FM transmitter question

[kissfan4]

Ok so i was wondering what the laws are regarding the use of a transmitter, so i emailed the FCC and this is what they sent me. Figured i would post it if anyone else was wondering.


Carrier Current Stations, also referred to as Campus Radio Stations or free radiator devices, do not require a license to set up or operate.

A license or a construction permit is required for forms of operation in the AM and FM radio broadcast bands which cannot be classified as Part 15 or Carrier Current Stations. This license or construction permit must be obtained from the Commission prior to construction of a broadcast station and before operations may commence. For example a license is required to operate a low power FM ("LPFM") or noncommercial educational ("NCE") college station.

Another unlicensed option for groups considering a carrier current station is to stream a signal over the Internet. At the present time, Internet radio is not regulated by the FCC. However, copyright and music licensing procedures must be followed.


Rules: CFR 47, Sections 15.207©, 15.209(a), and 15.221


Websites:
http://www.fcc.gov/oet/info/documents/bulletins OET Bulletin 63


Title: Low Power Campus Radio

FAQ's

1. What is the effective service range of these stations?
2. What frequency range do these stations operate on?
3. Do they require a license?
4. How are call signs assigned to these stations?
5. Are there any restrictions on content or hours of operation?


1. What is the effective service range of these stations?
The effective service range of a carrier current station is approximately 200 feet (61 meters) from the power line; however, a carrier current signal will not pass through a utility transformer.

2. What frequency range do these stations operate on?
A carrier current station consists of an AM radio frequency signal on a frequency between 535 kHz and 1705 kHz being injected into a power line.

Carrier current operation in the FM band is not technically feasible.


3. Do they require a license?
Carrier Current Stations, also referred to as free radiator devices and Campus Radio Stations, do not require a license to set up or operate. Although an operator does not have to obtain a license to use a Part 15 transmitter, the transmitter itself is required to have an FCC authorization before it can be legally marketed in the United States. This authorization requirement helps ensure that Part 15 transmitters comply with the Commission's technical standards and, thus, are capable of being operated with little potential for causing interference to authorized radio communications. Carrier current stations and other Part 15 operations must not cause interference to authorized stations, and must accept any interference caused by authorized broadcast stations.


4. How are call signs assigned to these stations?

The FCC does not require or assign call signs for these stations. If the station wishes to select its own identifying sign it may do so. However, to avoid potential confusion with licensed stations and any trademarks they may hold, the station should not re-use a call sign assigned to any existing station that is capable of being received in the same area.

5. Are there any restrictions on content or hours of operation?
FCC rules such as minimum operating schedule and public service requirements do not apply to unlicensed stations. Carrier current stations may air advertisements. The FCC's enforcement of indecency polices does not extend to carrier current stations. However, the college administration generally implements and administers its own policies on such matters. General First Amendment principles apply. For example, content that is obscene or likely to cause imminent public harm (such as yelling "fire" in a crowded theater) is not protected speech and could subject the operator to action by a private party who experiences resulting harm.

AND

Unlicensed operation on the AM and FM radio broadcast bands is permitted for some extremely low powered devices covered under Part 15 of the FCC rules. On the FM broadcast band, these devices are limited to an approximate effective service range of 35-100 feet. The Maximum Effective Radiated Power (ERP) is .01 microwatts. The rule actually specifies a limit of 250 micro-volts per meter at 3 meters. See Part 15.209 and 15.239. These devices must accept any interference caused by any other operation, which may further limit the effective service range.

These devices must accept any interference caused by any other operation, which may further limit the effective service range.



Rule: Part 15

Web Site(s): www.fcc.gov/oet/info/documents/bulletins OET Bulletin #63

1. What are the permitted power levels for these devices/ transmitters?
The Maximum Effective Radiated Power (ERP) is .05 watts on the AM band.
(See Part 15, 207, 15.209, 15.219 and 15.221)

The Maximum Effective Radiated Power (ERP) is .01 microwatts on the FM band. The rule actually specifies a limit of 250 micro-volts per meter at 3 meters. (See Part 15.209 and 15.239)

2. What is the approximate range of these devices/transmitters?
On AM broadcast band, these devices are limited to an approximate effective service range of 200-250 feet.

On the FM broadcast band, these devices are limited to an approximate effective service range of 35-100 feet.


3. What are examples of these devices/transmitters?

At any time of day, most people are within a few meters of consumer products that use low-power, non-licensed transmitters.

Low-power, non-licensed transmitters are used virtually everywhere. Cordless phones, baby monitors, garage door openers, wireless home security systems, keyless automobile entry systems and hundreds of other types of common electronic equipment rely on such transmitters to function.

Other examples:

-Small FM radio transmitters designed to hook to the audio output of an iPod or other portable audio device and broadcast the audio so that it can be heard through a car audio system that is not equipped with an audio input.

