardless of output power or antenna design.
There is no reasonable defense against an idiot with an agenda
:wq
...are complete pieces of shit. I've owned two; the first was bought for a rental car in California. It was by far the most pathetic little piece of trash I've ever seen, but, since the car came without a cassette deck, it was the only way to get a good amount of decent music into the radio and through the speakers. Only it worked for about ten minutes at a time, in fuzzy, flickering, tinny-sounding awful FM stereo. Whenever we'd near anything resembling civilization, the signal would fade and disappear as bigger FM stations overpowered it. At some points, moving the little channel selector on the unit and changing stations had absolutely no effect on the (complete lack of) quality of the sound. I was extraordinarily unimpressed by this $30 piece of crap.
So, obviously, I bought another one, later on, for another rental car. This was the Monster Cable version, which a few people had told me was totally awesome. Turns out, it had a really phat red LED on the top of it, but, if you can believe it, it actually sounded worse! Never before had I heard something so awful that cost so much (comparatively). I threw it away and used a $10 cassette adapter, which sounded about 100 times better and didn't fade in and out of listenability.
Has anyone ever used one of these things and had results that couldn't be characterized as "complete and utter shite"? If so, how far from civilization do you live? I'd be more than amazed if anyone had something good to say about these little turds of technology.
- A.P.
"Remember when the U.S. had a drug problem, and then we declared a War On Drugs, and now you can't buy drugs anymore?"
Hey from Pacific Grove California I could regularly hit 2m repeaters on the Santa Cruz mountains (about 40 mi) using a dummy load as an antenna from a 100mw handheld.
And of course I was able to hit satellite transponders routinely with my 2m ht so... don't underestimate the power of line of sight 73 Ko6eb
These folks have a PCI FM transmitter. It's been in production for a couple of years, going through various versions. From what I've read, they all worked very well. It used to have a Linux driver, although I can't check now as it is requiring registration. :(
Anyways, just another option if you're looking for this type of thing.
And being a licensed ham, the FCC can come knocking on your door at any time to inspect your equipment, as I understand it.
Actually, on ham bands, you cannot legally broadcast -- unless it's an emergency. You have to actually be talking to someone.
Play nice, and don't broadcast on or near anyone else. And give something back to the public by playing alternative news or other content that you wouldn't normally hear on the radio.
Usually you will get a warning letter first. If you shut down on receipt of this letter, they will leave you alone. If you continue to broadcast (or respond to their letter with one of your own that says "In your face, FCC! First Amendment Rights!" or something like that, they may just send a SWAT team.
I have heard that if you make it easy for them to find you (periodically broadcast a message that says "This transmitter is operating under Part 15 of FCC rules. If you are experiencing any interference with a licensed broadcast station, please call (your home phone number) to report it.") that they will be more likely to go easy on you. I've also heard some people say that you should do occasional station breaks for a station on the same frequency in the next state, so if your neighbors hear it they think it's just some weird atmospheric condition or something causing a far-away station to come in. The choice is yours, but be prepared to live with the consequences.
At 2W output, how efficient is the transmitter? Can I stick it into a 10cm radius ball covered with 10% efficiency solar cells, with battery, and hang several around an area for an "FM mesh" repeater network that's truly wireless?
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make install -not war
So you complain about the story of this hackable geek toy because it's for sale, yet you post an inferior product actually sold by a Slashdot advertiser? How many Slashdot "Good News for Nerds" articles report products for sale? How often does that piss you off? Why do you still read Slashdot?
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make install -not war
Bruce,
Unless you have a way to precisely measure the field strength of your transmitter, I would be wary of using an external antenna. I built a Ramsey Electronics FM transmitter kit once, and if I remember correctly the instructions indicated that the 250 microvolts at 3 meters should give you several hundred feet of range at best. You want to keep your ham license - just unplug the thing. You've announced to the world what you're doing, and the FCC loves to make examples out of rule-breakers.
