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FM Transmitter problems


wicket82

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This is my first year having a show. I've got the show up and running with no problems as far the lights and controllers go. The only problem I've ran into is the fm transmitter. It's an EDM transmitter. No matter what channel I set it, I'm getting static in my car when I try to listen to it. Ive tried a different antenna and even moved the transmitter outside for testing. Same results. I have a stereo inside and it seems to work on that but it's only like 20ft away. Anything over like 30 or 40 ft, it has static and is sounds really bad. I've tried to adjust the settings on the transmitter with no luck.

The main power panel for the house is about 4ft from the transmitter. The only thing I can think of is that is interfering with it. Has anybody else had any trouble like this?

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This was posted on the EDM Users Group:

Often people end up driving too high level audio into the EDM units. This causes terrible distortion on the receive side making users to think that they received a faulty unit.

Please remember that the EDM units require consumer level -10dBv line-level audio. The output from a MP3 player or PC sound card may be much too high for the EDM.

Simple rule of thumb: If your audio source is strong enough to power a set of headphones or earphones, the chances are very good that you will end up with distortion on the receiver side.

The simplest solution is to add a inline volume control to bring the range low enough for the EDM units to handle.

http://www.dealextreme.com/p/3-5mm-to-rca-stereo-audio-cable-with-volume-controller-2650

These are very cheap and comes with free shipping.

EDM Team

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I've turned the volume down on the computer but I havent tried all the volume settings. I'll try that when I get home and see if that helps any. Thanks for the quick responses.

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The volume should be causing distortion, not static. From my experiences, and I am NO expert on radio signals, static comes from low signal or not on the correct frequency.
I'd help more but my EDM was ordered 2 1/2 weeks ago but has not shown up yet ;)

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I guess distortion would be more of the problem, not static. I was wrong in saying that. I mean there is a little static but it's more distorted than anything. My bad. Haha. I'll try and get it straight next time. Ha. Once again thanks. I'll repost and let everybody know what I come up with.

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I turned the volume down on my computer to almost nothing. It seams to me working a lot better now. Thanks for all the info.

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When you over deviate a FM signal, a receiver will wind up only capturing part of what is being transmitted, being limited by its bandpass. A better reciever may be less impacted, but as the transmitter is over deviating, it should still not sound good to the ear. Folks may perceive what they are hearing as static...

Remember these inexpensive transmitters will never be as "loud" as commercial FM stations, even if you use audio compression. If you turn up your input volume to make them as loud as the commercials, in most cases you will wind up over deviating the transmitter.

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