FM Transmitter problem - Electronic Circuits Projects Diagrams Free

Zarniwoop · 19th October 2003, 07:41 AM

G'day all,

Shortly after purchasing a PDA I found that I would like to play the MP3's stored on it through my car radio. Upon finding the manual for the radio, I discovered no auxiliary input for it, which made my task somewhat more difficult.

I then decided the easiest way to achive my goal is to build a small FM Transmitter and have it broadcast to the antenna in the car, in a sort of 'pass-thru' arrangement, similar to aftermarket CD Changer units.

Getting to the point, I purchased a Velleman-kit K1771 FM Oscillator hoping this would do the job. It seems that this kit is designed for an Electret microphone and not for the output of a PDA/MP3 Player/PC.

What needs to be done to the signal to make it appropriate for this transmitter? I can tune it in on a house radio, but the signal seems to be over-driven and comes out very distorted.

Cheers!
Grant

Sebi · 19th October 2003, 09:01 AM

Can i see Your circuit?

Zarniwoop · 19th October 2003, 10:31 AM

In the search for the online version of the circuit diagram, I found the revised manual, which is MUCH better than the one that came with it. The manual also contains the procedure for connecting a source such as CD player, mixer, etc. The solution is a 47K Logarithmic pot in the circuit as shown here.

http://www.velleman-kit.com/Download...nual_K1771.pdf

Cheers anyhow!

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19th October 2003, 07:41 AM	(permalink)
Zarniwoop	FM Transmitter problem G'day all, Shortly after purchasing a PDA I found that I would like to play the MP3's stored on it through my car radio. Upon finding the manual for the radio, I discovered no auxiliary input for it, which made my task somewhat more difficult. I then decided the easiest way to achive my goal is to build a small FM Transmitter and have it broadcast to the antenna in the car, in a sort of 'pass-thru' arrangement, similar to aftermarket CD Changer units. Getting to the point, I purchased a Velleman-kit K1771 FM Oscillator hoping this would do the job. It seems that this kit is designed for an Electret microphone and not for the output of a PDA/MP3 Player/PC. What needs to be done to the signal to make it appropriate for this transmitter? I can tune it in on a house radio, but the signal seems to be over-driven and comes out very distorted. Cheers! Grant __________________ \"How can I tell that the past isn\'t a fiction designed to account for the discrepancy between my immediate physical sensations and my state of mind?\"

19th October 2003, 09:01 AM	(permalink)
Sebi	Can i see Your circuit?

19th October 2003, 10:31 AM	(permalink)
Zarniwoop	In the search for the online version of the circuit diagram, I found the revised manual, which is MUCH better than the one that came with it. The manual also contains the procedure for connecting a source such as CD player, mixer, etc. The solution is a 47K Logarithmic pot in the circuit as shown here. http://www.velleman-kit.com/Download...nual_K1771.pdf Cheers anyhow! __________________ \"How can I tell that the past isn\'t a fiction designed to account for the discrepancy between my immediate physical sensations and my state of mind?\"