fm power amplifer

Discussion in 'The Projects Forum' started by tefavolc, Jun 21, 2012.

  1. tefavolc

    Thread Starter New Member

    Nov 10, 2010
    4
    0
    i am working on fm power amplifer , i ve designed the circuit on the orcad , and implement it on the breadboard . i bough a car fm transmitter to use it as rf source .the fm modulator contain kt0803l ic which by looking at its datasheet has rf o/p at the pin no 16 . i connect pin 16 to the amplifer i/p and the ground of the transmitter to the ground of the amplifer . but the problem is that the radio is receiving the fm signal from the transmitter and i didnt see any type of antenna in it in order to remove it .

    i ve upload the pic of the transmitter and the amplifer hoping any one would help me to make the fm stop transmitting and direct the o/p rf to the amplifer .
     
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  2. w2aew

    Member

    Jan 3, 2012
    219
    64
    Sometimes these FM modulator/transmitters use a wire in the power lead for an antenna. Since the transmitter is so close the the intended receiver, it doesn't have to be very efficient.
     
    tefavolc likes this.
  3. tefavolc

    Thread Starter New Member

    Nov 10, 2010
    4
    0
    i bought a new transmitter and the good new is that i found a node labled by ant and the bad news is that the same problem is still there . i ll upload a two photo , first for the new receiver and the sec is for the breadboard connection .
     
  4. bertus

    Administrator

    Apr 5, 2008
    15,645
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    dataman19 and tefavolc like this.
  5. tefavolc

    Thread Starter New Member

    Nov 10, 2010
    4
    0
    is there any other way to test the circuit before implementing it on a pcb !
     
  6. radiohead

    Active Member

    May 28, 2009
    474
    31
    You can use a technique called "Manhattan" or "Dead Bug" (air circuits) that uses a piece of single sided copper clad board to prototype your project. Keep your leads as short as possible with RF circuits. Try to isolate the stages by using metal shielding. Use coaxial cable (RG-58 series) for your input and output feedlines. How many watts is this amp supposed to push?
     
  7. tefavolc

    Thread Starter New Member

    Nov 10, 2010
    4
    0
    almost 4 watt at 50 ohm antenna load and 18v source
     
  8. absf

    Senior Member

    Dec 29, 2010
    1,492
    371
    tefavolc likes this.
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