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FM Transmitter aka Spy Bug

Discussion in 'General Electronics Discussion' started by electronoobz, Oct 23, 2012.

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  1. electronoobz

    electronoobz

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    i want to make one for me and my friends. A small one with a static frequency, if possible higher than what a radio could reach and just make a special receiver for it.

    is this possible? Thanks. I wish it is possible and small in size.
     
  2. donkey

    donkey

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    what do you mean by higher?
    why would you want a special reciever for it? this defeats the purpose of being an fm bug, it then turns into a super secret bug with special reciever possibly using the fm bandwidth.

    anyway if you are doing what I think you are then try a walkie talkie. if this is for spying then go buy one from a retail shop and while you're there ask them the legalities pertaining to invasion of privacy and the fines/jail time you could be facing if the device is improperly used.
     
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Look here. Typically they transmit (illegally perhaps) to normal broadcast band radios.
     
  4. CocaCola

    CocaCola

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    Apr 7, 2012
  5. electronoobz

    electronoobz

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    Jan 14, 2012
    yah! That's it. A walkie talkie similar.

    i dont want to get caught by others.

    let's say the max. freq the radio can seek is 107 mhz. I would like to make a receiver with a freq of 108 mhz. Get it now guys?
     
  6. CocaCola

    CocaCola

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    Then don't do it...

    You can say it all day long, doesn't make it so...

    Get a radio scanner or twist the dial just that much more on an older analog radio...

    We never didn't get it...
     
  7. electronoobz

    electronoobz

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    Jan 14, 2012
    didnt get your reply.

    what im trying to do is make a hi freq spy bug and make a special receiver for it. Lets say that my target freq is 110 mhz because it's a freq our radio cannot reach.
     
  8. CocaCola

    CocaCola

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    Yes, we know what you want, no one is confused... You are likely to not find much help here as it's illegal in most areas to do what you want to do... That is unless you have a broadcast license for said frequency...
     
  9. electronoobz

    electronoobz

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    ok. I found a scheme but it's highest freq is 107 mhz. How will i increase it?
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    smaller inductor and/or capacitor in the tuned circuit(s)
     
  11. davenn

    davenn Moderator

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    retune the oscillator to a higher frequency


    You still dont seem to understand that radio receivers DONT stop at 108MHz.
    There are all sorts of receivers that cover huge ranges of frequencies.... as one of the other guys mentioned scanners

    My scanner goes continuous coverage from 100kHz to 2400MHz. it will pick up your signal regardless of the freq you used in that range ( if I lived in your region)


    Dave
     
  12. electronoobz

    electronoobz

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    Jan 14, 2012
    smaller inductor? Like decreasing the number of turns of the original?

    how about the other one with the caps im a bit confused.
     
  13. electronoobz

    electronoobz

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    Jan 14, 2012
    dont worry sir Dave. 108-110 mhz is fine..
     
  14. electronoobz

    electronoobz

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    Jan 14, 2012
    bump..
     
  15. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Decrease the number of turns (you're probably looking at very few turns anyway, so reducing it by 1 turn may be plenty. Alternatively you may be able to just stretch it out a bit.
     
  16. electronoobz

    electronoobz

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    Jan 14, 2012
    let's say i did it already and im ready to build its special receiver. What freq should i set it? Thanks steve. Just a little bit more and im ready to build it
     
  17. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    New definition of "privacy": An archaic concept once thought sacred by early man.


    Chris
     
  18. davenn

    davenn Moderator

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    there's no such thing as a "special receiver"

    you just need a receiver that covers the frequency of your transmitter

    Dave
     
  19. electronoobz

    electronoobz

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    Jan 14, 2012
    that's what i mean sir.
     
  20. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Get a receiver and transmitter that work together then make similar modifications to both.

    And call him Sir. ;)

    If you're using a standard FM radio, you *may* be able to "tune" it (de-tune actually) to cover a slightly different range of frequencies.

    Perhaps more reliably, you just go out and buy a receiver that covers the band you're interested in.
     
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