-Very low power transmitters, often referred to as "talking roadsign", "talking houses" or "talking billboards", which will air a repeating loop of highway construction, traffic, promotional or advertising information. A sign placed near the transmitter is used to entice passersby (nearly always in automobiles) to tune in. The talking house gets its name from the fact that many such transmitters are installed at houses that are up for sale, thus enabling a passerby to find out details about the interior of the house without actually touring the building.

-Wireless microphones and headsets, which broadcast the speakers voice to a receiver which amplifies the audio. Wireless microphones allow the speaker to move about freely, unlike a conventional microphone, and are thus popular with musicians.
-Toys such as the popular late-1970s toy Mr. Microphone and its imitators, which would broadcast the user's voice to a nearby AM radio. Variations on this type of transmitter were advertised for sale in radio magazines as far back as the 1920s.

[axmoran]

Umm, think you're overcomplicating, unless you're one of those big park sized shows.

You can buy small transmitters that will go 200 feet without need of a licence, but their kind of pricey. That's what i plan on using this year.

As long as your not plugging into giant antenna without licence, broadcasting miles on end, i can't see the FCC throwing a big fit over anythign you can buy that is intended for home use if you don't modify it.

IF you have a park thing, might be easiest to set up a bunch of points to re-broadcast the signal, but to do that cheap, you'd loose audio quality each time.

What are you trying to do?

[aurickle]

That was funny, Jeff!

According to everything I've been reading, the FCC does tend to turn a blind eye to most everything you can do -- so long as it is not forming any kind of local annoyance. In other words, if your broadcast is able to travel as far as a block or two they're not going to throw a fit unless it's causing interference with something. Even then, they'll start by simply asking you to turn it off.

The time they get nasty is when you are creating interference and they have to work to try and track you down. That means that between every few songs in your performance it can't hurt to provide some kind of "station identification" that lets listeners know where the broadcast source is located. (For example, "This is the Jameson house broadcasting on 96.8 FM wishing you all a very merry Christmas.") In other words, if your broadcast is a nuisance but they can easily contact you to ask you to fix it, no problem. But if it's a nuisance and they have to expend time and money to find you they're going to be far more likely to slap you with a fine.

Regarding call signs, the bit that is quoted by the OP ONLY applies to current carrier signals. If you're using an FM transmitter, don't make up a call sign. This is especially true if you're already pushing things a bit by broadcasting a signal that can be tuned into past 100 feet.

Another thing to do is take the time to look up the licensed broadcast stations in your area. You can do this very quickly and easily at http://radio-locator.com/. Not only will this ensure that your choice of broadcast frequency won't interfere with any local licensed broadcasters, it will also ensure that they don't interfere with you! The last thing you want is for your "Silent Night" to get injections of "Hear the bodies hit the floor"!

Regarding the transmitter itself, many of them come with an optional extra antenna wire. The device is only 100% legal for use in the U.S. without that antenna attached! Unfortunately, depending on your home you are extremely likely to find that the signal works just fine within the house and is completely useless from the street. I had that happen last year -- I could tune in clearly from my garage and even the all-weather radio I had set up next to the house picked it up clearly. So I thought it was fine until friends told me that they couldn't pick it up from their cars just 20' farther away. So I had no choice but to attach the antenna, which suddenly let the signal come in clearly from over a block away but also guaranteed I was not compliant with the FCC.

By the way, this year I'm going with http://www.amazon.com/gp/product/B003FO4UHW. Thanks to the 0.1 watt capability it is going to be able to be heard perfectly without needing to attach any extra antenna. However, even at that lowest setting it's still 10 times more powerful than what the FCC considers kosher. If you're in a heavily urbanized area, I wouldn't recommend it. If you're rural enough that you only have a half dozen licensed stations to contend with you shouldn't have any problems.

[MikeH]

aurickle wrote:

By the way, this year I'm going with http://www.amazon.com/gp/product/B003FO4UHW. Thanks to the 0.1 watt capability it is going to be able to be heard perfectly without needing to attach any extra antenna. However, even at that lowest setting it's still 10 times more powerful than what the FCC considers kosher. If you're in a heavily urbanized area, I wouldn't recommend it. If you're rural enough that you only have a half dozen licensed stations to contend with you shouldn't have any problems.

This link works better, had to take the period off at the end.

http://www.amazon.com/gp/product/B003FO4UHW

[james campbell]

On the FM broadcast band, these devices are limited to an approximate effective service range of 35-100 feet.




wow I think most of us are over that:shock:

[LarryDrumAZ]

MikeH wrote:

aurickle wrote:

By the way, this year I'm going with http://www.amazon.com/gp/product/B003FO4UHW. Thanks to the 0.1 watt capability it is going to be able to be heard perfectly without needing to attach any extra antenna. However, even at that lowest setting it's still 10 times more powerful than what the FCC considers kosher. If you're in a heavily urbanized area, I wouldn't recommend it. If you're rural enough that you only have a half dozen licensed stations to contend with you shouldn't have any problems.

