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RF Audio?

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chriswatts19

New Member
im trying to make a recevier transmitter pair to make some wireless speakers for my laptop.. just wondered if anyone had any ideas? any circuit designs etc..
anything is better than nothing:)
 

chriswatts19

New Member
is was just more of a task to see if it could be done and to understand RF a little better.. i realise that by using a wire the audio quality can be better.. just thought id have some fun:D
 

Nigel Goodwin

Super Moderator
Most Helpful Member
is was just more of a task to see if it could be done and to understand RF a little better.. i realise that by using a wire the audio quality can be better.. just thought id have some fun:D
First problem is making it stereo - it's not a trivial task overall, and you can buy such units for very little money, far less than the parts would cost you.
 

audioguru

Well-Known Member
Most Helpful Member
You can make simple crappy circuits that are used in chidren's walkie talkies.
But they sound awful.
 

chriswatts19

New Member
i can get parts from stores free of charge.. so cost isnt really a problem thank goodness.. just want a couple circuit diagrams, made a transmitter using a transistor, i made two and tried turning one into a receiver, though need to build an amplifier for it to work i think.. not sure, just wanted to see what other routes there are..
 

crutschow

Well-Known Member
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You could make two FM transmitters to operate at different frequencies (one for each stereo channel) and use two FM receivers to receive the signals.

Better is to use an FM transmitter with a stereo modulator chip and receive the signal with an FM pocket radio.
 

flat5

Member
You could use an mp3 transmitter. Don't really know what to call it at the moment.
The device that an mp3 player plugs into. It then broadcasts to a car FM radio. It should work but you won't really learn much.
There are low power stereo FM band transmitters in kit form.
Use Google to find them. Just reading about them you will learn something.
 

Triode

Active Member
Those MP3 car models only reach about 3 feet and even at that range they sound crappy. I dont even know that a more expensive one would be better, I think they may be that weak because they have to transmit on comercial broadcast frequencies to be useable and law limits the power of such devices.
 

flat5

Member
Triode, are they really that bad? I never tried one. They cost 25 Euros. I would expect better results.
 

audioguru

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The good FM stereo transmitters have excellent sound. The poor quality ones are terrible. My son bought a cheap Chinese one that was labelled STEREO on its cover. It was mono only, drifted its frequency all over the place and sounded bad.
 

tcmtech

Banned
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Ive got a portable Xm unit in my pickup and if I park my truck within 20 feet of my home sound system I can get a good clear stereo signal with it.
So the actual range and quality of the store bought units seams to vary widely.
But still as a just for fun learning project I would look at the FM stereo modulator IC's. There are lots of them out there and some of the circuits are rather simple.
 

audioguru

Well-Known Member
Most Helpful Member
This FM stereo transmitter IC replaced the lousy old BA1404 stereo transmitter IC. This one has a crystal controlled frequency synthesizer and phase-locked-loop for excellent frequency stability. The project has an attenuator at its antenna to restrict its range but the attenuator can be removed.
 

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