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Some More Simple FM Transmitters

Discussion in 'Electronic Projects' started by Iceman_Chris, Nov 28, 2004.

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  1. whiz115

    whiz115 Member

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    Audioguru it's not that sensitive... so it can catch am radio...
    atleast mine it isn't...

    do you think if i lower the 10K resistor i can improve it's sensitivity?
     
    Last edited: Jul 23, 2009
  2. audioguru

    audioguru Well-Known Member Most Helpful Member

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    It is not supposed to be sensitive. It is supposed to show the output strength of your FM transmitter when it is about 1m away from the signal strength antenna. At a distance of only 1m the signal is pretty strong.

    Try it.
     
  3. whiz115

    whiz115 Member

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    1m distance? :D if i don't tie the antennas together it doesn't do a thing!

    ok i'll try lowering it...though i would prefer the circuit to light a led if it if the radiation is above a certain level... i don't know if it is possible using a darlington so i can amplify that 0.000005A and light a led.
     
  4. dave

    Dave New Member

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  5. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If you tie the antennas together then you change the tuning of the output tuned circuit.
    The voltage from the signal strength circuit is much too low to light an LED without an amplifier.
    I think my circuits produced a few hundred milli-volts.
     
  6. mkwatis

    mkwatis New Member

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    @audioguru
    it takes how far/meters?
     
  7. audioguru

    audioguru Well-Known Member Most Helpful Member

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    My FM transmitter, the Mod4, has a range of over 2km to a very sensitive high quality home stereo or a good car radio over an open river valley when its 9V alkaline battery is brand new.
    Its range is 300m in the open to a cheap Sony Walkman radio.
    Its range is across the street to a cheap scanning FM "radio" from The Dollar Store.
     
  8. ladybliss

    ladybliss New Member

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    Can you give me some specifications of this transmitter?..
     
  9. ladybliss

    ladybliss New Member

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    Can you give me some specifications of this transmitter?..
     
  10. ladybliss

    ladybliss New Member

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    And can you give a good antenna for this transmitter?
    Included its diagram?
    Im just new in this kind of stuff.. Got only a year of learning only theories of this.
     
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