how does this work?

Discussion in 'Wireless & RF Design' started by bug13, Mar 11, 2018.

  1. bug13

    Thread Starter Senior Member

    Feb 13, 2012
    1,644
    62
    Hi guys

    I come across this little transmitter only tag, I am just curious how it may work. I am guessing the pic (12f629) send out some kind of on/off keying to the oscillator, and the receiver decode those info.

    Another question is how can they make the antenna so short?? it's 433MHz transmitter!!

    Thanks guys

    IMG_3544.JPG IMG_3545.JPG
     
  2. bertus

    Administrator

    Apr 5, 2008
    19,507
    3,972
    Hello,

    Did you see L2 on the PCB?
    That is part of the antenna making it longer.

    Bertus
     
    bug13 likes this.
  3. bug13

    Thread Starter Senior Member

    Feb 13, 2012
    1,644
    62
    I thought that might be the case, what do I need to google to read more about this? eg how to decide what inductor to use to make a Xmhz 1/4 wave antenna into Ymm??
     
  4. MrChips

    Moderator

    Oct 2, 2009
    18,461
    5,854
    Bottom loaded antenna
    Bottom loaded vertical antenna
    Base loaded antenna
     
    simozz, KJ6EAD, bug13 and 1 other person like this.
Loading...