Any Beginning Advice For A New FM Broadcaster?

Read this:

http://www.fcc.gov/eb/FieldNotices/2003/DOC-260868A1.html

and see how your fellow Hoosier State FMers are doing 🙂

You're not going to legally get that 5 mile range on FM in most places in the world, never mind North America.

In the U.S., you can maybe get 1/2 to 1 mile range using a legal Part 15 AM transmitter, depending on your definition of a good signal at the other end and the receiver (most likely a car radio).

On FM, you may get 800 feet or so to a good car radio on a legal Part 15 transmitter (probably 200 feet or so to an inexpensive home radio).

In Canada, you're allowed slightly more power, and a range of up to 1 km is possible (3000+ feet), with direct line of sight to the antenna from a good car radio (at least, that's what I was able to achieve with a Canadian certified transmitter).

Of course, you can always choose to go the illegal transmitter route, but that's way beyond what's discussed in this Forum (which is focused on legal, unlicensed use).

One thing to think about - if you simultaneously stream your radio signal over the Internet, you will be able to effectively have anyone in the world listen to it. The trick, of course, is getting interested people to find it.

With my Ramsey FM 25b i am covering 600 to 900 feet to a sensitive factory car stereo beyond that it is very noisy and un-listenable.

My FM 25b has the RF output turned down as low as it will go and the transmitter is connected to a home made ground plane 8 feet off of the ground.

Since i do not have the equipment to measure my field strength, i gauged what my legal range should be by using the Scosche FMT-4 transmitter.

FMT - 4 Review : http://part15.us/node/2006

If you are not familiar with the Scosche FMT-4 then let me break it down for you.

Basically this little transmitter was built to plug into your i-pod, computer or portable cd player and has a few channels in the lower end and upper ends of the FM band. It really has no antenna other than the stereo headphone plug which uses the i-pods added circuitry as the antenna system.

The company that makes this device even claims the legal 3 meter usable range. Anyway, the fmt-4 just plugged into the speaker jack on my Dell computer has a service range of about 600 feet, at about 400 feet the static starts to creep in and there are a few times the signal drops out. I live in a mobile home so I may have the worst case scenario here as my signal has to go thru the walls of my house and out into the street. Not to mention the other homes in the park .

So even with my Ramsey fm 25b connected to a ground plane antenna on the porch my signal still has the same coverage you would expect out of the Scosche FMT -4 with no real antenna.

Chances are I could still be violating FCC limits even though i used a certified fm transmitter to set up my station as close to legal as possible.

AM is by far the best way to cover more ground and still remain legal.
If you have the room to setup a good outdoor antenna for AM then by all means re-consider your broadcasting options before making a costly mistake later down the road.

If i was in the position to do so, my choice for legal part 15 broadcasting would be the shortwave band where we are allowed much more power and a real antenna system.

Plug and play for the most part.
Sadly 5 miles isn't legally possible Under Part 15.
But you could easily cover a block or two with a legal FM like I do.
I cover 79 homes or so With mine. Its just a C Crane with a 6 foot antenna I believe strapped to it.
Sounds great and gets out pretty good depending on the day.
Some days its clear as can be, others not so much.
Put the antenna where its not obstructed try not to go way over on the range limit and you'll do great!

All of your comments helped! I am still looking for an FM transmitter, but i really no longer care what the range is as long as it is longer then 700ft. And I am also a little confused about the whole FM transmitter kits. Do you build it yourself? Anyways, thanks again!

Using a Antenna with part 15 FM is illegal only way you can use a antenna if you is really lossy the antenna will put you way over the legal field strenght level

I built a Ramsey FM 25 from a kit for use here. Here's some information which I hope you find useful.

There are two ways to approach this. One is to buy a FCC certified transmitter such as the CCrane. If you do this, you may not modify it in any way including changing the antenna provided by the manufacturer. Doing so will void your authority to operate the transmitter.

Another is to build a transmitter from scratch or from a kit. This does not require FCC certification but operation must follow the FCC rules which limit the radiated field strength. All kits I know of are capable of producing field strengths which far exceed the limits depending on the antenna used so there is some truth to the post preceding this one. It is not true, however, that any antenna at all will be illegal. Recall that the limit is on the field strength and not on the antenna dimensions as is done for AM. Unfortunately accurate measurement of field strength is beyond the capability of almost all part 15 hobbyists. What can be done is to adjust the antenna length so that the range is about 200 feet with a good car receiver. This will get you close to compliance and is probably the best we can do. Changing the antenna length changes the match with the transmitter and thus the amount of power radiated which determines the field strength. For example, my FM 25 yields a range of 200 feet with the provided telescoping whip antenna set to about 4 inches in length. Fully extended the range is around 1000 feet but this is most likely not legal.

You might consider part 15 AM since the technical limits of the FCC rules are well defined and legal range is greater than that of FM.

Neil

I believe that the FCC uses 200 feet with a standard radio (i.e., home radio) as a barometer for field strength. Car radios usually have much greater sensitivity and adjacent channel rejection, which gives you much greater range - I often find it's the selectivity of a radio that limits the reception of a low power FM signal rather than the sensitivity (high power stations 'bleed' into your frequency).

Alexjilee,
Just in case you did not see this thread , http://part15.us/node/1862

The second post on that thread shows links to all of the known Certified FM Transmitters on the market now. My suggestion is not unlike most of the other members, stay away from the kits and buy something that is already built and Certified by the FCC.

The cheapest and probably the best transmitter to start out with is the one by C.Crane Co. http://www.ccrane.com/radios/fm-transmitters/fm-transmitter.aspx?RefID=WS110401WSDG0100

$69.95 is a good price for a legal fm transmitter and the C.Crane unit has been praised by many part 15 Broadcasters as having the best sound for the price and reasonable range for the price.

For good and bad reviews of part 15 certified transmitters, follow this link to http://www.hobbybroadcaster.net/reviews_lab.html

The engineers test every brand of transmitter on the market to help first buyers like yourself make a more informed decision when choosing a transmitter for their part 15 needs.

Good Luck and Keep On Rockin'

EDIT: I want to correct my use of the word "cheap" , i did not mean that the c.crane transmitter was built poorly. I should have used the word affordable. Cheap, just sounds... cheap.