FM transmissions

[86GN-862+2]

Hello Ladies and Gentlemen,

I am wondering if any of you enjoy the radio transmission hobby in any form. Short wave or long wave or FM modulation. I have a few questions mainly concerning FM transmissions regarding those little neat gizmos called FM modulators which one can use to transmit music from cd/i-pod/walk-man or other source not originating from the radio in your car. If any of you are knowledgeable on this subject please post up! I know it's a long shot but never hurts to ask Thanks a bunch! JR

 

[Brad Conley]

I'm a ham (amateur radio) and may know an answer to your question. Post it up, I'll try.

 

[86GN-862+2]

Great! What I would like to know is if it is possible to transmit a signal such as by using an FM modulator but to the whole range of the FM band. Usually, the FM modulator uses the lower end of the FM band around 88mHZ. I live in the country and the purpose of this would be to transmit certain music in an area of around 2 acres WITHOUT the need to TUNE into any specific point in the FM band. The unit would be around 250mV(I think). To play from the laptop or PC. I would really like to broadcast to all ranges 88mHZ-108mHZ SIMULTANEAOUSLY Can it be done? . Please see link below for an example.

The USB FM Transmitter that covers your entire home, GUARANTEED!

 

[dr_frankenstein]

im not a ham operator, but i do alot of RF testing.

thats a rather large range to try and broadcast on. I would pick one band and concentrate your power on that. it will be much easier to build for one channel. You could probably do 1 channel for 2 acres with about 10 watts.

A.j.

 

[charlief1]

I know that you can transmit with a signal that covers no more than 1/4 mile without having a liscence. You can get a low powered 9V transmitter that is adjustable for about $20 but it is very limited. FM based.

 

[Brad Conley]

What AJ said. Too broad of a radio spectrum to try to broadcast upon. Concentrate on one or two frequencies and you should have no problem covering 2 acres.

Of course, anything is possible given enough $$ and time...

 

[GSTOY]

I'm a TV Broadcast Engineer and a Ham, KE5IOB.

First off, you can't make a transmitter that will cover the entire FM frequency range, because in the eye's of the FCC, that wouldn't be allowed.(jamming)

Reason #2 would be the technical problems you would have in trying to create a wide band transmitter that could even possibly do it, along with the expense.

Your problem is that you want to cover 2 acres, but you will be limited to 250m/v power output due to part 15 of the FCC. That will only cover 100 to 200 feet at the most, depending on your antenna and terrain, and, since you are not a licensed operator, your station must accept interference, that this why the FCC keeps keeps the power low, so you don't create interference to others in the spectrum.

Last year the FCC was looking at reducing even those power levels because it was causing interference from car to car, such as portable cd players, Ipod's, and now the aftermarket dvd players that broadcast the audio to the radio.

Honestly, without a license, their is not a eloquent way of doing what you want to accomplish without running illegal output power, which I don't advise even if you live out in the country....FCC fines are pretty steep nowadays.

You might look into doing a LPFM station if you want this to be a continuous broadcast, but their are equipment costs, licensing and FCC requirements.

In 2000, the Federal Communications Commission established the Low Power FM (LPFM) radio service -- noncommercial, local, low-powered radio that schools, community groups, churches, and any nonprofit could use to broadcast local information to their local community. LPFM stations may have a small broadcast range – they operate at 100 watts or less and have a broadcast reach of just a few miles.

Steve