Matt
N3SOZ
8 bit computing - It may be 2007 out there, but it's 1983 in here!!
Oh, there's no need to be super paranoid about it. Just dial the thing down to 10 or 20 mw, attach it to a 1/4 vertical and relax.
... I haven't been studying for my Extra class ham license like I should, but it's not too hard to calculate the field strength based on the transmitted power, coax cable, and antenna properties. Most station license applications base their results on these kind of calculation instead of extensive field measurements (or at least they did 20 years ago when I worked at a community radio station.) I *should* know how to do this.
-kf6iiu
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
Am I the only one who thought about putting together a cheap mini-ITX system, dropping the 2Watt model in, dressing the box up as something non-descript and totally not-computerific, configuring the system to play DI.FM's trance channel and dropping the whole contraption off in some non-descript closet in a forgotten office with a nearby LAN jack??
Might do wonders for improving music taste.
To clarify, HAMs can transmit one way traffic in the following conditions: A) emergency information, B) information of interest to Hams in general like ARRL reports or morse code practice, C) short transmitter tests, D) calling other HAMs, specifically or generally (CQ). These low power FM transmitters have nothing at all to do with ham radio. And if you use one and happen to be a ham, you are governed by Part 15 same as anyone else. Your ham license is irrelevant.
--Slashdot: News for Turds. Stuff that Splatters.
I see a lot of posts here about how this transmitter could possibly get one into a lot of trouble with the FCC. My question is: how are they going to know if I'm broadcasting a technically illegal FM signal that only travels a very small distance like a block or so? Do they have undercover listening stations set up every 1/2 mile in the city? Do they patrol the streets daily in black vans looking for unlicensed signals? Or do they only rely on complaints from citizens? (In the latter case, few are going to be smart enough to tell the difference between my private household MP3 station and bona-fide radio...)
Actually there is one part of Part 97 that may very well apply. IF You do identify your FM part 15 station with your ham radio call letters, then you are stating you are using it as a ham station, being it is both broadcasting and transmitting in the FM broadcast band, you are Violating your ham license as a ham license does not allow you to do either. So IF you use your ham callsign outside the ham band you are in violation even if your are legal in every other aspect under part 15.
See the Pictures of the Flood of '08
Actually there are many times you can broadcast on the ham bands. You can re-BROADCAST NASA transmissions for one, and that is allowed. Also there are such things as Beacons... those are broadcasting too, and they are also allowed. You may also broadcast bulletins of general interest to the Amateur Radio community --- these are called QSTs and are also explicitly allowed in part 97. There are even a few other cases where broadcasting is allowed.
For others reading this post do not confuse BROAD-CASTING with TRANSMITTING. Broadcasting is essentially point-to-multipoint transmitting or blanketing an intended area with a signal so many stations may receive it. Broadcasting is also ONE-WAY transmitting or sending a signal where a response is not expected, intended or even desireable.
Transmitting is merely sending a signal regardless whom or what the inteded recipients are.
See the Pictures of the Flood of '08
funny how your only other post on slashdot COMPLETELY CONTRADICTS your claim of snipers FBI and SWAT teams
Are you full of Shit Now or were you full of shit then?
It also sounds like your company couldn't get their shit together and every microwave outage was blamed on Pirate radio stations because the fucktard techs couldn't stop scewing up the system.
Snowden and Manning are heroes.
The FCC can "inspect my equipment" any time they want.
Snowden and Manning are heroes.
Most station license applications base their results on these kind of calculation instead of extensive field measurements (or at least they did 20 years ago when I worked at a community radio station.)
Fantastic, I can ask people who hate community based radio how to remain legal!
it's not too hard to calculate the field strength based on the transmitted power, coax cable, and antenna properties.
All the calculations in the world will do no good if the FCC decides to give you trouble and they walk in with a measuring device that says something bad. You are screwed the same way if you measured wrong.
