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Need help building RF Detector

Discussion in 'Radio and Wireless' started by PoorDIYer, Jan 29, 2014.

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  1. PoorDIYer

    PoorDIYer

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    Jan 29, 2014
    My sister is renting from a guy n we're worried he has recording devices in the house. I would buy a RF Detector but I cannot afford to. So I am looking into making one myself but I cannot find detailed instructions online. Can anyone help in any way possible please? Thank you.
     
  2. Arouse1973

    Arouse1973 Adam

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    davenn likes this.
  3. PoorDIYer

    PoorDIYer

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    Jan 29, 2014
    Like I said, I can't afford one. I looked online and the prices are way out of my range.
     
  4. PoorDIYer

    PoorDIYer

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    Jan 29, 2014
    I'm looking for help to make one.
     
  5. PoorDIYer

    PoorDIYer

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    Jan 29, 2014
    I'm sorry, I stand corrected. I just looked at your link. That is actually affordable. Thank you. Still tho, if someone can provide me with detailed instructions it would be greatly appreciated. Thanks.
     
  6. Arouse1973

    Arouse1973 Adam

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    Ok so what type of bug do you think it is? Microphone or camera.
     
  7. PoorDIYer

    PoorDIYer

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    Jan 29, 2014
    I suspect microphone, but wouldn't rule out camera either.
     
  8. Arouse1973

    Arouse1973 Adam

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    For the minute if you have a phone that supports Android, have a look, someone might have done an application.

    If you want to build one it will need to be a high bandwidth version and we really need to know the frequency range. this can be from say 10Mhz to 8Ghz.

    I'll have a dig about.
     
  9. Arouse1973

    Arouse1973 Adam

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    Ok I have had another idea. Play some loud music in the room you suspect the bug to be in. Get a radio with a head phone socket or use a phone which has radio. Scan up and down the FM stations bit buy bit and see if you can here the broadcast from your music. If it's an FM bug then it will probably be using a band within the radio frequency allocation.

    My name's Bond, James Bond
     
    Last edited by a moderator: Jan 30, 2014
  10. hevans1944

    hevans1944 Hop - AC8NS

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    I wanna bump this thread from 2014 to 2019 with some newer tech that was available then, but may be a lot cheaper now...

    The more sophisticated "bugs" are silent, not transmitting anything until they receive a coded command sequence. The digital coded command sequence can be almost anything the "bug" can respond to, from a simple "wake-up call" to begin listening, to a command to "chirp" out or transmit in a few milliseconds a recording that could be several hours in the making. It is pretty easy to "filter" such recordings... digital representation of sound picked up by an analog microphone... to remove silent periods and transmit, at faster speeds than that at which the recording was made, the stored data. The data packet "headers" can contain embedded time information to allow "real time" reconstruction of the recorded audio, including the "silent" periods if desired.

    The only time the "bug" is detectable is when it is sending the recorded data. This occurs infrequently, for very short intervals, at random times, and at the discretion of whoever planted the "bug." It takes a sophisticated, real-time, fast Fourier transform, spectrum analyzer to even "see" these events. A conventional heterodyning, frequency sweeping, spectrum analyzer won't "see" the "bug" except by accident, and then probably only for one transmission. If frequency hopping technology is also implemented, the "bug" mostly just fades into the background of random noise sources even if you know where to look... and realistically, you don't know where to look.

    Conducting all "sensitive" conversations inside an RF-shielded room, with two "airlock- type" RF-shielded doors, where both the inner door and the outer door must be closed before anyone is allowed to enter or exit, is a pretty effective defense against remotely triggered "bugs," but the shielded room must still be periodically physically searched in a thorough manner from time-to-time. With modern electronics miniaturization techniques, even such a physical search is no guarantee that a "bug" will be find.

    Crafty electronics hackers may want to see what they can "cook up" in the way of stealth bugs using commercial off-the-shelf (COTS) components. Range should not be a problem if you can get close enough to your bug to aim a high-gain Yagi-Uda antenna at it, assuming perhaps that your "customer" planted the device in sight of or near an exterior window. Have fun and report back here to the Mothership if you have any success. Do not ask for bail money.
     
  11. Nanren888

    Nanren888

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    Nov 8, 2015
  12. davenn

    davenn Moderator

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    Sep 5, 2009

    this is a 5 year old thread
    the OP never returned



    thread closed
     
    hevans1944 likes this.
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