adjustable 1 watt FM transmitter?

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bob
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adjustable 1 watt FM transmitter?

Post by bob »

Hi
I've built a 1 watt (fixed) FM transmitter that I would like to modify for adjustable power output. (I want to LOWER the RF power output, crazy I know!)
This circuit design utilizes two transistors, the second feeding power to the antenna.
I'm guessing, if I limit the supply voltage to the power transistor, it would reduce the output of the transmitter. Can anyone comment?
I don't want to limit the voltage for the entire circuit because of the PLL circuitry.
Thanks for your help!
Bob
bob
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Post by bob »

I designed a solution and it seems to be working well.
I added an adjustable voltage regulator just before the ferrite bead and rf choke on the supply for the last power transitor. Running at a fraction of the power runs alot cooler and uses less power. nice!
rich.freeman
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Hi Bob,

Post by rich.freeman »

Could you send me details of the circuit you are talking about,
I am interested in making a similar circuit to send stereo analogue sound from mp3 player to car radio? if this is possible.

Thanks in advance.
Black_Hawk
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Post by Black_Hawk »

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