This link works better, had to take the period off at the end.

http://www.amazon.com/gp/product/B003FO4UHW

That link doesn't work either... :X

[aurickle]

*sigh* No idea why those links aren't working. Sorry about that. Try this: http://www.amazon.com/0-5-Fail-Safe-Long-Range-Transmitter/dp/B003FO4UHW

Alternatively, it's the Fail-Safe transmitter w/new Hi Lo.

[james campbell]

aurickle wrote:

*sigh* No idea why those links aren't working. Sorry about that. Try this: http://www.amazon.com/0-5-Fail-Safe-Long-Range-Transmitter/dp/B003FO4UHW

Alternatively, it's the Fail-Safe transmitter w/new Hi Lo.

the picture on that link is the same transmitter I have but it is much cheaper on ebay

[Max-Paul]

You know what? I love bear bait. You know, the guy or gal that is running down the hi-way 10 mph faster than you. Ya just know that the police are going to pull them over and leave you alone. Well I see a lot of people buying transmitters that qualify as bear bait.

[aurickle]

Max-Paul wrote:

You know what? I love bear bait. You know, the guy or gal that is running down the hi-way 10 mph faster than you. Ya just know that the police are going to pull them over and leave you alone. Well I see a lot of people buying transmitters that qualify as bear bait.

I think it really comes down to some common sense. It's not like there's an FCC policing force that drives around looking for violations. The way they're going to be brought in is if there is a complaint. The way there's going to be a complaint is if your broadcast is interfering with a licensed broadcast. Even then, you're PROBABLY not going to get fined unless A) they have to expend resources to track you down or you're flagrantly violating the regulations.

So IF you buy one of the more powerful transmitters the for then love of Christmas, make sure to set it on the low watt range!!!!

IF you use that transmitter or even one of the lower power ones and attach the longer antenna to it, make sure you choose a frequency that has no chance of interfering with any licensed broadcast from any point within your own broadcast area. You don't want your neighbor to suddenly be unable to tune to his favorite evening program.

And make sure that you periodically identify yourself over the air. This accomplishes two things. First, if you do somehow annoy a neighbor they are far more likely to speak to you directly. Second, if they do file a complaint the FCC isn't going to have to hunt for you and you will most likely only be asked (told) to turn it off.

Regardless, Max-Paul is absolutely right: Using one of those transmitters is knowingly violating the FCC rules. Doing so is something you do at your own risk. No matter how small the risk might be and no matter how smart you might be about it, it is still a risk.

[Max-Paul]

And then there is something else to keep in mind. How many of you think that some of the stuff coming in from China is cheaply made? Well one of the problems with cheaply made transmitters is that they can create harmonics. Harmonics will cause a dirty signal that can bleed over onto adjacent frequencies or channels. So, even though you think you are transmitting on a clear frequency (which you are). But you are splattering over on other channels a few houses around you. Just keep this in mind with those supper cheap transmitters. So, when you test fire you transmitter, best go a few houses away and just check up and down the spectrum and make sure your not splattering all over the place. And for those of you who do not know me. I am KF0OX advance classed Amateur Radio OP and was a 30474 Ground radio repair man in the USAF.. Not bragging, just qualifying what I am saying.

[KStatefan]

What transmitter do you recommend?

[JBullard]

EDM

[EARLE W. TALLEY]

EDM

[CKSedg]

EDM!

[Guest guest]

I'm know I'm going against popular opinion here, but I really like my EDM...:cool:

[KenL_MCSE]

My first 2-3 years of broadcasting I used a Mobile Blackbox 4000. The sound was great. This year I listened to everyone and took their advice - BUY AND EDM!!!!

The sound is better, the distance is better. And I now have RDS.

My EDM on .01 mw broadcasts further than the MBB did with 500 mw. When I put the EDM on 100 mw I broadcast over 2 miles.

EDM Rules!

[Max-Paul]

Well looks like you already have gotten your answer from several fellow members.

My next transmitter will also be an EDM.

[Nurples]

james campbell wrote:

aurickle wrote:

*sigh* No idea why those links aren't working. Sorry about that. Try this: http://www.amazon.com/0-5-Fail-Safe-Long-Range-Transmitter/dp/B003FO4UHW

Alternatively, it's the Fail-Safe transmitter w/new Hi Lo.

the picture on that link is the same transmitter I have but it is much cheaper on ebay

I have the Ebay transmitter also... Much cheaper... The quality seems to be much cheaper also! I haven't tested it outside yet, but sitting in the corner of my living room, with the transmitter on max (0.5W) was the only way to clearly hear it on the reciever. With the transmitter on the .1W setting, the signal was very fuzzy. The transmitter and receiver were only about 15 feet apart.

[Max-Paul]

Nurples,

There is a thing called front end overload. A receiver is built to take a very small signal and amplify it. What happens when you amplify a signal to much? Well it goes from looking like an "S" laying on its side to a "S" but in a digital form (squared off at 90 degrees lines). That is called clipping and sounds like crap. So back off from the transmitter like go outside and see how it sounds. Also you might need to turn down the volume of your computers output. Might be over driving the transmitters audio circuits and clipping there too.