This has been done before. When ham radio operators figured a way to deliver moving pictures, the TV industry changed the law to make it impossible. The effort was transparent then and it's transparent now. The federal government has been used again to shut down a potential competitor, regardless of how small a real competitive threat is represented.
This time, however, it's not going to work. People have discovered just how poorly the music industry has served them and they are not going to go back. Radio and recording as they existed 60 years ago are both dead.
Friends don't help friends install M$ junk.
I agree with most of the comments from everyone.
But range is not the only consideration here. Signal quality is VERY important for something like music, and it's tough to compare the usability of something like this with operating a low power ham station. If music was the signal quality of most of the ham stations/repeaters in my area, I would go NUTS! Not to mention the constant intermodulation and natural interferance.
Alas, someone in our neighborhood has a pirate station, and he's belting it out so high that we get interference on Ch 6 both off the air and on cable. Outside of driving around looking for a melting antenna, any idea how to sniff these idiots out?
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
If you wish to assert that FCC sends the hostage recovery team to prosecute teenagers for out-of-spec transmitters that interfere with private microwave links and sends their moms to jail for 5 years, you will have to show:
Bruce
Bruce Perens.
you tried to use them across a different circuit (e.g., one in a bathroom, one in the kitchen, both on different breakers). Then there was a ton of interference. Otherwise, it was a pretty amazing set of cheap little boxes. I don't know if anything like that still exists today or not, but it was cool at the time (20 years ago).
That bitch is hot! Right Click ==> Save images as...
The CCRane FM Transmitter is well-liked on places like fixup.net and XMFan.com. The power output is "adjustable", too, if you don't mind voiding your warranty.
http://www.ccrane.com/fm-transmitter.aspx
Saving random seed...
If these little contraptions could transmit in tiny, precise bandwidths, like 89.01-89.02MHz (20KHz wide), they could transmit practically any human-audible signal, but allow a thousand stations to overlap signals in space. The FCC could carve out bands within the existing FM band for unlicensed operation at power levels large enough for a block.
With digital radio and DSP, the bands could be much narrower, Pulse Code Modulating the amplitude to signal in a single frequency. So a station could use maybe 89.0000001-89.0000002MHz, leaving space for 2 billion channels from 88-108MHz. That's a large enough space that it probably doesn't need registration - the odds of randomly stepping on someone else's channel are very slim. Optionally, one could just notify the FCC that one is transmitting at GPS coordinates x,y,z on frequency Q, so a later transmitter randomly starting up can be required to switch based on the prior registration. And, if the data is encrypted (even weakly) so access is only by explicit agreement between transmitter/receiver parties, the FCC really has no other business in regulating the transmission.
This all depends on improvements to the tech. Perhaps locatable transmitters, via phased-array receivers, or microbandwidth PCM transmissions, will arrive first. With open GNURadio "universal antenna" HW/SW now available, maybe it will come much sooner. It certainly won't come too soon for us to free ourselves of the FCC autocracy that rules us in the name of a "lowest common denominator" of public exposure that is governed by concerns "for the children".
- I'm Janet Jackson's less-famous other nipple, and I approved this message.
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make install -not war
I have a jos MP-300 and a lexar ldp-600 player. Lexar sucks, it does't even work at 1 foot proximity to the reciever. Moreover its uses my body as ground, have to touch their supplied antenna all the time.
But the jos MP-300 works well both in my car as well as at my home. I get a stereo quality. I can go 10-15 feet way from the reciever and still play it in my bose lifestyle speakers without any quality loss. I don't know its power. But it works though!
They would sue YOU.
This company has a FM stereo transmiter kit for $45 + $10 for AC adapter.
c tronics.com/cgi-bin/commerce. exe?preadd=action&key=FM10C
www.ramseyelectronics.com
http://www.ramseyele
But the point is, he is not using the part 15 rules anyhow (too much power) so nothing permitted under part 15 applies.
Good point about the lack of intersection between then FM radio band and the call-sign rules. Mea culpa.